Of course style/design dictated the huge wheels. I'm sure you've seen the picture of a 5th gen with 4th gen wheels on it that was posted here a while back. It looked ridiculous, way worse than a 2nd gen with 14s.

 

Would definitely like to see that, lol...if you know where it is a link would definitely be appreciated. I bet that looked ridiculous...

 

Because a properly constructed 17" rim will and has been ran on a 5th gen with the 14" brembos in place . The 20's were all about style , 100% .

 

Yes but did you not imply that 19" were also "BIG" in your opinion? To that end they are there purely for design purposes only - you did indicate that did you not?

Yes, you could fit 14" rotors under 19" wheels but so what's the big deal about going one size bigger? Don't tell me it's all about weight?

 

The Corvette is also a lot lighter and the CTS-V is not as quick (nor as heavy as the current model!

You guys should read up on how good a HSV GTS stops in contrast to the Brembo equipped Camaro. The bigger rotors are a class bigger than the Corvette's, I believe and the GTS some 700lbs heavier. EDIT: How does the notion of 380mm front rotors grab ya? Tell me what size wheels you need to accommodate such rotors. The brakes are simply amazing.

The point is, the more air that circulates around the rotors and calipers, the better the braking performance although I accept its also a law of diminishing returns.

 

I don't think the GTS is that heavy. 700 pounds heavier than a Camaro SS would put the GTS at over 2000kg -- close to 2100. Isn't it closer to 1850-1900?

 

Perhaps my math is letting me down but I assume the C6 is around 1450kg (?)and the GTS is 1829kg... so I estimated the difference to be 700lbs approx.

All I'm saying is that the Camaro could have even bigger and much more powerful stoppers, courtesy of the mighty HSV GTS.

The problem there is that the HSV GTS stoppers are quite expensive... but if you race your cars around a circuit, you are hardly going to complain about bigger brakes and wheels... plus you could probably afford the expense.

 

I thought you were comparing with a Camaro. Your math is close enough

The Corvette is a little heavier than 1450kg, which would be ~3196 pounds. 1829kg is ~4031 pounds.

 

The point is that brakes of the sizes I was mentioning fit under wheels smaller than the absurdly large 20" wheels that are becoming too common. The Camaro didn't go to 20" wheels to accommodate its brakes. Neither did the new Shelby. And I'm sorry, but brakes over 14" in diameter are not somehow small just because the HSV apparently offers a set of nearly 15 inchers.

These ~15" rotors you are describing on some HSV car have nothing to do with the Camaro's current wheels.

By braking performance, do you mean fade resistance? Because I guarantee that, even with much smaller brakes, the Camaro would be able to lock its wheels (without ABS of course). I think braking these days is typically traction (tires) limited, not braking power limited. The cooling aspects you mention above would offer improved fade resistance on a braking-intensive road course.

 

You are correct on all fronts but what I was alluding to was a possible upgrade path for current Camaro owners on 20" wheels. I dare say the current Brembo's would contribute to the 'push' that has been noted on some circuits by various testers. A better brake package would alleviate the understeer problem. Yes?

Yes you are right when you say tires play a part (as do brake fluid temps) which brings me to this point: I do wonder how many tire makers make good, soft, track rubber for 20" wheels... I'm guessing not many.

By "braking performance" I mean better brake cooling, better heat dissipation and distribution across the big rotors, less fade, shorter stopping distances, just better track potential over a number of laps.

Btw, just as an aside, I wonder which car would stop better between CTS-V and Camaro SS? If the Camaro stops better, then would you not conclude that the heavier CTS-V is under-braked and/or under-tired?

 

Why would the brakes have anything to do with an understeer problem?

Assuming by "stop better", you mean shorter stopping distances in a braking test (not necessarily the ability to last 20 hot laps with no fade), I don't think the Camaro out stops the CTS-V, though I really don't recall their numbers offhand. But if it did, I'd look at the CTS-V's higher weight, weight distribution, tire compound / size, and I suppose suspension setup, not so much the brakes (given the braking hardware each car has).

 

Chassis dynamics and overall balance - if you can't slow a car down in time you can't expect the suspension/steering to compensate.

With respect, does it really matter? I mean, if the brakes are still strong over 20 laps... they should be darn good in the braking test too, yes?

 

Btw Joe,

I do have to correct you on the CTS-V... the standard brake package fits under the 18" wheels... but there is also a Track Pack version that comes with 19" wheels!

See here...

Brakes, front 15.0-inch ventilated disc
Brakes, rear 14.7-inch ventilated disc

Therefore, I am correct when I say there is increased functionality behind the 19"/20" wheels.

 

So you brake earlier. Sorry, but you could use 10" drums at all four corners. If they had the same mass and rotational inertia as the big discs, handling isn't going to change. You aren't going to fix any understeering tendencies by improving the front brakes. Sure. I'm just saying they won't necessarily stop any shorter. Once you get to the point that you have more braking power than available grip from the tires (which any of these braking systems have), then it doesn't matter if you have 13" or 18" rotors. Except for dissipating heat (at the expense of increased mass and rotational inertia).

As you pointed out above, at some point you start approaching diminishing returns. Do you really think a jump to 14.9" rotors from 14" rotors is going to make a notable difference for a street car?

 

It seems to me that this is reinforcing my point.

Actually, that article doesn't imply anywhere that the track brakes are any larger than the standard brakes. It says they are solid instead of slotted (interesting, since the whole slotting / cross-drilling idea was cooling, I thought), and I assume they use a more track-friendly pad compound. But it doesn't say anything about going to a larger wheel to clear these same-size brakes. The CTS-V has 19" wheels standard. It may be that they needed 19" wheels to clear the brakes. But those are the standard sized brakes and wheels. It was the previous generation CTS-V (with smaller 14.x" rotors) that had 18" wheels. When did I say otherwise that you needed to correct me?

Anyway, obviously when you go to extreme brake sizes (for bragging rights or performance or whatever), you will need the wheels to be able to fit over them. I mean, you aren't going to fit a 14" rotor and caliper assembly inside a 15" wheel. But the Camaro most certainly does not need 20" wheels (or even 19" wheels) for the brakes it has, which is what started this whole discussion.

As for these track brakes on the new CTS-V, they sound pretty awesome. I would imagine that it is actually the pad material that allows the brakes to work even better when they get a little heat in them.

As an aside, this was actually a problem with some other cars that had early implementations of carbon-ceramic brakes. They were stupidly powerful, but only after they got some heat in them. The first few applications were often noisy and less powerful than expected, with unsatisfactory pedal feel (again, until the temperatures elevated some).