Why the narrow wheels on the C7 Z51?
05-27-2013, 12:33 PM
#41
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GM's official line:
http://media.gm.com/content/product/...7/chassis.html
The Corvette Stingray rides on new 18 x 8.5-inch front and 19 x 10-inch rear wheels, while models with the Z51 Performance Package roll on 19 x 8.5-inch front and 20 x 10-inch rear forged aluminum wheels. New Michelin Pilot Super Sport run-flat tires developed specifically for the seventh-generation Corvette deliver comparable levels of grip than the wider tires of previous models.
As a result, the Corvette Stingray with the Z51 Performance Package is capable of 1g in cornering acceleration – comparable to the 2013 Corvette Grand Sport. Significantly, that is achieved with narrower and lighter wheels and tires. The reduced “footprint” reduces rolling resistance, steering effort and road noise , contributing to a more nimble feel, more immediate steering response and greater touring comfort and efficiency.
Dimensionally, the new Corvette’s wheelbase is approximately an inch longer than the previous generation, with front and rear tracks that are almost an inch wider. Those changes provide a more stable feel, particularly at high speeds, while the turning radius is decreased by approximately two feet for greater maneuverability in tight turns.
As a result, the Corvette Stingray with the Z51 Performance Package is capable of 1g in cornering acceleration – comparable to the 2013 Corvette Grand Sport. Significantly, that is achieved with narrower and lighter wheels and tires. The reduced “footprint” reduces rolling resistance, steering effort and road noise , contributing to a more nimble feel, more immediate steering response and greater touring comfort and efficiency.
Dimensionally, the new Corvette’s wheelbase is approximately an inch longer than the previous generation, with front and rear tracks that are almost an inch wider. Those changes provide a more stable feel, particularly at high speeds, while the turning radius is decreased by approximately two feet for greater maneuverability in tight turns.
05-27-2013, 12:48 PM
#42
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Let me start off by saying that this is not a bash C7 thread. I am one that personally likes the styling and engineering that went into the new C7 ... Will I trade my GS for a C7? ... not sure right now.
Anyway, I am still scratching my head as to why the engineers selected narrower wheels for the C7 Z51 than what is standard on the C6 GS.
I am not comparing the base C7 wheels to the base C6 wheels here.
I choose to compare the C7 Z51 wheels to the C6 GS wheels because both these cars have upgraded performance suspensions and brakes in comparison to the base versions of each.
C6 GS
18" x 9.5"(front) . . . . 19" x 12"(rear)
C7 Z51
19” x 8.5"(front) . . . . 20” x 10"(rear)
Most significant is the 2" difference in rear wheel width. And that really is a big difference! ... Any ideas as to why GM may have done this?
Also, I am wondering if the smaller width of both the front and the rear wheels on the C7 Z51 may have an impact the car's Skid Pad numbers? If the C7 Z51 achieves the same 'G' numbers as the C6 GS, that's great! ... but could the C7 have achieved even better 'G' numbers had it been equipped with wider wheels / tires (such as the size already on the C6 GS)?
What ya think?
Anyway, I am still scratching my head as to why the engineers selected narrower wheels for the C7 Z51 than what is standard on the C6 GS.
I am not comparing the base C7 wheels to the base C6 wheels here.
I choose to compare the C7 Z51 wheels to the C6 GS wheels because both these cars have upgraded performance suspensions and brakes in comparison to the base versions of each.
C6 GS
18" x 9.5"(front) . . . . 19" x 12"(rear)
C7 Z51
19” x 8.5"(front) . . . . 20” x 10"(rear)
Most significant is the 2" difference in rear wheel width. And that really is a big difference! ... Any ideas as to why GM may have done this?
Also, I am wondering if the smaller width of both the front and the rear wheels on the C7 Z51 may have an impact the car's Skid Pad numbers? If the C7 Z51 achieves the same 'G' numbers as the C6 GS, that's great! ... but could the C7 have achieved even better 'G' numbers had it been equipped with wider wheels / tires (such as the size already on the C6 GS)?
What ya think?
They are two different models. If they already made the Z51 like the GS then there wouldn't be a need for the GS. When the GS comes, you expect it to be better than the Z51.
There is natural progression of model development. Let it happen.
05-27-2013, 12:52 PM
#43
Le Mans Master
"Actually, I cant wait to line up with that over weight barge!
