The conventional wisdom on syncro tires is that they should be virtually identical in diameter, to prevent spurious activation of the VC.� I believe it has been said that the diameters should not vary more than 3/8 of an inch.

But consider this:� What if the inflation of the 4 tires is not equal, which is often the case?� Wouldn't that affect the diameter by easily 1/2 to 3/4 of an inch?

Here's my dilemma.� On my van I have the Bridgestone Dueler AT Revo, in the 225-70R-15.� Bridgestone has discontinued this size....though not the Revo model.� I have 3 nearly new tires, but one tire (and the spare) are worn a good deal on the outer 1 inch or so.� This is from when they were on the front with a marginal alignment, since adjusted.� Although the center, and inside, of these two tires is very good, the conventional wisdom says I really need two more tires in exact diameter, and I can't get them in the Revo.

Bridgestone recommended a Firestone tire that was similar to the Revo.� My question for the list is this.� Can I substitute 2 new tires of a similar tread and diameter to the Revos in a 5 wheel tire rotation without cooking my VC?� Right now I hate to throw away 3 perfectly good tires...to say nothing of spending $600 + on new replacements.

Thanks, Anthony
'89 Syncro GL (Hidalgo)