C3 Wheels
Thread Starter
Burning Brakes
Joined: Sep 2011
Posts: 960
Likes: 40
C3 Wheels
I'm researching wheel and tire sizes for a racing class and I found some interesting wheels.
Wheel sizes I'm not interested in (because of tire choices):
Eagle Alloy 227, 20 x 8.5, -5mm
Eagle Alloy 227, 20 x 10, +2
Eagle Alloy 211, 17 x 9.5, -5mm
Eagle Alloy 211, 20 x 8.5, -5mm
Eagle Alloy 211, 20 x 8.5, -18mm
Eagle Alloy 211, 20 x 10, +1.5mm
Eagle Alloy 211, 20 x 10, -11mm
Eagle Alloy 211, 20 x 10, -24mm
Wheel sizes I am interested in:
17 x 8, 0mm, on one of the popular websites
AR Torq Thrust 2.1, 17 x 8, -11mm
AR VNT70R, 17 x 9, 0mm, bolt pattern (?)
SSR SP3 or MS1
18 x 8.5, 0mm, HP
18 x 9, -7mm, HP
18 x 9.5, -3mm, MD
18 x 9.5, -13mm, HP
19 x 8.5, 0mm, HP
19 x 9, -7mm, HP
19 x 9.5, -3mm, MD
19 x 9.5, -13mm, HP
One way of looking at it is the 255/40-18. Which wheel fits the tire on the car best, the 18 x 9 -7mm, the 18 x 9.5 -3mm, or the 18 x 9.5 -13mm ?
Another way of looking at it is a 255/35-19. Which wheel fits the tire on the car best, the 19 x 9 -7mm, the 19 x 9.5 -3mm, or the 19 x 9.5 -13mm ?
Also, some tires in those sizes have a tread width only 0.4" narrower than the section width. Or that's tread widths up to 9.9".
.
.
.
Wheel sizes I'm not interested in (because of tire choices):
Eagle Alloy 227, 20 x 8.5, -5mm
Eagle Alloy 227, 20 x 10, +2
Eagle Alloy 211, 17 x 9.5, -5mm
Eagle Alloy 211, 20 x 8.5, -5mm
Eagle Alloy 211, 20 x 8.5, -18mm
Eagle Alloy 211, 20 x 10, +1.5mm
Eagle Alloy 211, 20 x 10, -11mm
Eagle Alloy 211, 20 x 10, -24mm
Wheel sizes I am interested in:
17 x 8, 0mm, on one of the popular websites
AR Torq Thrust 2.1, 17 x 8, -11mm
AR VNT70R, 17 x 9, 0mm, bolt pattern (?)
SSR SP3 or MS1
18 x 8.5, 0mm, HP
18 x 9, -7mm, HP
18 x 9.5, -3mm, MD
18 x 9.5, -13mm, HP
19 x 8.5, 0mm, HP
19 x 9, -7mm, HP
19 x 9.5, -3mm, MD
19 x 9.5, -13mm, HP
One way of looking at it is the 255/40-18. Which wheel fits the tire on the car best, the 18 x 9 -7mm, the 18 x 9.5 -3mm, or the 18 x 9.5 -13mm ?
Another way of looking at it is a 255/35-19. Which wheel fits the tire on the car best, the 19 x 9 -7mm, the 19 x 9.5 -3mm, or the 19 x 9.5 -13mm ?
Also, some tires in those sizes have a tread width only 0.4" narrower than the section width. Or that's tread widths up to 9.9".
.
.
.
Last edited by B Stead; Sep 5, 2011 at 02:47 AM.
Thread Starter
Burning Brakes
Joined: Sep 2011
Posts: 960
Likes: 40
Take it up to bigger tire sizes:
What wheel works best to get the 275/40-18 tire on the C3 ? The 18 x 9.5 0mm, 18 x 9.5 -3mm, or the 18 x 9.5 -13mm ?
Also there's the 275/35-19 and wheel sizes of 19 x 9.5 0mm, 19 x 9.5 -3mm, and 19 x 9.5 -13mm .
Those are SSR wheel sizes.
Also there's the 265/35-19 tire size.
What wheel works best to get the 275/40-18 tire on the C3 ? The 18 x 9.5 0mm, 18 x 9.5 -3mm, or the 18 x 9.5 -13mm ?
Also there's the 275/35-19 and wheel sizes of 19 x 9.5 0mm, 19 x 9.5 -3mm, and 19 x 9.5 -13mm .
