<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:<hr /><font size="1" face="Verdana, Helvetica, sans-serif">Originally posted by Monty0007:
Is there any alteration to the existing alloy wheels (Spacers) or is it a straight tyre swop from 205 to 225's</strong><hr /></blockquote><font size="1" face="Verdana, Helvetica, sans-serif">Spacers fit between the wheel and the hub, so the wheel actually remains unmodified. All this does is push the wheel further out, it does not widen the tyre.
All wheels have a measurement stamped on them somewhere and it will say something like 6J x 16. This is in inches and means the wheel is 6" wide, and 16" in diameter. Tyres are in millimetres e.g. 205. 205 mm is over 8" wide, so in effect you have an 1" of rubber either side of the wheel. This provides a cushioned ride and a certain amount of protection for the wheel. BUT this also means you get a softer ride and spongier responses. If you stuck a 225 tyre on the same wheel, that is another inch of rubber spread across the same 6 inches of wheel = more sponge!
There is a bit of an urban myth that wider tyres makes your car handle better... it provides more grip (in the dry), so you hold the road better, but the actual driving process may not be as pleasant and you get increased tramlining and camber following. It does however look bloody good.
If you go up to an Alfa 17" rim for the GTV, you will find it is 7.5" wide which takes a 225 tyre nicely. UK dealers have an accessories binder which lists all the wheels and which cars they fit. I wanted some 166 alloys for my 156 SW, but went for some 7 x 17" Selespeed style wheels with 215 tyres. Note 147 & 156 alloys do not fit the GTV...
Hope that's a help. Apologies if I'm teaching anyone to suck eggs...