Superstock TT Technical Regulations 2023

29.13. Carbon Fibre / composite wheels are permitted only when fitted as original
equipment on the homologated machine and have been certified by the
manufacturer as “Fit for purpose” for racing use on the TT mountain course.
Optionally, these may be replaced by an alternative ALUMINIUM wheel from the
same manufacturer or an aftermarket racing wheel supplier. In any case they must
be of the same diameter and rim width as the Carbon Fibre / composite wheel they
replace and weight must be no lighter than the homologated composite wheels.