Nora wrote: Sat Sep 22, 2018 12:27 pm
If anyone with a new Gti has the 18 inch brescias, could they do me a favour and measure the diameter of the wheel inc tyre.
As I want to look at how they compare in Diameter with my current wheels and tyres on the 6R, and as I have a full set of winter tyres on steel rims for the 6R, I’m looking as a temporary measure and using those while I detail, prep and seal the new brescias rims with a ceramic coating in the initial weeks of ownership
625mm, tread to tread on the shoulders, there'll be a few extra mm at the centre due to the shoulder taper at the edge I measured. The Wheel is 215/40 R18, so you can work out the diameter pretty easily:-
215/40 is tread width and ratio of width to sidewall height. 40% of 215 = 86mm (the tyre sidewall height), 18" wheel has the diameter of 457.2mm. Calculated Diameter is (2x86mm) + 457.2 = 629.2mm
If you're going 215/45 R17, diameter should be 625.3mm
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If you go 195/50/R16 (a common VW Winter wheel size) then you end up with 601.4mm diameter, effectively 4% less rolling circumference. From my measurements on caliper clearance for the GTI/GTI+, you should be looking for at least an offest of ET40 for caliper clearance. I have been looking for a bargain on the 16" Merano wheels, but everywhere is selling them full bat or close to it.