1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Rims questions...

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Old Aug 23, 2003 | 08:12 PM
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Rims questions...

I have a few questions about rims...

1. Is there a large difference between the handeling of 17" rims and 16" rims?

2. Is it a good idea to get front tires that are thinner than normal for more stability at high speeds, or will this have a negative effect on handeling enough to make thin tires unworthwhile?

3. How much effect on speed do larger rims have? And what do you have to do to compensate with the speedo?
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Old Aug 23, 2003 | 10:14 PM
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1( no
2( no/yes/unworth while
3(it is the tire differance in rad/hight not the wheel
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Old Aug 23, 2003 | 10:42 PM
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1. Yes. Even if the weights are the same, the larger wheel has a higer rotational inertia because the weight is further from the center. This means if you have a 17lbs 16" rim, and a 17lbs 17" rim, the 16" rim will be easier to accelerate, decelerate and turn because the mass is closer to the center. This is small but still important to know. The main difference is usually 17" rims are a few lbs heavier than 16" rims. This adds to your unsprung mass, along to adding to the inertia thing mentioned above. In other words, you'll notice a differnce and it does matter.

2. How will thin tires give you more stability? You're better off adjusting caster to get your car to track at speed. Are you taling width or profile?

3. Yes, tire size is the real concern. You can upgrade to a larger rim and smaller tire and not change the overall diameter at all. Your speedo would be unchanged. This usually isn't the case though, and a speedo shop will install a different gear or a gear box that will modify the signal. Cost ranges from $30-200 usually.
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Old Aug 24, 2003 | 12:03 AM
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agin the anser to question 1 is no, no big differance. gsl 302 tech you have the knowlage to figure a differance that is there but you are still incorect. the differance is small on rims with the same weight and alot of 17 inch rims are lighter than some 16 inch rims. the lighter ones may have a smaller inertia than 16 inch rims and the major thing would be the rim design. you know where the weight is on the rim as oposed to only considering the size in dia. and with our steering he probly will not notice any differance or may like the way the 17 is oposed to the 16. most people staying with the same size dia tire notice a differance because of the lower aspec ratio of the tire on the 17 inch rim not anything else.

2) this question needs to be reformed. the first time I read it, it sounded like may be 3 questions but now after you ansered it like you did I have the same thought ( what is he realy asking? ) and now more so after reansering these questions

3) hopefuly he wont spend any where near 200 for reseting the speedo.
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Old Aug 24, 2003 | 12:11 AM
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Originally posted by '85 GSL 302

Are you taling width or profile?
I was talking width. What I meant I guess is... I've heard that low pro wide front tires tend to jump around alot on bumps and stuff.. just wondering what people think...

I'm looking at Velox 16 or 17inchers...

Last edited by excitingleopard; Aug 24, 2003 at 12:15 AM.
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Old Aug 24, 2003 | 03:36 AM
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Will teh speedo read faster or slower?

Zachstylez
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Old Aug 24, 2003 | 08:44 PM
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I would think the speedo woulc show faster than it's really going, right? Hmmm...heheh...

Here's the rims I'm looking at. I think they'll look awsome on my black FB.
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Old Aug 24, 2003 | 08:50 PM
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Here's the other...
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Old Aug 24, 2003 | 08:54 PM
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And the last one...

Let me know which you think will look best with black.
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Old Aug 24, 2003 | 09:00 PM
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the speedo would read slower than normal because the circumferance of the tire is larger so each revolution covers more distance than the smaller rims/tires
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Old Aug 25, 2003 | 09:39 AM
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Aah well, that was my other answer.

I guess that does make sense, but it depends on how thin (low) your tires are. Like kuhlrx7 said, you can just get bigger rims and smaller tires, which is what I'll do if I can.
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Old Aug 25, 2003 | 09:53 AM
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Hey now..

No copying my wheels!


For what it's worth, the 1st two are only avalaible in 17"x7.5" and if I remeber from when I was looking the offset would be too high to work on out cars.
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Old Aug 25, 2003 | 09:57 AM
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as for exactly what size wheel vs tire aspect ratio needed to keep the speedo working?

go here...
http://www.miata.net/garage/tirecalc.html

Look at the Vx-6r also... different style, but narow enough to fit up front.


or the PG-5s. these weren't out when I bought mine..
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Old Aug 25, 2003 | 11:05 AM
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where can we get those rims? they fit too?
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Old Aug 25, 2003 | 11:21 AM
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Oh wow... I really like those, I've never seen 'em before. I'll definitely check those out.
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Old Aug 25, 2003 | 11:24 AM
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Originally posted by rx7gslse
Hey now..

