Tom Stephens:Our upcoming programs have aggressive mass targets
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Joined: Mar 2005
Posts: 3,123
From: Melbourne, Australia
Hmmm....shades of ignorance on the matter?... by that reasoning, a cutting edge F1 car unencumbered by rules should weigh as much as an M1-A1 and be rolling on 40 inch wheels with 30 inch rotors.
No, of course a greater thermal heat sink, swept area and leverage are benefits, but there is also the rule of diminishing returns you are not considering.
Additionally, you fail to consider the marketing factor. For example, C6 engineers have quietly admitted at some club gatherings that the factory non-ZR1 drilled rotors were... wait for it.... a marketing driven decision and NOT an engineering one.
I was right. You sir, have just exposed your ignorance.
I am no fan of NASCAR but their brake tech is outstanding. In fact there have multiple write ups in Racecar Engineering magazine ( http://www.racecar-engineering.com/) regarding exactly that.
Still not convinced? Well, the Australian V8 Supercar series seems to do quite well with 14.8 inch (376mm) rotors inside 17 inch wheels.
And before you go on about clearance issues related OEM durability and servicing, let me point out that my truck has huge twin piston calipers placed close enough to the wheel that one would be hard pressed to insert a paper clip in the space available.
In conclusion, huge ridiculous wheels are not required for world class braking and are simply a styling / marketing choice.
No, of course a greater thermal heat sink, swept area and leverage are benefits, but there is also the rule of diminishing returns you are not considering.
Additionally, you fail to consider the marketing factor. For example, C6 engineers have quietly admitted at some club gatherings that the factory non-ZR1 drilled rotors were... wait for it.... a marketing driven decision and NOT an engineering one.
I was right. You sir, have just exposed your ignorance.
I am no fan of NASCAR but their brake tech is outstanding. In fact there have multiple write ups in Racecar Engineering magazine ( http://www.racecar-engineering.com/) regarding exactly that.
Still not convinced? Well, the Australian V8 Supercar series seems to do quite well with 14.8 inch (376mm) rotors inside 17 inch wheels.
And before you go on about clearance issues related OEM durability and servicing, let me point out that my truck has huge twin piston calipers placed close enough to the wheel that one would be hard pressed to insert a paper clip in the space available.
In conclusion, huge ridiculous wheels are not required for world class braking and are simply a styling / marketing choice.
).However, the Camaro weighs some 900 lbs more and does not need to be forced to race. But thankfully GM cater to enthusiasts who like to take their Camaros to tracks. That's less than 1% of the customer base we're referring to but it's not irrelevant. It's also a safety issue.
While we're on the subject of fast cars, tell me why performance cars like the GTR, ZR-1, BMW M5 have 20" wheels? I guess they also don't NEED them either?
Stop, I Say
There should be no dispute about the effectiveness of the ZR1's brakes. The rotors are as large as or larger than most wheels were just a decade ago.
In what must be a very sweet moment for a longtime Corvette engineer, Juechter notes that the monster 15-inch Brembo carbon-ceramic rotors fitted as standard to the ZR1's rear wheels are the brakes originally designed for the front of Ferrari's 650-hp Enzo supercar. In the front of the ZR1, you'll find even larger 15.5-inch carbon-ceramic units.
Juechter says, "The only vehicle I know of that has these brakes as standard equipment is the 1,000-hp Bugatti Veyron." Then he adds with a grin, "Although I think you can get them as a $20,000 option on the Ferrari 599." We get the sense Juechter will be using these laugh lines many, many times in the near future.
http://www.edmunds.com/insideline/do...ticleId=124018
There should be no dispute about the effectiveness of the ZR1's brakes. The rotors are as large as or larger than most wheels were just a decade ago.
In what must be a very sweet moment for a longtime Corvette engineer, Juechter notes that the monster 15-inch Brembo carbon-ceramic rotors fitted as standard to the ZR1's rear wheels are the brakes originally designed for the front of Ferrari's 650-hp Enzo supercar. In the front of the ZR1, you'll find even larger 15.5-inch carbon-ceramic units.
