Suspension suggestions?

[zack]

Ok, so i did a bit of a search but i'd like to hear some of your thoughts... I've had my super low King springs on my EG for almost a year now and i'm ready to buy some new suspension.

To be honest, i'm liking the price of the Tein SS but obviously the Flex are a better product. What are the Cons of the SS? I've never tracked my car but maybe i will on the odd occasion. I'd say 99% of my driving will still be on street though.

Will the SS do the job?

Thanks for any help!

[zack]

Forgot to ask, how low will these go on an eg? Lower than the super lows at the moment?

[Kiz_EG6]

Buying a new suspension setup is basically a toss up between comfort and handling...
If it is a daily driver, my personal opinion is that i would not put coilovers on it.
I know a lot of people will disagree with me on this, but coilovers seem to just be the new big thing, as the prices have dropped substantially over the past few years.
It is very possible to get a very good handling package, while maintaining some amount of comfort for the occupants of your car.

I would probably go for a progressive rate spring set, something like whiteline does, then some koni yellow shocks, as the damper on these is still reasonably easily adjustable if you do decide to do some track work.
I would also upgrade swaybars and install front/rear camber kits if you want to go to the next level, and of course strut braces front and rear also for rigidity!

If you hunt around you will find that buying all these items, you will still come out with more change than you would buying any decent coilovers!

I put a whiteline kit including most of these items in my EG and purchase price came out well under 2k with some haggling :)

[T-onedc2]

I agree with Kiz on this, too many people say get coilovers, but I guess they only ever had Kings springs on cheap shocks.
I have ITR stock suspension with Spoon progressive springs coming soon, and currently the setup has been unbeatable for quality on 99% of roads.

[90xsi]

like everyone has mentioned above
set out a target and a budget
personally you cant beat koni's for comfort,
teins are a cheaper alternative you can look into if you want coilovers

[Jonald]

I recently bought Koni yellows and eibach pro. I've got the koni's on stiffest setting atm only because of my rim size and believe me, its stiff ;) But when i had it on the middle setting, it was real smooth, if not smoother then my stock ride.

[JohnL]

I recently bought Koni yellows and eibach pro. I've got the koni's on stiffest setting atm only because of my rim size and believe me, its stiff ;) But when i had it on the middle setting, it was real smooth, if not smoother then my stock ride.

Could you explain (please) why the rim size has an influence on the settings your choosing to use on your dampers? I have Yellows on my Accord at the stiffest setting because it assists in sharpening up steering response, and it certainly is quite stiff! Though that said I think the front dampers could be somewhat stiffer in the bump setting, pity only the rebound is adjustable.

Don't get me wrong, I think the yellows are a great damper, best quality available (probably along with Bilstein). If I had the spare cash I'd have adjustable bump valves install in the front pair, or at least have them revalved a bit stiffer. Then they'd be even better!

[EK1.6LCIV]

Kiz is on the money, Koni Yellow's are more than perfect for handling of most street cars. My set-up consists of the Koni yellow struts with the matched koni springs for my EJ8. Since having them installed I've only added the Spoon front and rear top strut braces to stiffen it up a bit, still a comfortable ride that handles very well.

[teh_mechanic]

Could you explain (please) why the rim size has an influence on the settings your choosing to use on your dampers?

Hes running 18" gestalt wheels on an eg civic sedan,so its set super stiff to reduce tyre scrubbing on the inner wheel arch round corners etc.

[JohnL]

Hes running 18" gestalt wheels on an eg civic sedan,so its set super stiff to reduce tyre scrubbing on the inner wheel arch round corners etc.

I can see that a stiffer damper setting may reduce how often such scrubbing occurs by slowing the rate at which the body rolls, but it won't stop it from happening altgether. The damper doesn't control the ultimate amount of body roll, it can only control the rate at which it happens, so in shorter / sharper manouvres with increased damper rate there may be some benefit in this respect because there is insufficient time for a lot of roll to occur, but if you're in a long corner and going a bit hard (e.g. on a big roundabout or similar looong corner) then the scrub is still likely to occur even with a stiff damper setting, just not as soon. For this arch scrubbing problem a stiffer damper is a band aid at best.

The only way to ensure it never happens is to move something, like the metal where the scrub is occurring, or change the position of the wheel via camber adjustment, rim width / offset change / narrower tyre etc (not a good reason to change these things, unless you intended doing so already for handling / grip reasons). Second best bet to stop the arch scrubbing would be stiffer springs and / or ARBs which may prevent body roll enough so it doesn't occur in practice even if theoretically it still could. This said, if your springs and / or ARBs are already at the rates you want, then stiffening them up just to avoid arch scrubbing isn't great either. You could try longer bump stops, but again not a good solution, and possibly a very bad one!

[SeverAMV]

Could you explain (please) why the rim size has an influence on the settings your choosing to use on your dampers?


ill probably appear noobish by saying this, but normally bigger wheels means lower profile tyres, which means less air required for same tyre pressure and more responses from bumps on the road, so in that regard it could affect damper choices, altho not by much. i went from 13s with high profile grippy tyres to 15s with low profile grippy tyres and the response difference when you go over a bump is more noticeable, with the 13s and the bigger tyres being more floatier, and the 15s being more responsive and slightly annoying on bumps.

[Jonald]

teh_mechanic hit it on the head. I have the koni's on stiffest setting because of the scrub issue. I had it on sports setting(which i believe is middle turn) and with just me in the car, no scrub... Once i had a passenger it was burrrrr. Put it on stiffest, i can get 4 ppl in the car before it starts to burrr.

The only other time it will start scrubbing as you said is it really uneven roads and while turning hard. But the koni's have definately helped my scrubbing issue

[Jonald]

btw brendan, empty your inbox bro!

