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#1063324 - 08/26/19 09:55 PM 18x8 Rim with 255/40-18; Downsides?  
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Fred SS Offline
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I have a question concerning tire fitment. All tire manufacurers say the minumum recommended rim width for a 255/40-18 tire is 8.5 inches. What would be the downside of running it on a 8 inch wide rim? I'm toying with the idea of getting G-Body Parts new GNX replica rims in 18x8x4.0BS, with 245/40-18 front and 255/40-18 rear. Comments?


87 SS, Harwood cowl induction hood, UMI trailing arms. Edelbrock TES Headers (Jet Hot Coated). Goodwrench 350, Ported TPI, Trick Flow 56cc alum heads, SLP runners, Comp Cams 260AH-12 cam, Trick Flow 1.5 roller rockers, Bilsteins, TCI 2400 stall converter, Ramcharger fans, Denny's 3.5" Driveshaft, GBodyParts GNX Wheels.
#1063342 - 08/27/19 03:49 PM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
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Fred - always good to connect. Still owe you one!
Here's my take on this as a (somewhat) tire guy and from discussions with my favorite dealers:
It appears you are OK with this set up.
The contour (axial profile) of tire treads has evolved and these guide lines are recommended to give optimal foot print (contact patch) assuming you don't have a specific tire/wheel preference.
Of course all this changes anyway when you alter inflation pressure.
Generally the tire industry offers this as a useful (necessary) means to guide optimal tire fitment (fuel efficiency, braking and handling), and minimize liability (from a really stupid mismatch).
Dealers install outside of this and see this all the time; my guys report no problems. 1/2" outside the recommended rim is reported to not be an issue and even 1" is not felt to be outside of the norm.
I personally was less worried about the tread than I would be about seating the bead, but again this does not appear to be an issue.
I like the wheels BTW. Might have done this myself at one time.
In fact, I now regret having given away my near mint stock 15x7 wheels as I could have put on the 275 Nittos, which are listed as preferring 7.5" rims!
Please note that these are just my current opinions and I accept no liability for what you do - hahaha
Reach out to me anytime if you want to discuss.
Best as always,
Gordon

Afterthought - Fred, you know those wheels are only rated for 145 mph?
G

#1063352 - 08/28/19 01:20 AM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
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Thanks Gordon for your insight. I did not know the wheels are only rated for 145 mph. I never knew there was a speed rating for rims. Not that I plan on going that fast. No place around here to get the Monte up to that speed safely. How did you find the speed rating on the GNX replicas?


87 SS, Harwood cowl induction hood, UMI trailing arms. Edelbrock TES Headers (Jet Hot Coated). Goodwrench 350, Ported TPI, Trick Flow 56cc alum heads, SLP runners, Comp Cams 260AH-12 cam, Trick Flow 1.5 roller rockers, Bilsteins, TCI 2400 stall converter, Ramcharger fans, Denny's 3.5" Driveshaft, GBodyParts GNX Wheels.
#1063353 - 08/28/19 02:13 AM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
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https://gbodyparts.com/reproduction-wheels-p-3498.html
First line of the large paragraph in the middle.
Teasing you a bit. I don't recall ever having seen a speed rating on a wheel before either.
145 mph seems reasonable in any case.
Possibly some unique speed testing done to gain basic safety approval, yet avoid using expensive design/testing protocols/costs (possibly destructive testing) which only the big guys have readily available????
Insight from anyone?
One wonders if OE wheels were ever rated? Probably not. After all many of these cars had 85 mph speedos.
I see they have the stock Monte Carlo "Chevrolet" center cap design that came with our cars on that page, too. You might want to look for an "SS" center cap somewhere else or something custom to compliment your paint job.?
Let us know how it turns out.
Again - a very nice looking wheel with large appeal.
So glad you found this.
Gordon

#1063358 - 08/28/19 08:11 PM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
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Hi Folks,

Using this equation from the sticky:

Wt = (Wr-8.4mm)/[1-0.42*((AR-5)/100)]

