Discs for PS-1 caliper

[kapps]

I'm working on matching up our braking system and have a question. We plan to use Wilwood PS-1 calipers all around and I am having a hard time finding brake discs that will fit. Wilwood says the discs can't be thicker than .20". Most discs I've found are much thicker than that.

It seems like a lot of teams are using custom discs. Are these made in-house or outsourced? This is my first year doing the braking system so any help would be appreciated.

Thanks.

[kapps]

I'm working on matching up our braking system and have a question. We plan to use Wilwood PS-1 calipers all around and I am having a hard time finding brake discs that will fit. Wilwood says the discs can't be thicker than .20". Most discs I've found are much thicker than that.

It seems like a lot of teams are using custom discs. Are these made in-house or outsourced? This is my first year doing the braking system so any help would be appreciated.

Thanks.

[Conor]

Get them water jetted out of steel plate. It's quick, easy, and cheap. It's the best way I know of. Also, you might want to be a little weary of using ps-1's all around. We're using them in the rear, but opted for a larger caliper in the front with a targeted maximum pedal force of roughly 70-80 lbs. Some people will want to argue with me on this, but anything higher will likely induce driver fatigue and the judges will let you know that. Also, don't forget that the largest force produced in any of these cars is usually the front brake torque.

[David T.]

http://www.hrpworld.com/index.cfm?form_prod_id=255,164,..._1338&action=product (http://www.hrpworld.com/index.cfm?form_prod_id=255,164,49,363_1338&action=product)

thats where we get ours from. We also use PS-1 Calipers

[kapps]

Thanks for the info guys. Conor, I know we are going to have a heavy pedal this year. We had our minds set on the PS-1 for a while now but I may switch to a larger one if it really proves to be a problem. Our FSAE team hasn't exactly had a stelar record for the past few years so we don't have much to base our decisions off of.

[Conor]

Kapps,

We went through the same argument because we planned to use the ps-1's all the way around too. Basically, we calculated how much pedal force was required with all ps-1's and then the pedal force with ps-1's in the rear and a larger caliper in the front. In the end, we grabbed a bathroom scale, propped ourselves between a wall and a pillar in the building and pushed on the scale with one foot to see how each pedal force felt. I invite you to spend the extra 3 hours of effort before you decide to just bolt the system in. You may find that the ps-1's are more then suitable. But using the bathroom scale will put your mind at ease and assure you that your decision was a good one.

[Drew Price]

Conor, completely agree with you. We did the same, and were surprised how much force even our smaller member could exert.

We use stock front brake rotors from a Yamaha R1. They came in about exactly the size we needed, and got a good discount from the motorcycle dealership who helped get us our drivetrain. We just sent two people over to the dealership with a caliper and a ruler, and measured a bunch of rotors on the bikes on the showroom floor to find which ones would fit.

Best,
Drew

[kapps]

Cool. I'll definitely try the scale test and see what we feel comfortable with. I found a couple brake rotors laying around the shop that look like a good fit (8.5" diameter and .19" thick). Now I just have to figure out what bike they came off of.

[poweredbyvdub]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by David T.:
http://www.hrpworld.com/index.cfm?form_prod_id=255,164,..._1338&action=product (http://www.hrpworld.com/index.cfm?form_prod_id=255,164,49,363_1338&action=product)

thats where we get ours from. We also use PS-1 Calipers </div></BLOCKQUOTE>

you can compensate for a really small caliper with either smaller master cylinders or a higher pedal ratio. with both, you'll end up with higher line pressures and a longer pedal, but it's probably better than not being able to pass brake test at comp because you can't push hard enough. although i wouldn't consider these alternatives if you see your line pressures are already on the high side.

[Grant Mahler]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Drew Price:
Conor, completely agree with you. We did the same, and were surprised how much force even our smaller member could exert.

We use stock front brake rotors from a Yamaha R1. They came in about exactly the size we needed, and got a good discount from the motorcycle dealership who helped get us our drivetrain. We just sent two people over to the dealership with a caliper and a ruler, and measured a bunch of rotors on the bikes on the showroom floor to find which ones would fit.

Best,
Drew </div></BLOCKQUOTE>

We are in fact using the stock rear rotors off an R6, but if someone had tried to use the fronts off an R1 that would have become immediately obvious.

[Kyle Roggenkamp]

I've got a related question, hope I'm not hi-jacking the thread here. We are looking at using the Dyna Pro calipers from wilwood instead of the PS-1's, because the PS-1's don't provide enough clamping force for the diameter rotor we want to run. Does anyone run a small-diameter, thick rotor? We are looking at having some 6" dia rotors with a thickness of .25-.30" made for the Dyan Pro's.

Also, for those that are making their own rotors or having them made, do you heat treat them?

[Drew Price]

Is anyone not getting their rotors hot enough to take any heat treat back out of them? Maybe because our cars are so light it won't, but I expect after a few very spirited sessions you would have annealed rotors.

Best,
Drew

[Vinnie]

ISR brakes in sweden made for Delft customized self designed brakde discs. we just could design our own brake disc with every dimension we wnat. they give also 50% discount to FSAE teams so we paid like 100 euros a piece. they were full floating. the link to their website is:

http://www.isr-brakes.se/

and they don't have e-mail, so you have to phone or fax. but its a great company with a funny director...

cheers vincent
Delft '05 '06 '07
Brookes '08

well and good work will be noticed as the October issue of Racecar Engineering stated: