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Old 03-04-2012, 07:26 AM   #1
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295/45ZR18 too much sidewall?

I'm thinking of getting 18x10s all around, with Nitto NT05 295/45ZR18s.

Benefits: Really light rims (21 lbs per rim), maintains stock ride height (I am already lowered and scraping on speed bumps), really sticky tire for track and can run on street too.

Possible drawbacks: Very tall sidewall, some grinding of knuckle required (no biggie).

Nine Ball cautions that this high sidewall could negatively affect hard cornering on a road course.

Anyone actually running this combo who could comment?

Tony suggests shorter tires, but that would drop me another inch and require tuning to calibrate correct speed, etc. On the other hand, a shorter tire is more response in turns maybe



Thanks
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Old 03-04-2012, 08:07 AM   #2
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I am looking at doing something similar, but going with the 285/40/18's I know I will drop approx. another inch, and need to be re-calibrated. That is what tunes are for.

Subscribed to hear other responses too.
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Old 03-04-2012, 10:02 AM   #3
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Total weight

I'm just playing around with different combos to get total weight of tire + rim here, in case anyone finds this useful.

OPTION 1 : LIGHTEST KEEPING OEM RIDE HEIGHT
18x10 F14 wheels = between 21 lbs (courtesy of Nine Ball)
Nitto NT05 295/45ZR18 = 33.22 lbs (hard to say, Nitto does not list but some resellers list weight. These from tireswheelsdirect.com)
TOTAL = 54 lbs. Light, but huge sidewalls. Tire is 28.46 high, so that means 5.23 inch sidewalls

OPTION 2A : FATTEST REARS OEM RIDE HEIGHT
20x10.5 F14 wheels = 28 lbs
Nitto NT05 315/35/20 = 35.86 lbs
TOTAL = 64 lbs
But, this is a much fatter tire. OEM is 64 rear. Tire is 28.6 high, so 4.3 inch sidewalls.

OPTION 2B : MATCHING 20 INCH FRONTS OEM RIDE HEIGHT
20x9.5 F14 wheels = 26.5 lbs
Nitto NT05 275/40/20 = 33.51 lbs
TOTAL = 60 lbs. OEM is 60.7 front. Also 4.3 inch sidewalls.

OPTION 3 : LIGHTEST AND SCREW OEM RIDE HEIGHT
18x10 F14s = 21 lbs
Nitto NT05 295/35/18 = 29.7 lbs
TOTAL = 51 lbs. But this is only a 26.18 inch high tire, so car gets lowered, gotta tune for phantom mileage, etc. But, 4.14 inch sidewalls.


I still gotta say that Option 1 looks great on paper but I wonder what the extra inch in sidewall does.

Option 2 gets more meat on the back but at quite a weight cost (+10lbs each back wheel, +6 lbs each front vs Option 1).

Going with Option 3 and a tune would be cool but I would be swapping back to my winter tires at times (gotta drive in snow sometimes) and so would be swapping tunes, etc. too.

The reason I am obsessing on weight is that apparently rotating mass has a big impact - some say 1 lb of reduction in unsprung weight is the equivalent of 10 lbs reduction of sprung weight. So, 32 lbs diff = like having a car that is 320 lbs lighter. (not saying for sure this is true, but what I have heard)

Would love to hear from people who are doing any of the above (esp Option 1) and who have personal experience with that sidewall height on road course conditions.
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Last edited by SSSoon; 03-04-2012 at 10:16 AM.
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Old 03-04-2012, 03:04 PM   #4
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Everyone has opinions and this is mine. I am not a fan of the Nitto range with the exception of the NT05. The OEM Pirellis are a good quality tire woith good grip, but that are too tall. When we looked for a replacement we settled on the Bridgestone RE-11 305/30/19/XL for several reasons. It is by far, again in our opinion, the best combination street track tire on the market. The only size they had available to suit the Camaro was and is the 305/30/19. Michelin Pilot Sport IIs are a great tire and available in sizes to suite the Camaro. Our choice in this range would be the 305/35/20 on a 20x10.5 rim. We ran this on the LPE L/28. They performed very well, but not as well as the RE-11 in the smaller size. The new Super Sport is a very good tire available in a 295/35/20/XL, 29 pounds and at 27" is only a bit over an inch smaller than the OE Pirellis. They should be mounted on 10.5" rim width. If I were to go with a 20" wheel again, this would be my tire choice.

