Interpreting alignment diagram

[MikeJ]

Apologies for the noddy question but I'm getting myself in a twist interpreting the standard Hunter alignment print out.

Attached is a previous readout of the Esprit. Two questions for you guys with respect to the rear wheel marked as 0deg32' toe.

1. Is this the O/S drivers side that its talking about?

2. Does a +ve figure mean toe-in? i.e the front of the rear wheel is closer to the chassis than the rear of the rear wheel.

Hope you can help please.

cheers Mike

 

Edited December 29, 2019 by MikeJ

[TAR]

Does this help? 

 

 

[MikeJ]

Thanks for that, looks like the print out is as if you were looking down at the top of the car. My wheel in question is therefore the O/S and I need to reduce the toe in by about 20' to get in in spec.

cheers

Mike

[C43]

Hi Mike

yes that is O/S driver side and yes it has too much toe in at the rear on one side. 

I have an 84 turbo with both rear wheels toe in too much, by about 1mm each side measured at the rim. I think this means I have to add about 2 - 3mm of shim. I have bought the shim and was looking last night at the logistics of fitting the shim. Its a bit of a PITA but I must admit I am tempted to leave it as is. The car drives really sweetly and from many years of racing experience the upside of too much toe in at the rear is increased rear end stability. The downside it gives more mid corner understeer. However, since I don't struggle with mid corner understeer I am tempted to leave as is. I know its different from the book but we have a massive difference on our cars from how they left the factory in that we are running different rubber.

You might be tempted to change yours to equal them up though. BTW if you are doing this would be a good time to renew the rubber bush at the front of the trailing arm if not done recently.

cheers

C43

[MikeJ]

Thanks for that, good advice. My main motivation is to get the thrust angle to near zero. However, I'm probably not a sensitive enough driver to notice the difference!

 

cheers

Mike

[andydclements]

I don't think there's specific adjustment for the thrust angle on the Esprit.

 

It will be altered as you alter the rear toe, but it's more of  by-product. You alter rear toe by moving the front mount point in wards/outwards of the trailing arm, but the rear mount point isn't in the centre of the wheel hub, it's a but further back. The rear mount is effectively between the upper and lower links. So, by moving the toe of the car inwards, you also move that rear wheel in very very slightly. That will alter your thrust angle (unless you alter toe of both rear wheels by the same amount. You do something similar if you alter rear camber (if you have adjustable rear upper links).

If you really desperately needed to be able to adjust thrust angle, you could do it by making adjustable lower links for the rear of the car (and upper ones if you didn't already have them), you'd then move the rear wheel inwards/outwards by adjusting at all three points. That would move the centre-line of the rear wheels, although it wouldn't alter any rear set-back if you had any.

 

Personally, I'd do as Christian ( @C43) suggests, and equalise rear toe and do so by adjusting the RHS rear one (LHS is only fractionally out of tolerance although both are nearly the same amount out), and see how it feels (should be better both even than just both within tolerance), if you then really feel  you need to get back to book spec got toe, then at least you have an equal starting point on both sides.

[MikeJ]

I know its easy to convince yourself that the change has made an improvement but I've added the shim to the O/S rear and it does drive much better. Left handers now feel the same as right handers!