cutting coilovers? is it bad?

[siknis]

now that i have everyones attention, this is long so your going to need your reading glasses :p

this is going to apply to anyone running wide wheels(8.5" and up and wheels 19" and up) maybe even people under that i dont really know

my euro is 3 days old, i already have the coilovers, there going in the car tomorow. mate already has these in his car, the brand is MD, not very popular in australia but there on par with tein flex, made in japan to order to customer specs and requirements. nobody currently imports them to any english speaking countries so you wont find much on the net about them.

here is the dillema, for myself a mate and a few people im aware of, temptn being one of them from what i hear.

when fitting wider wheels to the rear of a euro, the edge of the rim comes closer to the strut, when fitting a stronger and fatter overall coilover that gap is again reduced. when trying to find a wheel that can fit inside the guard you can be faced with some big problems, namely tucking inside the guard and not hitting the coilover either. we have found that +45 for an 8.5" wheel is all thats going to work for BIG drops on coilovers or bag kits

here comes the bad bit, when the car is stationary, theres abour a 3mm gap between coilover and rim. when you hit a big bump the natural curve of the suspension is on a different axis to that of the coilover so naturaly the rim hits the coilover, yeah ouch i know.

to cut a long story short, rim hitting coilover results in the coilover basicly having a grove cut out of it, so far on my mates car he's just worn through the lower perch adjuster, so he's ordered a replacement part and start the process all again, this took all of 20k to occur.

heres where i come in. pick up my car from the dealership and say lets fix this problem and find a way around it,

now people will go err wrong offset this that, we need this offset to get the rim to tuck, but i will go into more detail

http://img210.imageshack.us/img210/2439/suspny4.jpg

a little pic i did on autocad :p im on the laptop so thats a no go, paint will help illustrate my ideas

the red line is the imaginary line that the wheel follows, which is the problem and leads to the cutting of the coilover from the wheel rubbing against, it only on big bumps.

now ive talked suspension profesionals and some have suggested cutting the bushes on the bottom of the coilover and shifting it to one side more, or some how re drilling the strut hole in the arm, or making a new plate and having it welded on, but these all alter the suspension geometry pretty intensly and im not that keen on breaking a less than 1 week old car just yet :D

heres the theory so far, now this is going to sound simple and a really easy fix but is this all that its going to take to correct the problem. in theory

fit camber kit to the car (ingalls) adjustable tie rod type. now we cant actually take any camber away, because you will end up hitting the outside guard on big bumps with the rim because the wheel width and offset have already put the rim so close to the outer guard. but if we were to take our +45 rim to the shop, machine 2mm off the back of the wheels hub (offset now +43) bringing it closer to the coilover but further away from the guard by 2mm. then fiddle with our new camber kit, remove that 8deg of camber and bring it back to 5deg, and voila our wheel is now running less camber (woo more rubber), we are also able to clear the coilover on the bumps as the wheel is basicly standing upright more as such, further from the coilover and the same distance from the guard so no scrubbing issues.

everyones tip top and the problem is solved easily and cheaply, and as a bonus your tyres last an extra 2k lol.

i would imagine some pretty complicated mathmatical formulas would be required to actually calculate the required offset and camber adjustments so im hoping somone around here is really smart with the physics and maths and can help me out or push me in the right direction :)

looking for lots of constructive imput please guys :D

cheers,
dim

[m0nty ITR]

The way I see it you have 2 choices.

Buy rims that fit with better clearance or just run a camber kit and induce more positive camber and roll the guards rather than go to all that trouble of fabrication and cutting.

[tony1234]

It's not worth all that drama.Just stick some 17s with 225/45 tyres or 18s with 225/40s.With the money you save invest in some good rubber.IMO you should buy the best tyres you can afford.They're the ONLY thing between your car and the road.

[JohnL]

Sounds like you're biting off more than the car can reasonably chew with your mods. Personally I'd be going for a narrower tyre / rim, and / or a different coil-over (i.e. one that actually fits).

