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Bigger rotors are always heavier, adding mass and rotational inertia to the vehicle, and additional unsprung weight to the suspension. There's no free lunch. That's physics.
I don't agree with the above statement "always heavier" I'm using the aluminum hat 13.250 diameter wilwood GT1 rotors and they are lighter than stock C-3 rotors.
personally i believe in bigger dia wheels and get lots of air around the brakes.
I don't agree with the above statement "always heavier" I'm using the aluminum hat 13.250 diameter wilwood GT1 rotors and they are lighter than stock C-3 rotors.
True, unless you used larger diameter rotors with your hats, then..........
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Originally Posted by gkull
I don't agree with the above statement "always heavier" I'm using the aluminum hat 13.250 diameter wilwood GT1 rotors and they are lighter than stock C-3 rotors. I'm using aluminum hats also. But if you weigh the rotor part of the assembly, your 13" rotor is going to weigh more than the 11.75" rotor part of my disc assembly. There's more cast iron in the 13" rotor.
personally i believe in bigger dia wheels and get lots of air around the brakes.
That's what I'm doing. Running 11.75" rotors inside a 17" track wheel gives a lot of free space for the hot air to be flung out of the rotor.
Last edited by 69427; Dec 5, 2016 at 04:47 PM.
Reason: Spelling correction.
That's what I'm doing. Running 11.75" rotors inside a 17" track wheel gives a lot of free space for the hot air to be flung out of the rotor.
Way back when, the Buhatti Bros. had brake overheating issues. They tweaked the spokes on their spring steel wheels to make them fan blades to help with cooling. Does anyone make alloy wheels that mimic this? Seems to me it would not be a huge engineering feat to make wheels that fan the brakes.
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Originally Posted by Big2Bird
Way back when, the Buhatti Bros. had brake overheating issues. They tweaked the spokes on their spring steel wheels to make them fan blades to help with cooling. Does anyone make alloy wheels that mimic this? Seems to me it would not be a huge engineering feat to make wheels that fan the brakes.
Several Corvettes and Porsches in the 70s and 80s had fan setups that bolted to the wheels to pump out the air from the brakes. The Porsche guys used some high dollar BBS wheels with that fan option, while the Corvette guys initially ran Corvair engine cooling fans adapted to their wheels.
I've been working on making a pair of aluminum disc fans that would bolt between the front hub and wheel, and would pump air to both cool the brakes, and evacuate some of the undercar air in the process. Making the vanes consistent in shape is slowing me down at the moment.
I've been running these 11.75" rotors from VBP to drop some weight. These with the aluminum hubs lost 5 lbs per wheel over the stock rotor/hub. So far after installing cooling ducts I haven't had any rotor issues ... knock on wood. When that time comes, I'll have to think seriously about up sizing my rotors to something like gkull's.
Last edited by Jason Staley; Dec 3, 2016 at 06:11 PM.
I've been running these 11.75" rotors from VBP to drop some weight. These with the aluminum hubs lost 5 lbs per wheel over the stock rotor/hub. So far after installing cooling ducts I haven't had any rotor issues ... knock on wood. When that time comes, I'll have to think seriously about up sizing my rotors to something like gkull's.
Speak of the devil. I pick mine up tomorrow. Same set up.
Larger rotors do not have to be heavier....most two piece are lighter than one piece. The value of that however is not as significant. The moment of inertia remains very similar. The weight loss is in the center.
Aluminum hubs with Colman rotors will be I reliable combo at a reasonable cost if the hub is durable and the bearing races stay put.
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The aluminum hubs have proven to be a reliable part with acceptable rotor runout and no bearing race issues. Been using this setup for ~15 years on the street and with some track use too. Prior to installing brake cooling ducts I did warp one set of rotors.
I agree not much change in inertia, but with my SSBC aluminum calipers I lost 10 lbs of unsprung weight per wheel. I put this setup together years before there were any BBK's for C3's. So far its treated me fairly well with only one breakdown due to a seal leak.
Aluminum hubs with Colman rotors will be I reliable combo at a reasonable cost if the hub is durable and the bearing races stay put.
I originally had the colman rotors. Was it a bad batch or were my H compound wilwood pads too aggressive. I'll never know because i went to Wilwood rotors and BP wilwood pads after my second set of colmans.