The XL designation is important is you run aftermarket wheels They protect your wheels. Getting your tires mounted on the correct rim width is mission critical. Based on the number of Camaros we have set up, we and the owners have settled into thinking the 30 profile is best.

The bigger the rear tires, the more push your 5th Gen will have. It isn't as well balanced or as light as a Vette where the staggered setup is highly desirable. We already have more than enough push in the 5th Gen.

I vote for Option #4 Michelin Super Sport 295/30/20/XL on 20x10.5 wheels.

Again, these are just my opinions.
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Old 03-04-2012, 03:29 PM   #5
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Originally Posted by JusticePete View Post
The new Super Sport is a very good tire available in a 295/35/20/XL, 29 pounds and at 27" is only a bit over an inch smaller than the OE Pirellis. They should be mounted on 10.5" rim width. If I were to go with a 20" wheel again, this would be my tire choice.

The XL designation is important is you run aftermarket wheels They protect your wheels. Getting your tires mounted on the correct rim width is mission critical. Based on the number of Camaros we have set up, we and the owners have settled into thinking the 30 profile is best.

I vote for Option #4 Michelin Super Sport 295/30/20/XL on 20x10.5 wheels.

Again, these are just my opinions.
Hey Pete, thanks for your thoughts. Very helpful.

Obviously the specific brand / design / rubber compound used is important, but if we took that out of the equation for a moment (assume we are talking about the same tire in all configurations), would you say that:

1: tire width and aspect ratio is MORE important than wheel weight when it comes to road course performance?

2: the upside of a drop in wheel weight from smaller diameter rims is LESS important than the downside of a taller sidewall, based on what you have seen (again, assuming a road course scenario not a drag strip scenario)?

It really helps to hear experience talkin'... thanks man.

Pete

PS I just checked the weights:
Forgestar F14s 20x10.5 = 28 lbs (thanks to Nine Ball)
Michelin Super Sport 295/30/20/XL = 29 lbs
TOTAL = 57 lbs per wheel
SAVINGS vs OEM = 4 lbs on each front wheel, 7 lbs on each rear = 22 lbs savings total. In the best 18 inch scenario above I had a total of 32 lbs savings I think. Almost doesn't seem worth it to go for the 18 now that I calculate it out.
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Last edited by SSSoon; 03-04-2012 at 03:45 PM.
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Old 03-04-2012, 03:41 PM   #6
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When I first got my 18s I originally went with 28" tires and it handled like crap compared to the stock 20" tires. I was at the tire shop getting them taken off with in 30 min. I went with stock sized sidewall tires and it was a world of a difference! The handling back and then some, it didn't feel like an SUV anymore.


If you aren't going with a shorter tire with the 18s, then I wouldn't do it.
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Old 03-04-2012, 03:54 PM   #7
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Quote:
Originally Posted by SSSoon View Post
Hey Pete, thanks for your thoughts. Very helpful.

Obviously the specific brand / design / rubber compound used is important, but if we took that out of the equation for a moment (assume we are talking about the same tire in all configurations), would you say that:

1: tire width and aspect ratio is MORE important than wheel weight when it comes to road course performance? and Contact Patch. There has to be enough suspension and enough sidewall flex to keep the tire on the track surface. I would trade a couple of pounds for a bigger contact patch and increased control. Now is we are talking slicks the 18s...

2: the upside of a drop in wheel weight from smaller diameter rims is LESS important than the downside of a taller sidewall, based on what you have seen (again, assuming a road course scenario not a drag strip scenario)?

Yes sir.

It really helps to hear experience talkin'... thanks man.

Pete

PS I just checked the weights:
Forgestar F14s 20x10.5 = 28 lbs (thanks to Nine Ball)
Michelin Super Sport 295/30/20/XL = 29 lbs
TOTAL = 57 lbs per wheel
SAVINGS vs OEM = 4 lbs on each front wheel, 7 lbs on each rear = 22 lbs savings total. In the best 18 inch scenario above I had a total of 32 lbs savings I think. Almost doesn't seem worth it to go for the 18 now that I calculate it out.
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Old 03-04-2012, 06:48 PM   #8
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Originally Posted by JusticePete View Post
The new Super Sport is a very good tire available in a 295/35/20/XL, 29 pounds and at 27" is only a bit over an inch smaller than the OE Pirellis. They should be mounted on 10.5" rim width.
Did some digging, and am trying to get my head around the pros/cons of different rim sizes.

