Kart brakes, go-cart, shifter kart, superkart, etc.

[Mechanicaldan]

OK, because of the "Life, the Universe, and ..." post, I went digging to explore the kart brakes option.

There is an Italian company called Wildkart, and they make some really nice products. The interesting thing to note is that the calipers were designed to have the pads pulled away from the rotors with springs. Very nice. The vented rotors are 200 mm and 210 mm, which would seem to me to be the right diameter for a Formula car. I don't know what pads are available, but EBC seems to make a lot of pads for karts. Brembo and Wilwood also make kart brakes.

Here's some picture of the Wildkart brakes.
http://www.wildkart.it/products/img/MPFA2DX-SX.jpg
http://www.wildkart.it/products/img/MPFA4DX-SX.jpg
http://www.wildkart.it/products/img/MDFPA12.jpg

[Mechanicaldan]

OK, because of the "Life, the Universe, and ..." post, I went digging to explore the kart brakes option.

There is an Italian company called Wildkart, and they make some really nice products. The interesting thing to note is that the calipers were designed to have the pads pulled away from the rotors with springs. Very nice. The vented rotors are 200 mm and 210 mm, which would seem to me to be the right diameter for a Formula car. I don't know what pads are available, but EBC seems to make a lot of pads for karts. Brembo and Wilwood also make kart brakes.

Here's some picture of the Wildkart brakes.
http://www.wildkart.it/products/img/MPFA2DX-SX.jpg
http://www.wildkart.it/products/img/MPFA4DX-SX.jpg
http://www.wildkart.it/products/img/MDFPA12.jpg

[Denny Trimble]

Don't kart calipers with return springs require special master cylinders (closed system instead of open)? I'm sure some kart guys will let us know.

[drivetrainUW-Platt]

shifer carts are a LOT lighter then the average fsae car, but since duel rear brakes are becomming more popular, they would prob do the job there

[Big Bird]

Cheers Dan, that is great info. I owe you a beer!

[SeanM]

We use kart breaks on our car, they don't seem to be to good for us thats simply because our master cylinder wasn't really meant for the setup we're using, but they've been good enough so far. BryanP would probably be able to answer your questions he used to build and race shifter karts

[BryanH]

The hydraulic advantage on a kart is much lower than used on a car. This is achieved by running small dia. pistons, typically 1" on a 2 piston. with a 7/8" or 15/16" master. Purpose of this is small fluid displacement v. piston travel.
They travel a lot due to the unique situ in a kart where the axle flexes in the chassis enough to need the pads to be pulled off the discs at least .030" per side to stop any drag.
(when you only have 100cc it all counts)
At the end of a long race clearance can be up to .120" which = loong pedal. U need to be constantly shimming the pads (pain in ass).
AP master cyls can be used, much safer than the sealed systems the Italians love, small leak=no brakes.

Dent kart brakes (OZ) manafact. ported master cyls.

[fsae_alum]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Denny Trimble:
Don't kart calipers with return springs require special master cylinders (closed system instead of open)? I'm sure some kart guys will let us know. </div></BLOCKQUOTE>

The key is to look at the brakes that ENDURO karts use. They have bigger engines and run on much bigger tracks and use much bigger brakes. Top speeds can be above 120 mph!!

www.kelgate.co.uk (http://www.kelgate.co.uk) makes some 6 piston REAR enduro kart brakes that could be adopted for front caliper use.

BTW...what's wrong with using enduro kart master cyliners, lines, and pedals already designed to match those 6 piston calipers they sell?

[BryanH]

"The key is to look at the brakes that ENDURO karts use. They have bigger engines and run on much bigger tracks and use much bigger brakes."
No they are not, FormulaA,Rotax Max,Superkart use the same components but there is obviously diff brands. 4 & 6 piston is in common use but I didn't want to complicate the post. Kelgate is the AP of the kart world, very reliable systems and for that reason are used by most superkart manfacturers. Several brands come with or without spring retraction and it is not used on 250 superkarts which btw max out at 265kmhr + For 10" wheels the rear kart disc dia. is too big and the fronts are tiny.

I'm wrong, Kelgate now make very nice 6.5"
front discs in various thickness incl. vented but not cheap!