But the colman rotors were in the dumpster or metal bin After a weekend of SCCA racing. When the metal got really hot the pads just ground the metal away. Two or three hours of total running and they were gone. I showed them to my racing driver boss and he said that they must be made out of butter
I posted some pictures on here of the front rotors and a quarter sitting level with the ridge around the outer lip of the rotor. My racing front tires were R1 295 17 slicks on 10 inch wheels. My tires and rotors had to be replaced after every weekend
I've been working on making a pair of aluminum disc fans that would bolt between the front hub and wheel, and would pump air to both cool the brakes, and evacuate some of the undercar air in the process. Making the vanes consistent in shape is slowing me down at the moment.
How do those Dyson fans work? Any possibility that is an alternate approach?
So I think the OP got his ?? answered and.....then some , Im just curious why new caliper upgrade? Do the OEM ones not stop well enough? Planning one other "upgrades" to make it faster and your ensuring you can stop it?
My plan is to keep the 15" wheels, so the new rotors will be 11.75", upgrade the braking system, suspension, drive train, and hp in my 454 to somewhere around 500 hp and throw in a 2004R. Mostly highway driving with some foothill twisting roads. I don't want a monster, just something fun to drive. Thanks for all the information. Greg
My plan is to keep the 15" wheels, so the new rotors will be 11.75", upgrade the braking system, suspension, drive train, and hp in my 454 to somewhere around 500 hp and throw in a 2004R. Mostly highway driving with some foothill twisting roads. I don't want a monster, just something fun to drive. Thanks for all the information. Greg
Greg I do clients stock brakes. I buy NAPA premium rotors and dial indicator them to get sub .002 runout. I replace all of the rubber lines with steel braided. I buy stainless steel sleeved o ringed calipers
That base model wilwood don't give increased braking so it is hard to justify the cost for the weight loss
I originally had the colman rotors. Was it a bad batch or were my H compound wilwood pads too aggressive. I'll never know because i went to Wilwood rotors and BP wilwood pads after my second set of colmans.
But the colman rotors were in the dumpster or metal bin After a weekend of SCCA racing. When the metal got really hot the pads just ground the metal away. Two or three hours of total running and they were gone. I showed them to my racing driver boss and he said that they must be made out of butter
I posted some pictures on here of the front rotors and a quarter sitting level with the ridge around the outer lip of the rotor. My racing front tires were R1 295 17 slicks on 10 inch wheels. My tires and rotors had to be replaced after every weekend
Something is amiss with that for sure.
While I obviously deal in Wilwood product I sell hundreds of our custom Coleman made rings a year on a huge variety of kits. Be hard to pinpoint the exact cause but my thoughts are on non stress relieved parts and a mis match of pads to use. Speaking for H pads they are far and away the most popular track pad we sell. As for the BP: what BP? There are 10, 20, 30, and 40 compounds.
No point in reliving the entire story I know...but I've got so many Coleman rings in hard core service that it doesn't make sense.
I recently noted not only are their castings popular on a LOT of things today (that you may not know is from them...) but they were good enough to run on the Nissan GTP car circa 1990.
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Originally Posted by gkull
To the poster I would get modern larger diameter wheels because of the availability of AA A traction and temp rated tires.
This why they are lighter. of course the aluminum hat center and bolts ad to the weight, but they are slightly lighter than the stock 11.75
Oh, I was wrong the diameter is 13.06 inches.
Just doing some math on a gray cloudy day.
I looked up the weights and dimensions of our respective rotors. I didn't bother with the hat weights at the moment, but I expect that the effects will be similar.
Your 13.06" rotor is 3.5#/40% heavier (12.3 vs 8.8 pounds) than my stock-size 11.75 rotors, and the radius of gyration (the main factor in calculating moment of inertia, the resistance to rotationally accelerate or decelerate the rotors) is 11% higher due to the increased diameter. Doing the comparative MoI calculations (I=(k^2)m) shows that the bigger rotor has a MoI 74% bigger than the 11.75 size rotor. I haven't done the math on the hat weights, but the bigger and heavier hat for a 13" application will boost up the unsprung weight total and the MoI percentage even higher comparatively than the numbers just from the rotor calculations.
This is part of my reasoning for pulling weight off my car. Heavier cars need bigger/higher hp engines to get them moving, and then bigger/heavier brakes to get them to stop. It's a snowball effect.
Revolution/Compomotive 15X9.5, used with a 12" Wilwood 2-piece hat & rotor and somewhat factory remounted J-56 endurance calipers, notice the built-in wheel fans on the back side, they exhausted so much heat I was losing wheel weights covered in duct tape, I went to silicone around the weight and HVAC shiny tape with the peel off backing.
, Im just curious why new caliper upgrade? Do the OEM ones not stop well enough? Planning one other "upgrades" to make it faster and your ensuring you can stop it? 