The maths and geometry you're after aren't all that complex, but what will be more difficult is that you'll need exact dimensions for the suspension geometry, rim dimensions / offsets, tyre dimensions (I mean exact not basic statistical dimensions), and bodywork dimensions in relationship with the tyres, suspension etc. Even then I think the margin for error will tend to too great to make any calculation of this meaningfully accurate, as I get the impression from your post that you'd dealing with mm changes to make this work (i.e. just 'squeaking it in').

You say: "now ive talked suspension profesionals and some have suggested cutting the bushes on the bottom of the coilover and shifting it to one side more, or some how re drilling the strut hole in the arm, or making a new plate and having it welded on, but these all alter the suspension geometry pretty intensly and im not that keen on breaking a less than 1 week old car just yet"

My impression of what you say they is that you would be moving the bottom of the strut inboard by offsetting the holes in the lower strut mount on the strut itself, and any modification would be to the strut and not the car. This would not affect suspension geometry as such, but would affect the 'wheel rate' of the suspension, i.e. the leverage ratios acting on the strut would be increased thus making the suspension effectively softer despite no actual change to the spring or damper rates.

Just how much the wheel rate will change would depend on how far inboard the bottom of the strut were moved, though I doubt it would or could be much of a decrease in effective rate as I doubt you'll be able to move the strut by much. Keep in mind that if you moved the bottom of the strut inboard by X amount, and that (say) the rim were contacting the strut half way up the strut, that the change in lateral position of the strut at the point at which it's fouling the rim will only 50% of X.

The only practical way I can think off to make this work with the struts, tyres etc that you want to use is to decrease camber and flare the wheelarches. I don't think there is any reasonably easy answer to solving your problem as you want it solved (other than rethinking the whole thing from scratch), which isn't to say it couldn't be sorted as you want given time and money...

[m0nty ITR]

I just tried giving you a rep point John, but I apparentely haven't "spread them around" enough.

Top work. I give you 1 pseudo rep point.

[Killa From Manila]

run some really narrow tyres stretched out over ur rims like the drifters do. wil give u more gap between coilover and tyre and also between tyre and guard. looks mad too :P

[m0nty ITR]

run some really narrow tyres stretched out over ur rims like the drifters do. wil give u more gap between coilover and tyre and also between tyre and guard. looks mad too :P

That's VIP style. D1 is actually very close to race cars for setup now. Gone are the days of crazy camber, tiny offsets and stretched tyres.

[Killa From Manila]

That's VIP style. D1 is actually very close to race cars for setup now. Gone are the days of crazy camber, tiny offsets and stretched tyres.

haha yeah


note..i dont know how safe it wud be to do this so yeah..at ur own risk

[JohnL]

I just tried giving you a rep point John, but I apparentely haven't "spread them around" enough.

Top work. I give you 1 pseudo rep point.

Get this sorted out, I want my real rep point. What happens when I have enough, do I win a car...?!

[JohnL]

note..i dont know how safe it wud be to do this so yeah..at ur own risk

It's not unsafe as long as the tyre manufacturers recommended max rim width isn't exceeded. Problem is that the OP's problem as it stands now seems to relate more to the rim edge fouling the strut rather than the tyre itself, though if he decreases camber to clear the rim from the strut he may well be fouling the tyre.

[siknis]

thanks very much for responses guys, john L especially

regards to stetching the tyre, there are 225's on a 8.5" wheel which is quite alot of stretch already, the rim hits the coilover, NOT the tyre. this is where the problem lies.

narrower tyre and wheel combo isnt really ideal, 90% of 20" wheels around are 8.5" wide.

john i belive you are at an understanding with the problem i am having.

this problem has occurd with tein, MD, Ksport and D2 coilovers on a number of different cars. coilovers cannot be faulted. only incorect wheel fitment.

the suggestion to re mount the strut to the hub would affect the ratio to which wheel movement would affect the coilover, which is what concerns me most about considering that an option.

guard rolling has already done as much as possible and doesnt leave too much room to mess around with. pinky gap between guard and rim when tucking.

what i might do is just start off little by little, take 1mm off the offset, then dial in 2deg less camber and see how we go.

