Rim size on Group2 and ST

[PorscheFanNo1]

Hi everyone.

I've always been wondering, in the 90s during the Group2 and SuperTouring days they used 19" wheels, but where they also allowed 18" at some point? Cause while watching videos from 92-93 some cars seem to have bigger wheels then others, or is it just my eyes that fails me? And also during a ASTC race the commentators said the Alfa 155 had got brand new 19" rims from the factory, sounding a lot like it had been using smaller rims before that.

So can anyone shed some light on this?

[kmchow]

Yes, there was a change from 18" to 19" wheels from Class 2 to ST? I think it did occur in between the '93 and '94 season? As a result some organizers could have given dispensation?

OTOH, alloy wheels supposedly weaken structurally over time so getting a new set could improve the handling, but how much is hard to say? I don't think the ASTC Alfas ran smaller sized tires though.

[Notso Swift]

I am pretty sure that that the time wheel size (diameter) was not a regulated component and the change to 19" was based on a peformance advantage (preceived or real) from either the Wheel or the tyre

[PorscheFanNo1]

I see, so they where indeed running on 18" in 91-92 and around there? Anyone know for sure that this was the case?

[Sodemo]

The bigger the wheels, the shorter the braking distances.

I personally like the 18" size, and think that 19" is just too big.

[WebberForWDC]

For the early 90's 19" was very radical surely? Did most performance (raod) cars come with meagre 17" wheels at the time unlike the 19 to 21" units they are fitted with nowadays.