[Limbo]

if your gonna only drive on the road save your money and get a decent brand shock & spring combo. Try finding something that has already been matched as they usually ride alot better.

Coilovers are crappy rides, they are mainly for track where you need to be able to adjust your height in a hurry.

ALso since your new it could take you forever to even know what settings to adjust your coilovers to. If you adjust it wrong you will hate them for the wrong reasons.

[JohnL]

teh_mechanic hit it on the head. I have the koni's on stiffest setting because of the scrub issue. I had it on sports setting(which i believe is middle turn) and with just me in the car, no scrub... Once i had a passenger it was burrrrr. Put it on stiffest, i can get 4 ppl in the car before it starts to burrr.

The only other time it will start scrubbing as you said is it really uneven roads and while turning hard. But the koni's have definately helped my scrubbing issue

Understand. My point is that while this may help alleviate the symptom it's really the wrong medicine for the illness. The side affects will affect handling and ride characteristics, maybe in a a good way but maybe in a bad way. If it works well enough for you and the side affects are good or indifferent then I suppose it's a legitimate 'treatment'. The only way to completely cure the malady with no side affects is by surgery, i.e. panelwork.

Personally, I like my Konis on the stiffest setting, but only because of how it makes the car handle (though I am probably attempting to make up for the too soft standard springs, with stiffer springs the 'best' damper setting may well be softer, i.e getting the desired handling responsiveness from stiffer springs rather than overly stiff damper settings). To get this responsiveness I'm happy to put up with a harsher ride, though it's only a real issue on broken surfaces.

The good side affect in my car's case is that this lessens how often the rear suspension bottoms out with a back seat full of passengers / bootfull of crap, which is a bit strange because the adjustment is supposedly only for rebound, which you wouldn't think would affect this problem as stiffer bump valving would?

It may be that there is some 'crosstalk' in the damper, i.e. in theory the rebound adjustment is independant from the bump valving, but in practice the rebound adjustment may not be 100% independant from the bump stiffness. This is apparently quite common with adjustable dampers (i.e. a change to either bump or rebound having some unplanned affect on the other setting), but more so / often with lesser quality brands than Koni (though I read that it's very hard to completely eliminate this from an adjustable damper).

[JohnL]

ill probably appear noobish by saying this, but normally bigger wheels means lower profile tyres, which means less air required for same tyre pressure and more responses from bumps on the road, so in that regard it could affect damper choices, altho not by much. i went from 13s with high profile grippy tyres to 15s with low profile grippy tyres and the response difference when you go over a bump is more noticeable, with the 13s and the bigger tyres being more floatier, and the 15s being more responsive and slightly annoying on bumps.

All else being equal, I think it's less the volume of air (i.e. the size of the air cavity) inside the lower profile tyre than the shorter side wall being inherantly stiffer (than with a higher profile tyre) that increases response to steering input as well as increasing harshness over bumps etc.

Tyre profile (and psi and sidwall stiffness generally) affects overall spring rate because the tyre is effectively the first of two springs in series (the tyre, then the coil spring itself), but it's hard to predict what the affects of increasing tyre stiffness might be for damper rates because the tyre is an undamped spring that is typically very much stiffer than the coil spring, which is damped.

Note that in F1 cars and similar, that the tyre is the major spring in that it's usually (always?) softer than the coil and accounts for the majority of the 'suspension' compliance.

[string]

JohnL have you actually dialed down your Koni's to a softer level and tested the "handling". Steering response is far from a good gauge.

Also, if you wanted something with more bump damping you shouldn't have gone with Koni's in the first place. High rebound is all part of the Koni experience.

[Jonald]

I forgot to mention that i agree with what you mean JohnL. It does give me better handling. All the points you mentioned i agree with.

[JohnL]

JohnL have you actually dialed down your Koni's to a softer level and tested the "handling". Steering response is far from a good gauge.

String,
Yes, and I do know good handling from bad. I used to have a 'clubman' style sportscar that would out-steer and out-corner almost anything on the road (out accelerate and brake most too), an Alfa Romeo which was just really sweet in it's handling (had Koni 'reds'), and I raced karts for years and was fairly good at it. I've also owned quite a few fairly ordinary handling cars as well as some real shitboxes...

I've had the front Koni's just about everywhere from full soft to full hard. Of these settings I prefer the full hard, really disliked full soft. The rears are more problematic to adjust, you tend not to do it just on a whim because they need to come out to make any change. I first installed the rears at 1 turn from soft (which was good), then tried full soft (which I did not like), now at full hard (best yet).

I really like good steering response, so long as it doesn't also mean erratic or unstable handling. I may possibly be giving up some outright grip with the stiff damper settings (may not, grip is pretty good considering the cheap hard tyres I'm running, surprisingly so), but when there are a lot of potholes it's nice to be able to just twitch the steering wheel a little this way and that and have the car go just where you want it when you want it to (an important part of this is getting the pressures right for the tyres you're running). For me it's a major part of the enjoyment of the driving experience, more so than pulling really big Gs around corners (what can I say, I'm getting older!).

My car's handling is very good considering the springs are way too soft, those tyres, and that it could really use a stiffer rear ARB (it's getting close to neutral because of some other tweaks I've done but a bit less understeer would be nice, and it does still roll a bit too much in longer corners). At first I was wary of full stiff, I more than half expected it would make the car twitchy and hard to deal with at speed on bumpy sirfaces, but this hasn't turned out to be the case.

On full stiff it's very well damped / controlled in roll and also provides rapid weight transfer in transitional states (which is what gives the good steering response, that and properly high tyre pressures, and / or better tyres), but it's also remarkably compliant over more savage bumps. I can only assume Koni has the low shaft speed input vs high shaft speed input damping well sorted.

