Wheel Alignment - Odd Tyre Wear

[eg5civic]

Yeah they shouldn't wear that much over the period of the month right.....

Cheers for that

[aaronng]

Your left rear toe is worrying...

[eg5civic]

Hmm tis my thinking exactly... i'll give them a call now

Edit- and he says to bring it in tomorrow arvo, after i explained twice it was the rear tow not the camber that needed adjusting

[aaronng]

The rear toe has to be equal on both sides, because it doesn't have steering like the front, which helps it self-centre. For the front, it doesn't matter if both sides have unequal toe, as long as the camber and castor are correct, because the steering self-centers. You just worry about total toe for the front.

[JohnL]

, not to get a lecture on how terrible my suspension setup is .

Aplologies, not meant as a lecture, just observations on camber. So many people use so much, seemingly for no better reason than that they see a lot of racing sedans using a great deal, without really understanding why nor what the compromises might be.

I do stand by my asssertion that cars with double wishbone suspension require and benefit from less static camber than cars with Mac struts.

My suspension is being held back to Macpherson strut performance because my front suspension is Macpherson strut .

I feel for you, really I do! Having bagged them so hard, Mac struts can be set up to work OK, amd a well set up Mac strut will outperform a poorly set up anything else...

I can nearly lift my inside front wheel on track so I am not super worried about the very poor camber that the inside wheel has.

IMO it's not such an issue at mid corner at high levels of weight transfer with the IF largely unloaded, but leading up to mid corner when lateral acceleration and weight transfer are less and we are depending to some degree on IF grip then poor IF camber can contribute to understeer.

You are correct though, tyre temps suggest that my camber is a little excessive with higher inner temps and a differential of a few degrees across the tread. Nothing extreme though and the setup works.

Good! Mac struts can work better than they have any theoretical right to, though I still contend, all else being equal, a good double wishbone will always beat a good Mac strut...

[chargeR]

@ eg5civic: you should definitely get that toe sorted. 3mm of total toe in at the rear of my car was enough to cause inner shoulder wear with moderate camber after not a lot of k's.

Apologies, not meant as a lecture, just observations on camber. So many people use so much, seemingly for no better reason than that they see a lot of racing sedans using a great deal, without really understanding why nor what the compromises might be.

No need for apologies I found your post and interesting read . I was forced into running the amount of camber I have due to using suspension designed for N1 racing in Japan, and I try not to kid myself that it is the perfect setup . And your observations about grip in the lead up to mid corner when the outside front is not fully loaded are quite astute as this phase of the corner can be a slight problem in my car, I am thinking about trialling my car with no front sway bar to see what happens .

[Zilli]

guys, back to my original issue... although some great reading by some obviously very knowledgable people...

Ive been noticing a large amount of roar when the car is riding, and im thinking my wheel bearings are shot... could this be contributing to my issue? just a thought that popped into my head, im yet to get the time to go and get the wheels aligned.

[aaronng]

guys, back to my original issue... although some great reading by some obviously very knowledgable people...

Ive been noticing a large amount of roar when the car is riding, and im thinking my wheel bearings are shot... could this be contributing to my issue? just a thought that popped into my head, im yet to get the time to go and get the wheels aligned.

I would blame the roar on your tyres first, if you are still running the semis.

[tknova]

guys, back to my original issue... although some great reading by some obviously very knowledgable people...

Ive been noticing a large amount of roar when the car is riding, and im thinking my wheel bearings are shot... could this be contributing to my issue? just a thought that popped into my head, im yet to get the time to go and get the wheels aligned.

Also possible that your tyres are shot due to toe settings, I have the same problem, rear tyres are loud as due to incorrect toe and are now featherd.

[JohnL]

And your observations about grip in the lead up to mid corner when the outside front is not fully loaded are quite astute as this phase of the corner can be a slight problem in my car,

This is one reason why front drive cars have the 'roll couple' (i.e. front / rear relative roll stiffness bias) biassed toward the rear (i.e. stiffer in roll at the rear). Less front roll stiffness results in less lateral weight transfer at the front and more at the rear (i.e. the IF remains more heavily loaded for longer in the corner).

This gives not only better traction to the driving wheels (the IF in particular) exiting corners, but more front grip in total for both trail braking and lateral grip going into the corner (needed with very front heavy FWD cars). This is because having the two front wheels more equally loaded is in effect the same as having more 'rubber on the road' at the front and relatively less at the rear. However, having one of those front wheels at a very poor camber is reducing 'rubber on the road', and reducing front grip.

This is why large caster angles are a 'good thing'. i.e. caster creates a steered gain in neg camber at the OF and a steered gain in pos camber at the IF. Both these steered camber gains are what we want to keep the treads more squarely presented to the road (i.e. maximise front contact patch size).

This means that with larger caster angle we can use less static neg camber, as much as we can engineer in without creating mechanical problems is usually the 'right' amount (there are limits on what is practically posssible). Some Mac strut suspended racing cars use as much as 20° of caster (yes really!), which is why if the power steering stops working the race is usually over...

I am thinking about trialling my car with no front sway bar to see what happens .

My car (CB7 Accord) is only a road car, but I removed the front ARB and am very happy with what this has done. Body roll is increased noticably but not nearly as much as I was half expecting (Konis help to keep roll under control in 'shorter' corners, though not in 'longer' corners such as roundabouts etc). Understeer is definitely reduced and general handling balance improved. The car needs a stiffer rear ARB, when funds allow...

[eg5civic]

Well i went back and asked them and the guy reckons he can't fix it as there is no toe or camber adjustment in the rear... i can understand camber but the toe??

Does anyone know if an EG Si Hatch has rear toe adjustment.... if so pic with the adjuster circled so i can point it out to the guy

[chargeR]

Well i went back and asked them and the guy reckons he can't fix it as there is no toe or camber adjustment in the rear... i can understand camber but the toe??

Does anyone know if an EG Si Hatch has rear toe adjustment.... if so pic with the adjuster circled so i can point it out to the guy

Not sure if this will help but here is the section regarding toe adjustment from the Helms manual: