Will Hamann 18s Make My Car Slower?

[ArcaneParadise]

I was thinking about getting Hamann HM2 18s on my car. First of all, does anyone know how much they weigh compared to stock M3 wheels (not contours). (The ones in my sig.). Also, since they have a larger diameter, does that make my car slower, or even feel slower?

[///M3ryder NY]

The larger diameter doesn't matter, as long as you run a tire size that compensates for that increase in diameter. There is a good tool somewhere on the net, which makes calculating diameters of differing tires sizes very easy. Basically if you run a 225/40/18 up front, you'll be very close to stock diameter up front. In the rear, a 245/35/18 is almost exact as well. Many people run a slightly larger diameter though, and I've never really heard anyone complain all that much. We're talking 10ths of a second at best I would think.

What you lose down low, will be gained on top end though. Also, your speedo will be slightly off with a larger diameter. What is of more significance, IMHO, is how much more weight you gain at each corner. That will affect the speed of the car more than anything i believe.

[extremeM3]

Yeah u wont feel anything noticable.... PM quest330is about it. He is running 18's and was recently @ the track. I am sure he can tell you what the story is.

[Zoso]

I'd have to disagree... If I remember my findings from a few years ago the Hamann HM2s are some heavy rims. I think you'll feel the extra rotating weight... maybe just slightly on the butt dyno. If you had been neck and neck racing a friend, you'd probably be losing 2 of 3 times to him now.

I ended up going with BBS RCs. They are lighter than stock and very strong. I put 245/35/18s on all four corners with my stock suspension. No rubbing anywhere. It may have been my imagination but the car felt a bit peppier and lighter.

[///M3ryder NY]

zoso, how do you like the 245 toyos though? Good tires? That size is odd, and there aren't many offerings. What offset are the RCs that they allow that fitment?

[mmmvious]

That size is odd - I believe the Toyo's, Pirelli PZero Rosso's, and Goodyear Eagle F1 GS-D3's are the only tires in that size (245/35/18) -

I run the Goodyear's and love them!

(Don't know if that helps - but figured I'd chime in - )

[mmmvious]

By the way -
the offset on the RCs should be et 38

Most of BBS's wheels in the 5x120 pattern (BMW fitment) are that offset - (the cast wheels anyway - RC, CH, RS2, etc)

[Croak]

24.71 inch diameter on 245/40/17

24.97 inch diameter on 225/45/17

24.75 inch diameter on 245/35/18

24.20 inch diameter on 225/35/18

Any extra weight is unsprung, and pushed out further from the center of rotation with 18's, which isn't a good thing especially if the 18's are heavier than the 17's they replace.

Any diameter increase of the rear wheels will act as taller gearing, reducing your accelleration a bit, but giving you a bit higher top speed in every gear.

225's will give you less meat in the rear, reducing traction a bit as well.

And finally, with 225/35/18's you'll have a 78mm sidewall, with 245/35 you'll have an 84.75mm, vs your current 101.25mm front and 98mm rear. That's going to make your ride noticably more harsh, there's 20 to 23mm less rubber to absorb impacts, but the upside to that is less possible sidewall flex in hard cornering.

In my opinion "plus sizing" 18's or larger on an E36 M3 is mostly bling, since the performance tradeoffs are almost all negative. That's not always the case, lightweight wheels can offset or negate the unsprung weight issue, and going with wider (instead of plus sizing) rubber can get you some handling benefits that may justify the reduced quickness.

[Armo95]

Croak,

I'm going to FI myself:) I thought I could resist the temptation, but I couldn't :( Talk to you later man...

[Drea///M3]

I agree whole-heartedly with Croak...He hit all the main points.

[BSH]

other members haven't really noticed a performance difference with a heavier/lighter wheel, as long as you keep the same overall diameter.

[technom3]

I hate to chime in but, I have noticed a huge difference between in both of my cars from switching from a heavy wheel to a light wheel. Wheel weight affects so many different things (already mentioned in this Thread) The advantages of a light wheel are worth the extra cost! Trust me! I like to think of the wheels almost like 4 flywheels, but with slightly more importance because they effect ride and handling. Anyways, thats my take on it.