im replacing the 4 tyres again on my car, usually go for 205/45/17's as thats what was on it when i got it, whats the pros/cons on the slightly smaller rolling radius bu fitting 205/40/17?? lower top speed, better acceleration? will i notice any difference? will it still be ok on my car?

also what difference would fitting the slightly wider 215 make?

cheers rory

my car is a 97 uk turbo btw with twin 6 spoke techno mag wheels.

 

I'd stick to standard, i.e. 205/45/17 or 215/40/17 (which is roughly equivalent rolling radius)

I don't think you'll notice the extra 10mm if you go for 215/40/17.

If you fit other sizes your speedo will be out.

Most people fit 215/40/17 instead of 205/45/17 as they are more widely available (Toyo, Goodyear, etc.)

 

What about 215/45/17 ?
That is what I have on my '00 classic (came with wheels I fitted recently )
Would this affect gearing or speedo reading ?
I have not felt any rubbing and they look and feel "right"
Any thoughts ?
Al.

 

go for 215/40/17 had them on my classic and they felt great! the stiffer sidewall makes the car more precise

 

Compared to your original 205/50/16, you will find 215/45/17 have a circumference which is 2.3% larger and when speedo reads 70 mph you are really doing 71.6 mph.
The effect is to lengthen the gearing slightly - you will have poorer acceleration but higher top speed in theory.

205/45/17 are only 0.8% bigger and 215/40/17 are 1.2 % smaller so are a closer match to the original.

There are various calculator tools on the web you can work this out with.

I would have the 205/45/17 if possible, but since I'm using 7.5" wide rims I have 215/40/17 as 205 are not wide enough.

 

i got the same dilema at the moment
i have 17x7.5" rims so will fit 215's
but after just waving goodbye to 2 eagle f1's last night ,im tempted to up from the 40 profile to 45 and get something with a stiffer sidewall.

am i likely to get any rubbing or any other problems ??

 

But bear in mind that the speedo is already reading high by several percent (e.g. showing 74 on the dial at a true 70), so a few percent more won't help at all...

 

You will probably get away with it. But you run more of a risk the more things from standard you vary. You have gone for wider rims, a wider tyre and are now thinking of a taller tyre too. You can only push it so far without problems. I expect the decider will be how far off the original wheels the offset is. If it is very similar you might be OK. If it is a bit out too you may get a little rubbing.

The only real way to know is to find someone with your exact wheels and tyres on a similar car.