Brake rotor material?

[exFSAE]

Aluminum rotors are certainly feasible with the right pads... but if you're just dicking around with the car, 1018 rotors are nice from a maintenance standpoint. One set will last a long time without having to worry about it.

With respect to metalworking, there are wheels of a special material that let you lightly "grind" on aluminum with no issue and no material loading on the wheel. They are not stone. Great for deburring.

[Demon Of Speed]

Originally posted by exFSAE:
Aluminum rotors are certainly feasible with the right pads... but if you're just dicking around with the car, 1018 rotors are nice from a maintenance standpoint. One set will last a long time without having to worry about it.

With respect to metalworking, there are wheels of a special material that let you lightly "grind" on aluminum with no issue and no material loading on the wheel. They are not stone. Great for deburring.

Yup, they defiantly do make special abrasives for aluminium.

I know proper Al rotors will last 20+ hours of hard use without a problem. That should be good enough for at least 2 years.

[Ben K]

Originally posted by Demon Of Speed:
I am guessing no one in this thread is a metallurgist.

If you think that using steel is a better idea for such a low mass vehicle than a proper aluminium rotor then you are wrong.

Please do yourself a favor and know what you are talking about before you post.

As to the original question, make sure the rotors are hard anodized, and the anodizing has not worn off. I know Wilwood purple pads are specially designed for Al rotors, and I am sure you can find aluminium pads in other brands.

Now I don't disagree that you COULD use aluminum as a rotor. But there are more negatives to positives here. Thermal expansion, transfer, as well as warping are all much larger issues in an aluminum rotor. With proper considerations, they MIGHT work, but for a starting team I certainly wouldn't consider it.

Ben

[thewoundedsoldier]

Who said anything about a 'starting team'? This appears to be a guy who purchased an old car and is wondering about its upkeep.

And it might be unfair to suggest that thermal expansion, transfer, and warping are the most important issues in rotor material design. How about coefficient of friction? How about young's modulus? Weight/strength ratio? Ductility? IMO all of those properties point towards a well-designed aluminum rotor.

I see a lot of stigma in formula student--some of it is for good reason and some of it makes me scratch my head.

[Mbirt]

I've seen a team get two competitions, two non-sanctioned competitions, an SCCA auto-x, and plenty of testing out of one set of 4 aluminum rotors. They use the aforementioned Wilwood pad. The rotors can and do last in an FSAE application.

[Ben K]

As I said, they might work. I haven't done the design work specifically for an aluminum rotor, so I stand corrected if someone has actually been able to pull them off for long term use.

[Demon Of Speed]

Originally posted by Ben Kolodner:
As I said, they might work. I haven't done the design work specifically for an aluminum rotor, so I stand corrected if someone has actually been able to pull them off for long term use.

Please see MBirt's response.

[Adambomb]

We used Al front rotors in '03. The car was 450 lbs, and as I recall the rotors were about 0.25" thick and 9" OD, built for Wilwood Dynalite calipers. Had cooling grooves, but the combination of low thermal mass and low high-temp hardness caused severe galling.

We used an Al rear "sprotor" from '04-'05. 0.25" thick, something like 12-13" diameter, designed for Wilwood Dynalite calipers. Both of those cars were also about 450 lbs. After something like 30 hrs of run time all of the sprotor teeth went from being radially oriented to something that resembled a circular saw blade with several missing teeth.

[chrisbowie]

1018 steel is an good option. It is generally available in round rod, square bar, and rectangle bar. It has a good combination of all of the typical traits of steel - strength, some ductility, and comparative ease of machining. Chemically, it is very similar to A36 Hot Rolled steel, but the cold rolling process creates a better surface finish and better properties.

[PatClarke]

I can't believe it!!!

A real live semi useful response from a spambot!!!

Pat