Which cane be re-arranged to solve for Wr as follows:

Wr = 8.4mm + Wt*[1-0.42*((AR-5)/100)]

Where:
Wt = advertised tire width
Wr = rim width (inside of lip to inside of lip)
AR = advertised tire aspect ratio

Get for 245/40-18 for the front: Wr = 217mm = 8.6"
Get for 255/40-18 for the rear: Wr = 226mm = 8.9"

To improve grip with the car undergoing roll in a cornering situation, the better direction to go with the rim is wider rather than narrower, than what this formula suggests. All "super cars" are set-up with this bias, often with the rim 1" to 2" wider than sidewall verticality, which is the basis for my equation. See the sticky comment about tire "self-cambering."

8" is definitely narrower than optimal, especially at the rear. The result will be that you won't get full performance from the tires for roadhandling, and you'll get higher wear in the center of the tread than at the edges for straight-line driving. But as Akron says, the difference with an 8" rim isn't big enough to obsess over IMO. Now having said that, I wish I could tell you what fraction of cornering acceleration you'd be losing compared to an optimum rim width, but I can't. Insufficient data!

HTH,
MAP

Last edited by MAP; 08/28/19 08:18 PM.
#1063359 - 08/28/19 08:44 PM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
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Thanks MAP. Definitely something to think about. GBodyParts do have the rims available in 18x9x4.25 BS. But, I don't think a 9 inch wide wheel with 4.25 backspace will work very well on the front of our Monte's. Would hit the top of the wheel well opening on bumps. I could run the 18x9 on the rear with the 255 tire. But at 4.25 backspace, my measurements show that I will have to roll the fender lips. I'm currently running 17 inch SLP ZR1 replicas with 245/45-17 front and 255/45-17 rear. Looking for something different without spending thousands. I draw my line at about $2000 for new rims. Forgline has a couple of great looking concave wheels, but at $1500 a wheel, I cannot justify spending that much.

Last edited by Fred SS; 08/28/19 08:59 PM. Reason: Add more text

87 SS, Harwood cowl induction hood, UMI trailing arms. Edelbrock TES Headers (Jet Hot Coated). Goodwrench 350, Ported TPI, Trick Flow 56cc alum heads, SLP runners, Comp Cams 260AH-12 cam, Trick Flow 1.5 roller rockers, Bilsteins, TCI 2400 stall converter, Ramcharger fans, Denny's 3.5" Driveshaft, GBodyParts GNX Wheels.
#1063361 - 08/28/19 09:31 PM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
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Hi Fred,

I truly wish I could say you were wrong, but unfortunately, you're exactly right. Our cars weren't designed for very wide wheels. My past experience was that tire widths going in excess of about 245mm rapidly engendered fitment issues. Must say that was my main motivation for wanting to stretch the width of the car by about 4" at the front and rear, with gentle bulging of the fenders and quarters. It would have definitely changed the lines of the car, but in a nice way, or so I thought, according to some clay mockups I did on a scale model. Or, you could do it the way GM did that one-off MCSS about five years ago, by adding pronounced upper-wheelwell "eyebrows" that projected outwardly to about the same extent, preserving the 1980s theme that they executed on their IROC Camaros.

So yes, you're in a tough spot and I feel for you. In light of all of the other costs involved with making things right, putting tires on rims that are about an inch too narrow, doesn't look quite so bad. Best of luck to you on this quest.

Thanks,
MAP

On edit: I'm amazed to see that my old photos and sketches are still in the album repository! Look under MAP and there's a good sketch from 2005 of a front 3/4 view that shows what a stretched-width MCSS would look like. There are two MS-painted photo concept views as well. (These show width-stretching in conjunction with moving the front wheels 3" forward. Must say that after several years of not looking at this concept, it still strikes me as surprisingly viable.)