Koni uses a 'digressive' damper curve, meaning that the damper is effectively stiffer at low shaft input speeds (for better control of low speed inputs such as body roll, and speeds up the rate of weight transfer for faster response) than it is at faster shaft speeds (to allow adequate compliance over larger or sudden bumps).

To be clearer, a digressive damper isn't actually softer at faster shaft speeds, but if you draw it out on a graph with shaft input speed on one plane and damper resistance on the other plane, then the resistance component of the curve will flatten off as shaft speed rises, compared to a 'linear' damper where the 'curve' will be a rising straight line, or a 'progressive' damper where the curve will rise more steeply as shaft input speed increases.


Also, if you wanted something with more bump damping you shouldn't have gone with Koni's in the first place. High rebound is all part of the Koni experience.

What would you suggest then? There's bugger all around better than the Koni, except perhaps a Koni fitted with a bump stiffness adjuster as well (they can be retro fitted for additional $). The problem is you don't know what you've got until you have it on the car, but having said that I'm very happy with them, they just 'feel' a little soft in bump (fronts more so than rears). If I were to have stiffer bump valves fitted, it might not be so good, I really have no way of knowing without trying it. I suspect stiffer springs would probably help by adding more resistance to bump forces.

[SeverAMV]

All else being equal, I think it's less the volume of air (i.e. the size of the air cavity) inside the lower profile tyre than the shorter side wall being inherantly stiffer (than with a higher profile tyre) that increases response to steering input as well as increasing harshness over bumps etc.

Tyre profile (and psi and sidwall stiffness generally) affects overall spring rate because the tyre is effectively the first of two springs in series (the tyre, then the coil spring itself), but it's hard to predict what the affects of increasing tyre stiffness might be for damper rates because the tyre is an undamped spring that is typically very much stiffer than the coil spring, which is damped.

Note that in F1 cars and similar, that the tyre is the major spring in that it's usually (always?) softer than the coil and accounts for the majority of the 'suspension' compliance.

sorry if my explanation seemed vague but that was generally what i was implying. a higher sidewall profile means that more air will be required for the tyre to reach the same pressure, thus making the tyre seem more bouyant/floaty as there is more air between the tyre and the wheel, thus making response slightly dull. but the other stuff you mention is interesting.

[JohnL]

sorry if my explanation seemed vague but that was generally what i was implying. a higher sidewall profile means that more air will be required for the tyre to reach the same pressure, thus making the tyre seem more bouyant/floaty as there is more air between the tyre and the wheel, thus making response slightly dull. but the other stuff you mention is interesting.

I doubt it's actually the volume of air in the higher profile tyre that causes it to be "slightly dull" and "bouyant/floaty" compared to a lower profile tyre. I think its more likely that it's the sidewall compliance itself that causes this. The problem with seeing the difference is that the two tend to go hand in hand, i.e. low profile and less air volume, easy to mistake the affect of one for the affect of the other.

The sidewall stiffness of a low profile tyre tends by necessity to be stiffer than sidewall of a higher profile tyre. But, if the sidewall stiffness were the same with both kinds of tyre, then both kinds of tyre would 'compress' to the same degree for the same loading or impact on the tread and behave more or less the same up to a certain point, but after that point the tread on the lower profile tyre would 'bottom out' against the rim before the tyre with the higher sidewall would. This would cause an instantaneous and very harsh impact on the rim itself, causing an effective abrupt increase in the tyre 'spring rate' (to infinity) that could cause handling issues as well as rim damage. The issue is the distance from tread to rim and sidewall stiffness, not the air volume.

In reality the sidewall of the lower profile tyre is very likely to be significantly stiffer than that on the higher profile, at least partly to avoid this potentially catastrophic problem (though some higher profile tyres will have quite stiff sidewalls, rally tyres for instance). As a consequence of this an increased loading or an impact to the tread will be absorbed with greater resistance by the stiffer sidewall of the lower profile tyre than with the softer sidewall of the higher profile tyre. The occupants of the car will feel this as the tyre being less 'dull or 'bouyant/floaty'.

I hope I'm being clear, it's harder to explain than you'd think!

[SeverAMV]

I doubt it's actually the volume of air in the higher profile tyre that causes it to be "slightly dull" and "bouyant/floaty" compared to a lower profile tyre. I think its more likely that it's the sidewall compliance itself that causes this. The problem with seeing the difference is that the two tend to go hand in hand, i.e. low profile and less air volume, easy to mistake the affect of one for the affect of the other.

The sidewall stiffness of a low profile tyre tends by necessity to be stiffer than sidewall of a higher profile tyre. But, if the sidewall stiffness were the same with both kinds of tyre, then both kinds of tyre would 'compress' to the same degree for the same loading or impact on the tread and behave more or less the same up to a certain point, but after that point the tread on the lower profile tyre would 'bottom out' against the rim before the tyre with the higher sidewall would. This would cause an instantaneous and very harsh impact on the rim itself, causing an effective abrupt increase in the tyre 'spring rate' (to infinity) that could cause handling issues as well as rim damage. The issue is the distance from tread to rim and sidewall stiffness, not the air volume.

In reality the sidewall of the lower profile tyre is very likely to be significantly stiffer than that on the higher profile, at least partly to avoid this potentially catastrophic problem (though some higher profile tyres will have quite stiff sidewalls, rally tyres for instance). As a consequence of this an increased loading or an impact to the tread will be absorbed with greater resistance by the stiffer sidewall of the lower profile tyre than with the softer sidewall of the higher profile tyre. The occupants of the car will feel this as the tyre being less 'dull or 'bouyant/floaty'.