Michelin lists rim size as 10-11 inches for the above tire.

Forgestar has lightweight CF10, 20x10, that they list at 24.6 lbs.

Curious as to why you would recommend a 10.5" rim width over a 10" (or even an 11") and what the difference would be (driveability, sidewall flex, rim protection ...?)

Really appreciate your thoughts!
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Old 03-06-2012, 05:44 PM   #9
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Thanks SSSoon for starting this informative thread.


On a side note. I just wish tire manufacturers (namely Bridgestone) release tire sizes that would better complement the maro. The available selection of compatible tire sizes and manufacturers for the camaro is pathetic...

For instance, I'm still trying to figure out a good road course tire for the camaro and the events I need the tires for has size restrictions. If I choose to go with what Bridgestone currently has available in the RE-11's, I am limited with the 285/35-19's. That works out to being almost 1 1/2" shorter that the factory tire sizes. A 285/40-19 or 285/45-19 would be perfect but they don't exist...
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Old 03-06-2012, 05:49 PM   #10
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Quote:
Originally Posted by SSSoon View Post
Hey Pete, thanks for your thoughts. Very helpful.

Obviously the specific brand / design / rubber compound used is important, but if we took that out of the equation for a moment (assume we are talking about the same tire in all configurations), would you say that:

1: tire width and aspect ratio is MORE important than wheel weight when it comes to road course performance?

2: the upside of a drop in wheel weight from smaller diameter rims is LESS important than the downside of a taller sidewall, based on what you have seen (again, assuming a road course scenario not a drag strip scenario)?

It really helps to hear experience talkin'... thanks man.

Pete

PS I just checked the weights:
Forgestar F14s 20x10.5 = 28 lbs (thanks to Nine Ball)
Michelin Super Sport 295/30/20/XL = 29 lbs
TOTAL = 57 lbs per wheel
SAVINGS vs OEM = 4 lbs on each front wheel, 7 lbs on each rear = 22 lbs savings total. In the best 18 inch scenario above I had a total of 32 lbs savings I think. Almost doesn't seem worth it to go for the 18 now that I calculate it out.


Yes, but the stock tires are only 245s front and 275s rear. In the example above, you're using 295 series tires (much wider front and back). So your losing rotational mass (not just static weight) and running a wider tire front and back (larger contact patch).

I just know the drag racing guys save a ton of weight going to 18" wheels. Here's Padre's example using TSW Nurburgrings (which I run in 20").
Not the best road course setup (too much sidewall in his tire choices), but it puts wider tires up front and back. For drag, an even skinner front tire would be better.

TSW Nurburgring 18x8 (35mm offset), 18x9.5 (40mm offset), matte gunmetal
Nitto 555, 265/50-18 and Nitto 555R, 305/45-18 - these maintain the stock height.

Fronts weigh 50.5 lbs each vs. 62.3 lbs stock.
Rears weigh 53.5 lbs each vs. 68 lbs stock.

104 lbs vs 130.3 lbs.
So that's a 26 lb reduction in rotational mass and the ability to run a 18" drag radials that hook much better than 20" drag radials.

Also, 26 lbs of rotational mass needs to be multiplied to equal static weight. (worth a lot more than 26 lbs as far as performance). Don't forget its rotating mass not just dead weight on the car.

So for the drag racers, dropping to 18" wheels is very beneficial.
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Old 03-06-2012, 09:01 PM   #11
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Quote:
Originally Posted by jrv2kgt-s View Post
Thanks SSSoon for starting this informative thread.


On a side note. I just wish tire manufacturers (namely Bridgestone) release tire sizes that would better complement the maro. The available selection of compatible tire sizes and manufacturers for the camaro is pathetic...