Last edited by MAP; 08/28/19 10:46 PM.
#1063391 - 08/31/19 04:17 AM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
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I have had several email exchanges with G-BodyParts sales department. I mentioned to them about getting a "SS" center cap inlay like Gordon mentioned. The sales person says they have graphics people who could get it done. I sent them a picture of an SS emblem and that I would want red "SS" letters on a black background. I have to take a few more measurements on the Monte before I hit the "Buy" button. Need to see how centered my rear axle is. I have UMI adjustable rear control arms on the car so I could adjust if needed.


87 SS, Harwood cowl induction hood, UMI trailing arms. Edelbrock TES Headers (Jet Hot Coated). Goodwrench 350, Ported TPI, Trick Flow 56cc alum heads, SLP runners, Comp Cams 260AH-12 cam, Trick Flow 1.5 roller rockers, Bilsteins, TCI 2400 stall converter, Ramcharger fans, Denny's 3.5" Driveshaft, GBodyParts GNX Wheels.
#1063412 - 09/02/19 03:53 AM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
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I have taken allot of measurements and I think the GNX Reproduction Rims will work on my SS, but depending on how lowered the car is, it could be an issue. My Monte is lowered about 1.5 - 2.0 inches. I have OPG 2 inch drop springs on the front, but my front end is lighter due to aluminum heads, alum radiator and fiberglass hood. The rear has Detroit Speed 2 inch drop springs. My car has a slight rake. I may have to roll the rear fender lips. but I will wait until I have the rims and tires. Eastwood's fender roller is about $89 bucks. The sales person at GBodyParts.com seems to think that all G-Bodies are the same. They invited me to check out their Oldsmobile H/O Cutlass with 305 tires on their 18x9.5 rims that fit. The Cutlass has wider wheel wells than the SS. But I decided to leave it alone and not get into an argument. I appreciate them at least discussing the issues with me. My rear is centered within an 1/8 inch, relative to the fender lips. When I originally centered the rear, I used the frame as my reference. Tires are going to be Firestone Firehawk Indy 500 Summer tires. 245/40-18 front and 255/40-18 rear. I have been running Firestone Firehawk Indy 500 Summer tires for about 9 years now on 17 inch ZR-1 Replica rims. Those tires are awesome. Stick like glue and predictable. Rims will be GbodyParts.com 18 x 8 x 4.0 BS front and 18 x 9 x 4.25 BS rear. When I get the rims I will start another thread for the benefit of the forum.

Last edited by Fred SS; 09/02/19 05:09 AM. Reason: more info

87 SS, Harwood cowl induction hood, UMI trailing arms. Edelbrock TES Headers (Jet Hot Coated). Goodwrench 350, Ported TPI, Trick Flow 56cc alum heads, SLP runners, Comp Cams 260AH-12 cam, Trick Flow 1.5 roller rockers, Bilsteins, TCI 2400 stall converter, Ramcharger fans, Denny's 3.5" Driveshaft, GBodyParts GNX Wheels.
#1063414 - 09/02/19 06:30 AM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
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Hi Fred,

Just one comment from me: in terms of A/G-body room for wheels, they are definitely not all created equal. Close, maybe, but not equal. It's been quite a while, but I seem to remember that my '78 Malibu had about 3/4" less width clearance per tire in the front compared to an MCSS, and about 3/4" more in the rear compared to an MCSS.

I also seem to remember about 7(+/-?) years ago that someone made GNX-like flares for the MCSS. I thought the styles clashed, but that might just be me.

HTH,
MAP

#1063416 - 09/02/19 11:04 PM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
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Thanks MAP. I do remember someone selling GNX style rear fender flares for Monte Carlo SS many years ago. Never saw a picture of them.

The person I have been exchanging emails with at GBodyParts.com sales dept says that other Monte Carlo owners have bought their GNX reproduction rims without clearance issues. If so, those monte owners are not advertising it. I'm interested to see what GBodyParts can do for me concerning center caps with a "SS" emblem/inlay.


