Ed Smalley wrote into Torsen to ask:


My 2018 Ford Mustang GT350 has an OE Torsen® differential and I would like to know if using a mini spare tire is possible. The original tire diameter is 27.4″ and the spare tire diameter is 27.7″. What say you?

Ed Smalley


Thanks for contacting Torsen.  Our products have been used in vehicles that have had a mini-spare tire that was as much as a 25% difference in diameter smaller than the main tire.  If kept to the operational restrictions (speed and distance), this falls within what the differential can handle.  In the case of a tire that’s only about a ¼” difference in size, it is a relative non-issue – for the Torsen differential.

I cannot say, however, if Ford has other considerations that prevented them from packaging the spare with the cars that come equipped with a Torsen.  I believe fitment of the spare wheel over the brake calipers is part of that.  So bear that in mind as well.


JTEKT Torsen North America, Inc.