tyre width vs performance

[bigman_10]

i was thinking about this the other day as my mate bought some new hoops for his audi a2. he did have standard 185 tyres before and now his upgraded to 205s. then we started a debate about how they'd effect his performance. and we both agreed that it'd corner faster, reduce the mpg, and reduce the top speed because of the rolling resistance but i wasn't sure about the acceleration? i was thinking about drag cars and then the wider the better but i doubt that'd matter on his 1.4 tdi (even if his remap claims 125bhp). so basically how badly does tyre width control things and are they really noticeable?

chris

[Horney]

Percentage wise it's very small. Rolling radius makes more of a difference.

Nick

[cняis]

i'd imagine that drag cars have wider tyres to put more power down on the road.

what does affect acceleration is the profile of the tyre, i.e. how big the sidewall is in relation to the wheel diameter. drag cars have higher profile tyres 

[mk2mark]

Basically wider tyres just change the shape of the contact patch. Instead of long and narrow you'll have a more square shaped contact patch. Which is good for aquaplaning amongst other things, so try and get good tyres. Answers: http://www.carbibles.com/tyre_bible.html

[Uruk Hai]

If you go too wide on a rim then it can make the car handle worse than the standard set up.