Light Weight Material for Disk Brake Rotors
Light Weight Material for Disk Brake Rotors
(OP)
I am interested in the carbon/carbon rotors or other lightweight solutions to reduce rotating mass in a drag race car.
I know carbon/carbon are used in F1, so should be durable enough for a drag race car, and should significantly reduce the inertia of the wheel hub assembly.
I guess I will also do a Google search, but I expect I will get more qualified and objective advice here.
I already asked this question in another thread in another forum, but I think this is a more appropriate place, and so as to avoid hijacking another thread, I will transfer the answer already received over to here, and then red flag that post and answer
I know carbon/carbon are used in F1, so should be durable enough for a drag race car, and should significantly reduce the inertia of the wheel hub assembly.
I guess I will also do a Google search, but I expect I will get more qualified and objective advice here.
I already asked this question in another thread in another forum, but I think this is a more appropriate place, and so as to avoid hijacking another thread, I will transfer the answer already received over to here, and then red flag that post and answer
Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.





RE: Light Weight Material for Disk Brake Rotors
Pat carbon/carbon won't work well for drag racing, they only have good braking at high temperatures. You will want to look at carbon/ceramic discs, they are slightly heavier than carbon/carbon 2g per cc vs 1.7g per cc. And go for 10000UK Pounds per wheel, discs and pads. You can get them for half the price if you are willing to machine it yourself, but you require diamond tooling, its almost as hard as silicon carbide.
If you are still interested in Carbon/Carbon, you will require high density medium quality and a coefficient of friction .35 or more(I'm sure you already know this), the cost is $250-$400 per kilogramme, and should weigh around 2KG per disk and pad. Good luck in finding a manufacturer willing to supply you with low quantities though usually its 500KG minimum, there is one company I know off that sells them at US $1200 per wheel, pads and discs so a lot more than the $250-$400 per kilogramme but at least they supply low quantities.
Let me know if you are interested and I'll provide you with the info on where to get it and save you some time. These are for only the discs, so you will have to make your own hats.
SilverSSguy titanium will wear pretty quick, I don't know if you are willing to accept this. I have a profile suited to titanium if you are interested to compare to yours, I use solid edge but can export to parasolid or IGES for import to solidworks.
Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Light Weight Material for Disk Brake Rotors
Thanks for your help, but if the number of Zeros in the Carbon/Ceramic disk cost is correct, that makes them A$30,000 per wheel or $120,000 per car. That is way above our budget.
I may have hijacked this thread, but as the original question was about reducing drive-line inertia by removing weight from the brake system, I felt it was relevant.
I will start a new thread just in case an affordable solution comes up.
Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Light Weight Material for Disk Brake Rotors
What is the weight of the car and spped brakews need to operate from?
RE: Light Weight Material for Disk Brake Rotors
The lotus MMC discs are not manufactured anymore, I can't remember who made them, but they went bankrupt. Lotus also don't have any stock left.
RE: Light Weight Material for Disk Brake Rotors
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Sorry the pics aren't embedded, something wrong with eng-tips's processing tgml.
RE: Light Weight Material for Disk Brake Rotors
It currently has about 11.5" ventilated discs on the front, and slightly bigger but non ventilated on the back. They are cast iron units of mewdium to large family sedand from the late 70's early 80's. They do the job, but are very heavy. The backs get hotter than the fronts.
Even though the car probably has 55% of the weight over the front axle, it has much bigger rolling diameter and width on the back tyres.
Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Light Weight Material for Disk Brake Rotors
RE: Light Weight Material for Disk Brake Rotors
Worked for a machine shop in Stoney Creek, Ontario. They have done quite a lot of work on Prototype Aluminum MMC rotors for motorcycles, Chrysler (Anyone remember the Plymouth Prowler? - Aluminum MMC Rotors) and other car manufacturers.
The biggest problem with the rotors was the noises they made during operation.
Anyway, track down BSB Manufacturing Ltd. and talk to Narinder Bhogal. He might even be able to make them for you.
Their number is (905) 643-0101.
RE: Light Weight Material for Disk Brake Rotors
RE: Light Weight Material for Disk Brake Rotors
I'm assuming each run has a longish break before the next run and thus everything has time to cool down?
My first though was why not try a 50% solution and see if you can measure the improvement rather than fork out the money for the exotic. Wilwood have some cheap/light large diameter vented rotors and bells that are for nascar (similar weight/speed) oval racing. Some of these with lighter calipers?
I take back what I said re the ceramic, given that porsche GT3 drivers in the UK having their disc's replaced are reportedly up for 27,000 uk pounds for a set (seems an unbelieveable price, but that is what is reported)
RE: Light Weight Material for Disk Brake Rotors
We have at least an hour between runs, so it cools right down.