I have the same compound tires as the C7, just in Man size! If it has all the TQ everyone is flying their skirts about it's gonna be hard to hook up that little bitty tire. I will be long gone down the 1/4 mile!"
I'd actually love to see you line up with a C7 at a drag strip. You have a lot of disdain for this car and a lot of confidence in your car. I would love to see a youtube video of you racing a C7.
-Alex
I have the same compound tires as the C7, just in Man size! If it has all the TQ everyone is flying their skirts about it's gonna be hard to hook up that little bitty tire. I will be long gone down the 1/4 mile!"
I'd actually love to see you line up with a C7 at a drag strip. You have a lot of disdain for this car and a lot of confidence in your car. I would love to see a youtube video of you racing a C7.
-Alex
I make no bones about it, I dont care for the base car no matter how cheap the cost is. Im am dieing to get / see details of the high performance version though.Also, I dont really expect to beat it but I will give it a shot...Should be a good run!
Last edited by sam90lx; 05-27-2013 at 01:02 PM.
05-27-2013, 12:58 PM
#44
Le Mans Master
subscribed
05-27-2013, 12:59 PM
#45
One thing to realize is that the GS uses both wider wheels (and tires) and more outward wheel offset.
-------------------------------------------------------------
C7
245/40-18, 9.7" section width, 25.7" diameter, 8.5" wheel width
285/35-19, 11.4" section width, 26.9" diameter, 10" wheel width
C6 GS
275/35-18, 10.9" section width, 25.6" diameter, 9.5" wheel width, (9.5" wheel width is spec for the tire size)
325/30-19, 13" section width, 26.7" diameter, 12" wheel width, (11.5" wheel width is spec for the tire size)
So here on the C7, attempt a 9.5" front wheel width (with 275 tire) and a 11.5" rear wheel width (with 325 tire) but try the stock C7 wheel offset.
-------------------------------------------------------------------
C7 Z51
245/35-19, 9.8" section width, 25.8" diameter, 8.5" wheel width
285/30-20, 11.4" section width, 26.8" diameter, 10" wheel width
Possible alternative
265/35-19, 10.4" section width, 26.3" diameter, 9.5" wheel width
305/30-20, 12.5" section width, 27.3" diameter, 11" wheel width
And here on the C7, attempt a 9.5" front wheel width (with 265 tire) and an 11" rear wheel width (with 305 tire) but try the stock C7 wheel offset.
--------------------------------------------------------------
But also lowering the car can help fit a wider tire. On the outside the tire will have more camber and a faster camber curve. And on the inside the top of the tire is higher in the lateral fender space
.
-------------------------------------------------------------
C7
245/40-18, 9.7" section width, 25.7" diameter, 8.5" wheel width
285/35-19, 11.4" section width, 26.9" diameter, 10" wheel width
C6 GS
275/35-18, 10.9" section width, 25.6" diameter, 9.5" wheel width, (9.5" wheel width is spec for the tire size)
325/30-19, 13" section width, 26.7" diameter, 12" wheel width, (11.5" wheel width is spec for the tire size)
So here on the C7, attempt a 9.5" front wheel width (with 275 tire) and a 11.5" rear wheel width (with 325 tire) but try the stock C7 wheel offset.
-------------------------------------------------------------------
C7 Z51
245/35-19, 9.8" section width, 25.8" diameter, 8.5" wheel width
285/30-20, 11.4" section width, 26.8" diameter, 10" wheel width
Possible alternative
265/35-19, 10.4" section width, 26.3" diameter, 9.5" wheel width
305/30-20, 12.5" section width, 27.3" diameter, 11" wheel width
And here on the C7, attempt a 9.5" front wheel width (with 265 tire) and an 11" rear wheel width (with 305 tire) but try the stock C7 wheel offset.
--------------------------------------------------------------
But also lowering the car can help fit a wider tire. On the outside the tire will have more camber and a faster camber curve. And on the inside the top of the tire is higher in the lateral fender space
.
Last edited by B Stead; 05-27-2013 at 01:19 PM.
05-27-2013, 01:07 PM
#46
Safety Car
For All The Above Reasons
The OP asked, "Anyway, I am still scratching my head as to why the engineers selected narrower wheels for the C7 Z51 than what is standard on the C6 GS."