87 SS, Harwood cowl induction hood, UMI trailing arms. Edelbrock TES Headers (Jet Hot Coated). Goodwrench 350, Ported TPI, Trick Flow 56cc alum heads, SLP runners, Comp Cams 260AH-12 cam, Trick Flow 1.5 roller rockers, Bilsteins, TCI 2400 stall converter, Ramcharger fans, Denny's 3.5" Driveshaft, GBodyParts GNX Wheels.
#1063421 - 09/03/19 08:25 AM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
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Hi Fred,

It took a while to dig-up this information, but it turns out it was 12 years ago, and the company was Prodigy Customs in FL. The flares were made from fiberglass, and only for a single car. AFAIK they never made it to production. The owner shared photos of the car on this site, but all the photo links I found are broken. The owner of Prodigy Customs posted here once, that many people had seen the car at a certain car show. He seemed to let-on that the overall reaction to the flares wasn't very positive.

The shape of the flares clashed badly IMO with the downwardly-swooping crease lines the factory put into the MCSS fenders, doors, and quarters. But again, that's probably just me. The real GNX lacks those crease lines, so the conflict doesn't exist on that car. The GM MCSS show car from roughly 5 years ago (?) had flares similar to an IROC from the 1980s, and those visually worked far better. They covered only the top half of each wheel arch, extending down to the horizontal beltline of the car.

Best,
MAP

#1063423 - 09/03/19 02:46 PM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
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Moving back to the subject of the 18" "GNX replica wheels" I'm the owner of 8 16" GTA wheels, 0 offset. One is an original GM wheel, 5 are Classic Industries bought in 1999 manufactured by the original Japan manufacturer and two are Classic Industries repops I bought several years later which are Chinese.
The first 6 wheels all have JWL cast into the wheel meaning they are from Japan and approved by JWL. Here's WIKI info on the JWL markings. Few people know about this spec on wheels.
https://en.wikipedia.org/wiki/JWL_standard

What i found on the Chinese wheels was the clear coating was junk, the hole for the valve stem compromised install of the stem, and who knows about the quality of the alum used, and no JWL on the wheels.

Kirbin tried to offer a "replica of the GNX wheel many years ago in 16", I looked at it, not even close, he didn't sell many.

Have watched the "GNX replica" ordeal as it has been a hot/cold subject over the past decade. I'd be a little leery of the quality being you know they are Chinese repops. If just for looks they may be ok, as a race wheel I'd be hesitate.
Can't speak about the available offsets. My car is a modified B spindle setup to get to 9 1/2 caster in front, 255/50x16. In the rear an 8 1/2, alum drum, 10mm spacer so 255/50x16, 275/45x16 and 11.5x26x15 QTP Hoosiers all fit nicely. Absolutely no tire rubbing anywhere running a 16x8 zero offset GTA front and rear. QTP are on a steel rally wheel, 15x8.

The original GNX wheels had unique wheel offsets front and rear.
Bob

#1063425 - 09/03/19 03:32 PM Re: 18x8 Rim with 255/40-18; Downsides? [Re: mmc427ss]  
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Thanks Bob for the info. No, I'm not racing (neither autocross/nor drag racing). I just cruise till the sun goes down. I do have a photo of a Monte that I got off the internet, I forgot where, that shows a white Monte with what appears to be 16 inch GTA wheels with drag radials. It does look good.

Last edited by Fred SS; 09/03/19 03:33 PM.

87 SS, Harwood cowl induction hood, UMI trailing arms. Edelbrock TES Headers (Jet Hot Coated). Goodwrench 350, Ported TPI, Trick Flow 56cc alum heads, SLP runners, Comp Cams 260AH-12 cam, Trick Flow 1.5 roller rockers, Bilsteins, TCI 2400 stall converter, Ramcharger fans, Denny's 3.5" Driveshaft, GBodyParts GNX Wheels.
#1063428 - 09/03/19 09:10 PM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
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Fred, what spindles are you running up front?
Bob

#1063430 - 09/03/19 10:44 PM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
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Bob, I'm running stock G-body spindles with the larger metric calipers.

Last edited by Fred SS; 09/03/19 10:44 PM.