For instance, I'm still trying to figure out a good road course tire for the camaro and the events I need the tires for has size restrictions. If I choose to go with what Bridgestone currently has available in the RE-11's, I am limited with the 285/35-19's. That works out to being almost 1 1/2" shorter that the factory tire sizes. A 285/40-19 or 285/45-19 would be perfect but they don't exist...
305/35/19/XLs on 19x10.5s
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Old 03-06-2012, 10:44 PM   #12
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Quote:
Originally Posted by SGOS252382 View Post
I just know the drag racing guys save a ton of weight going to 18" wheels. Here's Padre's example using TSW Nurburgrings (which I run in 20").
Not the best road course setup (too much sidewall in his tire choices), but it puts wider tires up front and back. For drag, an even skinner front tire would be better.

TSW Nurburgring 18x8 (35mm offset), 18x9.5 (40mm offset), matte gunmetal
Nitto 555, 265/50-18 and Nitto 555R, 305/45-18 - these maintain the stock height.

Fronts weigh 50.5 lbs each vs. 62.3 lbs stock.
Rears weigh 53.5 lbs each vs. 68 lbs stock.

104 lbs vs 130.3 lbs.
So that's a 26 lb reduction in rotational mass and the ability to run a 18" drag radials that hook much better than 20" drag radials.

Also, 26 lbs of rotational mass needs to be multiplied to equal static weight. (worth a lot more than 26 lbs as far as performance). Don't forget its rotating mass not just dead weight on the car.

So for the drag racers, dropping to 18" wheels is very beneficial.
For real weight savings you have to step down in tire size.
My street set up 18s are 66 lbs lighter than stock and my track set up 18s are 102 lbs lighter than stock.
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Old 03-06-2012, 11:10 PM   #13
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Originally Posted by SSSoon View Post
Did some digging, and am trying to get my head around the pros/cons of different rim sizes.

Michelin lists rim size as 10-11 inches for the above tire.

Forgestar has lightweight CF10, 20x10, that they list at 24.6 lbs.

Curious as to why you would recommend a 10.5" rim width over a 10" (or even an 11") and what the difference would be (driveability, sidewall flex, rim protection ...?)

Really appreciate your thoughts!
SSSoon,

The 10.5 will stretch the tire and give you great feedback. The ten very good, but not as good as the 10.5. The 11 stretches the tire tighter for a really crisp feel, but watch the pot holes.
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Old 03-07-2012, 07:04 AM   #14
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Quote:
Originally Posted by SGOS252382 View Post
I just know the drag racing guys save a ton of weight going to 18" wheels. Here's Padre's example using TSW Nurburgrings (which I run in 20").
Not the best road course setup (too much sidewall in his tire choices), but it puts wider tires up front and back. For drag, an even skinner front tire would be better.

TSW Nurburgring 18x8 (35mm offset), 18x9.5 (40mm offset), matte gunmetal
Nitto 555, 265/50-18 and Nitto 555R, 305/45-18 - these maintain the stock height.

Fronts weigh 50.5 lbs each vs. 62.3 lbs stock.
Rears weigh 53.5 lbs each vs. 68 lbs stock.

104 lbs vs 130.3 lbs.
So that's a 26 lb reduction in rotational mass and the ability to run a 18" drag radials that hook much better than 20" drag radials.

So for the drag racers, dropping to 18" wheels is very beneficial.
Yeah, I'm coming to realize the big differences in priorities for drag vs. road course. Tall sidewalls = good idea on the drag strip, but not a good idea for cornering. I guess that is why guys who are real serious have different rims+tires for each.

One of the reasons I posted the calculations I did up top was to try to figure out the true benefits of smaller rims. If you maintain stock height and go with an 18 inch rim, you have to make up the difference with rubber - in general, comparing within tire brand, the tires are heavier than those made for a 20 inch rim. So it seems like to make a good decision you would want to:

1. Find a light rim
2. Reduce overall tire height
3. Find a light tire

BUT, then comes the hard part - how grippy is the tire you picked? The wear ratings can tell you generally what is roughly comparable but it seems as though the best indicator of grippyness is to talk to people who have actually personally tried different tires and can offer firsthand evidence. And, even more important, have they tried using those tires for the purposes that you plan on using them for? Lots of tires get rave reviews for certain purposes - drag guys like one thing, track guys like another, some people are just delighted to get a tire that lasts a long time and seems marginally better than the Pzeros. It's probably obvious to many people but it took me a lot of digging to really accept that no tire can do it all.

