Wandering steering

[macdog320]

My integra ever since I bought it has had the tendency to wander in the steering, especially on bumpy roads. It has 18' Wheels and has been lowered and brand new tyres. I just had an alignment and balance and that did nothing. Any ideas what im looking at here? I think the uni joints may be modified and are binding, but not sure.

[AsH_]

i had the same problem in my eg...

i had change my steering rack, cv joints, control arms, bushes, etc...

im sure your not at that stage yet.

but it bald my front tyres in 2 days... i went through 8 tyres in just over a week...

4 on the car and 4 spares i had...

cost me about 900 incl. labour

[macdog320]

My tyres are wearing perfectly even though. From what I understand the problem is purely with that uni joint. I need a new control arm, but that wouldnt be wats making the steering wander so baldy would it? More likely to be the uni joint?

[55EXX]

wow thats full on ash!

this is my educated guess. the 18" wheels have very low compliance due to the very small profile of the tyres which cause excessive bump steer. bump steer is the tendency for a wheel to steer (change direction/toe out) as it moves upwards during a bump. Excessive bump steer increases tire wear and makes the vehicle more difficult to handle on rough roads

The linearity of the bump steer curve is important. If it is not straight then the length of the tie rod needs to be adjusted. Bump steer be adjusted by lifting the rack or dropping the outer tie rod, if the rack is in front of the axle. The reverse applies if the rack is behind the axle. Usually only small adjustments (say 3mm) are required. this is something i recommend professionals do. a specialist suspension garage withsuitable equipment is needed. this is what the extreme case of ash would have been i'm guessing. totally incorrect camber and toe kills tyres lightning fast. bet it was your inside edge dying.

for you mac dog my guess would be your wheels. change them to something with more side wall and it will most probably solve the majority of you problem

try and sit a flat tyre suface with no give on a angled surface you will see that only half of the trye will contact the road surface, or less. this puts more weight on the side of the steering axis and because of this it will want to wander. ever notice how you tram line along the road in the rut that trucks have squished into the road? also having your rear wheels aligned is a good idea! or even to toe in slightly? talk to pros about that. it keeps the rear more stable.

[AsH_]

i took my car to pedders suspension to get checked out...

they showed me under the car...

my cv joints were leaking... big split... and everything was worn out to nothing...

my all my tyres were on to the metal threads... and all along the sides of my car was black bits of rubber stuck to the panels... rubber was shredding a melted on the doors... i looked at it and was like wtf is this shit?

[55EXX]

man thats unreal! so the cause was everything worn?nothing in particular? what year car was this?

[AsH_]

'93 gli civic

previously tracked a bit...

also it was very lowered.. past the guards...

[macdog320]

Yeh my car really wants to follow any type of inperfection on the road, especially where you hit a different type of seal on the road surface and there is an angle between the old and new seal. So could you just further explain, what my wheel is doing I dont quite understand what you said? everything is wearing perfectly and the front did just get an alignment. Is it the size of the wheel? or the actual structure of the wheel?

[JohnL]

Please preface all my comments with IMO...

this is my educated guess. the 18" wheels have very low compliance due to the very small profile of the tyres which cause excessive bump steer.

Getting warm. Bump steer isn't the issue, at least not likely to be the major problem if some exists (some nearly always exists).


for you mac dog my guess would be your wheels. change them to something with more side wall and it will most probably solve the majority of you problem

Hot! Too much wheel and not enough tyre, not enough vertical compliance in the short / stiff sidewall.


try and sit a flat tyre suface with no give on a angled surface you will see that only half of the trye will contact the road surface, or less. this puts more weight on the side of the steering axis and because of this it will want to wander. ever notice how you tram line along the road in the rut that trucks have squished into the road?

Getting colder and warmer at the same time.

As you traverse ruts / irregularities in the road the centre of loading on the contact patch migrates laterally across the contact patch, and this changes the 'effective scrub radius', which is I think the root of Macdog's problem when coupled with low profile tyres.

Explantory note for those who don't know: Scrub radius is the the length of a virtual line drawn laterally from the centre of the contact patch to the point at ground level at which the steering axis intersects the ground. This line is typically short to zero in length, closer to zero with most FWD cars. The steering axis is a virtual line that passes through and defined by both the upper and lower ball joints, or with Mac struts through the ball joint and the steering pivot at the top of the strut.

The nominal scrub radius (i.e. the scrub radius as designed by Honda) will be zero or very close to zero, but this assumes the centre of average contact patch loading to be in the centre of the contact patch.

In the real world the centre of loading moves laterally across the contact patch face with camber change and with irregularities in the road surface that cause weight to be carried more heavily and more lightly on different sides of the CP. This changes the 'real' scrub radius ('effective' SR), even though the nominal SR doesn't change.

These changes in effective SR affect the manner in which contact patch forces are fed into the steering rack via the steering axis (increasing and decreasing the 'leverage' of the forces generated at the CP ), and cause momentary steering pulls that cause the car to veer left and right depending on the exact nature of the irregularities the car is driving over.

With tyres that have very stiff sidewalls (especially with a wider CP) this affect is magnified relative to tyres with more vertically compliant sidewalls, because the stiffer the sidewall (or tyre case in general) the more the average centre of CP loading will migrate across the CP face (i.e. changes in loading are less 'absorbed' by casing deflection). The stiffer and wider the tyre the more likely this is to be a problem on rougher roads.