87 SS, Harwood cowl induction hood, UMI trailing arms. Edelbrock TES Headers (Jet Hot Coated). Goodwrench 350, Ported TPI, Trick Flow 56cc alum heads, SLP runners, Comp Cams 260AH-12 cam, Trick Flow 1.5 roller rockers, Bilsteins, TCI 2400 stall converter, Ramcharger fans, Denny's 3.5" Driveshaft, GBodyParts GNX Wheels.
#1063434 - 09/04/19 04:17 AM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
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Hi folks,

Not to slow-down the current progress of this thread, but I finally did find information on that (1988 as it turns out) MCSS:

https://www.chevrolet.com/performance/1988-monte-carlo-ls376

The "eyebrow" flares are a nice compromise for additional width without getting into the major bodywork of my approach. And they look far better than the GNX flares. (Hmm.. maybe someone can mold those up and sell them instead?)

Fred, somehow I got the wrong idea about how serious you were about getting the ultimate handling performance out of your car. "I just cruise til the sun goes down," was a major recalibration for me. Sorry if I was pulling you in a direction you didn't want to go. Maybe this is a good place to say that going a bit narrow with the rims (8", specifically,) doesn't sound like as big a compromise for you as I had first guessed.

Best,
MAP

Last edited by MAP; 09/04/19 04:19 AM.
#1063439 - 09/04/19 04:17 PM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
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Thanks Map, I appreciate your help and the help of other forum members. I am indeed concerned about handling performance. I do not plan to autcross my Monte, but I do want my Monte to handle good and predictably. I have UMI rear adjustable control arms, stiffer spings, 1-5/16 front roll bar, 1 inch rear roll bar, a front brace that ties the front frame horns together (bought from Dennis Kirban) and Kirban rear seat cross brace. Someday I may get the UMI tubular upper control arms with the tall ball joint and an improved steering box.

As of this post, my current plan is to get the 18 x 8 x 4.0 Backsapce rims (245/40-18 tires) for the front and 18 x 9 x 4.25 Backspace rims (255/40-18 tires) for the rear. The reason for the slightly larger size in the rear is that I always did like a staggered setup. My Monte is lowered about 1.5 inches. My measurements indicate that I will have to roll the rear fender lips or raise the car. I ordered the Eastwood Fender roller yesterday.

GBodyParts says that they can do a centercap with a red "SS" inlay.

The backspace dimensions of the GNX reproduction rims do present a problem. They will restrict my ability to do a big disk brake conversion for the front. For instance, Baer Racing's big brake kit for G-Bodies increases the front track width by 0.400 inches per side. With the 4.0 inch backspace of the GNX front rims, another 0.400 inch movement outward would probably cause contact at the top of the wheel well when hitting bumps.

Last edited by Fred SS; 09/04/19 04:30 PM.

87 SS, Harwood cowl induction hood, UMI trailing arms. Edelbrock TES Headers (Jet Hot Coated). Goodwrench 350, Ported TPI, Trick Flow 56cc alum heads, SLP runners, Comp Cams 260AH-12 cam, Trick Flow 1.5 roller rockers, Bilsteins, TCI 2400 stall converter, Ramcharger fans, Denny's 3.5" Driveshaft, GBodyParts GNX Wheels.
#1063443 - 09/04/19 09:38 PM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
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Hi Fred,

Ah, the limitations of language. I wish I could get inside your head to find out exactly what "good" means. But even if I could, then it would take potentially years research to determine which package(s) would satisfy that definition.

9" rim width in the back: please don't forget that you need additional transverse clearance around the tire for unexpected things like:

1. transverse compliance in the suspension between the rear and frame;
2. transverse compliance in the connection between the body and frame;
3. transverse migration of the wheel as the suspension moves, considering the instant roll center location;
4. rim/axle-flange flex;
5. tire section distortion while cornering and with road undulations.

There are probably more considerations, but that's what immediately comes to mind.