[JohnL]

narrower tyre and wheel combo isnt really ideal, 90% of 20" wheels around are 8.5" wide.

Well, serves you right for fitting a 20" wheel!

Sorry but this fashion for huge wheels and tyres resembling rubber bands stretched around the rim is one of my pet automotive peevs (and that's all it is, a fashion, a fad, it serves no real purpose and is often counter productive to handling etc).

The 20" rims are obviously unsuitable for the car, my strong advice is to get some sensibly sized rims, 17" are perfectly adequate for improved handling etc and far more practical. I seriouly think you're pushing the proverbial uphill perservering with such unecessarily oversized rims...


john i belive you are at an understanding with the problem i am having. this problem has occurd with tein, MD, Ksport and D2 coilovers on a number of different cars. coilovers cannot be faulted. only incorect wheel fitment.

There you go, you've said it yourself...


what i might do is just start off little by little, take 1mm off the offset, then dial in 2deg less camber and see how we go.

Is all this aggravation, effort and expense really worth it just to have rims that are in reality too big anyway??

[siknis]

to be honest i absolutly love the way it looks on the stock wheels lowerd about 3.5" front and back.

this may be a fashion to some, everyone has different tastes i suppose and this one suits mine at the moment. ive also been through the huge deep dish faze and had hubs shortend and guards pumped so i could do it. ive had cars with smaller made to order 3 peice wheels too, so dont discount me as being silly, its just what i feel like putting on this car for the time being, but ill probably change my mind in 6 months :p

but for the moment the problem is at hand and im not making too much headway in relation to finding a true answer or how i should go about calculating it. surly there are more than a couple people who have had this problem

[2002 TeGgY]

The way I see it you have 2 choices.

Buy rims that fit with better clearance or just run a camber kit and induce more positive camber and roll the guards rather than go to all that trouble of fabrication and cutting.

yeh y dun u jus get a camber kit?

[m0nty ITR]

what i might do is just start off little by little, take 1mm off the offset, then dial in 2deg less camber and see how we go.

Can I ask how much you're running now to back it off .2? I run -3.5 front on a fully fledged track car. Sounds like you're car will handle like a truck on Maccas trays.

[siknis]

no actual idea, at a guess 6deg or so on the rear, still waiting from my ingalls kit to be sent from pumped and then i throw that in and take it for an alignment.

its not a sports car, and i find it funny that anyone would do up a euro as a race car, there slow and very unresponsive through the steering in my experience.

enough with the why do you want to do this stuff guys, you cant knock it till you try it :p

[m0nty ITR]

no actual idea, at a guess 6deg or so on the rear, still waiting from my ingalls kit to be sent from pumped and then i throw that in and take it for an alignment.

its not a sports car, and i find it funny that anyone would do up a euro as a race car, there slow and very unresponsive through the steering in my experience.

enough with the why do you want to do this stuff guys, you cant knock it till you try it :p

You need to read this. Whilst I doubt you have -6.0` camber, I'm pretty sure you're running more than is safe on the roads.


On most street cars, camber is not easily adjustable. However, if you choose to purchase aftermarket camber plates, you can set camber to improve handling. More negative camber tends to increase tire grip in corners. Therefore, if your car experiences understeer, you can decrease front camber (make it more negative) to improve front grip or increase rear camber (make it more positive) to decrease rear grip. Remember not to add too much negative or positive camber since it will decrease the life of your tires and may cause a blowout. Even pure race cars rarely use more than about 3 degrees of camber.