I hope I'm being clear, it's harder to explain than you'd think!

yeah, your explanations are understandable. im just not too good with the mechanical explanations you post in the other threads. my mechanical knowledge is quite limited compared to my physics knowledge.

but back to the start, i believe the bridgestone adrenalin tyres (forgot to mention earlier) use a softer sidewall than most high performance tyres from what im hearing. so it is rather similar to using higher sidewall profile tyres made out of an equally soft compound. but swapping to a bigger rim size can bring out more of the steering quirks outta the suspension setup. since the swap to low profile tyres and bigger wheels, i can notice the tyres going over every bump and the places where i would be able to 'float' over with the high profiles now trigger bump steer. but thats probably more due to dead shocks and increases in responsiveness of the tyres thats causing it. should be sorted out shortly once i can sort out the problems with my coilies.

[JohnL]

yeah, your explanations are understandable. im just not too good with the mechanical explanations you post in the other threads. my mechanical knowledge is quite limited compared to my physics knowledge.

IMO an understanding of the basic first principles of physics is essential to any meaningful understanding of chassis dynamics, Newton will take you far if you apply him thoughtfully!


but back to the start, i believe the bridgestone adrenalin tyres (forgot to mention earlier) use a softer sidewall than most high performance tyres from what im hearing. so it is rather similar to using higher sidewall profile tyres made out of an equally soft compound. but swapping to a bigger rim size can bring out more of the steering quirks outta the suspension setup. since the swap to low profile tyres and bigger wheels, i can notice the tyres going over every bump and the places where i would be able to 'float' over with the high profiles now trigger bump steer. but thats probably more due to dead shocks and increases in responsiveness of the tyres thats causing it. should be sorted out shortly once i can sort out the problems with my coilies.

My bet is that while this tyre may have a softer sidewall than other tyres in it's class (and I don't know, I'm accepting your description), it will be relatively softer, but still likely to be significantly stiffer than most high profile tyres. A harsher ride is to be expected when changing from a higher to a lower profile tyre.

You say "bump steer" and "since the swap to low profile tyres and bigger wheels". Does this also mean a significantly wider tyre than standard? If so then an increase in what may seem like bump steer isn't to be unexpected. Assuming this isn't actually bump steer (and it probably isn't if it wasn't there before with the high profile tyres, though it could be...), it may be torque steer associated with effective 'scrub radius'. You don't need to be accelerating hard for torque steer to occur, anytime some power (with a front driver) or braking is being applied and you encounter an irregularity in the road surface it's possible to experience significant torque steer if the steering geometry and / or tyres makes the car susceptible to it.

Scrub radius is defined as the 'lateral distance from the point at which the steering axis intersects the ground to the nominal centre of the contact patch'. Note that I placed 'nominal' in italics, and also note that the centre of the contact patch really means the point that represents the average point of loading of the contact patch, which may not be in the geometric centre of it. E.g. if you have say neg camber then the 'centre' of the contact patch will be somewhat toward the inside of the contact patch, being the 'centre of loading', and would be toward the outside with pos camber.

The problem is that the 'centre of loading' is not static, it moves across the face of the contact patch as camber changes or you traverse bumps and undulations (anything that causes more weight to be carried on one side of the contact patch vs the other).

So what does scrub radius do, I hear you ask. It causes the steering axis to be offset from the centre of contact patch loading so tyre forces are fed into the steering from a laterally offset point. I.e. it creates a relatively small virtual 'lever arm' through which tyre forces are fed into the steering axis, and has the affect of causing the wheel to pull one way or the other, depending on whether SR is pos or neg (pos SR is when the centre of loading is to the outside of the steering axis, and neg when the centre of loading is to the inside of the steering axis).

It adds some weight and feel to the steering, but on a smooth road the forces it induces are in balance side to side, so the car doesn't pull to one side but tracks straight. For most front drivers the nominal (on paper) SR is zero or very close to it in order to minimise torque steer effects, but that's not the whole story.

Here's where 'nominal' comes in. The actual SR isn't static, the effective SR changes if the centre of loading changes (bumps etc), and when this happens on one wheel the affect becomes unbalanced side to side and the car will momentarily pull to one side. This is normal, and gives some 'feedback' to the driver, but you don't want it to be excessive or the steering will get twitchy and torque steer under hard accelration will become problematic on less than smooth roads (try driving a Camira with wide tyres, it can nearly rip the wheel out of your hands on poor sufaces!). However, when you put substantially wider tyres on the car the range of possible effective SR change increases, more so the wider the tyres are. This means that problems associated with torque steer can increase beyond what is comfortable for the driver.

[kraiye]

has anyone tried KYB's ?

[SeverAMV]

such a large post... i'll read it when im not tired after work at 4am in the morning.

i guess i did swap to much wider profile tyres. i think the stock tyre width for an ed6 is 145? im currently using 195, so yeah, big difference. and its not so much torque steer, my car doesnt have enough torque for torque steer due to some engine issues atm. i'd like to fit my coilovers as soon as possible, but most mechanics are closed over christmas. right now, my dead shocks borderline dangerous. i can feel my front left shock compress, but take a few seconds to decompress. the hovering scares the shite outta me.

[JohnL]

such a large post... i'll read it when im not tired after work at 4am in the morning.

I specialise in long posts! You think thats long? You should see some I've posted on kart racing forums when discussing weight transfer theory, pages and pages, you guys here are getting off lightly!


i guess i did swap to much wider profile tyres. i think the stock tyre width for an ed6 is 145? im currently using 195, so yeah, big difference. and its not so much torque steer, my car doesnt have enough torque for torque steer due to some engine issues atm. i'd like to fit my coilovers as soon as possible, but most mechanics are closed over christmas. right now, my dead shocks borderline dangerous. i can feel my front left shock compress, but take a few seconds to decompress. the hovering scares the shite outta me.

