Lightweight wheels

[Matty]

Is there a benefit of fitting lighter wheels like OZ superleggeras to a car?

From my cycling background I understand and rotational weight saving is worth twice as much as any sprung weight saving. Theory is it is a lot easier to pedal a lighter wheel up a hill.

Not sure if on a car it works the same. Does it accelerate better as in cycling? Would it help suspension work better through having a lesser weight to move up and down?

Like the superleggeras and would fit them if 15s came in gold to give a Williamsesque look and if there was a benefit to be had.

Another question, I believe smaller wheels, i.e. 15s to be better for handling, as dont the championship cars run them also. Bigger is heavier and just for looks? 15" tyres are cheaper too....

Any thoughts? Beats talking about Induction kits!!!!!

 

[orlandopaulo]

15" superleggeras and 15"tyres are less expensive, more lighter..

But wheigt and suspension.. suspension will be more effective.. when car "jumps", a lighter wheel will go back to the ground faster.. Total weight will be less, but a bit different from cycling.. a change of 1 kg on a 13kg bycicle is a big difference, and off couse a lighter car even with less 20kg, is a lighter car, but if it weights 1110kg the difference wont be big..

A friend of mine that works on ibizas tdis, says that removing 5kgs on each weel is "faster" that a car that takes off 20Kgs of other car parts.. He has tryed it and says it is better to get a lighter weel, than a lighter car (in the same proportion, off course)

If I were you i would buy 15"superleggeras..and "throw away" my spare tyre.. that less 17kgs.. 20+17=37kgs..

Orlando Pereira

 

[Fred@BTM]

Ive got 17inch superLs and the tyre (205/40) weighs more than the wheel!!!!

 

[SoLow]

My super Ls wiegh less than the origional alloys/tyres that came with the car. It does make a difference the weight of the wheel. I tried some OZ titans on b4 the super ls and the car felt alot more sluggish!

Go on a set of 15s with 195/45/15 and slam it on the floor and it will handle liek a dream and accelerate better!(but look crap imho)

 

[Captain Slarty]

Acceleration is about power to weight.. it DOESNT MATTER where that weight is proportioned, or indeed removed from. (apart from overall weight distribution !)

HANDLING - or more precicely, the ability for the suspension to track and follow movement IS proportional to unsprung weight.

Lighter wheels enable the suspension to work in a more effective way.

there ya go.

Joe.

 

[maciek]

disagree with you slarty... it does matter

rotational weight is more important to acceleration than the mass of any other points...

its like orlando said... "He has tryed it and says it is better to get a lighter weel, than a lighter car (in the same proportion, off course)"

you should try it youreslf, then you would belive...

 

[Captain Slarty]

No probs, disagree away

I have tried it MANY time m8... it makes sod all difference in the great scheme of things. However, the benefit to suspension control is definite. (unless some muppet then adds uprated shocks to remove any benefit lol !)

Moving a few pounds off the flywheel is one thing, doing the same to the wheels is another, there is an effect, however it is of nowhere near the same benefit or quantifiable gain.

Mathematically, Yes, there is bound to be a benefit by reducing rotational mass, but you wouldnt feel it unless you went from lumpy great steels to super lightweight mags. What you WOULD get is better grip / traction, that, would almost certainly be noticable.. even then the gains diminish with modern suspension design where a responsive setup and reasonably light weight mass is already there.

So, yes it helps, but not for that reason specifically.

Which then brings up the question.. whay do most talk about tyres as tyre x is better grip than tyre y etc.. when one of the main factors should be.. most are simlar in grip, but tyre z actually weighs less lol !!.

Joe.

 

[RSTDL]

I agree with slarty - had 17s and 16s and 15s on my old 1600 16v - tested them all - no noticable diifernce - only differnce in 15s and 17s was the roll and grip factor. Power to weight means just that - how do u expect a car with supposedly lighter rims to go quicker than a car thats stripped out inside?????? The car with oh so lighter rims is still carrying the same weight!!!!???? Nuff said.

 

[RSTDL]

Maybe Renault or Ford or VW should go back to 14 inch steel rims to help performance......lol - I think not

 

[maciek]

"Moving a few pounds off the flywheel is one thing, doing the same to the wheels is another"

i never insisted that removing 2 kgs per wheel will make your car go madly quicker.

but removing weight from wheels is closer to shaving flywheel than to removing carpet in your boot and like orlandos friend said - 20 kgs off the boot does not equal to 20 kgs, of the wheels (hubs, rotors, discs ) thats all.

do u expect a car with supposedly lighter rims to go quicker than a car thats stripped out inside??????

if the weight diff is the same: i do exepct this...

 

[Tom]

unsprung weight reduction improves something but i cant remember

maybe capn will appear and tell us

 

[maciek]

he already said it - susp. performs better...

 

[Nick Read]

well all I know is that going from fairly light factory 15s to bloody great heavy 18s made a very noticeable difference in terms of acceleration off the line. The tyres do grip better down to the extra width even though they are a lower profile and dont really squash much at all. Anyway to get back to the wheels, my impression is that on 15s its a lot easier to spin up the wheels, once they bite then you can make some pretty rapid progress. 18s do definitely seem to take longer to get off the line and are harder to spin up, but once youre rolling theres not really a lot in it, say from 20mph onwards.

In fact strangely enough, my 60ft times (when Im quarter miling) were better on 18s than 15s, and it wasnt some freak result, I tried again and again to make sure. Probably its easier to get the power down on the big wheels. But the final 1/4 mile time and speed at the line were significantly better on the 15s even with the slower start.

Make of that what you will, but I had heard that if you are gonna ditch some weight, the wheels are the best place to do it. Seems to make sense.