SOURCE - 240EDGE.com (http://www.240edge.com/performance/tuning-camber.html)

These cars here would be running around -3.0` camber.
http://www.procar.com.au/wallpapers/03_pcs1_apcc_beetle_800.jpg
http://www.procar.com.au/wallpapers/gtp_wp_wk_holt_s.jpg
http://www.procar.com.au/wallpapers/03_pcs1_apcc_loadsman_800.jpg

Note that the rear wheel of the Commodore is pretty much straight up and down. This gives optimum grip through corners. Since you have a FWD car your ability to accelerate through corners is greatly reduced. There is more weight over the front wheels in cornering. The emphasis is to have more negative camber at the front since that's where the weight is under heavy cornering. Rear camber should be less extreme on a FWD car.

This "don't knock it till you try it" mentality won't do really well at all. Running excessive camber will just make your tyres wear to quick and unevenly. The worst part is you'll think the outside has tread whilst the inside will be bald and possibly even down to steel belts. With such excessive camber you may have as much as 8mm tread on the outside which can mislead you.

You've asked us for our advice. Perhaps you should take your car to a tyre expert to have the car set up properly. Running alot of camber doesn't help your car in handling. Your contact patch in day to day driving will be smaller than the factory setting. Only when the car is pushed hard will your cars handling improve, but even then -6.0 is far too much.

[JohnL]

to be honest i absolutly love the way it looks on the stock wheels lowerd about 3.5" front and back.

Then why change the wheels, especially as this whole project seems to be for cosmetic purposes???


this may be a fashion to some, everyone has different tastes i suppose and this one suits mine at the moment. ive also been through the huge deep dish faze and had hubs shortend and guards pumped so i could do it. ive had cars with smaller made to order 3 peice wheels too, so dont discount me as being silly, its just what i feel like putting on this car for the time being, but ill probably change my mind in 6 months :p

It's not that it's a fashion only "to some", but that it's only fashion period. You seem to be doing it entirely to suit your current 'taste', which you say may well change in 6 months, and seem unconcerned with any actual dynamic improvement or even impairment to the car. I'd suggest that you fit the definition of 'fashion victim' perfectly!


but for the moment the problem is at hand and im not making too much headway in relation to finding a true answer or how i should go about calculating it. surly there are more than a couple people who have had this problem

You want a "true answer", but I'd suggest that your question is the wrong one in the first place. I could ask "how can I get 1000 hp out of my Accord's engine", and while I know it is actually possible to get this much power (however briefly!) if I really wanted it and could pay for it, there are a whole lot of reasons why the concept would be seriously flawed.


no actual idea, at a guess 6deg or so on the rear, still waiting from my ingalls kit to be sent from pumped and then i throw that in and take it for an alignment.

I'll bet it's not that much (at least I hope it isn't!), but if you could possibly think it might be that much just from looking at it then whatever you do have is way too much. A large amount of camber is problematic (not to mention potentially dangerous), especially with wider tyres that have an extremely low aspect ratio and thus very little vertical sidewall deflection.

Your contact patch (i.e. that part of the tread that is significantly to heavily loaded, not that part that is merely touching the ground) will be on the inner edge and tiny, and provide very little grip in cornering or under brakes (not to mention subject to rapid wear). No amount of likely body roll is going to get the outside tyre to present it's contact patch 'flat' to the road.


its not a sports car, and i find it funny that anyone would do up a euro as a race car, there slow and very unresponsive through the steering in my experience.

Then why try to make it look like a sports car? Fashion victim, or not? You don't even sound as if you really like your car apart from it's looks and maybe comfort?


enough with the why do you want to do this stuff guys, you cant knock it till you try it

Yes we can! The project is flawed, you want to make serious changes apparently for purely cosmetic reasons that are impractical, and counter productive to the car's handling, braking and general dynamics, possibly to the point of making the car less safe than stock. This might be OK for a show car that is purely an exercise in artistic experimentation and never gets driven, but not really for a useable road car.

[tony1234]

^^^^I agree.

