alright folks, what's the opinion on the correct rolling radius/profile etc for a felicia

i've got a set of g60 steels to go on but i can't decide which tyre profile to use on them.. i was thinking 195/45/15 or 195/50/15 both of which are very close to the original rolling radius, i've got a 1300 box in so i've got very short gearing so i was leaning more towards the 50 profile plus they will probably be cheaper...

whatdaya reckon?

Sounds good to me. The approved sizes given in the handbook vary from ~168cm to ~178cm rolling radius on 13" and 14" wheels, so 195/50/15 is a wee bit bigger. However it's almost exactly the same as the 175/70/13s mine had on the front and they were absolutely fine - in fact the speedo was dead on against my GPS all the way up to 70MPH, compared to a slight over-read now I'm on 'proper' 165/70s.

Id go 50s mate although we tried putting 55s on my old mans and they caught the bottom of the spring cup

excellent point ^^ i'd never considered the clearance to the spring cup

I used to have 195/50/15s on mine, much better than the 195/40/16s i have on it now. Ive also noticed that its probably made my car slightly slower having wheels that are smaller than the orginal 14" wheels as the revs seem to rise quicker but i loose mph, for example in second gear at 4k revs id be doing 40mph but now with my smaller wheels at 4k revs id only be doing 35mph, just a random thing lol

I found this site useful when choosing mine

http://www.alloywheels.com/tyrecalc.asp

at the moment i'm running round on the standard 13" alloys which are 165/70/13

in thoery having a smaller rolling size should make the acceleration faster at the expense of top speed, ie the engine is revving more for whatever given speed you are doing, but we are only talking a few per cent at the most.. don't think i will notice the difference with mine though, i've more or less decided to go for the 50 profile tyres because they are far cheaper

at the moment i'm running round on the standard 13" alloys which are 165/70/13

in thoery having a smaller rolling size should make the acceleration faster at the expense of top speed, ie the engine is revving more for whatever given speed you are doing, but we are only talking a few per cent at the most.. don't think i will notice the difference with mine though, i've more or less decided to go for the 50 profile tyres because they are far cheaper

Yeah i think thats the best option, plus the 50s will give you a more comfortable ride, with my 40 profile tyres the ride is very harsh! lol

...in theory having a smaller rolling size should make the acceleration faster at the expense of top speed, ie the engine is revving more for whatever given speed you are doing, but we are only talking a few per cent at the most...

Indeed, and in theory is where that argument stays, since a real tyre on the road isn't circular and it's effective rolling radius depends on so many factors it gets very difficult to even approximate. It wouldn't be impossible even to end up with a smaller effective rolling radius with the larger profile since the sidewalls are more flexible. And that's before we consider that all the dimensions are nominal anyway...