If you read my post carefully you'l notice I said that torque steer affects can occur even when only light power or braking forces are being applied, you don't need to be pushing any pedals through the firewall or have a high torque output motor. Torque steer will tend to be stronger when trying to accelerate (or brake) hard, and with a more torquey motor, but can be noticable even with low power or braking inputs, if the steering geometry and tyre width work to create a strong tendency toward torque steer.

Torque steer can supposedly be generated by driveshafts of unequal torsional stiffness (typically if one shaft is a lot longer than the other), meaning one shaft will tend to wind up more than the other, but in this case it requires a high torque input or hard braking effect to significantly cause any twisting of the shafts. This used to be 'accepted wisdom' in the days when front drivers mostly had unequally stiff drive shafts, but these days this fault is much less common.

In any case I do have some doubts about this theory, IMO its not likely to have more than momentary significant affect due to the affect of the differential accounting for this unequal shaft wind up, though it might cuase the steering to be more twitchy under hard acceleration / braking rather than 'torque steering' for more than a moment or so. Geometric affects associated with scrub radius and uneven road surface seems much more likely to me to be responsible for what most people would understand as torque steer as felt by the driver.

I could be wrong, but I'm suggesting that what you are percieving as bump steer may instead be momentary manifestations of torque steer associated with the increased tread width, and that you don't need big torque for this to occur. If I'm right the problem would tend to diminish or disappear if you just allowed the car to coast rather than holding speed with light throttle.

It sounds like you're increase in tyre width might be enough to cause at least some increase in torque steer affects on uneven roads, but your problem may be more associated with the blown damper(s) causing a wheel(s) to momentarily unload excessively. Sounds to me like you still have rebound but have lost bump damping, which would explain the lag in 'decompressing', keeping in mind that the bump stiffness of other dampers (most probably the damper on the diagonally opposite corner) may contrive to 'hold down' that corner of the car with the blown rebound.

[SeverAMV]

nah, even when coasting, bump steer manifests itself. its effects are probably enhanced by the bad wheel alignment that bridgestone did on my car. once i fit the coilovers, i can see if it was indeed the dead shock causing the bump steer. if it isnt, then its back to the rather expensive drawing board.

[JohnL]

If your effective scrub radius has been increased enough to cause noticable torque steer like effects at each steered wheel, and considering that when traveling in a straight line on a smooth road these torque steer effects will be in balance side to side (and hence no pull to one side), then a bad damper causing one tyre to excessively unload in bump might cause the still loaded wheel on the other side to no longer be in 'torque steer balance' with the unloaded wheel and for a torque steer from the still loaded wheel to be felt and a momentary pull to one side that feels like bump steer??

That's a lot of words with no full stops, apologies for the poor punctuation!

Anyway, the short of the above is that it's not unlikely that a blown damper might at least be excacerbating any problem that may exist (even if it may not be the actual cause), and new dampers may reduce the symptom to a degree that it's not noticable.

It's not impossible that when coasting the rolling resistance in the tyre might be enough to trigger an affect as described above, even with no engine or braking torque involved (?), but I might just be trying too hard to defend my theory!

PS,
Just noticed your sig. You mustn't have driven a well sorted carburettor set up, DCOE Webers (and other good carbs) can make very good power! Though you may not get quite the same 'drivability' as with a good EFI set up.

[JohnL]

Do you know what true bump steer is and what causes it? I ask because its a geometric thing that won't change because of a rim and / or tyre change, you need to alter something (a few things will affect it) in the geometry for it to exist where once it didn't. Bump steer can't be caused by bad dampers, though they could make it more obvious.

[SeverAMV]

If your effective scrub radius has been increased enough to cause noticable torque steer like effects at each steered wheel, and considering that when traveling in a straight line on a smooth road these torque steer effects will be in balance side to side (and hence no pull to one side), then a bad damper causing one tyre to excessively unload in bump might cause the still loaded wheel on the other side to no longer be in 'torque steer balance' with the unloaded wheel and for a torque steer from the still loaded wheel to be felt and a momentary pull to one side that feels like bump steer??

That's a lot of words with no full stops, apologies for the poor punctuation!

Anyway, the short of the above is that it's not unlikely that a blown damper might at least be excacerbating any problem that may exist (even if it may not be the actual cause), and new dampers may reduce the symptom to a degree that it's not noticable.

It's not impossible that when coasting the rolling resistance in the tyre might be enough to trigger an affect as described above, even with no engine or braking torque involved (?), but I might just be trying too hard to defend my theory!

PS,
Just noticed your sig. You mustn't have driven a well sorted carburettor set up, DCOE Webers (and other good carbs) can make very good power! Though you may not get quite the same 'drivability' as with a good EFI set up.

bad dampers in conjunction with a bad wheel alignment (courtesy of bridgestone port adelaide) could cause bump steer tho, right?

oh and i havent updated my sig in a while, i was just messing around with the factory setup at the time. i've done the tweaks to the keihin cv carbs already. currently, im waiting for my high compression kit to arrive, as well as new camshaft, valvesprings, retainers, which should get my compression ratio in the 11s, if not the 12s.

i've also got a pair of dual sidedraught skracing carburetors sitting around waiting for a manifold to be made. theyre dcoe 40, and apparently combine the weber and mikuni designs, so they shouldnt be too bad. once all that is done, i dont think my car will be making monstrous power, but it should have a notable increase in midrange and topend response. i find that the drivability of carbs can be better than efi in some respects, but thats just a personal opinion. most of the efi cars i've driven have lacked bottom end response, including a quad throttle ae101 sprinter, but carbs seem to have plenty of bottom end response, even when theyre tuned for top end. but this is just an opinion, and comparing carbs to a quad throttle sprinter in regards to bottom end response is flawwed as quad throttles are generally aimed at top end power and response.

