Re: Tyres, aspect ratio

[Steve Spiers <s.spiers@domain.elided>]

You forgot some important points. This is seen easier with smaller cars. If you put bigger
wheels on and then not go for a small enough profile and the overall wheel/tyre is larger,
then you will be gearing up the car. This is quite noticeable expecially if you are racing,
you have to make the odd downshift as the engine cannot pull as well as it did before at a
certian RPM. Also with lowered suspension you should never have a problem with rubbing aslong
as the tyre height is not changed, if it does, then it will usually start to rub. I just
helped out a mate choose the right tyre size for some 15" wheels that he got. The car is a
Fiat Uno Turbo. The stock tyre size 175/60/13. this is quite small. You can safely go to
185/60/13's though. So when putting 15x6.5" wheels on the best tyre size is 195/45/15's (they
do not make 185's and 195's dont rub anyway). We had a look around and found out that
195/45/15's are really expensive. you could buy 50 series 16 or 17 inch tyres cheeper.
Because of this he opted for a set of 195/50/15's, these are under half the price! He said
the extra heigh will probably not be a problem, ~20mm. Well, wrong, he could not even back
out of the driveway without it rubbing. A new set of 195/45/15's were ordered.

Steve

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