RuFFy

Hewwo!

My E60 has the standard 16" rims (225/55/R16 : front & rear) - I avoided the biggers rims because they all came with run-flats. I decided to let my tred-depth wear out before considering a change of rims. In about 6 months they will need a change and because I'm new to the whole idea I've been doing a little early research - it seems there's a lot to consider in every aspect - safety, peformance, economy. In fact all these problems have just scared me off the idea so you now have the task of convincing me it's all going to be worthwhile.

I was looking at some 18" rims with 245/40/R18 tyres - front & rear. This is apparently a good fitment and just keeps the speedometer over-reading instead of under-reading. First question - you guys think this is a good choice?

Secondly, I hear people talking of handling improvements - in what sense? Cornering? Turning sharpness? I notice 16"s are very "spongy" in corners and I have to apply a very significant amount of steering lock to achieve sharp low-speed turns (plenty of those in London) and it gets awfully tiring because the nose just doesn't swing in when you turn it! Same thing with my previous E46, also on 16"s but strangely not on my friends 1.6 FSI Golf, which turns in very sharpley on 16"s. Unless a larger rim/lower profile tyres make a serious difference, I'm not bothering with a change at all.

Thirdly, the inveitable question of what the hell are offsets and spacers? What they are for, when to use, if to use, how to use?

Lastly, I don't mind the comfort compromises required for low-profile tyres - but how significant are they and what differences do they cater for?

Thanks in advanced, appreciate any feedback. I've attached a profile shot of the car, so if any photoshop magicians want to strut their stuff, please do

znod

I think that one is better off to stick with BMW specs. So, for example, on the 545i, you can get in-spec fitaments in 17's, 18's, and 19's. If you go this route, then you go with the work BMW already has done in deciding what is best for your car from an overall perspective. Even though I went with 19's, if I had it to do over again, I probably stick with 18's for the higher profile. The lower the profile the higher the probability of vibrations and damage from potholes with only a minor improvement in looks. If one goes out of spec (e.g., goes bigger than 19's on my car), then he or she better know what's up to minimize the downsides of worse handling, worse braking, etc. And, car's can start looking like my avatar. If you go with the advice you will get here, then you will be going with the advice of amateurs--not pros like those who set the BMW specs. If you want to read about some of the topics you mention, then you might want to go to tirerack.com--which has a fair number of technical "articles" all in one place.