who makes there own bobbins and rotors...?

[Homemade WRX]

I was wondering what teams make their own bobbins and what material you use?

also what grade alum. are teams using on there rotors? I'm think 7075...?

I had planned on making our hats of 7075 as well.

Thanks, Micah

[Homemade WRX]

I was wondering what teams make their own bobbins and what material you use?

also what grade alum. are teams using on there rotors? I'm think 7075...?

I had planned on making our hats of 7075 as well.

Thanks, Micah

[Jersey Tom]

Rotors.. out of 7075? I was under the impression 7075 lost a large percentage of its strength at elevated temperatures. And I'd think a brake pad would just tear the thing apart unless you had it ceramic coated or something.

Tryin to think what wrought alloy it was that had good high-temperature qualities.. might have been 2124..

Our rotors are just plain hot rolled steel. We don't run a top hat, just the rotor floating on the hub. Buttons are steel, not sure what grade. Nothing fancy though.

[Homemade WRX]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Jersey Tom:
Rotors.. out of 7075? I was under the impression 7075 lost a large percentage of its strength at elevated temperatures. And I'd think a brake pad would just tear the thing apart unless you had it ceramic coated or something.

Tryin to think what wrought alloy it was that had good high-temperature qualities.. might have been 2124..

Our rotors are just plain hot rolled steel. We don't run a top hat, just the rotor floating on the hub. Buttons are steel, not sure what grade. Nothing fancy though. </div></BLOCKQUOTE>
that's why I'm asking...I haven't had materials yet and am asking for that reason. I think the pad would eat the rotor too...

[Jersey Tom]

Anything high temperature, 2124-T8 would be ideal IMO, if you're using an aluminum alloy that needs to be machined. And a tophat bolted straight to the rotor is gonna get hot.

I'm a fan of using plain hot rolled steel for rotors. Cheap, easy, and it works.

[Garbo]

I would suggest not using aluminum for the rotors and not using 7075 for the hats. We had some problems with the rear brakes last year which we believe was caused by the 7075 diff case, to which the rotor was mounted, heating up and losing strength (replaced with 2024). We were using a steel rotor, floating on steel bobbins.

So, 2000 series Al, with much better strength at high temps works better for hubs with floating rotors though I think many would insist on steel for top hats (and hubs).

Steel rotors seem to work well, they can be made very thin but beware what type of steel you use. 'Engineer to Win' has a line something like: 'God help anyone who tries to make rotors out of sheet steel.' (they are likely to warp).

Cheers
Garbo

[Denny Trimble]

Once again for your viewing pleasure:
http://students.washington.edu/dennyt/fsae/al_yield-vs-temp.jpg

Data taken from ASM online handbooks. If you want to update the chart with more alloys, here's the spreadsheet (http://students.washington.edu/dennyt/fsae/al_yield_vs_temp.xls) .

[McFly]

We use cast iron for the brake rotors, 7075 hard anodized for bobbins and brake hat. Everything is made in house and we have never had any problems. We have had problems with the bobbins yielding if they were not anodized.

[Rob.C]

we used to use mmc discs! (rotors) untill a couple of years ago when we used cast iron for the fronts, (as thats what pads we could get hold of)

now we use stainless steel rotors, both for weight and the fact that we can get hold of the pads to match!! (wost thing in the world using pads that dont match the discs ure using!!)

[Homemade WRX]

so cast or a steel rotor is what you guys are all saying...some of you say steel hat and some alum(hardened 7075 or 2xxx)...but steel bobbins is the way to go...
I was looking at alum for saving on rotor weight and that we had used it for the past two years with no problems (though I dislike not have a choice of pads)
thanks, Micah

[Marshall Grice]

we're using brembo bobbins from a motorcycle rotor and they're aluminum. although i don't know what type of aluminum they are.

[B]

has anyone had any experiance with using Wilwood's B compond pad on hardened martensitic stainless steel rotors?.. or any stainless for that matter?

[CornellGixxer]

We've been using grey cast iron for a while now with good results, and at thicknesses less than Carroll Smith's mminimum of 1/4". Although it was before my time, the team did experiment with MMC rotors and found that on a warm day, they will become mush and melt.

In a pinch, when the supplier we had to machine our rotors ran a bit over schedule, we fabricated some mild steel units out of 1/4" plate. It wasnt pretty but it got the job done for a few snowy doughnuts behind the lab on Feb, 1. Other than that they were garbage.