Audi TT roadster wheels and tyres

[Bobio]

My 2014 TT roadster came with new wheels and tyres. Looks like genuine rotor-style 19 inch wheels but I would not be surprised if they are actually a copy of the Audi wheels. The tyres are Chinese "Kpatos" 235/35Z R19 91W. This is OK, I think, for speed and load rating, but the Audi spec for 19" wheels is 255/35. So is 235 width OK or should they be changed for 255? The car handles and drives well and I don't plan for any track use. What do you guys think?

[MustangGT]

It does not look like 235/35/19 is the correct size for a 2014 TT. From what I can find it should 245/35 or 255/30. Having the wrong size means a number of things:

1) Legally needs to be declared to insurance as a modification
2) Alters the rolling circumference which affect speedo accuracy and gearing slightly.
3) Less width means less mechanical grip.

In your case running tyres to small means the speedo will over-read and you will travel less miles than recorded, however, it is only in the region of 1% so is well within acceptable limits. The width is a minor change also within the range of tyres available for a TT so no real worry.

That leaves item one, to inform your insurance company.

[Bobio]

Thanks for the reply MustangGT. I will have to inform insurance company then. Incidentally, the tyres plate on the car only shows one option for 19" wheels, and from the VIN number the original wheels were 18". Checking speed with GPS it is pretty accurate at 30 mph. Have not checked other speeds yet. Thanks again.