Those are SSR wheel sizes.
Also there's the 265/35-19 tire size.
Last edited by B Stead; Oct 6, 2011 at 02:55 AM.
Thread Starter
Burning Brakes
Joined: Sep 2011
Posts: 960
Likes: 40
Also, I'm running same size wheels and tires front and rear. And I'm not raising the rear or sticking the tires out.
I'm interesting in these tire sizes:
255/40-18
255/35-19
275/40-18
275/35-19
265/35-19
I've found these wheel sizes listed:
18 x 9 -7mm
18 x 9.5 0mm
18 x 9.5 -3mm
18 x 9.5 -13mm
19 x 9 -7mm
19 x 9.5 0mm
19 x 9.5 -3mm
19 x 9.5 -13mm
And those are SSR wheel sizes but I found a subject on this forum that had AR wheels in 18 x 9.5 -6mm. That's interesting but I can't find a detailed AR catalog.
Okay, now I'm finding wheel dealers that offer US Mag wheels in 18 x 9 and choice of backspace and that offer AR wheels in 18 x 9.5 and choice of backspace. These are 7 week special order and only about 40% cheaper than the SSR wheels which are also special order.
18 x 9, 5" BS is 0mm offset
18 x 9, 4.75" BS is -6mm offset
18 x 9, 4.5" BS is -13mm offset
18 x 9.5, 5.25" BS is 0mm offset
18 x 9.5, 5" BS is -6mm offset
18 x 9.5, 4.75" BS is -13mm offset
I'm interesting in these tire sizes:
255/40-18
255/35-19
275/40-18
275/35-19
265/35-19
I've found these wheel sizes listed:
18 x 9 -7mm
18 x 9.5 0mm
18 x 9.5 -3mm
18 x 9.5 -13mm
19 x 9 -7mm
19 x 9.5 0mm
19 x 9.5 -3mm
19 x 9.5 -13mm
And those are SSR wheel sizes but I found a subject on this forum that had AR wheels in 18 x 9.5 -6mm. That's interesting but I can't find a detailed AR catalog.
Okay, now I'm finding wheel dealers that offer US Mag wheels in 18 x 9 and choice of backspace and that offer AR wheels in 18 x 9.5 and choice of backspace. These are 7 week special order and only about 40% cheaper than the SSR wheels which are also special order.
18 x 9, 5" BS is 0mm offset
18 x 9, 4.75" BS is -6mm offset
18 x 9, 4.5" BS is -13mm offset
18 x 9.5, 5.25" BS is 0mm offset
18 x 9.5, 5" BS is -6mm offset
18 x 9.5, 4.75" BS is -13mm offset
Last edited by B Stead; Oct 6, 2011 at 10:40 PM.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
FWIW, one reason you may not have gotten responses thus far is that very many of us here in the shark tank view backspacing (BS) in inches as the much preferred measurement to work with rather than converting from offsets and/or metrics. Stock C3 BS is 4".
That said, with 18" rears you can push BS up to 5.5" before significant mods may become required; which means you shouldn't find difficulty running as much as 285/40-18's on 18x10's out back within the stock fenders as long as the planets align properly (crooked chassis or body can possibly present issues).
In any event, a good rule of thumb for responsive handling is to run the widest practical wheel within a given tire's recommended fitment range, but I'd strive to keep the section to wheel width differences as close to the same front/rear as you can. My $.02
TSW
That said, with 18" rears you can push BS up to 5.5" before significant mods may become required; which means you shouldn't find difficulty running as much as 285/40-18's on 18x10's out back within the stock fenders as long as the planets align properly (crooked chassis or body can possibly present issues).
In any event, a good rule of thumb for responsive handling is to run the widest practical wheel within a given tire's recommended fitment range, but I'd strive to keep the section to wheel width differences as close to the same front/rear as you can. My $.02
TSW
Thread Starter
Burning Brakes
Joined: Sep 2011
Posts: 960
Likes: 40
...many of us here in the shark tank view backspacing (BS) in inches as the much preferred measurement to work with rather than converting from offsets and/or metrics. Stock C3 BS is 4".
That said, with 18" rears you can push BS up to 5.5" before significant mods may become required; which means you shouldn't find difficulty running as much as 285/40-18's on 18x10's out back within the stock fenders...
TSW
That said, with 18" rears you can push BS up to 5.5" before significant mods may become required; which means you shouldn't find difficulty running as much as 285/40-18's on 18x10's out back within the stock fenders...
