I was admiring Lou's lovely wheels below, but how much difference do they actually make to the acceleration? I assume you'd need to really keep to the same wheel size to see any real gain, or are they so much lighter that it doesn't matter if you go up an inch or two in diameter?



Cheers,
Gaz

 

IIRC I think some bright spark worked out that if the wheels were the same weight but two inches more in diameter it would have a 1-2% degradation in performance. (I am sure that's what I read in the wheel forum)
This would equate to the car being 0.14 to 0.28 seconds slower over a quarter mile.
Judge for yourself but the diff = SFA IMHO.

 

Well if you compensate with the profile of the tyre the over all diameter will be the same.
Then if the wheel is same weight then everything should be the same.

If the wheels are lighter then there are benefits all round, handling,acceleration etc.

What you talking about is Unsprung (rotational) weight some say that for every pound that comes of the Unsprung rotational weight its worth 10 pounds of sprung weight on the chassis but i'm not sure on this.
The easy way to explain this is the ligher the wheels the less inertia has to be pushthough/overcome to get moving.
Also Less unsprung weight = more responsive suspension = better traction and handling

see this site

http://victorylibrary.com/mopar/sprung-c.htm

 

The "clever gits" used the reasoning that the bulk of the wheel, and the tyre, would be nearer the outside of the circumference therefore centrifugal forces would make the differences I mentioned above.

Don't look at me... These guys sounded very clever... they used big words and all sorts.

 

he he,

Thanks.

Mine are 17's and weigh in about 13.9 front and 14.5 rear.

Whether they make a big difference to performance i can't tell really! I'm sure they do really - well i keep telling myself that But along with all my mods they are about performance 1st and style 2nd.

Here they are on the J's Racing Super-Taikyu car!

 

Those are one sexy set of wheels.

Anymore piccies please?

Where did you get them from and how much?

 

They are very tidy wheels indeed.

 

yes
very nice wheels indeed, spill the beans

 

Lou got them from Bulletproof IIRC

https://www.s2ki.com/forums/index.ph...=178608&hl=SSR

 

I've been reading up about this recently. Unsprung weight is a different issue I think, and has more bearing on suspension/ handling performance than acceleration, rotational mass is what affects acceleration (and braking). It takes more force to start and stop a wheel with larger rotational inertia. There are lots of websites out there that go into detail about motion physics, this one explains it quite well: http://kosmoi.com/Science/Physics/Me...s/tpecp2.shtml

No idea how much difference it makes, I'm sure it depends a lot on specific wheels/ tyres, but it does make a difference.