CS Legal Wheel

[xwd]

Originally Posted by Biggins

That is my plan right now, but I'd be open to something from Team Dynamics, 949 Racing, or anything else.

I was looking at older 17x7 OZ Superleggeras from early WRXs that might work with (or without) hubcentric rings, though the offset was still +48.

There was a guy I directed to this site selling an old set of Superleggeras for pretty cheap I would have picked them up if I didn't already have a set of wheels.

[Miniata]

Originally Posted by simpleisbest

Man I wish 949 would come out with a Stock class legal wheel.
I love their dual valve set-up!! Don't ever see it happening though...

The Kosei K1-TS wheels that I have on my BRZ have the dual valve stem setup (just like the 949's I have on my Miata), stock class legal, and very lightweight too, at 14.6 lbs each. I originally had the Kosei wheels on my Forester, but couldn't resist putting them on the BRZ when I got it (along with some new Star Specs)

[ABQautoxer]

Aren't they +50 offset?

BTW why do you all care about the dual stems? Are you actually bothering with nitrogen?

[simpleisbest]

Dual stems are nice especially if you're lazy!

So convenient to adjust tire pressures with a real tire gauge while the compressor is still attached.
I never tried them with nitrogen, so it was just the convenience factor.

The Kosei's sound nice, but +50 offset is a deal breaker for me at this time.
I don't know how wide I will be going for tires once things are all sorted out, so I want to have some flexibility with the extra inside space of a +42.

[ABQautoxer]

Ah. I just over fill them before I run and then bleed out just before my first run and go from there.

I agree, getting closer to 42-45mm just leaving a little more flexibility since I have no fear of running a 3mm spacer later without changing studs. The +50 is of course workable just potentially less flexible and since I'm starting with nothing I might as well get the correct max offset to start with.

[Miniata]

Originally Posted by ABQautoxer

Aren't they +50 offset?

BTW why do you all care about the dual stems? Are you actually bothering with nitrogen?

Yes, they are 50mm offset, same as the even lighter Kosei K4R wheels. They wouldn't be my first choice if buying new for stock or RTR class autocrossing (I'd probably wait for the 42mm offset RPF1), but I already owned them, so that's what I went with for now.

Personally I've never needed/used the dual valve stem feature some of my wheels have had, it just so happened the wheels I wanted to buy had dual valvestems.

[ABQautoxer]

Yeah I had K1-TS on my NB Miata. If I had used ones like you, I would absolutely use them. I don't understand why no +45 for Kosei wheels as they have that on their 17x8s.

[mla163]

Regarding weight of wheels, GRM ran an article comparing times of their STR miata with heavy wheels versus stockish wheels. There was not an appreciable difference in times. Mythbuster's style internet arguments ensued.

The moral of the story is that wheel weight matters, but not as much as you'd think. It's not worth it to spend $1000 to save 1 lb per wheel.

[ABQautoxer]

While I'm sure that's true, I still believe in running a car as light as possible. The wheels are an easy 24lbs, the muffler is 22lbs or so, and perhaps the front bar will net a pound with a hollow 22mm. That's about all we can do so would you pass up a chance to take out half the allowable reductions? Especially when that costs about the same as a catback? Personally I'm trying to offset my choice for a BRZ Limited over an FRS.

[mla163]

Originally Posted by ABQautoxer

While I'm sure that's true, I still believe in running a car as light as possible. The wheels are an easy 24lbs, the muffler is 22lbs or so, and perhaps the front bar will net a pound with a hollow 22mm. That's about all we can do so would you pass up a chance to take out half the allowable reductions? Especially when that costs about the same as a catback? Personally I'm trying to offset my choice for a BRZ Limited over an FRS.

I agree. But I am not planning on spending extra for super lightweight Volks when I can just get lightweight Enkeis.

[ABQautoxer]

Originally Posted by mla163

I agree. But I am not planning on spending extra for super lightweight Volks when I can just get lightweight Enkeis.

Agreed, otherwise I would have some CCWs made.

[dsgerbc]

Originally Posted by mla163

Regarding weight of wheels, GRM ran an article comparing times of their STR miata with heavy wheels versus stockish wheels. There was not an appreciable difference in times. Mythbuster's style internet arguments ensued.

The moral of the story is that wheel weight matters, but not as much as you'd think. It's not worth it to spend $1000 to save 1 lb per wheel.

A wheel could be heavier than OEM but have lower moment inertia. And that's what matters the most in wheel's effects on acceleration.

[mla163]

Originally Posted by dsgerbc

A wheel could be heavier than OEM but have lower moment inertia. And that's what matters the most in wheel's effects on acceleration.

:hug:

I love that I'm not the only person that knows this. I wish that manufacturer's would list this in their specs. I'd love to see a comparo that addressed it. Low weight means nothing if the polar moment of inertia is high. And the biggest contributor to this is the tires.

For the non-engineers:
It is easier to accelerate or decelerate a wheel if the mass is closer to the axle than if the weight is further out. The physics 101 example is how figure skaters pull their arms in to spin faster. A 5 lb wheel with a 45 lb tire will be significantly slower than a 25 lb wheel with a 25 lb tire. Tire weight matters more than wheel weight. Another reason to shave tires.

[xwd]

That topic almost always comes up in wheel weight discussions. In this context we are talking about a wheel which has the exact same size as the stock wheels. As for where the weight lies that's usually a little hard to calculate and when you are talking about a bunch of lightweight wheels which differ by 1-3lbs I don't think there is really a whole lot of difference. Most of the construction is very similar at least in a single piece wheel.

The weight of the wheel also has an effect on suspension performance as well, and autocross lots are not always smooth like a race track.

The strength of the wheel can be an issue too if the wheel flexes.

I don't think you can go wrong with a set of RPF1s though, they are plenty strong, lightweight, and relatively cheap.

Nobody in this thread is spending $2500 on a set of custom 17x7 Volks. I spent $1K for a set of 12.5lb rims and that's the absolute limit of what I was ready to spend.