Juechter says, "The only vehicle I know of that has these brakes as standard equipment is the 1,000-hp Bugatti Veyron." Then he adds with a grin, "Although I think you can get them as a $20,000 option on the Ferrari 599." We get the sense Juechter will be using these laugh lines many, many times in the near future.
http://www.edmunds.com/insideline/do...ticleId=124018
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Joined: Apr 2001
Posts: 3,698
From: USA
With the Brembos..it is more about how wide the spokes are. The Brembo caliper is wide. On the G8 GT and GXP, both have 19's, but the 19" rim on the GT will not clear the Brembos.
As for big brakes an 18" wheels..the Z06 has 18" wheels up from and 6 PISTON calipers.
As for big brakes an 18" wheels..the Z06 has 18" wheels up from and 6 PISTON calipers.
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Joined: Jul 2001
Posts: 3,132
From: Santa Clara, CA
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Joined: Oct 2001
Posts: 859
From: AR (PA born and fled)
Wow.
The sound everyone just heard was my point(s) whizzing by our Australian friend's head.
And yes, I am a big fan of your Supercar series.
Unfortunately the (nonexistent) coverage it garners here is criminal. I seldom get to see any of the great, great hard nose racing in that series.
The sound everyone just heard was my point(s) whizzing by our Australian friend's head.
And yes, I am a big fan of your Supercar series.
Unfortunately the (nonexistent) coverage it garners here is criminal. I seldom get to see any of the great, great hard nose racing in that series.
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Joined: Aug 2000
Posts: 6,165
From: Sterling Heights, MI
You know what auto manufacturers have gathered from the "Dub" craze? People like big, shiny, blingy wheels. I'm absolutely convinced it is the OEMs getting in on the action. People equate ridiculously big wheel/tire combinations with aggressiveness, attitude and high-end cars now.
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Joined: Mar 2005
Posts: 3,123
From: Melbourne, Australia
Sorry, I'm with Chewbacca here. If you put a 17" wheel on any of the cars you mentioned, they would look positively dorky, especially on a car you're charging that kind of scratch for. You have to admit that style is certainly a consideration - if not a large part of it. Heck, you can get 18" wheels on a Dodge Caliber R/T - and don't tell me it's necessary because a 4-cylinder Caliber has an "engineering need" for them. So, are you going to offer your supercar with the same size wheels as what's available on an econobox? Not likely.
You know what auto manufacturers have gathered from the "Dub" craze? People like big, shiny, blingy wheels. I'm absolutely convinced it is the OEMs getting in on the action. People equate ridiculously big wheel/tire combinations with aggressiveness, attitude and high-end cars now.
You know what auto manufacturers have gathered from the "Dub" craze? People like big, shiny, blingy wheels. I'm absolutely convinced it is the OEMs getting in on the action. People equate ridiculously big wheel/tire combinations with aggressiveness, attitude and high-end cars now.
Thanks for the engineering explanation, btw!
Big Brakes
So why do we want big brakes? The main answer is heat, and how it is dissipated. Your car could have very small rotors installed, and still be able to lock up the wheels at 60MPH. Try to do it repeatedly, however, and you’ll notice that on the fifth or sixth hard stop from 60MPH, those same brakes no longer lock up the wheels. Keep at it, or use higher speeds, and you’ll have trouble slowing down at all, no matter how hard you push on the pedal. Keep at it still more, and the pedal will start to become soft and possibly drop to the floor and you’ll loose braking altogether! As the temperature of the pads and rotor heat up, the friction generating capability between the pads and rotor go down. It’s a bummer, but it’s true. Small rotors heat up faster because there is less mass, or material to heat up. Larger rotors take longer to heat up, and will therefore withstand more repeated stops, higher speeds, and larger loads. The second reason for larger rotors is a longer torque arm. The larger rotor allows the pads to be placed further away from the center of the wheel/hub. By increasing this lever-arm distance you can increase the braking force. Using multiple pistons on calipers allows a more even force to be applied to the pad, and can also give the pedal a more firm feel. With a larger the number of pistons, you can apply force to more parts of the pad. It’s the old how many circles can you fit in a rectangle problem. In addition, on calipers with 8-12 pistons, you’ll notice that the manufacturer places more of the pistons toward the outside of the pad, which again increases that torque arm length.