When, last October, GM took a 2013 Base Z06 to VIR, with its 505HP and its 275/325 tires, they, right afterwards, made one change, and that was to jack up the car and substitute the new C7 wheels with Michelin 245/285 tires. How much faster was Jim Mero with the Z06 (same tire sizes as on the C6 Grand Sports) on the track with the C7's much narrower tires, again the only change made?
1.2 seconds per lap faster.
So, we get better tires, which can go around a track faster, get better fuel mileage, produce less noise, cost less to replace, weigh less, etc. with narrower tires.
Question answered.
When, last October, GM took a 2013 Base Z06 to VIR, with its 505HP and its 275/325 tires, they, right afterwards, made one change, and that was to jack up the car and substitute the new C7 wheels with Michelin 245/285 tires. How much faster was Jim Mero with the Z06 (same tire sizes as on the C6 Grand Sports) on the track with the C7's much narrower tires, again the only change made?
1.2 seconds per lap faster.
So, we get better tires, which can go around a track faster, get better fuel mileage, produce less noise, cost less to replace, weigh less, etc. with narrower tires.
Question answered.
05-27-2013, 01:12 PM
#47
Race Director
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2021 C6 of the Year Finalist - Modified
elegant ... that pretty much sums it up as far as road racing is concerned.
05-27-2013, 01:13 PM
#48
Safety Car
Wrong. First, I bet the tires are not cheaper. Better fuel mileage, yes. That's just the way of the car biz today with $5/gal coming soon.
But if the new car does not handle or corner better than the old car, it's a massive fail.
It won't fail. The new tires are better than the old tires -- therefore you can get your cake and eat it too.
But if the new car does not handle or corner better than the old car, it's a massive fail.
It won't fail. The new tires are better than the old tires -- therefore you can get your cake and eat it too.
05-27-2013, 01:22 PM
#49
Racer
[QUOTE=BMadden;1584001172]I guess you'll be putting me on ignore too because as far as I can tell your post is 1000x more ridiculous than his. He simply asked why the C7 has narrower wheels and tires than the C6 and you label him as a troll. Enjoy a big pitcher of C7 Kool-Aid on Memorial Day.
05-27-2013, 01:22 PM
#50
Le Mans Master
If you want the wide azz tire like I do just wait...it will be on some variation soon. Did the C6 base have big rubber? No. Why would the base C7?
05-27-2013, 01:27 PM
#51
Race Director
I dont have disdain for it...I like to mess with it though. I make no bones about it, I dont care for the base car no matter how cheap the cost is. Im am dieing to get / see details of the high performance version though.
Also, I dont really expect to beat it but I will give it a shot...Should be a good run!"
Haha, you sound like a good sport. I too shall impatiently await the more performance oriented models.
-Alex
Also, I dont really expect to beat it but I will give it a shot...Should be a good run!"
Haha, you sound like a good sport. I too shall impatiently await the more performance oriented models.
-Alex
05-27-2013, 01:44 PM
#52
Team Owner
Or just get wider wheels of your choice and run as wide as you want.
My FRC had C5z wheels with 305's in the back, and looks awesome. 305's would look every bit as good on the C7 and will probably be one of my only upgrades.
05-27-2013, 02:45 PM
#53
Melting Slicks
The simplest answer to the question of why narrower tires is to look at the real competition. The Viper is joke car, too much hp, almost no traction enhancing technology, and a **** poor transmission. It needs all that meat to even have a chance of going in a forward direction. The other thing to think about is contact patch...too much meat in the rear and your contact patch is effectively narrower than a smaller width tire that is made for the weight of the car on the given corner. Then the argument is let some air out to maximize contact patch...well this affects sidewall stiffness and allows the tire to deform under higher g turns which makes the contact patch deform which reduces traction.
The fact that Corvette is coming with slimmer tires means one thing, that the Engineers at GM understand that in order to make a driver's sportscar they need to focus on handling. The narrower tires will lend the car sharper handling, a more communicative front end and ultimately a lighter feeling to the handling. I understand that there are a lot of people who want the Corvette to be a drag car, but it looks like the Z28 and ZL1 are fitting that role, which leaves the Corvette to plug the hole for a true all around performance car. I understand the Z06 and ZR1 are capable cars but in the end their performance is really only accessible to a very select few individuals who typically drive them on race tracks with Left and Right turns. For the rest of us mortals the argument over more tire in the rear is moot. Buy it if you like the look, no one other than you has to like it anyways, or dont. Either way no one here is an engineer that worked on the Vette as far as I can tell, so its all speculating any ways.