Best,
MAP

Last edited by MAP; 09/04/19 09:39 PM.
#1063445 - 09/05/19 01:49 AM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
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Originally Posted by Fred SS
As of this post, my current plan is to get the 18 x 8 x 4.0 Backsapce rims (245/40-18 tires) for the front and 18 x 9 x 4.25 Backspace rims (255/40-18 tires) for the rear. The reason for the slightly larger size in the rear is that I always did like a staggered setup. My Monte is lowered about 1.5 inches. My measurements indicate that I will have to roll the rear fender lips or raise the car. I ordered the Eastwood Fender roller yesterday..


Fred, I plugged in the info you provided into the following web application (compares two wheel/tire combos)
https://www.rimsntires.com/specspro.jsp

If you have the SLP ZR1 17x8 with 4.5” backspacing, the front and rear will have more clearance toward the inside than you have now. The GNX front tire/wheel combo will stick out about 0.5” more and the rear will stick out about 0.8” (plus or minus a bit due to varying section widths).

I’ve been srtuggling a lot on wheels but finally made my mid up on a set of Intros - more than I wanted to spend but I figure if I don't get what I want I'll end up spending more later. If you’re not set on the GNX replicas, the AR Super Nova wheels below have the same offset in a 8" and 9" rim that you're running now (0) and wouldn't stick out any more than what you're running now.

[Linked Image]

These Vision 143s in a 18x8.5 with -6 offset (4.5" backspacing) just might fit all four corners with a 255/40/18.

[Linked Image]

#1063448 - 09/05/19 03:55 AM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
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MAP, I have considered allot of the issues that you mentioned. Thank You. I try to avoid making rush decisions and try to have a plan. At my job, it is called operational risk management. I have not laid it all down on paper in a spread sheet, but I have looked at several of the issues.

Kevin, I looked at the AR Super Nova, Visions 143 wheels and allot of others. I like the Vision wheels. They have the same offset as the stock rims. A forum member bought those rims about a year ago I think. But I really want a gloss black center. The Vision 143 wheels are a dark gray.

Really, the only thing that is holding up the purchase is trying to get an SS center cap inlay, instead of the standard "Chevrolet" inlay they sell now. I want red SS letters on a black background. GBodyParts wants me give them a graphics file and they will print it. I'll see what I can come up with tomorrow.

I always did like the GTA and GNX mesh wheels. Even though they are probably time consuming to clean. All those nooks and crannies. Will need a bottle brush.


87 SS, Harwood cowl induction hood, UMI trailing arms. Edelbrock TES Headers (Jet Hot Coated). Goodwrench 350, Ported TPI, Trick Flow 56cc alum heads, SLP runners, Comp Cams 260AH-12 cam, Trick Flow 1.5 roller rockers, Bilsteins, TCI 2400 stall converter, Ramcharger fans, Denny's 3.5" Driveshaft, GBodyParts GNX Wheels.
#1063450 - 09/05/19 05:05 AM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
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Fred, actually for the GTA wheels you need a few sizes of bottle brushes. If it wasn't for the dusting of the Hawk HPS pads cleaning the wheels is usually just a microfiber wash rag on the polished Seal and Shine finish. They are very easy wheels to maintain/clean after I got rid of the clearcoat. MUCH easier than the stock SS wheels that would cut you hand if not careful. I dislike (you can't say hate anymore) cleaning wheels!

Fred you mentioned the Baer brakes pushing the wheel outboard .400", got a Baer link to that setup? As a comparison the B spindle moves the wheel outboard about .440", an 8" wheel with 4 7/16" backspacing, zero offset, running a 255/50x16 BFG Comp 2 (ht is 26.1"- section width 10.4"), 5 degrees caster was my setup for many years before extensive LCA relocation. Only rub was at 9 o'clock, back, inside of well at full lock. No rub at the top of the wells. Have run a Camaro XH the whole time the 16" were on the car, the limited travel of that box prevents rubbing the 36mm bar or the frame in the rear at full lock.
Now run 9 1/2 caster by moving the ball joint forward 11/16" and absolute zero rub anywhere. Anything over 7 degrees before the mod and tire rub was not acceptable in the rear of the well.

