RotaryZZ

So seems like the SSR Competition is one of the lightest straight replacements for our OEM rims!

ZoomZoomH

iTrader: (1)

SSR Comps has always been a favorite of track drivers/club racers :D

RotaryZZ

Is the SSR Competition forged? And does it have the same offset as our OEM which is 50mm, I believe.

How much do they cost btw??

Matt RX8

I bought SSR GT2 to save money. They are 16.8 lbs and currently cost $339 on closeout at Tirerack. Offset is like 48 or 50 MM. Perfect fit for the RX-8.

SSR Comps are16.3 lbs in the stock size but cost closer to $500 each...

RotaryZZ

For a little over $300 for a brand name forged wheel, I think its a pretty good deal!

olddragger

iTrader: (3)

dont forget the Enkei rpf 1 wheels! I have the 18x8 with a 35 offset(little wider stance--no problems) and they weight 17.5 lbs apiece. Stock wheel is much heavier. I picked one up in the right hand and one of the enkeis up in the left hand. No comparsion the stock is much heavier.
And there is a noticible performance differance with the lighter wheel. Acceleration, braking and suspenion reaction.
olddragger

124Spider

RA-1s are excellent track tires, with long lives. And, for dry days, used or shaved is even better than new, unshaved.

Wheels which are a very few pounds lighter are not a particularly cost-effective mod, if all you're doing is lapping, where a few tenths is not important. You'll spend close to $2000 for a new set of light, forged wheels, and gain very little actual benefit. If you're racing, where a few tenths make a difference, or if you're a top-level autocrosser (and the aftermarket wheels are stock-legal), it makes sense, but, unless you have lots of money to throw around, or are more into bling than performance, the stock wheels are good enough for a long time.

Matt RX8

I disagree. For a little over $1200 you can get wheels that are nearly 6 pounds lighter than stock. That is a huge unsprung weight difference which creates noticeable performance gains. Furthermore, most people need an extra set of rims anyway to run snow tires which would cost at least $600 anyway so you are only talking about another $600.

And if you are running R comps, you are going to need an extra set of wheels anyway.

moRotorMotor

I got something here that is lighter than the SSR comps. Click here.

ULLLOSE

iTrader: (1)

It could be both. There are two vendors for the OE wheel to Mazda. Hitachi and U-Mold have both made the wheels in the past. This is normal, same thing happen on the Corvette years ago, when one company could not keep up a 2nd was contracted to build them also. Bonus was the second company built the "same" wheel a 1/2lb lighter.

Read this thread: https://www.rx8club.com/series-i-wheels-tires-brakes-suspension-55/stock-wheel-weight-56858/

124Spider

Sure, you need extra wheels for a variety of purposes (I have four extra sets of wheels for my car--snow tires; wet track tires; dry track tires; autocross tires), but all those are used OEM wheels, which cost a fraction of what new, lighter wheels cost.

If you have the money for brand new aftermarket wheels at $1200 a set or more, fine. But if autocross is in your future, keep in mind that there are stringent requirements for what aftermarket wheels qualify as stock.

And I don't agree that even 6 pounds lighter is "huge" in terms of absolute performance (especially if the lighter wheels are 17" wheels, which just adds to the weight of the tires you will need). Given that you can get a used set of OEM wheels for like $300, spending an extra $900 or more is a "huge" difference (especially when multiplied by several times, depending on how many sets of wheels you have). To me, it's all about how much a few tenths (or bling) are worth to you. Since I don't race on the track, and I'm not a particularly good autocrosser yet, used stock wheels work great for me.

Matt RX8

Your argument doesn't make any sense. You are comparing prices between USED OEM wheels and NEW aftermarket rims. If I wanted USED rims I could have bought USED rims for half the price. I think you are underestimating the price of used OEM wheels as well and ignoring shipping costs, etc..

The new rims I'm referring to are 18's and I'm running the stock tires for a few more track days. And as far as stringent requirements for autocross, the SCCA only requires that you keep the same size and width (18x8" in this case). So if I want to run in BS stock I could.

124Spider

This isn't really a big deal, obviously. All I'm saying is that it's more a matter of personal preference/size of pocketbook than of "huge" performance gains.

Of course I am. I'm merely saying that for $300, you can get a used set of OEM wheels. Add another $100 or so for shipping (you have to pay shipping when buying new, also). But that's precisely my point. Some of us don't have unlimited budgets for these things, and saving $500 or more per set of wheels is a lot of money, especially when multiplied by multiple sets of wheels. And all I'm talking about is wheels for function; if you're after appearance, that's another topic.
I've seen them for sale for $300 here. But, whatever, you admitted above that used OEM wheels will cost half of what new wheels cost (and I think you're overestimating the cost of OEM wheels). That's still a large saving.

And offsets very close to stock. I never said aftermarket wheels weren't stock legal; I only said that one has to be careful.

