A - B is the correct dimension. This has to be at the rim not the tire. In the past toe was measured with a rod between the two rims, therefore toe in mm is for both wheels.

 

Hi folks,

Some (basic!) questions about Toe-in / Toe-out settings and how they are measured/calculated.

I’m wanting to convert Toe settings from mm to degrees (and deg mins secs). The trigonometry is pretty straight forward, but I’ve never been sure if “1mm Toe in” refers to the total difference between both wheels, or if it’s a “one wheel” measurement. Looking at the figure below could someone confirm which measuerement it is.

Is Toe = A – B (This is what I’ve always presumed)

or

Is Toe = C (i.e. a “one wheel measurement”)




Cheers,
ColinU.

P.S.
It’s actually a Mini I’m getting lined up just now, but going back to the scooby world those Prodrive settings of “1mm toe-in” equates to an angle of 0.045 degrees (or 0deg 2mins 42secs) on each front wheel – assuming my assumptions above are correct. Isn’t it amazing how such a miniscule change can effect how the car handles!

 

hmmm....

Several articles / FAQ I've just found on the web indicate it's measured from the tyre extremity - not the wheel rim.

E.g. see

 

Double checked, it is definitely the rim (rims are more accurate than tires and for measuring a difference of only 1 mm you need al the accuracy you can get, therefore in the past I think they defined the measurement for the rims, now they use more and more angles with the modern set up equipement). The difference between 16" or 17" rims is negligible for setting up the Subaru.

By accident my car (MY99) was set up with 1 mm of toe out front and rear instead of toe in. You end up with a car that is very nervous in long fast turns. So want your set up quite accurate and checked regularly (once every 15,000 to 20,000 miles or so).

Good luck with the set up of your Mini, it is a pain in the ***. The dry rubber suspension gives you every time a different ride height when measuring (also summer or winter), making it very hard to get it right. But when you have it right your Mini will corner really well, no understeer! I did drive a Mini Cooper S for more than 5 years and enjoyed the driving very much . Might want to be carefull, ended up in a turn on the highway with a little rain with an oversteering Mini at 90 km/h. Tried to correct it and was facing the uncoming traffic , no damage (pfeeeeew!).