Ride height has everything to do with tire rub. Using a drywall T-square on the centerline of the spindle, a small T-square at the opening lip has been my standard to keep a very accurate ride height measurement for decades. For the type and location of the driving I do I run 26 1/2" ride height up front, 27 1/4 - 27 1/2 in the rear. The 255/50x16 is about 3/8-1/2" taller than most choices so it adds a little to the ride height. Any lower than that you really limit the compression travel up front, which is limited to start with. On both the front and rear you end up running on the bumpstops. Ride height is one of those subjects i don't like to discuss, to each his own.
Bob

#1063461 - 09/05/19 10:32 PM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
Joined: Apr 2009
Posts: 801
Fred SS Offline
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Fred SS  Offline
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Glassboro, NJ
Bob, the link to the Baer front big brake upgrade is below:

https://baer.com/13-Front-Track4-Brake-System-4301406.html

About a 1/3 of the way down the page is "Track Width Increase".

Fred


87 SS, Harwood cowl induction hood, UMI trailing arms. Edelbrock TES Headers (Jet Hot Coated). Goodwrench 350, Ported TPI, Trick Flow 56cc alum heads, SLP runners, Comp Cams 260AH-12 cam, Trick Flow 1.5 roller rockers, Bilsteins, TCI 2400 stall converter, Ramcharger fans, Denny's 3.5" Driveshaft, GBodyParts GNX Wheels.
#1063462 - 09/06/19 12:25 AM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
Joined: Feb 2008
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AkronAero Offline
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AkronAero  Offline
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Joined: Feb 2008
Posts: 751
Akron OH
Fred - will you be eventually upgrading the rears too? How about the master cylinder?
Haven't talked to Marcus Savitske at SC&C recently but had scoped out some changes a while back.
So the track 4 fronts are new (maybe replacing the SS4+ fronts?).
Like to follow what you are doing, and reconnect with Marcus this fall; lots of Baer stuff on his site.
Keep us posted.
Gordon

#1063463 - 09/06/19 04:01 AM Re: 18x8 Rim with 255/40-18; Downsides? [Re: Fred SS]  
Joined: Apr 2009
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Fred SS Offline
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Fred SS  Offline
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Posts: 801
Glassboro, NJ
Gordon, I only looked at the Baer front brake kit because Baer tells you the amount of track width increase There are other less expensive front brake upgrades, like LS1 and of course the C5 upgrade using blazer spindles. When will CPP have their G-Body/C-5 spindles ready? I have been watching their website for years and it still says "Coming soon". But I have to admit, Baer is a one stop shop. Their brake upgrade is bolt on. But Flynbye also has bolt-on kits. But I want to do the C5 front brake upgrade. I have the blazer spindles, adapter plate and other pieces from Kore3 but I am not sure if it will fit the GNX reproduction rims. I have the brake template from Kore3 and that will be the first thing I check when I get the rims. I also do not know how much of a track width increase I will see with the blazer spindles. Maybe someone can chime in who knows if there is a track increase with blazer spindles.

I managed to whip up an SS emblem today. Red letters on a black background. GBodyParts told me that they sent it to their graphics dept. I am ready to hit the buy button, but this center cap thing is holding it up. I think what is happening is that GBodyParts is concerned about liability. Their last email indicated that they plan to make 100 of these SS inlays in hopes that others will want them. I think getting me to do the graphic relieves them of some liability. Never thought I would need a lawyer to buy a set of rims.


87 SS, Harwood cowl induction hood, UMI trailing arms. Edelbrock TES Headers (Jet Hot Coated). Goodwrench 350, Ported TPI, Trick Flow 56cc alum heads, SLP runners, Comp Cams 260AH-12 cam, Trick Flow 1.5 roller rockers, Bilsteins, TCI 2400 stall converter, Ramcharger fans, Denny's 3.5" Driveshaft, GBodyParts GNX Wheels.
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