[JohnL]

bad dampers in conjunction with a bad wheel alignment (courtesy of bridgestone port adelaide) could cause bump steer tho, right?

From my understanding bad dampers and / or poor alignment couldn't be a (significant) cause of bump steer, but might increase the severity of an existing bump steer.

To understand why we need to understand what bump steer actually is. True bump steer is caused by dynamic toe change with bump or rebound (which is different to momentary torque steer effects that might feel similar to bump steer). This is typically caused by the steering rack being mounted too high or low, the tie rod end being mounted too high or low, or the tie rod itself being too long or too short. Any of these conditions will cause bump steer in some degree, from severe to not noticable. And, some of these things might only need to a bit 'off' to cause a noticable problem, and that problem may manifest to a greater or lesser degree depending on other factors such as tyre characteristics (i.e. a less directionally sensistive tyre will be less affected by a given bump steer / toe changes because it will 'smother' small steering inputs due to being unresponsive in nature).

As an e.g.;
Looking at a double wishbone suspension from front on we'll see the upper and lower arms pivotted on the chassis pivots, and each arm will rise and fall with the outer end describing an arc (and these arcs will be different depending on the length of the arm). We'll also see the tie rod rise and fall pivotted at the rack end joint, and the tie rod end describing an arc. The arc in which the tie rod end rises / falls should match the arc of the suspension at the point on the strut or upright at which the tie rod end attaches to it. To achieve this the rack and tie rod end must be at the correct heights and the tie rod at the correct length (though this is typically more or less impossible to acheive exactly due to toe being adjusted by means of changing tie rod length, though it will typically be quite close to the correct length within the range of likely toe adjustment).

If any of the above is wrong then bump steer will occur because as each component rises and falls in arcs the effective distances (of the ends of the arms and tie rod) from the centres of pivot become laterally longer or shorter, and if these distances don't become longer or shorter in a manner that is 'matched' to the arcs of the other components then the ends of the tie rod will move in or out (laterally) relative to the steering axis and the toe will change with bump and / or rebound. Got that?! This is hard to describe!

Possibly the most likely reason for introduction of excessive bump steer is modification of suspension / steering geometry. E.g. if you substantially increase caster by moving the top of a Mac strut or upright (of a double wishbone suspension) backward then you'll also tend to lower the height of the tie rod end because you will have 'rotated' the strut or upright around a point centred on the lower ball joint, which will cause the end of the steering arm to be lowered to some degree. On the other hand if you increase caster by moving the bottom of the upright or strut forward then any increase in bump steer will be less because you move the strut / upright in an arc centred on the top of the strut or upper ball joint, and the end of the steering arm will lower a lot less (maybe not at all, depending...) than if we'd moved the top of the strut or upright backward.

It's very difficult to design and build a suspension / steering set up that has absolutely no bump steer at all (with some suspensions it's utterly impossible, e.g. front trailing arms on old VWs where the suspension doesn't move in arcs but straight up and own but with the tie rods moving in arcs), but the designer will (should) attempt to achieve as close as possible to zero or minimal bump steer at / near the static ride height. Due to manufacturing tolerances it wouldn't be unlikely for a car to have some degree of significant bump steer from the factory, but unlikely to be a substantial problem most of the time (especially with less responsive tyres fitted). Having said that, a lot of effort might be put into dialling out any significant bump steer on a chassis intended for serious competition.

Even on a well set up car it wouldn't be unusual though for bump steer to become significantly worse the further into bump or rebound you go. So, if you have a bad damper you might expect to see more adventures deeper into bump (and rebound to a lesser degree), possibly resulting in noticably increased bump steer.

Poor toe alignment could in theory cause the tie rod to be too long or too short, and thus introduce some bump steer, but I suspect it would have to be quite a lot wrong to cause a significant problem (I could be wrong). Soft suspension bushes might also increase bump steer tendencies, though the mechanics aren't the same as above, it's more to do with the bushes compressing and allowing whole suspension arm to move inward and outward while the tie rod end doesn't.



i find that the drivability of carbs can be better than efi in some respects, but thats just a personal opinion. most of the efi cars i've driven have lacked bottom end response, including a quad throttle ae101 sprinter, but carbs seem to have plenty of bottom end response, even when theyre tuned for top end. but this is just an opinion, and comparing carbs to a quad throttle sprinter in regards to bottom end response is flawwed as quad throttles are generally aimed at top end power and response.

I think it's more to do with the nature of the set up. All else being equal, carbs with very large venturi will tend to be pigs at lower rpm, but scream in the top end. This is a problem for single throat carbs like the DCOE Weber and similar clones (more or less clones) such as DHLA Dellorto etc, i.e you can set them up with smaller venturis and get good bottom end / mid range, poor top end, or with larger venturis and get good mid range / top end, but poor bottom end. Splitting the difference might give good mid range with acceptable bottom and top. Despite having been used fairly successfully on a number of higher performance road cars (mostly Italian!), this sort of carb probably isn't the ideal choice for a road car, the design is primarily intended by Weber for racing applications.

In any case, even good carbs are archaic technology these days. EFI should be able to outperform carburettors on all fronts (power, tractability, economy) so long as it's in good condition and been correctly set up for the application.

