If you replace the standard 17's for lightweight wheels you can reduce unsprung mass. So for example, reduce the front wheels weight by 3KG and rears by 5KG that's 8KG, i read 1KG of unsprung is equivalent to 10KG of sprung mass so 80KGS! sprung mass!.

That's easily enough to make a difference of 0.1 in a 1/4mile of a mile.

I read however on tests they made little difference to acceleration but helping breaking and the suspension working.

What do folk think?

Initially you believe they will help acceleration but it appears not the more you look into it.

 

didn't time this but i felt the difference after RE30 installation.
not night and day of course....

 

Hi, Grassroots Motor Sports did a study 1or 2 years ago that showed the difference was so small is was not possible to measure any improvement consistantly. G to their web site and get all the details.

Bill

 

It's not even close to 10:1, maybe 3:1 on the driven wheels.

The difference could be detected, particularly on a low torque car, but you have to control a number of other variables. You would want to measure acceleration in a given gear. Launching introduces far too much variability. Varying shift times could skew measurements also.

Variations in IATs are prob more significant.

 

for non boosted car IAT is not significant.

 

So ignition timing is the same for IAT= 60, 100, or 140 degrees on a non-boosted car? I'm going to have to go ahead and disagree.

 

I'm also going to disagree with this as well. Car's run significantly better with cool air, in both N/A and boosted applications.

Lightweight wheels are well within driver noise. I highly doubt seat of the pants can truely notice lightweight wheels, if anything its just your imagination justifying the extra cost.

 

Considering the higher the weight is further out on the rim making more of a difference than weight on the inside, youd probably be better off getting slightly heavier or equal weight larger diameter wheels and put lighter tires on and produce better results

 

exactly as with lightweight wheels - the question is how much performance is improved in practice - i personally never felt a difference between 15c and 30c...

 

As far as acceleration, I can't tell a difference between my FN01R's and my CE28's, but I can definitely tell a difference in bump rebound, the chassis get's noticeably less upset by road imperfections with the lighter CE's.