At 50 passes a year, that is only 50 stops, so wear is not an issue, so thinning the pads, narrowing the callipers and shortening the pistons will all reduce weight a bit.
An aluminium hat with aluminium spokes in the shape of centrifugal fan blades, and with light weight steel or carbon friction surfaces attached might work at a reasonable price.
I am much more concerned with rotating mass rather than non rotating, so the Holden OEM aluminium callipers are OK at this stage, maybe with the rework above. Rotating mass is of much more interest, and the rotors and hats are also a lot heavier than the callipers.
Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Light Weight Material for Disk Brake Rotors
Just something else to consider.
For interrest how much are your discs currently weighing?
RE: Light Weight Material for Disk Brake Rotors
My main concern is whether or not the rotors will get hot enough for the aluminium to heat up to a level where it's strength becomes dangerously low.
Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Light Weight Material for Disk Brake Rotors
Do you think it will this make a conciderable difference? I am considering if its worthwhile for me to go for them as well, I also wan't to take part in track events and the car does not have much torque so it might make a bigger difference for methan you.
I assume you are running a V8?
RE: Light Weight Material for Disk Brake Rotors
Do you think it will this make a considerable difference? I am considering if its worthwhile for me to go for them as well, I also wan't to take part in track events and the car does not have much torque so it might make a bigger difference for methan you.
I assume you are running a V8?
RE: Light Weight Material for Disk Brake Rotors
Basically they could match any cast iron rotor application for heat and wear requirements. Just make sure you use organic pads. Also there was a lot of testing on racing motorcycles. I believe the heat requirements on those would be equivalent or similar to a drag race application.
I don't know if they will work but for the cost it would probably be worth investigating - we were making rotors for about $100 US ea. The one problem I see is that there isn't a lot of support out there for these rotors.
RE: Light Weight Material for Disk Brake Rotors
RE: Light Weight Material for Disk Brake Rotors
RE: Light Weight Material for Disk Brake Rotors
Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Light Weight Material for Disk Brake Rotors
I may have found another supplier willing to supply carbon/ceramic discs a little cheaper, but obviously no where near the Aluminium mmc prices. Hoping to get it for US $500 per wheel unfinished and $1000 per wheel for a machined product. I can afford that :)
RE: Light Weight Material for Disk Brake Rotors
RE: Light Weight Material for Disk Brake Rotors
RE: Light Weight Material for Disk Brake Rotors
RE: Light Weight Material for Disk Brake Rotors
Maybe on a heavier car it might be a bit of a problem, I am not sure. You have the same problem with carbon/ceramic discs if you try and use organic pads (Same grade as MMC discs can be used on carbon/ceramic discs), the pads just can't handle much over 400C. However if you use carbon/ceramic pads, you can go over 800C. If you look at the porche carbon/ceramic discs as well, they don't use carbon/ceramic pads, and their have been plenty of reports of the pads catching on fire. It doesn't seem to do any harm though.
RE: Light Weight Material for Disk Brake Rotors
As I recall from 6 years ago, under similar braking conditions MMC would only reach about 2/3 of the temperature a cast iron rotor would see. This was due to the better heat capacity and dissipation characteristics. It would take more heat to move the rotor temperature on an MMC rotor than it would in a cast iron.
I know you are thinking - wait we are talking about aluminum. The key to a MMC product is not the main matrix, it is in the additives. The aluminum was excellent at heat dissipation but the additive was excellent for temperature stability and heat absobtion. Each used its strength in this application.
Where a Cast Iron rotor might see 400 deg. C a MMC rotor might only see 275.
RE: Light Weight Material for Disk Brake Rotors
RE: Light Weight Material for Disk Brake Rotors
Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Light Weight Material for Disk Brake Rotors
RE: Light Weight Material for Disk Brake Rotors
For drag racing life is not even really an issue, as they might only do 6 or 8 stops at a meeting and 50 to 100 stops per season.
Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Light Weight Material for Disk Brake Rotors
There are a number of reasons. The first and strongest is cost. In an automotive aftermarket environment a single rotor would probably cost over $200US. The average person would not see a significant benefit to justify the cost.
The second reason - pads to match up with the rotors are expensive. See item 1 comment about average person.
Last I checked there were some lingering engineering issues such as excessive noise.
Because of the application originally mentioned is more weight driven and the availability of funds is appropriate I figured this might be something to check out. As mentioned I am not completely up to date on all the information but I gave information on where someone could start to find out more.
RE: Light Weight Material for Disk Brake Rotors
RE: Light Weight Material for Disk Brake Rotors
RE: Light Weight Material for Disk Brake Rotors