Could I get away with using some light weight r1 rotors/calipers on a locost?I understand that some machining and fabrication would be needed. The car won't be seeing any track use, and this would probably shave/hack about 15-20 pounds per corner from my mx5-miata setup. Or is this just asking too much from the brakes?

I thought about this a while ago .....

bikes do most of the braking with the front brake. Take a modern sports bike, put two passengers on it at 80kg each, add in the weight of the bike (no idea but 40kg say?) and you've got the front wheel doing up to 200kg braking....

now transplant that to a car - well 400kg braking on the front with an 70/30 split to the rear (made up numbers) and ....


you've got something that using my school yard logic and engineering skills would do the job......

Of course the question is - would you trust it? me, i'm using cortina m16 calipers

Might be worth asking Rorty's opinion, he plays about with bike kit on his "projects" and might have some experience of the subject
Shug.

Considered this myself.
Rough calculations-Fully fueled up bike 180Kg + rider and pillion and some luggage 170Kg =250Kg.

Bikes do 75% of the breaking on the front and have twin disks at the front so each disk is hauling up 94Kg approx.

Allowing for the safety factors designed into the brakes it is theorically possible but IMO you're asking a lot from them, particularly if you have a passenger.

Also I've warped bike brakes before on the track with no luggage and no passenger.

All IMHO
John

I thought as much. It's just that these brakes are so cheap on ebay. I might give it a go, I'll be sure to post here when I do. Thanks

Good luck.
Always nice when someone else does the R&D for you....

One other possible factor. Bike rotors are usually 320mm, make sure there is enough room for rotor and calliper in the wheel.

John

This sounds a very interesting way to reduce unsprung weight.

At my stage of build it is not something I have given allot of thought yet, but I like the idea.

Have you thought how you could mount them yet?.

Will there be a problem with overheating the disks? as the disks I assume will be effectively in the wheels.

I agree that it is not to hard to warp a bike disk having also done it.

Do you have a good source for cheap disks? as remember replacing a set on my last bike and it left a big hole in my pocket.

[Edited on 24/4/04 by Digger Barnes]

P.S. spunky

doesn't 180 +170 add up to 350 not 250?

And there are alot of bikes out there that are allot heavier than 180Kg

[Edited on 24/4/04 by Digger Barnes]

yup, could go for goldwing brakes, though that may defeat the weight issue...!

I am not really going to track the car, mostly street and autox. So the warpage is not really too much of a concern for me.
considering the power of the brakes, my tl1000r could easily do "nose wheelies" from about 40 mph so I think there is enough power to slow a locost.
spunky, I'm using 16's or 17's (part of my reason for wanting less unsprung), so no concern with the rotor diameter.
digger, I'll mount them using some type of machined steel bracket, and I can get a custom hat made to match the rotor to my hub. More pricey than standard brakes, but when you consider the price of heavier "big brake kits" it make some sense. Thanks for the suggestions.

I have owned nearly every type of motorcycle and have had quite a few discs warp on me so i dont think the calipers would be the problem but the discs would almost definently warp.With the hard breaking associated with cars i wouldnt risk it.Also a set of bike discs are 300 quid new.

I've got Hi-Spec ultralight 4 pots on the front and the caliper with the bracket is about 0.8 Kg, very light and they do a great job.

The two piece discs with alloy bell are also much lightat than Ford discs but I don't have an actual weight for them.

Oops!
Quite right Digger, I could argue it was a typo... but that would be a lie...

The theory was ok.

John

well on our formula student car we are running some wilwood calipers (2 pot) and a custom .25" rotor (solid, drilled) on campus we have had it up to about 80-90 mph and done lots of heavy braking and no warpage. I think the way to go would be a fabbed upright instead of a heavy OEM one and a lightwait AL caliper and a solid rotor. toss a small scoop on the upright and I think it would be fine.

6mm-8mm thick discs are the go with bike callipers mounted to fabricated uprights.
My site shows the discs and uprights, (but with some pretty ordinary little callipers which are more than enough for off-road).
I've had good results on road going cars (no pics though) with 4 and 6 pot callipers with the inner halves re-made to incorporate more manageable mounting lugs and also to re-site the feed inlet to the side instead of on the periphery.

Mike, is that as well as the rider, it will be a bit cramped on there. I picked a leaflet up at Stoneleigh yesterday about some cast component uprights by Raceleda
http://www.raceleda.co.uk
which look very light and expensive but you have to pay if you want the goods. Another was icondevs who do calipers and billet aluminium hubs for Cortina uprights

[Edited on 3/5/04 by Peteff]

I use the ZZR600 4 pot caliper with bike disks on the rear. I did a few trackdays with my car and braking is superb.
With my new (road going car) project I want to use 6 pot calipers on the front with fabricated uprights. The car should weight about 400 kilo, that means that the weight for braking on the front is about 260 kilo which isn't as far as a bike.
Rescued attachment EPSN0008.jpg

tigris - where are you based? I'm also using mx5 uprights (I'm gonna go for the wilwood 2pot brakes on each corner). You got a website or anything with info on your biuld - just interested to see how you've solved all the problems I'm having... (I say that, it's not bad really). I'm UK based but most other mx5 users are in the states.
cheers
Bob C

No website as of yet, but I am also in the states. erwe-more pics of those uprights, please!any from the other side?

my site is www.seven-nl.tk
It's not updated for a while but as I'm building the second one it will be soon.
pic of complete car:
http://www.dp-graphics.nl/rob-1.jpg

quote:

---

Originally posted by erwe
my site is www.seven-nl.tk
It's not updated for a while but as I'm building the second one it will be soon.
pic of complete car:
http://www.dp-graphics.nl/rob-1.jpg

---

I use the car for track only, the new one I'm building now will be street legal.
I have to see what the possibilyties are,
an extra brake cilinder in the rear break line or ......

why not use a decent mountain bike cable controlled caliper such as hope for your hand brake ??

regards

marc

quote:

---

Originally posted by marc n
why not use a decent mountain bike cable controlled caliper such as hope for your hand brake ??

---

I was also thinking about a Kart brake
Do I need one for each wheel or is one wheel enough?

quote:

---

Originally posted by erwe
I was also thinking about a Kart brake
Do I need one for each wheel or is one wheel enough?

---

Both wheels I believe...

Wilwood had a left and right caliper...
Can't find them on their website.

There are some mechanical calipers too that are used on pocketbikes...

[Edited on 19/6/04 by gys]