Personally I think 315 is as wide as I would go, gives me a bit more tire, especially since I wont run with run-flat garbage...Yokohama Advan AD08s for me thank you very much!
The fact that Corvette is coming with slimmer tires means one thing, that the Engineers at GM understand that in order to make a driver's sportscar they need to focus on handling. The narrower tires will lend the car sharper handling, a more communicative front end and ultimately a lighter feeling to the handling. I understand that there are a lot of people who want the Corvette to be a drag car, but it looks like the Z28 and ZL1 are fitting that role, which leaves the Corvette to plug the hole for a true all around performance car. I understand the Z06 and ZR1 are capable cars but in the end their performance is really only accessible to a very select few individuals who typically drive them on race tracks with Left and Right turns. For the rest of us mortals the argument over more tire in the rear is moot. Buy it if you like the look, no one other than you has to like it anyways, or dont. Either way no one here is an engineer that worked on the Vette as far as I can tell, so its all speculating any ways.
Personally I think 315 is as wide as I would go, gives me a bit more tire, especially since I wont run with run-flat garbage...Yokohama Advan AD08s for me thank you very much!
05-27-2013, 02:53 PM
#54
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The simplest answer to the question of why narrower tires is to look at the real competition. The Viper is joke car, too much hp, almost no traction enhancing technology, and a **** poor transmission. It needs all that meat to even have a chance of going in a forward direction. The other thing to think about is contact patch...too much meat in the rear and your contact patch is effectively narrower than a smaller width tire that is made for the weight of the car on the given corner. Then the argument is let some air out to maximize contact patch...well this affects sidewall stiffness and allows the tire to deform under higher g turns which makes the contact patch deform which reduces traction.
The fact that Corvette is coming with slimmer tires means one thing, that the Engineers at GM understand that in order to make a driver's sportscar they need to focus on handling. The narrower tires will lend the car sharper handling, a more communicative front end and ultimately a lighter feeling to the handling. I understand that there are a lot of people who want the Corvette to be a drag car, but it looks like the Z28 and ZL1 are fitting that role, which leaves the Corvette to plug the hole for a true all around performance car. I understand the Z06 and ZR1 are capable cars but in the end their performance is really only accessible to a very select few individuals who typically drive them on race tracks with Left and Right turns. For the rest of us mortals the argument over more tire in the rear is moot. Buy it if you like the look, no one other than you has to like it anyways, or dont. Either way no one here is an engineer that worked on the Vette as far as I can tell, so its all speculating any ways.
Personally I think 315 is as wide as I would go, gives me a bit more tire, especially since I wont run with run-flat garbage...Yokohama Advan AD08s for me thank you very much!
The fact that Corvette is coming with slimmer tires means one thing, that the Engineers at GM understand that in order to make a driver's sportscar they need to focus on handling. The narrower tires will lend the car sharper handling, a more communicative front end and ultimately a lighter feeling to the handling. I understand that there are a lot of people who want the Corvette to be a drag car, but it looks like the Z28 and ZL1 are fitting that role, which leaves the Corvette to plug the hole for a true all around performance car. I understand the Z06 and ZR1 are capable cars but in the end their performance is really only accessible to a very select few individuals who typically drive them on race tracks with Left and Right turns. For the rest of us mortals the argument over more tire in the rear is moot. Buy it if you like the look, no one other than you has to like it anyways, or dont. Either way no one here is an engineer that worked on the Vette as far as I can tell, so its all speculating any ways.
Personally I think 315 is as wide as I would go, gives me a bit more tire, especially since I wont run with run-flat garbage...Yokohama Advan AD08s for me thank you very much!
05-27-2013, 03:00 PM
#55
The simplest answer to the question of why narrower tires is to look at the real competition. The Viper is joke car, too much hp, almost no traction enhancing technology, and a **** poor transmission. It needs all that meat to even have a chance of going in a forward direction. The other thing to think about is contact patch...too much meat in the rear and your contact patch is effectively narrower than a smaller width tire that is made for the weight of the car on the given corner. Then the argument is let some air out to maximize contact patch...well this affects sidewall stiffness and allows the tire to deform under higher g turns which makes the contact patch deform which reduces traction.
The fact that Corvette is coming with slimmer tires means one thing, that the Engineers at GM understand that in order to make a driver's sportscar they need to focus on handling. The narrower tires will lend the car sharper handling, a more communicative front end and ultimately a lighter feeling to the handling. I understand that there are a lot of people who want the Corvette to be a drag car, but it looks like the Z28 and ZL1 are fitting that role, which leaves the Corvette to plug the hole for a true all around performance car. I understand the Z06 and ZR1 are capable cars but in the end their performance is really only accessible to a very select few individuals who typically drive them on race tracks with Left and Right turns. For the rest of us mortals the argument over more tire in the rear is moot. Buy it if you like the look, no one other than you has to like it anyways, or dont. Either way no one here is an engineer that worked on the Vette as far as I can tell, so its all speculating any ways.
Personally I think 315 is as wide as I would go, gives me a bit more tire, especially since I wont run with run-flat garbage...Yokohama Advan AD08s for me thank you very much!
The fact that Corvette is coming with slimmer tires means one thing, that the Engineers at GM understand that in order to make a driver's sportscar they need to focus on handling. The narrower tires will lend the car sharper handling, a more communicative front end and ultimately a lighter feeling to the handling. I understand that there are a lot of people who want the Corvette to be a drag car, but it looks like the Z28 and ZL1 are fitting that role, which leaves the Corvette to plug the hole for a true all around performance car. I understand the Z06 and ZR1 are capable cars but in the end their performance is really only accessible to a very select few individuals who typically drive them on race tracks with Left and Right turns. For the rest of us mortals the argument over more tire in the rear is moot. Buy it if you like the look, no one other than you has to like it anyways, or dont. Either way no one here is an engineer that worked on the Vette as far as I can tell, so its all speculating any ways.
Personally I think 315 is as wide as I would go, gives me a bit more tire, especially since I wont run with run-flat garbage...Yokohama Advan AD08s for me thank you very much!
05-27-2013, 03:03 PM
#56
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05-27-2013, 03:13 PM
#57
Melting Slicks
When I replaced the OE Goodyear tires(245/275) on my C5 with Michelin A/S 245/275 I lost ~1.5 MPG. Had nothing to do with tire size but with tire design.
When I replaced the OE Goodyear tires(275/325) on my Z06 with Bridgestone 275/325, I saw ~1MPG reduction in gas mileage. Again, same size tire but different tire construction, compound and tread design.
But I still average ~3 MPG better gas mileage in my Z06(505 HP) with the big tires(and .34 Cd) than I did with my C5(345 HP) with the narrow tires(and .29 Cd).
When I replaced the OE Goodyear tires(275/325) on my Z06 with Bridgestone 275/325, I saw ~1MPG reduction in gas mileage. Again, same size tire but different tire construction, compound and tread design.
But I still average ~3 MPG better gas mileage in my Z06(505 HP) with the big tires(and .34 Cd) than I did with my C5(345 HP) with the narrow tires(and .29 Cd).
Last edited by Minkster; 05-27-2013 at 03:26 PM.
05-27-2013, 03:13 PM
#58
Le Mans Master
05-27-2013, 03:14 PM
#59
Race Director
Supermassive then a question if you don't mind. Why then did Chevrolet decided to use wider contact patches for their most exclusive performance models ZO6 and ZR1? Of course they had to accomodate a larger barrel for the bigger calipers and rotors but that didn't mean the wheels had to be lighter. Something was there for the agrees to all agree that those models need wider patches. And it's not just Chevrolet, you see this with all manufacturers. Dodge, MB, BMW, Ford etc. If smaller tires allow for better handling, then why doesn't the GT500 come with the base Mustangs 235s instead of 285s?
-Alex
-Alex
05-27-2013, 03:26 PM
#60
Le Mans Master
I dont have disdain for it...I like to mess with it though. I make no bones about it, I dont care for the base car no matter how cheap the cost is. Im am dieing to get / see details of the high performance version though.
Also, I dont really expect to beat it but I will give it a shot...Should be a good run!"
Haha, you sound like a good sport. I too shall impatiently await the more performance oriented models.
-Alex
Also, I dont really expect to beat it but I will give it a shot...Should be a good run!"
Haha, you sound like a good sport. I too shall impatiently await the more performance oriented models.
-Alex