One thing I wish I understood better is contact patch. Sure, a wider tire gives you more contact, and in general I think everyone agrees that is a good thing for performance applications. But beyond that, I wonder how much difference overall tire radius has on contact patch. Is a 26" or 27" high tire really different from a 28.5" high tire? Or, does it all really not matter much and the real thing that matters is tire pressure? I bet getting the right pressure to maximize contact patch is key. I wonder how you can tell whether you have the best tire pressure. JusticePete points out that getting the rim width right for a certain tire is also key to maximizing contact patch. Lots of variables.
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Old 03-07-2012, 11:36 AM   #15
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Quote:
Originally Posted by SSSoon View Post
Yeah, I'm coming to realize the big differences in priorities for drag vs. road course. Tall sidewalls = good idea on the drag strip, but not a good idea for cornering. I guess that is why guys who are real serious have different rims+tires for each.

One of the reasons I posted the calculations I did up top was to try to figure out the true benefits of smaller rims. If you maintain stock height and go with an 18 inch rim, you have to make up the difference with rubber - in general, comparing within tire brand, the tires are heavier than those made for a 20 inch rim. So it seems like to make a good decision you would want to:

1. Find a light rim
2. Reduce overall tire height
3. Find a light tire

BUT, then comes the hard part - how grippy is the tire you picked? The wear ratings can tell you generally what is roughly comparable but it seems as though the best indicator of grippyness is to talk to people who have actually personally tried different tires and can offer firsthand evidence. And, even more important, have they tried using those tires for the purposes that you plan on using them for? Lots of tires get rave reviews for certain purposes - drag guys like one thing, track guys like another, some people are just delighted to get a tire that lasts a long time and seems marginally better than the Pzeros. It's probably obvious to many people but it took me a lot of digging to really accept that no tire can do it all.

One thing I wish I understood better is contact patch. Sure, a wider tire gives you more contact, and in general I think everyone agrees that is a good thing for performance applications. But beyond that, I wonder how much difference overall tire radius has on contact patch. Is a 26" or 27" high tire really different from a 28.5" high tire? Or, does it all really not matter much and the real thing that matters is tire pressure? I bet getting the right pressure to maximize contact patch is key. I wonder how you can tell whether you have the best tire pressure. JusticePete points out that getting the rim width right for a certain tire is also key to maximizing contact patch. Lots of variables.

Tire height is indeed crucial. For a drag racer you want to increase sidewall so that the tire can "wrinkle" and bite. The exact opposite is true for autocross and road racing. You want to decrease sidewall height so that the sidewall is stable during cornering.

As far as contact patch is concerned, the want the tire to be as square with the rim as possible or slightly smaller (stretched) for road racing. Going with a larger tire than the rim width does not help you at all in any scenerio. I see it all the time where a guy says he squeezed a 315 on the stock 9" wheel. That's great and all but contact patch remains at 9". The extra bulge over the rim width rolls under hard acceleration and provides nothing extra for grip.

What we are discussing is all geared towards the perfect combination for the application. Will the average driver ever know the difference between a squared up tire on the rim or a slightly stretched setup? Maybe, but doubtful.

I have heard that Factory Cadillac test driver John Heinricy can tell a 1lb tire difference in tire pressure. He's also a pro driver. What am I getting at? Don't beat yourself up over "the perfect combination". Sometimes having a tire with a little give can be a good thing for the novice driver. GM builds in the best performance they can while keeping the car safe. I can tell you from experience that having a stretched tire with very stiff sidewall and grippy tires can be a tad overwhelming when you find the limit. There's very little time between a hard corner and the point of traction loss that correction is nearly impossible for all but the very best drivers.

Unless your plan is to go pro and test out tons of combinations to find the best setup for your driving style, then subscribe to this formula. Smaller diameter wheels and tires give better performance. So pick a set of 18 or 19" lightweight wheels with about a 1" smaller overall diameter than stock. Pick a tire like the nitto NT05 and go out and enjoy yourself. Learn your car, and have fun. As you progress you may want to try something different.
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Old 03-07-2012, 12:01 PM   #16
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Also Lionel on the boards here runs our 18" lightweight wheels with a 295/45/18 and autocrosses most weekends. He is extremely competitive!
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Old 03-07-2012, 01:27 PM   #17
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Some good stuff in this thread. I've also been wondering about the higher sidewall since there seems to be an extremely limited choice of ultra/extreme performance tire in the factory height. I think the best we've found so far is the RE-11 in a 285/35-19 which is stll a good bit shorter than stock. What tire is everyone running for serious autocross/road course duty (other than R-comps)? Anyone have experiece with the NT-05's? How do they grip when cool?
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Old 03-07-2012, 08:16 PM   #18
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What we are discussing is all geared towards the perfect combination for the application. Will the average driver ever know the difference between a squared up tire on the rim or a slightly stretched setup? Maybe, but doubtful.

