I know man....I'm in agreement that a good driver in a average car can beat a poor driver in a good car.....I've beaten STi's and Evos at autocrosses, and a lightly-modded 3rd gen has beaten me (gabe is an awesome autocross driver)...

What I'm saying is that heavy wheels make a HUUUUUGGGEEE difference in handling ability. I autocrossed once on my 18's (which weigh 25lbs) and the car handled poorly and not responsively, as compared to the 17's (which weigh about 16lbs).

Most people talk about making their cars lighter to perform better....but what they DON'T realize is that unsprung weight (wheels/tires/rotors/calipers/hubs/spindles) has a much greater effect on handling than sprung weight (the rest of the car above the springs) does.

The correlation is that a reduction of 1 lb of unsprung weight is equal to 7 lbs of sprung weight...and it works inversely as well.

For example, if you were to replace your stock wheels (about 25lbs) with 20s that weigh 30 lbs (+5 unsprung lbs per corner) it is like adding 140 lbs to the car itself...to say nothing of the rotational mass moving outward on the rim/tire assembly.

Now I realize that you're not putting 20s on for performance, but the way you phrased it made it seem that you have an expectation of better handling by using a 40-series tire on the 20s for some reason.

My autocross tires are 45-series and they handle a hellovalot better than my 40-series street tires

As to coilovers...I don't feel that they give a performance advantage over certain spring/strut combos, depending on spring rate. Hell, one of the fastest maximas I've autocrossed against came within 1/2 a second of me running on STOCK springs/struts....

the lesson is that that spring/strut or coilover assembly plays a limited role in overall handling - it can help (if dialed in correctly) or hurt (if you're too low you cause bump steer and poor LCA angles, incorrect spring rates, etc etc).

overall....I'm at home on a Friday night....and......


you know I'm just giving you a hard time anyhow.

 

^^^^ i agree, and i know that 20s are in now way sport wheels, im just trying to speak up for us 6th gens, some times, we get treated like the ugly ducky of the family and thats not cool
allright its all good now

 

Hehe.

 

That's interesting, can you explain why the 45's handle better?

I noticed that on the new G35, even though they have wider rubber in the rears, they are 45's in the rear and 50's in the front. I was thinking that's rather a tall sidewall for nowadays. The 330i's got 35's in the back. I also wonder why the G35's rim resemble FWD while the 330's are quite deep dish. Nobody's been able to explain that thus far. Thx.

 

Well, the sidewall is actually the about same height, but since the aspect ratio is section height/section width, they have to reduce it a bit to compensate for the wider tires in the rear.

For example:
225/50 will have a section height of 225*.50 = 113mm.
245/45 will be 245*.45 = 110mm.
If they had used a 245/50 then the section width would be 123mm and the rear tires would have a noticeably larger rolling radius than the fronts.

Irish's 45 series tires handle better because they're mounted on much lighter wheels (FN01R-Cs, right?), probably have stiffer sidewalls (even if they're taller sidewalls), more absolute grip, and better behavior in general, just from the properties of the tire itself as compared to the all-seasons he probably has on his street rims.

 

Frank Fontaine....Morpheus said exactly what I would have said, so just read his post again! Damn that is a well-informed post

My track wheels are shaved to 4/32" as well

 

Why thank you.

But shaving wheels must be a new trend, never heard of it before...

 

doh!

um...yeah shaving wheels means I filed off the "5Zigen" logo to save 0.000002 ounces of rotational mass.



NOT.

To the rest of you....I meant shaved tires

 

Haha. I'd have a hard time shaving half of the tread off of any tires that I bought, even if it makes them less squirmy. You should have at least got them normally and then burned it off.