Does anyone know what the optimal toe settings are for the Sierra and Escort Cosworth, and especially why?

I know that it's always said that the setting at the front should be 2 mm toe in and on the rear 3 mm toe in. These are the same numbers Ford gives in the Group A and Group N manual for the Escort Cosworth. The thing I wonder about though is what is 2 or 3 mm toe in exactly? When I have the car aligned it's always measured in degrees, which is a good unit for alignment. For calculating the 2 and 3 mm back to degrees you need to know what rim size it's based on.

So what is the rim size it's based on? For the Sierra I assume this would be 15", but the Escort Group N manual talks about 16" and the Escort Group A manual about 17". And if you even look at the Escort WRC manual it says 18" rims.

Coming to the Escort WRC you also see different toe settings, 0 mm for the front and 2 mm toe in for the rear. Less toe in on the rear (3 mm vs 2 mm) I can understand because the WRC rear suspension has less bump steer. But why would the change the setting for the front from 2 mm toe in to 0 mm? Because as far as I know the front suspension setup is the same for all.

 

Its not as easy as A,B,C you have to set ride height first the measure the suspension travel/ compression then set the car up accordingly ! Unless your car is built like a group a the settings wont be right

 

Why would you need to do all that? Toe setting should be set at normal ride height.

 

Point being group a isnt normal ride height ! is your car ? toe changes when angles are changed when arm to rack angle is changed through ride height ! So thaat my point are your arms group a ? ect if not you need to set toe to spec

 

I don't see the point you are making. Yes, toe changes as the ride height changes, that's why the toe needs to be set at normal ride height. But the optimal toe setting is not ride height dependent. The group A manual states 2 and 3 mm toe in for both tarmac (ride height 160/170 mm) and gravel rallies (ride height 230/240 mm).

The question is especially why the front toe should be 2 mm toeing in. For an RWD car I can understand as the front wheels will be trailing along, which pushes them backwards and making them toe out. So during driving the 2 mm toe in will be neutral on a RWD car. But on the 4x4 it's different, the wheels are now pulling instead of trailing, so the wheels would pull themselves to toe in. From that point of view I can understand the 0 mm toe in on the 4x4, which apparantly is the factory setting and also the recommendation on the WRC.

 

Exactly so why are you asking group a questions ? is your car a group a setup ?

 

No it isn't. But the settings are the same for group A and group N and group N uses standard suspension components. And the toe settings are exactly the same as what Mike always adviced to use, so I have the feeling he has taken it from the group A/N manual.

 

He did yes but Only a start point as all the factors need to be taken into account

 

Complicated if you let it be , the Differences are brought about by improvements in the Rear of the car, the Toe in settles the front of the car down - once the rear suspension is improved over standard this becomes less neccessary, its more about driver feel than actual cast in stone numbers tho .

 

So that explains why the Escort WRC has the neutral toe at the front compared to the group A and N. I would have expected that the improvement of the 6 degree beam on the group A compared to the group N would be more significant than the change from group A to WRC.

But what I don't understand is that toe in is advised on the front, while the front wheels will toe even in more under load. But perhaps it's the braking stability when they start toeing out that is the reason for the 2 mm toe in.

Still strange that Ford advises to use 0 mm on the front of the Cosworth.

 

Front toe does not change under load on a wr car. That is unless we want it to.

 

The toe changing under load was meant for the standard car, since Ford apparently advises to run the front wheels parallel.

BTW, I think the front suspension on the Escort Cosworth group A is the same for the WRC, so the toe on a group A car shouldn't change either. But the group A manual advises a different front toe setting than the WRC manual.

 

The hubs and bearings are different on the wr cars when compared to the grpa, as are the track control arms and the comp strut brackets.

And thats just the front lol