[macdog320]

So the most probable solution would be new tyres? or smaller wheels?

[teh_mechanic]

yep,long story short,your big wheels that require you to run low profile stiff sidewall tyres are magnifying the normal effects john explained,magnifying them to a point where your car is doing annoying things.

to run those 18's you cant really just get tyres with more sidewall,that will throw your speedo and a whole host of other things off.

put simply,civics wern't designed to run 18's and if you do run them there are consequences like the ones you are finding

[JohnL]

So the most probable solution would be new tyres? or smaller wheels?

Both. As teh mechanic explained you can't just throw taller sidewall tyres onto the existing rims, you need ro maintain the circumference of the tyre (+ or - a small tolerance) or you will get substantial speedo error (and I think there may also be legal issues involved).

You need a smaller diameter rim for starters, say 15" or 16" (Civics have 14" stock?), then good tyres to suit those rims. I'll bet the handling improves as well, on smooth as well as bumpy roads. Very low profile tyres are bad news for handling, especially on real world roads.

Some race cars do use pretty low profile tyres on big diameter rims, but it's a compromise in order to be able to fit huge brake rotors, not because very low profile tyres intrinsically handle or grip better (in general they don't, compared to a somewhat more conservative profile). Such race cars will also have the suspension set up very carefully to minimise the downsides of very low profile tyres, which won't be so easy for a road car.

Very low profile tyres are a fashion statement, not a performance upgrade. Even car companies that offer very low profile tyres are generally pandering to market demand more than offering a genuine / effective 'performance' option (IMO).

[macdog320]

Just to clarify my car is an integra. Too be honest im not too concerned about being able to throw the car around a track, other than the wandering steering the car still handles better than the average car. The integra will get 17' on no problems? Will the bigger tyres i can get on the 17' be enough? For the time being i think i might just get a pair of original wheels cheaply for the front.

[JohnL]

Just to clarify my car is an integra. Too be honest im not too concerned about being able to throw the car around a track, other than the wandering steering the car still handles better than the average car. The integra will get 17' on no problems? Will the bigger tyres i can get on the 17' be enough? For the time being i think i might just get a pair of original wheels cheaply for the front.

My understanding is that Integra = Civic, at least the Integra is based on the Civic platform, so same basic suspension etc.

If you currently have 18" rims then 17" will of course fit and would I think be a better bet than the 18", but I suspect still on the big side.

What is your current tyre size? (i.e. section width? / aspect ratio? / 18")

[macdog320]

They are Wanli tyres, im guessing they're pretty cheap, going on the past owner. 215/ 35/ W84. Yeh i realised the 17's would obviously fit on but was wondering if the smaller diameter of the wheel could give me enough tyre to solve the problem. Ive seen 17's on integras before and they have no problems.

So just making sure, we dont think the wandering steering has anything to do with the binding uni joint? Would this just be more likely to make the steering tight in areas?

[55EXX]

yeah i don't know bout this uni joint. have it inspected if your paranoid.

i had 18's on my last civic 215/35's and 15"s on my now civic and the 215/45 out handle the big rims hands down! big rims are just for show. they have they're consequences

[JohnL]

First major problem; the tyres are Wanli brand (never ever heard a single good thing said about this brand of tyre, other than that they are cheap), second major problem, stupidly low profile on the tyres.

By the way, what is the current rim width?

I can't say with any authority that the CV is having no affect on the steering, but I'd be a little surprised. At any rate, if the CV is dodgy then it's a higher priority to fix than the tyres, so fix the CV first and then you'll know.

[JohnL]

Some options for alternative tyre / wheel sizes are:

Your current tyre:
215/35/18 = X diameter
(nominally 608mm according to the on-line calculator)

Compared to:
40/17 = Xd - 0.66%
45/16 = Xd - 1.32%
50/15 = Xd - 1.97%
55/15 = Xd + 1.64%

You want to attempt to keep rolling circumference to within 2% of the stock tyre, which for this rough comparison I'm assuming to be your current Wanlis, but of course these aren't the stock tyres so you really should make comparisons with the actual stock tyre size. Try the calculator at this site:

http://www.tyresave.co.uk/tyresize.html

Note that the 40/17 tyre is closest in diamater to the 35/18 Wanlis fitted now, but I still think 40 AR is too low for a street tyre. My choice for an all round road tyre would be the 50/15, despite it having the greatest diameter difference to the 'stock' tyre.

[macdog320]

So in theory if i took the stock wheels off my sisters car and put them on the front of mine i would be able to tell if it is in fact wheels causing the problem. they're just 15" wheels off a pulsar. Id rather be sure before i start changing stuff as either way it will be relatively expensive to fix.

[JohnL]

So in theory if i took the stock wheels off my sisters car and put them on the front of mine i would be able to tell if it is in fact wheels causing the problem. they're just 15" wheels off a pulsar. Id rather be sure before i start changing stuff as either way it will be relatively expensive to fix.

I don't see why not, if, the stud pattern is the same, the wheel centre hole (would need to be the same or bigger), and the offset at least close.

If not then possibly you might be able to borrow a couple of stock Integra wheels / tyres, or even 'rent' them briefly??

[macdog320]

Ok for everyone out there, do not put 18's on a dc2 integra. I buckled 2 wheels on the same 30 min trip. Guess i have to get those new wheels now.....