[TODA AU]

Bump steer is generally a geometry problem.
When the car is lowered beyond the limits of the standard parts, the geometry of the steering arms is compromised.
This can be cured with a variety of products.
Example: Ikeya Formula tie rod ends.
http://www.ikeya-f.co.jp/images/product_notice/foot_works/ntend.jpghttp://www.ikeya-f.co.jp/images/product_notice/foot_works/h.jpg

Use of these or similar products will allow you you achieve parallel steering arms & reduce if not negate bump steer on a lowered car.
Obviously the wheel alignment must be correct too, as this will only agrovate the situation.
When combined with roll centre adjusters, you can achive excellent handling when the car is set a a low ride height.
Without use of such products, it's difficult to get the most from your dampers at very low ride heights.

NB: At very low ride heights, other products such as adjustabletoe & camber arms are also advantageous to achieve desired wheel alignment.

Hope that helps
Cheers

Adrian

[SeverAMV]

Bump steer is generally a geometry problem.
When the car is lowered beyond the limits of the standard parts, the geometry of the steering arms is compromised.
This can be cured with a variety of products.
Example: Ikeya Formula tie rod ends.
http://www.ikeya-f.co.jp/images/product_notice/foot_works/ntend.jpghttp://www.ikeya-f.co.jp/images/product_notice/foot_works/h.jpg

Use of these or similar products will allow you you achieve parallel steering arms & reduce if not negate bump steer on a lowered car.
Obviously the wheel alignment must be correct too, as this will only agrovate the situation.
When combined with roll centre adjusters, you can achive excellent handling when the car is set a a low ride height.
Without use of such products, it's difficult to get the most from your dampers at very low ride heights.

NB: At very low ride heights, other products such as adjustabletoe & camber arms are also advantageous to achieve desired wheel alignment.

Hope that helps
Cheers

Adrian

this would only help if my car was lowered. but my car exhibits bump steering with the factory ride height and factory suspension. waiting till mechanics start working again before fitting the coilovers.

[TODA AU]

this would only help if my car was lowered. but my car exhibits bump steering with the factory ride height and factory suspension. waiting till mechanics start working again before fitting the coilovers.
Fair enough, definatly get it checked out.
(Sorry I didn't read that part earlier in the thread- my bad)
What condition are your castor rod bushes in? ED Civic right?

Also, is it bump steer that is the problem or is it more tram lining?

[JohnL]

Also, is it bump steer that is the problem or is it more tram lining?

SeverAMV suggested he may have a bump steer issue, and I questioned whether this might not be bump steer but in reality might be a manifestation of momentary torque steer that could be occuring when traversing road irregularities, and might be being mistaken for bump steer.

This is in effect a manifestation of momentary 'tram lining' which itself is a manifestation of a torque steer effect, even though it can occur with only light throttle or braking applications. Such an effect is associated with changes in 'effective scrub radius' as the average centre of loading moves laterally across the face of the contact patch as the tyre passes over bumps and along longitudinal 'trenches' in the road, and potentially being a greater problem with wider tread width than narrower tread width.

[JohnL]

Bump steer is generally a geometry problem.
When the car is lowered beyond the limits of the standard parts, the geometry of the steering arms is compromised.
This can be cured with a variety of products.

Adrian

Agreed, up to a point. If you've made substantial changes to ride height and / or caster angles then you may well end up with geometric bump steer (i.e. true bump steer, not a torque steer affect), and you may well be able to address it by arbitrarily throwing appropriate parts at the problem. However, the only way to know if you've actually cured it (other than the problem no longer being apparent when you drive the car) is to measure the bump steer.

This is done by maiking a tool that consists of two flat pieces of plywood hinged together so that they can open / close like a book. On one piece of ply you fit two pointers (can be anything, a couple of screws screwed though the ply so they protrude out the back will do fine) spaced apart so they match the rim diameter and high enough so they will be at hub centre height when you place the pointers against the rim.

But I'm getting ahead of my description. Place one 'page' of the bump steer tool / gauge on the ground near the wheel with the other page up against the wheel, and place some bricks on the 'page' that is on the ground to hold it in position while the bump steer test is performed. The pointers on the vertical 'page' are placed against the rim so that both are touching the rim. Now the car must be jacked up and down while you observe if one of the pointers moves away from the wheel rim with ride height changes, if so then this indicates a toe change with ride height change and thus bump steer.

In order to do this test you need to remove both coil springs on the front axle line in order to allow ride height change as you jack the car up and down. This is fairly easy with 'coil-overs', more of a pain with struts.

[JohnL]

This can be cured with a variety of products.
Example: Ikeya Formula tie rod ends.
http://www.ikeya-f.co.jp/images/product_notice/foot_works/ntend.jpghttp://www.ikeya-f.co.jp/images/product_notice/foot_works/h.jpg
Adrian

I'd be wary of using such a product if it resulted in the centre of the rod end ('rose' style joint) being spaced further away from the steering arm than the centre of the 'ball' would be with the standard tie rod end. My reason is that you might end up with excessive twisting of the the steering arm because the tie rod end (or 'rose' joint) is mounted to the steering arm in single shear, and as a result can impart a twisting moment into the steering arm that will be stronger the further from the end of the steering arm the centre of rod end / rose joint articulation is.

If this occurs it could become a source of bump steer in itself, though in a lot of applications the steering arm will be very rigid (enough to adequately deal with the increased forces fed into it), in others it may not be rigid enough even for the standard set up.

If you look at the steering arms on 'formula' race cars or similar, you'll see that the rod ends are typically mounted in double shear at the steering arms (steering arm itself being made up from two seperate pieces spaced above and below the rod end), the purpose of which is to eliminate any twisting moment in the streering arm, and also to allow the use of a lighter weight steering arm (less metal but stiffer due to superior design). You'll also probably note that such a set up usually allows a deal of latitude in exactly at what height the rod end can be placed on / in the steering arm, adjustment of this being by means of shims or different length spacers placed above and below the rod end. The purpose of this is to allow bump steer adjustment by raising or lowering the outer end of the tie rod.

