Wheel width VS wheel weight

[Artyracer]

So heres my dilema. I'm building a 92 s13HB to run in autocross. Class restrictions state that I'm limited to a 7.5" wide wheel and a 225 wide tire. I've narrowed it down to a few styles, I'm just not sure which way to go.

Option 1: Rota RB's 17x7.5 with a +20 offset. Exact weight is unknown, but roughly 18-19 pounds.Option 2: Centerline forged 17x7 with a +40 offset and 15mm wheel spacers to give me a +25 offset. And the centerlines weigh just under 15 pounds, and under $500.Cost wise, (after buying the spacers) they would both end up within a few dollars of each other. Either way I go, they will end up with Kumho Ecsta XS 225/45/17 tires on them.

What would I be giving up by going with a slightly smaller yet lighter rim? What would I gain by going with a slightly heavier yet wider rim? Or is it so close at this point that any gains or losses would be minimal?

[evildky]

centerline at last check will make the wheel to your offsset so you won't need spacers

the extra half an inch of wheel is not a substantial gain, ans the weight well that depends on your car, if you are running a stock low hp car then weight can be a huge factor, if you are running a high hp modified car the weight becomes less relevant

[Artyracer]

ThanksFound out the wieght on the Rotas are just a hair shy of 20lbs. The Centerlines should be here by the end of next week.

[crackler]

if you are running a high hp modified car the weight becomes less relevant

That is true for rotating mass, but not usprung weight.

[Cone Junky]

Sportscar (SCCA magazine or the Tire rack newsletter just recently tested the "light" wheel theory. The weight savings of a ligtweight wheel only gained 100ths of second on an auto-x course.So basically a wider wheel should give you more gains than a lighter wheel. Even if the tires are the same size, there is an advantage of the tire sitting more squarely on a wider wheel.

I was definitely glad to read this, especially since "light" wheels tend to be way more expensive.

[evildky]

That is true for rotating mass, but not usprung weight.

sure it is, you just need more power, my old miata with some generic 17 lb wheels really felt the lag of the added weight, when I swapped my 30 15x7 keizers (weight includes tire) for some 50 lb 17x12 CCW's (also includes tire, there was no noticible drag or power loss, if course we're talking about a 2100 lb car taht was putting 300 hp to the wheels