How much weight comes off a rotor?
05-28-2015, 08:57 AM
#3
Melting Slicks
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Interesting question.
Not for a corvette but I have a set of worn and brand new pfc rings from a bmw race car in my trailer. I'll try to remember to weigh them.
I bet it's not a lot of % change though
Not for a corvette but I have a set of worn and brand new pfc rings from a bmw race car in my trailer. I'll try to remember to weigh them.
I bet it's not a lot of % change though
05-29-2015, 10:23 AM
#5
That Centric is a C6 rotor, if you bought it as a C5 rotor they've probably just obsoleted the old C5 ones as they're interchangeable anyway. The added weight is likely due to the updated hat style which is intended to reduce cracking by allowing flex as the ring expands and contracts with changing temperature. The good news is that the added weight is close to the center so the effect will be minimal, and the added weight will slow you down less than a cracked rotor 
As for weight change with wear, I punched up a simple ring model in 3D and pulled a weight off of it based on 2mm worth of wear. Believe it or not, 2mm (1mm per side) worth of wear shows to be just shy of 2 lbs.
As for weight change with wear, I punched up a simple ring model in 3D and pulled a weight off of it based on 2mm worth of wear. Believe it or not, 2mm (1mm per side) worth of wear shows to be just shy of 2 lbs.
Last edited by LateBreak; 05-29-2015 at 10:27 AM.
05-29-2015, 02:01 PM
#6
Race Director
Thread Starter
That Centric is a C6 rotor, if you bought it as a C5 rotor they've probably just obsoleted the old C5 ones as they're interchangeable anyway. The added weight is likely due to the updated hat style which is intended to reduce cracking by allowing flex as the ring expands and contracts with changing temperature. The good news is that the added weight is close to the center so the effect will be minimal, and the added weight will slow you down less than a cracked rotor
As for weight change with wear, I punched up a simple ring model in 3D and pulled a weight off of it based on 2mm worth of wear. Believe it or not, 2mm (1mm per side) worth of wear shows to be just shy of 2 lbs.
As for weight change with wear, I punched up a simple ring model in 3D and pulled a weight off of it based on 2mm worth of wear. Believe it or not, 2mm (1mm per side) worth of wear shows to be just shy of 2 lbs.
Wow, I did not expect that!
Thanks for GOOD INFO on this thread!
That centric was 32.32mm new and out of service at 30.0 so that is about spot on, as you know, for regular wear.
Last edited by froggy47; 05-29-2015 at 02:04 PM.
05-29-2015, 07:19 PM
#7
Racer
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I had a set of Wilwood GT48 rotors. A couple of seasons on them and the slots had basically disappeared. So I ordered a set of HD48's in the same size. The HD48's apparently have a racier metallurgy. When the HD48's arrived I weighed all 4 rotors.
2 x worn GT48's: 24.4 lbs
2 x new HD48's: 24.4 lbs
lol.
Maybe there's a difference in the castings, but they *look* the same.
After 3 hours on the HD48's they still weren't working right: just not enough stopping torque. So I said buggerit and put the old GT48's back on.
Anyone wanna buy a set of nearly-new 13" wilwood rotors?
http://www.wilwood.com/Rotors/RotorP...emno=160-12786
2 x worn GT48's: 24.4 lbs
2 x new HD48's: 24.4 lbs
lol.
Maybe there's a difference in the castings, but they *look* the same.
After 3 hours on the HD48's they still weren't working right: just not enough stopping torque. So I said buggerit and put the old GT48's back on.
Anyone wanna buy a set of nearly-new 13" wilwood rotors?
http://www.wilwood.com/Rotors/RotorP...emno=160-12786
05-29-2015, 07:48 PM
#8
Former Vendor
The HD casting is simply the GT casting without slots. Both the newer Spec37 material. (derived from their military casting work)
If they were not "working" as well it would likely be due to lack of proper bedding and putting down the base transfer layer. Possibly not having cleaned the rotor before use of the oils to prevent rusting. Or may be a pad change from the previous use? Hard to say..but one won't make more torque vs the other - they're the same diameter.
If they were not "working" as well it would likely be due to lack of proper bedding and putting down the base transfer layer. Possibly not having cleaned the rotor before use of the oils to prevent rusting. Or may be a pad change from the previous use? Hard to say..but one won't make more torque vs the other - they're the same diameter.
05-29-2015, 09:21 PM
#9
Racer
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The HD casting is simply the GT casting without slots. Both the newer Spec37 material. (derived from their military casting work)
If they were not "working" as well it would likely be due to lack of proper bedding and putting down the base transfer layer. Possibly not having cleaned the rotor before use of the oils to prevent rusting. Or may be a pad change from the previous use? Hard to say..but one won't make more torque vs the other - they're the same diameter.
If they were not "working" as well it would likely be due to lack of proper bedding and putting down the base transfer layer. Possibly not having cleaned the rotor before use of the oils to prevent rusting. Or may be a pad change from the previous use? Hard to say..but one won't make more torque vs the other - they're the same diameter.
The rotors do take a long time to come in - for the first two sessions the GT rotors shed huge amounts of brake dust and didn't work well. After the surface grinding had been worn down they bedded and worked OK. The HD rotors (two years later...) didn't have as much (or any) grinding roughness and they didn't do this.
These HD rotors *look* OK: nice smooth and uniform surface. Shrug. I guess sometime I'll try them again.