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4 lbs less unsprung and rotating weight

Old 07-05-03, 07:58 PM
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4 lbs less unsprung and rotating weight

Racers, can you really tell the difference between 12lb wheels and 16lb wheels when it comes to course adhesion and acceleration / braking? I am agonizing over what wheels to get for my 87 base. All the light wheels are ugly and I can't fit the 11lb vert wheels due to my four lugs. However, there are many four lug Rota wheels in the 12lb range that will fit . . so is it worth it to get the lightest wheels at all costs?
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Old 07-06-03, 08:39 AM
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Given your example your wheels would be 25% lighter at each corner! That's huge! Lighter wheels are of course easier to accelerate and slow due to their lighter weight, but their true advantage is reducing the unsprung weight of the vehicle. A lighter whee/tire is much easier for the springs and dampers to control and will see big traction advantages compared to a heavier wheeel when the car is traveling over bumps.
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Old 07-06-03, 10:39 AM
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on street car you'll never tell the difference on a race car racing against similair cars you will see the difference even if you can't feel it. the lighter the rotating weight of the car and the lower the unsprung weight will help the car accelerate better and corner better, so with the heavy wheels you will see others tailights on the track. if it is a street car then go with the bling bling.
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Old 07-06-03, 12:46 PM
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Thanks guys.

I am mostly thinking of acceleration and braking performance for the street. I have Gsl-Se wheels which are 13lbs each and about 30lbs with the tires mounted, but I would like to upgrade to wider wheels and 50 profile tires and this usually means taking on more wheel and tire weight. So I am curious as to how much slower the car would be with four more pounds added to a ~30 pound wheel and tire combination.
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Old 07-06-03, 10:00 PM
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I completely agree with tims. Since this was posted in the "race" section I assumed it was for a competition vehicle. For the street buy whatever you think looks good.
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Old 07-07-03, 12:59 AM
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Originally posted by DamonB
Since this was posted in the "race" section I assumed it was for a competition vehicle.
Trust me, you guys know a lot more about chassis performance potential than either the second gen section or suspension / wheels / tires. That is why I check this board almost every time I am on the forum. This board has some of the fewest posts per day because there are so few "oh god, I screwed up my car" or "how much HP can I get" or "rx7's good cars?" etc (shallow) topics discussed. I need to build a race car some day. It looks like a really great way to legally drive very fast at the edge of the car's ability. I need to get that type of driving out of my system on a regular basis!
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Old 07-07-03, 09:37 AM
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hey 88integrals, get a second set of tires and rims and sign up for a drivers ed course at your local track. plenty of track time and great way to learn to go fast and get it out of your system legally.
later
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Old 07-09-03, 12:45 AM
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I saw your question in the other thread, but I'll reply here.

All I can say is that I went from the baloney slicers and 205s to Koseis and 225s. So there's the extra 1" of rim width, 20mm of tire width, and several pounds of weight. The car definitely likes the bigger wheels on the track. Turn in is crisper, I don't lock the brakes up as much (could be that I'm getting better and finding the lock up point and backing off too), and the car feels more stable, the 205s felt like they were squirming a bit under hard corners, where the 225s feel solid.

But is it worth the price for a street car? I'd say it all depends on how much cash we're talking. The Koseis are about 12lb each. I could have gotten SSR Integrals for 9lbs, but twice the price, I chose to go with the heavier Koseis.

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Old 07-09-03, 10:35 AM
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I went from 25lbs Enkei's to 17lbs rota's in my Honda. The difference was like night and day. It was so noticable that I'm probably going to sell the 17's and find a pair of 13lbs 15"s. You will notice a difference. The car turned faster, accelerated better, and was easier to stop. Go with the lighter rims.
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Old 07-10-03, 10:33 AM
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Swap over to the 5-lug. Don't waste your time and $$ getting 4-lug wheels. I bet you could find a complete parts car in a local Pick and Pull and get everything you need for $100-200.
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Old 07-10-03, 12:57 PM
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You will be suprized at how rare Junkyard 5 lug setips are getting - they all get snapped up by the Spec/Pro-7 ITs racers as fast as the show up.
Acording to the guys at MARIAH, down here in So Cal it is almost imposible to find a 5 lug junker that still has the hubs & axel on it
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Old 07-10-03, 01:30 PM
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last time I was at the Pick a Part type junkyards in Sun Valley there were several GXL's available. engine and trans were all gone but all the hubs an parts were there. it is true that second gens are harder to find these days. 5 lug wheels are better but all the five lug stuff is heavier.
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Old 07-10-03, 05:16 PM
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In Oregon it isn't hard to find one with 5-lug stuff on it. 88IntegraLS is here too.

All the 5-lug stuff isn't heavier. The calipers are lighter IIRC Tim.
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Old 07-10-03, 05:47 PM
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i have a good subframe over at my parents house that i need to sell, it has a broken wheel stud on each side though, oh and the lsd is not included in it. and I am sure we could also work something out for the front 5 lug conversion as well. Lates Matt22 pm me for more
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Old 07-10-03, 06:41 PM
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Really? Up here it's easy to find.. Now finding good spindles, that was kinda tough. Many of the junkyard spindles were scored/galled..

PaulC
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Old 07-10-03, 09:06 PM
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I noticed a huge difference between the s4 turbo2 rims and the regular s4 NA rims
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Old 07-10-03, 10:10 PM
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Thanks again for the comments guys. I think I am going to stick with the four lugs for a few years. I really want to go to driver school and get some track time . . . and in that arena the big brakes would be helpful. But for now I don't have the $$$. I am going to college and preparing to be broke beyond anything I have ever experienced. Just auto-xing this thing will be painful . . and my autox tires are on the 4 lug Gsl-Se wheels but don't that the wrong way turbojeff, I really appreciate you tipping me off to them being for sale so inexpensively. So I need another set of wheels anyways and found the really light 4 lug Rotas to be good candidates for me.
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Old 07-10-03, 10:50 PM
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Originally posted by turbojeff
All the 5-lug stuff isn't heavier. The calipers are lighter IIRC Tim.
If that is the case than I should just swap now before getting wheels. I thought the bigger brakes would be heavier. At least the Turbo (5 lug) stuff should be heavier than base model parts . . . or am I wrong in my reasoning? I have been under the impression that five lug swaps add unsprung weight.
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Old 07-11-03, 12:28 AM
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I haven't weighed the stuff, but I read in the Yamaguchi book or somewhere that the front brakes are like 2lbs lighter than base models.

The GXL, Sport package, TII and Convertible all have the same brakes. Front calipers are aluminum, that is most of the weight savings I think.

On another note, if the unsprung weight is higher it isn't much higher. The effect on rotational inertia is low since the brake rotor is so close to the center of the wheel. It would be much different if all that weight was at the edge of the wheel (if the 5 lug is heavier).

Go 5-lug. Get some 90+ 300ZX wheels, they are pretty light for 16 inchers and cheap too. It is worth it.

http://community.webshots.com/album/29829335dZcQQoISEZ

Otherwise it'd be good to see you at the auto-xes.

Later,
Jeff
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Old 07-11-03, 06:07 PM
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Thanks Jeff; so the five lug caliipers are lighter while their rotors are heavier, and the net weight difference to 4 lug parts is a slight gain in unsprung and rotating weight? That could be offset the .5 pounds less that stock BBS 15x6.5 wheels have compared Rotas . . . but now I am pretending to be an engineer (hope to be one some day). Although there is a market for Gsl-Se wheels and perhaps some five lug wheels in 14x6 out there to be had off ebay . . making it possible to get a few runs out of the autox tires that I do have.

Time for me to sell some stuff and raise the $$$.
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