I have heard that Factory Cadillac test driver John Heinricy can tell a 1lb tire difference in tire pressure. He's also a pro driver. What am I getting at? Don't beat yourself up over "the perfect combination". Sometimes having a tire with a little give can be a good thing for the novice driver. GM builds in the best performance they can while keeping the car safe. I can tell you from experience that having a stretched tire with very stiff sidewall and grippy tires can be a tad overwhelming when you find the limit. There's very little time between a hard corner and the point of traction loss that correction is nearly impossible for all but the very best drivers.

Unless your plan is to go pro and test out tons of combinations to find the best setup for your driving style, then subscribe to this formula. Smaller diameter wheels and tires give better performance. So pick a set of 18 or 19" lightweight wheels with about a 1" smaller overall diameter than stock. Pick a tire like the nitto NT05 and go out and enjoy yourself. Learn your car, and have fun. As you progress you may want to try something different.
Thanks for the response. Yep - sounds like a lot of experience talking there.

You're right. I am not going to test out a ton of combinations. I'm also not going pro any time soon just really starting out and trying to make good choices.

FYI in trying to compare relatively similar tires:

Michelin Pilot Super Sport 295/30/20/XLs = 29.6 lbs, 27" high
Michelin Pilot Super Sport 305/35/19/XLs = 29.9 lbs, 26.3" high

The sidewall for the 19s would actually be about .6 inches shorter than OEM. Too bad there isn't a 305/40/19/XL in the Super Sport.

The weight saving from going to a 19 inch rim (I am guessing about 2-3 lbs per rim) would be a clean gain.

Either way would have to adjust my coilvers because I don't think I can ride 1.1 inches closer to the ground and not be dragging...

Decisions, decisions...
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Old 03-07-2012, 08:49 PM   #19
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Thanks for the shout out!

If agree with what most are saying here... If you're after performance, a light 18" wheel, short and stretched, sticky tire is what you want...

I went with what I did based on a mixture of weight savings, performance, and comfort. The taller tire means I didn't have to tune to correct my spedo/odometer for the change in circumference and it wouldn't be so rough driving around my GF on date nights.

Now that I've been bit by the Autocross bug... I plan on going the performance route and not worry about the other things. I might even switch to slicks if I can progress in skills faster than my tires wear out. These NT05s are good but there are some others out there too.

Good luck with your build!
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Old 03-24-2012, 07:56 PM   #20
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Michelin Pilot Super Sport XL 295/30ZR-20 ready to go. Just waiting on rims.

27" diameter, so will get my tune updated from JRE to reflect smaller diameter.

Will have to raise my coilovers a little because these will effectively lower my car by another 3/4 inch. Don't want to be scraping...

4 weeks till Forgestar delivers!
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Old 03-24-2012, 09:29 PM   #21
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I'm just playing around with different combos to get total weight of tire + rim here, in case anyone finds this useful.

OPTION 1 : LIGHTEST KEEPING OEM RIDE HEIGHT
18x10 F14 wheels = between 21 lbs (courtesy of Nine Ball)
Nitto NT05 295/45ZR18 = 33.22 lbs (hard to say, Nitto does not list but some resellers list weight. These from tireswheelsdirect.com)
TOTAL = 54 lbs. Light, but huge sidewalls. Tire is 28.46 high, so that means 5.23 inch sidewalls

OPTION 2A : FATTEST REARS OEM RIDE HEIGHT
20x10.5 F14 wheels = 28 lbs
Nitto NT05 315/35/20 = 35.86 lbs
TOTAL = 64 lbs
But, this is a much fatter tire. OEM is 64 rear. Tire is 28.6 high, so 4.3 inch sidewalls.

