Some brake questions

[GNC]

I've searched the forum a couple time but didn't find the answer I wanted. I'd really appreciate your input on some brake related questions I have.

1. Some calipers have a specified minimum rotor diameter. What's the consequence of running a rotor that has a diameter smaller than that? Say I want to use calipers off some sportbikes, how would I know the minimum rotor diameter ?

2. What would be the best way to obtain technical specifications for those calipers off sportbikes? I know I could just measure them by hand but I don't quite feel like to spend the money if I'm not sure it's going to work.

3. For teams that runs calipers off a bike, what are your opinions on them?

Gary

[GNC]

I've searched the forum a couple time but didn't find the answer I wanted. I'd really appreciate your input on some brake related questions I have.

1. Some calipers have a specified minimum rotor diameter. What's the consequence of running a rotor that has a diameter smaller than that? Say I want to use calipers off some sportbikes, how would I know the minimum rotor diameter ?

2. What would be the best way to obtain technical specifications for those calipers off sportbikes? I know I could just measure them by hand but I don't quite feel like to spend the money if I'm not sure it's going to work.

3. For teams that runs calipers off a bike, what are your opinions on them?

Gary

[drivetrainUW-Platt]

I will give these a shot.

1. If you run too small of a disk for the pads, you may leave the corners of the pads not hititng the rotors, meaning they wont wear and will not do good things to the rotors as they may get very hard or hot.

2. Find out who makes them and sells them to the sport bike companies. Easier said then done but if you ask enough people you might get an answer.

3. Bike calipers always seem to have goofy mounting arangements since they are made to fit the frames of the bikes, not a FSAE car. It is also hard to get "opposites" since they only run one rear caliper and some only one front, if you flip them from side to side the bleeders/orientation may be upside down.

They are pretty cheap and easy to come by, with enough searching you may find a set that will work. Remember to do brake calcs before just finding something and bolting it to the car assuming it works with x masters and x rotor diameters.

[Jersey Tom]

We used to run Nissin calipers off the CBR. They worked fine and all, but the past couple years have used Wilwood billet DLS's. They're nice and light and grab real well.

Brakes are one of those things I'd always want to have 100% faith in so overbuilt isnt a bad thing. That and given how many teams have a hell of a time passing brake test every year..

[Buckingham]

1. Look at a model or physical sample of the caliper pad installed on the rotor diameter you want to use. If it doesn't look like a problem, it probably won't be a problem. We ran the same superbike caliper on ~6" rotors that we did on ~10" rotors for years.

2. Contact the manufacturer or measure it, there's not much other option unless you can get info from a sharing forum member that has already done the same.

3. The ones we ran were super expensive, super light, super compact, with good performance and good durability. Not very many options for pad compound, and not having a mirrored caliper was an annoyance to bleed (take caliper off the car) but wasn't a performance issue.

[Ian McMurdo]

If you're looking into Brembo calipers, there are technical drawings available of most of their calipers at this link:

http://kvickmc.se/brembo-mckatalog/

[GNC]

Thanks for the replies guys. I emailed Nissin USA but have yet to receive any reply from them. Guess I will email a couple motorcycle manufacturers too...

Ian, do you know who is the distributor of brembo calipers in North America? I would like to find out prices and availability information on those calipers...

[Ehsan]

http://www.tawvehicle.com/

Great folks. Easy to deal with and helpful. yoyodyneti also carries Brembo.

As for sportbike brakes, do your calcs and see if you really need 4 piston fixed calipers designed for 310mm rotors. Bike brakes are designed to haul down a motorcycle from 120+ miles per hour and be activated by 2 fingers on the lever. You are designing a system that will never see more than 70 mph at competition and is activated with 75+ pounds at your feet. And Japanese bikes have floating rear calipers = YUCK. you're on a good path with the brembos. Keep digging and good luck.

[Ian McMurdo]

we got ours from TAW as well, but for some reason ended up paying a LOT in shipping. I never did follow up with them to figure out why, but when you're ordering, be sure to get a shipping quote up front. They have a lower rate for SAE teams too.

If you look at the Brembo drawings for their larger calipers off the front of sport bikes, you will see that most of them are not suitable for the small size of discs that our cars run.

Also, on several websites there is a brembo model P30B listed. The packaging of this caliper looks really nice, and the smaller piston size would make it good for the rear. TAW lists a RH and LH model, but Brembo actually only produces one version. I asked the people at Brembo and TAW, as well as shops in Europe, several times - trust me, there's only one version.

[Jersey Tom]

I'm going to imagine Brembo aint cheap. Don't rule out anything. Do your own decision matrix analysis.. between Nissin, Brembo, Wilwood, AP, or whoever.

[JerryLH3]

The Brembo calipers we got from TAW this year were $70 each. That's not a bad price at all in my book.