[siknis]

wow go nuts and rip into me haha :eek:

im fully aware of vehicle characteristics, setup changes and how they effect the dynamics of a car, ive got my cams and have been racing karts since i was 9, but this isnt a race car, its my everyday driving car.

if those car are running 3.5deg then im sure i have about 6deg haha

i appreciate the detrimental effects on the cars performance, but as i said its not a race car to me, i use it for getting around town in style, and not so much comfort:p

this task is not unrealistic at all, i am trying to reduce my overall camber to minimise the ill effects of lowering the car alot and improve the tyre wear situation. im being faced with the problem of the rubbing coilover and guard that i have to address to be able to dial in more +ve camber. i understand treadwear thankyou, the tyres get flipped often so the wear stays even.

does anybody know the dimensions of the rear suspension so i can put it into autocad and create a model of the suspension movement. i basicly need distance from all subrame mounts to the hub mounts and there distance to the outer guard to reasonably acutatly calculate the movement of the arm and if it will foul the body.

[tony1234]

wow go nuts and rip into me haha :eek:

im fully aware of vehicle characteristics, setup changes and how they effect the dynamics of a car, ive got my cams and have been racing karts since i was 9, but this isnt a race car, its my everyday driving car.

if those car are running 3.5deg then im sure i have about 6deg haha

i appreciate the detrimental effects on the cars performance, but as i said its not a race car to me, i use it for getting around town in style, and not so much comfort:p

this task is not unrealistic at all, i am trying to reduce my overall camber to minimise the ill effects of lowering the car alot and improve the tyre wear situation. im being faced with the problem of the rubbing coilover and guard that i have to address to be able to dial in more +ve camber. i understand treadwear thankyou, the tyres get flipped often so the wear stays even.

does anybody know the dimensions of the rear suspension so i can put it into autocad and create a model of the suspension movement. i basicly need distance from all subrame mounts to the hub mounts and there distance to the outer guard to reasonably acutatly calculate the movement of the arm and if it will foul the body.
No one's ripping into you.we're just trying to give you our opinions.We(i'm sure i'm speaking for the others here)do not recommend what you are about to do for a number of reasons stated in previous posts.But at the end of the day it's your car so do as you wish.:)
BTW you should talk to euro03act,Justin he's in the ACT,he'll be able to give you some tips on how to mod your new car.

[JohnL]

I'm not trying to have a go at you, I'm just telling you what I think, it's the risk you run when you ask questions!

I raced karts for years too (and hope to again at some stage when / if I can afford to). I was Clubman Light Champion at my local club a couple of times (only a small club though, so it's less impressive than it sounds!). As a racer I'd have thought you might be more practical about your car mods. IMO just because it's 'only' a road car is no reason to make mods that may well lessen it's dynamic ability and safety, the road can be a more unpredictable and dangerous place than the race track...

It's good that you want take camber out, but I still think you have an uphill battle to get it how you want it to be. As to the dimensions you want, I expect you'll heve to measure it up yourself, which would be possible but not all that easy. Some of the dimensions would have to be estimated as it's hard to know where the exact centre of ball joints etc might be.

[siknis]

ok thanks guys no worries :)

i was hoping somone would save me some time and happen to have a diagram of the rear end for me to get mesurements from :p

the car isnt silly low to me and i dont have any problems scraping, but i guess ive been driving super low cars for long enough to judge driveways and speedbumps at the right angles.

ill continue down this path and see how i go, if i end up successful ill post up some advice for others who modify their cars the same as mine

[TEMPTN]

Delimea delima is all your gonna have when driving a decked car,
With coilovers and running 8.5 width tyres no matter wat off set u have its gonna hit the bottem coil lock, as like you mates 1 theres no way around unless u raise the car or let it cut into the lock and eventuly it will wear the excess metal away
Getting a camber kit past a certain point of been low is just a waste of time trust me! it make no diff unless u spend big bucks with modify custom control arms,
If u want to go lower and miss ur coil pm me and i might tell u my secret on how to avoid hitting the lock 9 / 10 in a bit bump and still have tuckage

[Drew]

Camber kits in the back and roll the guards, maybe a small spacer to push the wheel away from the coil over

Certainly not safe to be cutting into the strut