18's or 17's on a 90 525i with m20 concerns

[bigmuthatrucker]

I love my car.. and have been thinking about some bigger wheels.. However The m20 is not the most powerful engine in the world not that I am complaining but with the bigger wheels shouldnt there be some acceleration issues.. does anyone have an m20 with bigger wheels.. How much of difference is there speed etc.. I would like to put some 17's either style 5's throwing stars or M-par's
cheers
jim

[Qube]

Hmmm... grab some style 5s, then shark it to give it some more push off the line ;)

[Rus]

Acceleration issues will result if two things change. The first is the actual mass of the new wheels. Heavier wheels mean that you will experience a decrease in acceleration. The second factor is the actual circumference of the tires. If the circumference remains the same, you'll only have to worry about rim/tire weight. This factor will also affect the accuracy of your speedometer. HTH

[SC David]

When I got the Style 5's on my car I immediately noticed that because of the increased mass, the car had to put in extra effort to accelerate and decelerate, so be prepared for that. I'd say it's about where it was speed wise before I put the chip in, but it now corners even better than before with the narrower side walls of the tires.

[nizmainiac]

get some o.z superleggeras they only weigh 4.2 kg a wheel

[bigmuthatrucker]

hummm so basically as long as the wheels have the same total weight I be ok.. right.. Also Qube what does shark it mean? Does that mean add a chip?
thanks
jim

[Michael999]

Anyone with an M30 got a comment on the big rim decreased acceleration, ive only actually noticed the comment made by M50 owners.

Oh, and bigmuthatrucker id you get thinner tyres with the larger rims and keep the outside circumference the same then your speedo will not be affected just as Rus stated.

[nizmainiac]

its called rolling radius or rolling circumference, but all the same size tyres don't always have the same radius

[DanDombrowski]

http://www.bimmer.info/forum/showthread.php?p=71399#poststop

You can read that for a lengthy discussion on wheel diameters and wheel weights.

[ILoveMPower]

I have an M30, and yes of course the wheel upgrade was noticeable, but the smaller sidewalls gave me a tighter ride and I'm happy with the results.

[pundit]

Mine originally came with the standard 15" basketweaves and Bridgestone Turanza tyres.
Now it has factory 17' x 8" 'T' Stars and newly fitted Michelin Pilot Preceda PP2's (235/45/ZR 17"s).
The standard basketweaves are actually a fairly lightweight wheel and almost any aftermarket wheel will likely weigh more.
The 'T' Stars while being forged and relatively light (about 21lbs I think) still weigh more that standard basketweaves... I might actually do a weight comparison.
As far as acceleration between the two compares, I can't say I noticed any difference but a heavier wheel will take longer to accelerate and brake.

[shanek]

I have stock basketweaves for winter and 17" BBS RS for summer and I can't tell the difference in acceleration.