Again, all I'm saying is that if a few tenths, either on the track or on an autocross course (or, ugh, on a drag strip) are worth $500 or more per set of wheels, go for it, but that's all you'll get out of the weight saving. As I understand it, each pound of unsprung weight is worth two pounds of sprung weight (obviously a simplification, since weight on the outside of a wheel is much more burdensome than weight at the center of a wheel); if that's true, losing 25 pounds from wheels is like losing 50 pounds off the body, or a few gallons of gas. Not a big deal, unless you're a pro.

DARKMAZ8

I think a significantly lighter wheel will put less stress on the drivetrain in general. When your racing, you are stressing your transmission more often and lighter wheels and a light flywheel should help in the reliability department.

Matt RX8

I've seen the equation as being more like 4 lbs to 1 (sprung vs. unsprung) and as high as 10:1.

You are also neglecting the fact that the car will recover and regain it's composure much quicker after hitting bumps on the track and will handle much better in general with the lighter wheels. The car will also stop easier without the added rotational mass.

And even if the difference is a few tenths of a second (I still argue that it will be more), a few tenths of a seconds can be a huge difference in an autocross or a time attack. I will be racing this car so I will appreciate the gains.

You should research the issue of wheel weight more. You can find some intelligent discussion in here:
https://www.rx8club.com/showthread.p...M+wheel+weight
I suggest reading some of the articles pointed out by crossbow below. And if you have anything else to say on the matter, why not post in that thread rather than highjack this one.

crossbow

Don't forget as well...nobody said you had to buy expensive forged 18 lightweight rims...

17's will fit the MTX 8's...which provide a substaintal cost savings in both the tire and wheel selections. A set of koseii 17x8's weigh aproximately 15.4 lbs, and cost about 240 USD at tirerack... (+48 offset I believe)

Yes they are cast wheels, but they would be utterly fantastic for DE's, track events, and autocrossing in a non stock class. Actually correction...the new kosei's are supposedly using a new casting method which is significantly stronger then a standard process.

This is of course further ignoring the drop in cost of 17 inch tires vs 18's, and the advantages of smaller diameter wheels.

124Spider

No comment.

Ignoring the fact that the suspension is tuned to the stock wheels, I agree with this.

As I said, if you're racing, and/or if you're rich, the small actual time benefit may be worth it to you. Few of us race, and many of us aren't rich. I was just pointing out the high cost of a small benefit.

Interesting; the first link I looked at said that the ratio is about 1.5:1.

Yes, Daddy.

Matt RX8

You should go be troll in this thread https://www.rx8club.com/rx-8-multimedia-photo-gallery-6/new-wheels-73364/

This guy just posted pics of his nice 18" lightweight wheels. You could go in there and **** all over them and make yourself feel better.

124Spider

Gee, let's review the bidding here.

This thread started in March with a simple question. The question was answered in various ways, and the thread died.

You resurrected it a week or so ago.

It quickly morphed into a discussion about light wheels.

Someone, not you, expressed the opinion that light wheels are a very great benefit. I merely demurred, in a simple, non-conforntational post.Had you not declared war at that point, that would have been the end of it.

Now you accuse me of being a troll, apparently because I have the temerity to hold, and post, an opinion you don't want to hear, in a discussion to which that opinion was relevant?

Interesting conclusion.

Matt RX8

no need to air this out in public. PM sent.

MrWigggles

If you could provide me with the equation, I would be glad to review it.

For straight acceleration both those numbers are way too high. I have posted an equation in the past that came out to about 1.5:1 MAX. Another memeber also got a near identical figure from doing the physics equations a different way.

Handling is a different story and is far more subjective. There isn't a concrete figure that equates unsprung and sprung. But I would guess that 4:1 and 10:1 are still both too high.

The only way to test would be to do tests blind. Do a series of tests with a vehicle in various wheel weights and dead cargo weights configurations and see how fast each is. The important thing is for the driver NOT to know what configuration he is driving (that's what makes the test "blind"). When it is over you should have various answers: Was the car with 100 pounds of dead weight faster than the car that had 10 pounds less of wheel weight?

Tire Rack does a similar test for tires but I wish they would do a test for wheels as well.

-Mr. Wigggles

millyard

my prediction is that the theoretical maximum would be 2 times for the effective weight of the wheel during acceleration, which is the limit of the solution as all the mass is located on the outer edge of the wheel, in reality the effective radius of the wheel would actually be smaller because some of the mass is located more towards the center of the wheel and therefore has a slower velocity and therefore a lower kinetic energy

in reality, depending on where the center of mass of the wheel is, that value is likely between 1.5 and 1.7

millyard

humm now that I think about it it could even be less then i stated above, similar to what wiggles suggested, since it's dependent on the square of the radius, also since the wheel where the mass is lost is located further towards the center of the tire, could be as low as 1.3 say on a 16in wheel, it all depends on what radius the mass is lost at, but since its a squared relationship if the mass is located at 1/2 the radius of the wheel the ratio will be only 1.25 :1, if it's lost at 3/4 of the wheel radius it will be 1.56:1, I think it safe to assume it is between thoes numbers