dbur

Radius doesn't count for anything. You want your axles all to rotate at the same rate to keep stress off the viscous coupling. Each revolution of the tire goes down the road a distance equal to the rolling circumference, not related to the radius which is distorted by the weight of the car pressing down on it (only at the bottom though ) Measure the circumference of the tire off of the vehicle with a tape or ribbon. While unloaded radius is exactly related to the circumference, you will get more measurement error trying to measure the radius and then calculating the circumference, or matching radius tire to tire.

I'd say measure the rolling circumference like the first post of the thread says. Matching to within the spec is what is important. The transfer clutch cannot tell what tread pattern your tires have, only if they travel unmatched distances for each revolution.

From that other thread: ---------------------- ----------------------------------------- Two questions: 1. is this silicon fluid contained inside the housing in a secondary chamber with no access externally? I know my tranny is filled with 75-90 gear oil and when you remove the drive shaft it runs right out the back, so it seems to all be one chamber inside. 2. is there a way to tap into the control system and set up an indicator light that could tell you when clutches are engaging? That way if you see it going on all the time when you are not on a slippery surface you would know something was going on. I just replace a tranny on a 95 Legay L wagon that had been run with different wear level tires on the front and rear. Seems there is a lot of iffiness to measuring the circumference to within 1/4" (tire pressure, vehicle weight, on or off the car...) and a positive feedback that the clutches aren't over active would be comforting. Thanks.