TSW
But just couple the wheel backspace with the wheel width.
But yeah front and back on a C3 at stock height, the 275/40-18 on a 18 x 9.5 wheel since I'm finding two brand choices of 18 x 9.5 wheel. Then backspace choice is 5.25", 5.0", and 4.75".
Last edited by B Stead; Oct 6, 2011 at 09:48 PM.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
Unlike offset, backspacing does not vary with wheel width, and since BS is a somewhat critical factor in fitment converting back and forth between the two seems a bit of busy work (I'm capable of the maths, just not so inclined), unless BS numbers simply aren't available. With 275's on 9.5" rears, I'd most likely go with 5" BS, and let offset fall where it may.
Race Director
Joined: Jan 2007
Posts: 14,798
Likes: 3,274
From: NYC NY
SSR wheels are pricey. When you're looking at $600.00 plus per wheel there are options. If you are looking to put the biggest tire and widest wheel in the same size on all 4 corners I would give CCW a call. He does a lot of Corvette fitments, he is in that price range, and all his wheels are custom built to order.
Thread Starter
Burning Brakes
Joined: Sep 2011
Posts: 960
Likes: 40
Unlike offset, backspacing does not vary with wheel width, and since BS is a somewhat critical factor in fitment converting back and forth between the two seems a bit of busy work (I'm capable of the maths, just not so inclined), unless BS numbers simply aren't available. With 275's on 9.5" rears, I'd most likely go with 5" BS, and let offset fall where it may.
Yeah, that is interesting.
But the location of the center of the wheels on the car is one of the things that defines the roll centers !
Also, the wheel can often go wider without tire rubbing (with same size tire) because the wider wheel just tends to widen the tire down at the rim. But with a change in offset the top of the tire moves by the amount of offset change and that's something to watch out for.
Anyway, I found that AR wheel dealers can order AR Custom Shop wheels or AR Custom Built wheels and just specify the backspace.
And of course the SSR wheels are very sharp and available in 19" keeping in mind that the 275/35-19 does not have a super-super-short sidewall.
Also, there's two models of custom order SpinWerks wheels at racerpartswholesale.com but I don't know how active they are.
So at this point in the posting I'm looking at:
275/40-18 on a 18 x 9.5, front and rear
275/35-19 on a 19 x 9.5, front and rear
With the car at standard suspension settings.
Last edited by B Stead; Oct 7, 2011 at 01:44 AM.
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Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
If wheel backspace is held as the wheel width is changed, that puts the backside of the rim at the same point on the car as before but the center of the wheel lands at a different point on the car than before.
Yeah, that is interesting.
But the location of the center of the wheels on the car is one of the things that defines the roll centers !
Also, the wheel can often go wider without tire rubbing (with same size tire) because the wider wheel just tends to widen the tire down at the rim. But with a change in offset the top of the tire moves by the amount of offset change and that's something to watch out for...
Yeah, that is interesting.
But the location of the center of the wheels on the car is one of the things that defines the roll centers !
Also, the wheel can often go wider without tire rubbing (with same size tire) because the wider wheel just tends to widen the tire down at the rim. But with a change in offset the top of the tire moves by the amount of offset change and that's something to watch out for...
Thread Starter
Burning Brakes
Joined: Sep 2011
Posts: 960
Likes: 40
With same width wheels, backspace decreases as offset increases but both go to smaller numerical values.
With a wheel width-increase, backspace increases at half the wheel width-increase if offset is being held.
Or the viewpoint I wasn't expecting, backside rim clearance holds when the backspace is held with wheel width increases. Also, that's increasing wheel offset with increasing wheel width (with the offset increasing at half the wheel width-increase).
But what's the 275/40-18 on a 18 x 9.5 like on the front of the C3 ?
I'm looking at the 275/40-18 on an 18 x 9.5 front and rear on a C3 with stock suspension height.
And the wheels are easily available in any backspace as American Racing Custom Shop.
Maybe I should step down to the 255/40-18 (front and rear) which is stock optional tire width and just 1/2" less tire radius. Then wheel size is only 18 x 9 with wheels easily available in any backspace as US Mag Custom 2-piece
.
Last edited by B Stead; Oct 7, 2011 at 04:57 PM.
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
so moved the ebrake cable in rear, and limited the toss on the steering in front a bit.....still tight enough radius it's never missed in any street driving ....only been 16 years now....