OPTION 2B : MATCHING 20 INCH FRONTS OEM RIDE HEIGHT
20x9.5 F14 wheels = 26.5 lbs
Nitto NT05 275/40/20 = 33.51 lbs
TOTAL = 60 lbs. OEM is 60.7 front. Also 4.3 inch sidewalls.

OPTION 3 : LIGHTEST AND SCREW OEM RIDE HEIGHT
18x10 F14s = 21 lbs
Nitto NT05 295/35/18 = 29.7 lbs
TOTAL = 51 lbs. But this is only a 26.18 inch high tire, so car gets lowered, gotta tune for phantom mileage, etc. But, 4.14 inch sidewalls.


I still gotta say that Option 1 looks great on paper but I wonder what the extra inch in sidewall does.

Option 2 gets more meat on the back but at quite a weight cost (+10lbs each back wheel, +6 lbs each front vs Option 1).

Going with Option 3 and a tune would be cool but I would be swapping back to my winter tires at times (gotta drive in snow sometimes) and so would be swapping tunes, etc. too.

The reason I am obsessing on weight is that apparently rotating mass has a big impact - some say 1 lb of reduction in unsprung weight is the equivalent of 10 lbs reduction of sprung weight. So, 32 lbs diff = like having a car that is 320 lbs lighter. (not saying for sure this is true, but what I have heard)

Would love to hear from people who are doing any of the above (esp Option 1) and who have personal experience with that sidewall height on road course conditions.

I was wondering how wide I could go on a stock SS and your option #2 is wide enough for me. If I can track down those wheels I will get them and matching fronts but only 8.5 wide. Hopefully I will track these down soon enough. Thanks for the input.
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Old 03-26-2012, 02:17 PM   #22
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Michelin Pilot Super Sport XL 295/30ZR-20 ready to go. Just waiting on rims.

27" diameter, so will get my tune updated from JRE to reflect smaller diameter.

Will have to raise my coilovers a little because these will effectively lower my car by another 3/4 inch. Don't want to be scraping...

4 weeks till Forgestar delivers!


Anything under your 5th Gen that scrapes is self clearancing

Quote:
Originally Posted by Ed's 2SS/RS View Post
I was wondering how wide I could go on a stock SS and your option #2 is wide enough for me. If I can track down those wheels I will get them and matching fronts but only 8.5 wide. Hopefully I will track these down soon enough. Thanks for the input.
Go to the tire manufacturer's website and select the tire of your choice. Some where on the page will be a link to technical details. This is from the Michelin Super Sport Page.

Technical Specifications:
View Tech Spec details

Click on the Tech Spec link when it opens.

Check the MFG's Rim Width Range (Min/Max) The sweet spot will be in the middle of the stated range. Under no circumstances should you mount a tire on a rim that is below the MFG minimum width. You'll see a lot of people on C5 that put to wide a tire on too narrow a rim Follow the MFG
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Old 03-26-2012, 06:22 PM   #23
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Anything under your 5th Gen that scrapes is self clearancing
Scraped over a speed bump that caught on my exhaust - one tailpipe is now 2 inches longer than the other. Gotta get under there when it's cold to slide it back together...
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Old 03-27-2012, 11:16 AM   #24
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Scraped over a speed bump that caught on my exhaust - one tailpipe is now 2 inches longer than the other. Gotta get under there when it's cold to slide it back together...
Exhaust and lowered cars scrape. Get you exhaust exactly right and spot weld the joints. When you need to remove it a couple of small welds are easy to grind off.
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Old 05-06-2012, 09:04 PM   #25
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Got my 20x10.5 F14s (thanks Nineball!) fitted with Michelin Pilot Super Sports Thursday. They look and feel awesome. I'm running the 295 30z20s and these are 27 inch tires. The added torque from the smaller tires is really nice - the car feels like it is raring to go every time you touch the gas. I would highly recommend this combo to anyone.

Spent the day at my first autocross - what a blast. Came in 3/17 in my bracket (STU, I think). The tires really handle nicely. Thanks again JusticePete for the recommendation!

I got a square setup so that I could rotate tires. The fronts stick out a bit - see pix. I used a 12x36 plain black truck mud flap and arced it around the rim, screwed and clipped it in with some 3M tape in there too. Holds nice, does the job perfectly, and is pretty minimal. Am getting ZL1 mudflaps for the rear. Will match nicely I think.
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