[fsae_alum]

Whoa....calm down there Mr. Hester. Do you need a hug?

Who says you have to run 10" wheels?

Great...so they top out at 265 kmhr...all the more reason to look at using the brakes!

Take these brakes and couple them to a lightweight chassis and a Cannondale engine and you might have a nice FSAE car. Just a thought ya know!

[Homemade WRX]

I have had no luck getting measurements or any specs for that matter from wild kart or righetti rigoli on there rotors, pads and/or calipers...has anyone had any luck getting info from either?
thanks, Micah

[consig]

I dont know if anyone is still interested in these brakes or if anyone went ahead and used them but i figured i'd ressurect this thread to offer some CAD models in case anyone is interested.

http://img.photobucket.com/albums/v719/bigbrotherjohn/brakes.jpg

let me know you email and i can send the CAD file, it is a SW2007 file. If anyone wants to add it to on of those online CAD libraries thats good too.

I have a question for anyone who might have experience with these brakes or go-kart brake in general. As you can see in Dan's original post and in my CAD model the calipers only have one mounting hole. How are these supposed to be mounted? Do they have to be held against a surface on the upright or something? seems sort of silly that way.

[billywight]

Looks like the one hole is for a bolt and the hole directly above is for a dowel or something to react the torque. I don't really know though, just a guess from looking at the model. Check the other hole to see if it's a nominal size.

[consig]

ah, good eye but that hole is actually the fitting for the hydraulic line. There arent really any other available holes.

[js10coastr]

The bolts that hold the two sides together mount the caliper to the frame also.

http://express.howstuffworks.com/gif/ta-kart-wheel.jpg

[BenB]

I'm not sure about the Wild Kart brakes, but my kart's (Swiss Hutless) calipers look very simular. The way they work:

The 2 sets of springs actually pull the pad back against a set screw (the hole in the very center of the caliper under the "wild kart" inscription. Instead of shimming the pads you just adjust the set screw in to tighten the clearance and back it off and the springs pull the pads out to loosen the clearance.

My kart had reservoir master cylinders, but my old Tony Kart had the closed system setup. The closed system did really suck. You can use any master cylinders you want probably so you wouldn't have to stick with a closed system setup.

Shifter cart classes normally have a minimum weight of around 400 lbs (with driver) I remember I used to have to put about 100lbs of lead in the frame rails to make weight. (I'm only tippin' the scales at 155.) Anyways that is about the same as a formula SAE car so they should work.

A shifter kart normally has 2 small front calipers and 1 larger rear one, and stops all 400 lbs on a dime!

[drivetrainUW-Platt]

Yes, but what about the difference in tire diameters, you will have a lot longer lever arm to the ground from your axle center.

That and you have a lot more rotational mass to stop in a fsae car.

[BenB]

That's a good point. I didn't take that into consideration.

One question though, ignoring the increase in rotational energy (maybe you can't do this?) since the cars weigh approximately the same (again maybe I'm wrong, are most SAE car's rated weights with or without the driver?) If you are braking from 60mph in both cases aren't you disapating the same amount of energy?

I'm guessing FSAE car's are normally weighed without the driver because a 125cc shifter cart without a roll cage or suspension should be a lot lighter than a 600cc FSAE car with a suspension and roll cage. This is probally where I'm off...

[terra_dactile]

Hello BenB
E(joules)=Vehicle Mass(kg)* Speed(m/s)squared
So yes I belive you are right about the energy part of the debate, however I believe Mike Duwes point was more to do with the amount of pressure you would need to take care of the extra torque required when using larger wheels. More pressure equals more compliance in the system.

My question is why are we trying to use kart items, is it because they are cheaper,lighter etc.. ?

Because from my experience the lightest calipers you could get for fsae use( apart from custom magnesium penn state calipers) would be either the AP 4226-2S0 or the Brembo equivalent that come from the rear of a MOTOGP Bike. They however cost an arm & a leg and your first born child to buy.

Sorry to disturb the post about karting products, I was just unsure of what the advantages were by using these products, the calipers mentioned above way around 250 gramms, im pretty sure by looking at the pictures that the kart product are more in the region of 500 gramms plus.

Jude Berthault
ETS FSAE 2003-Current
Team Captain & Vehicle Dynamics Leader