Got an email with the following blurb in it - are these statements true?

"Loosing 1kg of rotational weight (ie wheel weight) is the straightline performance equivalent to removing 10kg from your car"
3 facts about lightweight wheels:

A lightweight wheel doesn't simply increase straightline performance, when you hit the bumps and twisties they come into their own.

A lighter wheel is much more eager to change direction.

Less unsprung weight means that your suspension won't have to try and control 25kg of wheel and tyre bouncing around in the arch.

Yup.

there is a formula which proves it.

MR2 turbo guys reckon fitting ultra lightweight wheels is like having a boost upgrade.

Its why proper lightweight wheels are expensive. My TOM's VP-8's are 11kgs each.....normally 19's are 16/16.5 kgs

Hmmm, interesting Dave. Thanks for the feedback.

So all those folks sticking upgrading and sticking bigger (non lightweight) rims on their cars are actually going to end up with a slower car that doesn't handle as well as it should?

in a word yes

Funnily enough, I asked a question a while back regarding this but I don't think anyone had ever tested it. I'd wondered how much the Mk1 GS300 18" Sport alloys (10" wide ones on the rear) effected accelleration compared to the standard 17" rims. It might explain why initial pickup off the line seemed a tad dull.

whole thing is logical if you think about it.

its unsprung weight.

like running with a rucksack with 20kgs or 40kgs your initial take off will be quicker with the lighter one............

same thing on big brake kits............OEM are cast iron BBK are alloy weight 1/2 as much.................

Interesting find here maneesh, I never considered them as I thought its only a few KG (on a LEX), but with a multiplyer of 8 or 10, it may be worth it.

Worth doing some more research into this area, does the same apply to Lightweight wheel nuts and brake discs? my 3G (Brembos) weigh a load.

lightweight brake discs (carbon fibre) cost an arm and two legs..............

on lightweight wheel nuts ...some race series do not allow them

How do lightweight stack up against OEM when you hit a pothole?

yeah ive heard from lots of friends that it makes a real difference having lightweight wheels. its just the price tag with them!! there not cheap!

i know it makes a difference with larger wheels. i bought a set of larger wheels for my crx and it slowed it down loads!!

and im sure hitting a pothole with lightweight wheels, they will buckle easier than they would with oem wheels.

That's not necessarily true either. My Rays Volks alloys are lightweight. The rims are rolled from a single billet and therefore doesn't have any welds and the centres are forged to shape, not machined, Both features provide additional strength with a lightweight design. Also with the rims being 19" diameter reduces the required tyre profile to maintain the same rolling radius, so a lot less rubber in the tyre which is the heaviest component. Makes hell of a difference.
The IS350 OEM calipers are also aluminium and lighter than the OEM 250 calipers...just the bigger 350 cast iron discs adding additional unsprung weight....but can live with that rather than part with a few thousand quid for carbon disks.

I thought about this when i picked up a 3G disc and OEM caliper (didn't realise each disc can weigh that much!!), i thought to myself, the amount of weight just at the wheel must be stupid heavy and unnecessary...mmm wonder what racing harts rs 721's weigh? lol (not like i can can afford them)