dead simple question

[hal 1]

Hi

Friend of mine is adjusting rear wheel camber and toe in on his sprint car,
are these adjustments made at the tyre or the rim of the wheel ?

[GreenV8S]

Camber is typically measured in degrees, so it doesn't matter. Toe is usually measure at the tyre, but you need to be clear whether the distance you're quoted is for one side or both sides.

[hal 1]

Thanks very much for that, we'll sort it next week

[denisb]

Toe in AND camber are measured at the wheel rim NOT the tyre.

The trouble with tyre is they are made of rubber and tend to bulge at the bottom, really messing up your camber reading!

[steve_D]

Don't forget these measurements are taken with the car on the ground.
After each change the car must be pushed several feet back and forwards to make sure the tyres and suspension are settled before the next measurement is taken.

Steve

[nightdriver]

Yes, dont do what I have seen many do. Jump up and down on the car a few times , then you just alter the ride height you're measuring from and dont settle the car at all...

[GreenV8S]

denisb said:

Toe in AND camber are measured at the wheel rim NOT the tyre. The trouble with tyre is they are made of rubber and tend to bulge at the bottom, really messing up your camber reading!

True. What I meant is that the camber is normally expressed in degrees, not as a distance. It is common to express toe-in a distance measured at the tread, but there are two forms - either the difference (front and back of the tyre) of the distance from the tyre to the center line, or from the tyre to the opposite tyre. You need to be clear what figures you;re using, because they differ by a factor of two.

[hal 1]

Thanks for all the replies folks, I was aware of the need to keep rolling back and forth and so on but confirmation of these steps to take are most welcome, I know its quite a lengthy job but we're doing it ourselves because local 'specialists' dont seem to know what's being asked of them,

One local tyre dealers offers four wheel alignment, when I took my car a few years back to have it done they just offered me a read out of the machine's diagnosis!
they didn't think to actually do any adjustment to either front or rear wheels ( which could be adjusted for tracking )needless to say I haven't been back there.

[nightdriver]

You could try contacting some local race teams, they will have all the gear and at this time of year would be happy for a bit of extra work...

[hal 1]

nightdriver said:

You could try contacting some local race teams, they will have all the gear and at this time of year would be happy for a bit of extra work...

Cheers I hadn't thought about that