http://www.lovehorsepower.com/Brakes.html
So why do we want big brakes? The main answer is heat, and how it is dissipated. Your car could have very small rotors installed, and still be able to lock up the wheels at 60MPH. Try to do it repeatedly, however, and you’ll notice that on the fifth or sixth hard stop from 60MPH, those same brakes no longer lock up the wheels. Keep at it, or use higher speeds, and you’ll have trouble slowing down at all, no matter how hard you push on the pedal. Keep at it still more, and the pedal will start to become soft and possibly drop to the floor and you’ll loose braking altogether! As the temperature of the pads and rotor heat up, the friction generating capability between the pads and rotor go down. It’s a bummer, but it’s true. Small rotors heat up faster because there is less mass, or material to heat up. Larger rotors take longer to heat up, and will therefore withstand more repeated stops, higher speeds, and larger loads. The second reason for larger rotors is a longer torque arm. The larger rotor allows the pads to be placed further away from the center of the wheel/hub. By increasing this lever-arm distance you can increase the braking force. Using multiple pistons on calipers allows a more even force to be applied to the pad, and can also give the pedal a more firm feel. With a larger the number of pistons, you can apply force to more parts of the pad. It’s the old how many circles can you fit in a rectangle problem. In addition, on calipers with 8-12 pistons, you’ll notice that the manufacturer places more of the pistons toward the outside of the pad, which again increases that torque arm length.
http://www.lovehorsepower.com/Brakes.html
Last edited by SSbaby; Aug 31, 2009 at 10:38 PM.
Thread Starter
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Joined: Nov 2000
Posts: 16,176
From: Chicagoland IL
I don't know which stories you've read, but I'd call it a pretty major complaint in most of the stories I've read.
PJ Jones called it a "pig" in Automobile magazine.
St. Antione in MT, "Against some of the truly great driver's cars here, the Camaro feels so big, bulky, dark, and...did I say 'big?
Jalopnik: Krewson: ***
Frankly, I didn't like driving the Camaro all that much. I didn't hate it-It grips pretty well, and its considerable mass is tautly strung together and evidently well-centralized, because it handles predictably and turns without yawing like a lifeboat and never seemed to want to plow the front under or spin the rear out. But it wasn't the happiest car I've ever driven, and when you took it through the tight stuff or changed direction quickly, it seemed to double in weight. Conversely, the steering was far too light and isolated from the wheels, making the car feel even less integrated.
Look up GRM. Same story. Here's a taste. "Sure, you may get accustomed to the restricted view, but you will never forget that you’re driving a seriously large machine. " and "Personally I like the look of the new Camaro, although I wish it was 5/8 scale."
I'll leave it there...
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Joined: Jul 2001
Posts: 3,132
From: Santa Clara, CA
I'm old school. I still like 16" wheels. I can see 17s on performance cars, and maybe 18s on heavy performance cars. I have 19s on my G8 GT, 'cause that's all they had within 100 miles at the time I bought. I did consider driving the 200 mile round-trip to get 18s, but I didn't have the time, and I figure if you're 100 miles from home, you've got a weaker bargaining position anyway.
Other people seem to like the 19s....
Other people seem to like the 19s....
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Joined: Jul 2001
Posts: 3,132
From: Santa Clara, CA
Probably for the best... I was just reading the Oct 09 MT tonight, and I did see what you describe. Interestingly the 2010 Cobra apparently felt lighter, in spite of being 20 pounds the other way.
I used to read the same sort of complaints about 3rd gens, though. It doesn't bother me....
I used to read the same sort of complaints about 3rd gens, though. It doesn't bother me....
Thread Starter
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Joined: Nov 2000
Posts: 16,176
From: Chicagoland IL
I'm old school. I still like 16" wheels. I can see 17s on performance cars, and maybe 18s on heavy performance cars. I have 19s on my G8 GT, 'cause that's all they had within 100 miles at the time I bought. I did consider driving the 200 mile round-trip to get 18s, but I didn't have the time, and I figure if you're 100 miles from home, you've got a weaker bargaining position anyway.
Other people seem to like the 19s....
Other people seem to like the 19s....
I like the 19's alot on the G8. In fact, a GT with the 19's is far better looking to me than the GXP.
Thread Starter
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But unlike now, the 3rd gen never lost any handling contests to the Mustang and certainly never came in last place out of 10...
Last edited by Z284ever; Sep 1, 2009 at 12:22 AM.
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Joined: Jun 2000
Posts: 1,215
From: Coppell, Texas
I still think styling is the driving factor behind big wheels. I think if a designer styled a car with 18's as the biggest wheel offering, they could look fine. And if the wheel were designed properly they could accomodate big rotors.