No copying my wheels!

For what it's worth, the 1st two are only avalaible in 17"x7.5" and if I remeber from when I was looking the offset would be too high to work on out cars.
Yes, I actually got the idea for the Velox rims after seeing your car. Although yours is tornado silver, and mine is "glossy" black. (black, with a gold base)

I thought all those models came in 16, but maybe I should check again.
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Old Aug 25, 2003 | 11:27 AM
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Just be sure to check the offset... for a 7" wide rim you need 38-40mm, no higher... (35 *might* work, I dunno)

I don't think you're going to get a 7.5" wide wheel up front.. I don't know of anyone getting that to work, and I know 7" is damn close.

BTW, I got a good deal on mine from www.afsmotorsports.com
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Old Aug 25, 2003 | 11:35 AM
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The VX 8R's come in 16x7.0.

Unfortunately, the smallest the other models usually come in is 17x7.5.

The VX 6R's come in 17x7.0. Sounds like that means they should work for an FB, right? They look pretty badass.


What width do you have on the front of yours, rx7gslse?

Last edited by excitingleopard; Aug 25, 2003 at 11:42 AM.
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Old Aug 25, 2003 | 11:36 AM
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Originally posted by excitingleopard
Yes, I actually got the idea for the Velox rims after seeing your car. Although yours is tornado silver, and mine is "glossy" black. (black, with a gold base)

I thought all those models came in 16, but maybe I should check again.
from what I've seen the VX-8r that I have on my car are the only ones that come is 16"
http://www.veloxperformance.com/whee...ition.asp?ID=3

most of the rest are 17/18" wheels.. (and they're a lot heavier)

also check out some of the Wheels that Rota makes if you like that style.. I was partial to teh sub-zeros myself...

http://www.machiii.net/machiii/html/Rota_wheels.html
http://www.jaydm.com/wheels.htm

Rishie can hook you up with great prices on Rotas as well (ARD T2 on the forum)
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Old Aug 25, 2003 | 11:38 AM
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Originally posted by excitingleopard
The VX 8R's come in 16x7.0.

Unfortunately, the smallest the other models usually come in is 17x7.5.

The VX 6R's come in 17x7.0. Sounds like that means they should work for an FB, right? They look pretty badass.
check the offset, but yeah, they should work. Run a 205/40-17 tire on all corners... or maybe a 225 in the rear if you like, but then ya can't rotate 'em.

I have 205 on all 4.
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Old Aug 25, 2003 | 09:32 PM
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So yours are 17's?.... hmmm...

Maybe I will get some17's.

They don't look too big like most people say.
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Old Aug 26, 2003 | 01:06 AM
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To answer some stuff here:

1) It really depends on the rims but the majority of the time the 17"'s will be slower. An exception to this is top dollar race cars that maximize the rim to run bigger brakes, have better brake cooling, and a lower profile tire to max super high G's. On a street car though, a smaller lighter rim is the way to go.

2) What you're talking about is actually two different things. There's bump steer, and pull steer. Bump steer is a result of poor suspension/steering rack geometry as a result from lowering a vehicle. When you hit a bump, the steering rack with bind and cause the car to steer off in a direction not intended. Pull steer is a result of the larger contact patch gripping the road and being pulled along the contours by the drag on the tire. Nearly all cars with large front tires will exibit this, you just have to get used to it. They will usually catch the valley's in the roads and track them, which isn't a problem. It usually only bothers you when one side is on a different surface than another. The answer is it's much better to run wider tires than skinnies. I'd happily put up with a little pull to the side occasionally than not be able to turn my car.
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Old Aug 26, 2003 | 02:31 AM
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I was looking at Velox's just recently as well. I came to own a set of new Michelin Pilot Sports in 17s that I wanted to get wheels for eventually, and I need a 17x7 for them to fit on, but the VX-8s are 17x7.5 which they would fit on too, but they wouldnt fit on the car then, lol . I want a gunmetal wheel with a polished lip like the VX-8Rs, but those are even smaller. Maybe Ill sell the tires and buy different ones later...

~T.J.

Last edited by RotorMotorDriver; Aug 26, 2003 at 02:34 AM.
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Old Aug 26, 2003 | 10:24 AM
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no, mine are 16"...

and yes, it "pull steers" like a biatch of a stretch of crappy road.. that's my #1 complain about the car.. (that and no turbo)
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Old Aug 26, 2003 | 11:46 AM
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Well thanks for all the help, guys.

I was a little foggy as far as the bump steer, pull steer thing goes. I can deal with a little muscle steering.

I think my decision will end up being my first choice anyway: Velox VX 8R.
whoops..doublepost
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