[SeverAMV]

i havent owned the car since it was first made, but from what i can tell, the original owners havent touched the suspension since it was first built. from what i can see, its still using oem shocks and springs from when it was built 18-19 years ago, and the missing chunks on the outer layer of the springs support my belief. i'll just work on one bit at a time. the coilovers should be the first step to rectifying the cause of the problem. after that i'll see what else i may need.

[JohnL]

its still using oem shocks and springs from when it was built 18-19 years ago, and the missing chunks on the outer layer of the springs support my belief. i'll just work on one bit at a time. the coilovers should be the first step to rectifying the cause of the problem. after that i'll see what else i may need.

The missing 'chunks' are just chips in the powder coating, mine has similar, not to worry. The springs on my CB7 are only a couple of years younger than your springs (just clocked up 250,000km), and both front springs are exactly the same free length as each other, as are the rear spring pair. This strongly suggests that none of the springs have sagged appreciably because it would be unlikely for both springs in each pair to sag to exactly the same degree, a testament to the quality of the OE Honda springs.

I think you're right in that if the dampers are at all suspect you should start there before thinking about anything else. You need a stable platform to be able to adequately feel whatever else the suspension may be doing.

Even if you do the time honoured test of pushing the car down hard at each corner and it feels nicely stiff and doesn't 'bounce', this is no test of the dampers. The dampers may well feel fine according to this 'test', but could still be utterly shot. When I bought my CB7 it passed this test easily and drove fine on smooth city roads at the pace I could get away with with the salesman sitting beside me, but as soon as I was alone with my new purchase on the open road at hwy speeds, and on rougher country roads it was painfully obvious the dampers were way past their use by date!

[SeverAMV]

my way of testing if my dampers were dead or not was kinda initial-d ish. you pretty much know something is wrong if you're driving on a perfectly straight and flat piece of road and the water still bounces everywhere.

and i dont think its powdercoating, unless these springs had more than 5mm of powdercoating.

[JohnL]

my way of testing if my dampers were dead or not was kinda initial-d ish. you pretty much know something is wrong if you're driving on a perfectly straight and flat piece of road and the water still bounces everywhere.

? I don't understand!


and i dont think its powdercoating, unless these springs had more than 5mm of powdercoating.

The spring coating is quite thick, not 5mm though, and I'm 99% sure it's some sort of powdercoat. It's certainly thicker than paint. If it's lifting in places and generally roughed up it might possibly give the impression of being thicker than it is(?). Peel a bit off and see.

In any case I can't see the "chunks" being depressions in the steel, flying stones etc certainly couldn't cause such damage, and not even severe corrosion is likely to be that bad (unless they'd been left in salt water for a few years!). Even considering that the springs are exposed to the elements and that the protective coating is damaged, IMO they just wouldn't stay wet long enough for more than surface rust to appear, even after 18 or so years (also considering that they are good quality steel, and good steel as a generalisation tends to corrode less than poor quality steel).

I've seen old leaf springs that have been sitting exposed in paddocks for decades, and while they'll be rusty there would be no corrosion on them even remotely close to 5mm deep, unless they were at least partially buried.

[SeverAMV]

? I don't understand!
stick a cup of water in your cup holder without a lid. if your shocks and springs are working properly, then on a straight and flat piece of road, the water should sit flat or ripple a little on imperfections on the road. in my car, it splashes at every little imperfection of road, even if it is just a 1cm high bump, or just a rock on the road.



The spring coating is quite thick, not 5mm though, and I'm 99% sure it's some sort of powdercoat. It's certainly thicker than paint. If it's lifting in places and generally roughed up it might possibly give the impression of being thicker than it is(?). Peel a bit off and see.

In any case I can't see the "chunks" being depressions in the steel, flying stones etc certainly couldn't cause such damage, and not even severe corrosion is likely to be that bad (unless they'd been left in salt water for a few years!). Even considering that the springs are exposed to the elements and that the protective coating is damaged, IMO they just wouldn't stay wet long enough for more than surface rust to appear, even after 18 or so years (also considering that they are good quality steel, and good steel as a generalisation tends to corrode less than poor quality steel).

I've seen old leaf springs that have been sitting exposed in paddocks for decades, and while they'll be rusty there would be no corrosion on them even remotely close to 5mm deep, unless they were at least partially buried.

haha, actually, it looks like someone got hungry. and im pretty sure its not powdercoating because i've peeled off a little to compare, and you can see the bits missing on the actual spring.

[JohnL]

stick a cup of water in your cup holder without a lid. if your shocks and springs are working properly, then on a straight and flat piece of road, the water should sit flat or ripple a little on imperfections on the road. in my car, it splashes at every little imperfection of road, even if it is just a 1cm high bump, or just a rock on the road.

My car doesn't even have cup holders, besides, I'm not American and wouldn't use it even if it did! But say for arguments sake I did use a cup holder, even though my dampers are in great shape they're set so stiff I'd still be spilling water at every decent bump, and there are quite a few of those around here!

I'd be surprised if your springs weren't working properly, but your water problem does sound like excessive 'wallowing' due to bad dampers.


haha, actually, it looks like someone got hungry. and im pretty sure its not powdercoating because i've peeled off a little to compare, and you can see the bits missing on the actual spring.

That does sound unusual. I wonder if the car ever lived by the ocean? Salt might have gotten under the peeling coating and caused some corrosion every time there was moisture about? Unless this were very extensive I doubt it would significantly affect the spring rate, but could concievably create stress points that might eventually lead to failure of the spring? I bought an old Fiat 124 Sports once (for the engine and gearbox), that car had lived by the ocean and was amazingly rotted, even by Fiat standards!