Outer Limits 4x4 Board

O.k here the deal l want to put a disc brake conversion on my portals and between me my old man and kenny l recon that a disc of machined plate will do as a rotor on the buggy seeing as how we are not doing a million miles an hour and if need be l can always drill or slot the plate if needed.Any coments welcome.

cant see why it wouldnt work

at the gokart track i used to work at we just used 8mm steel plate that was laser cut to size

Well any other comments lads

I have a mate who got front and rear disks laser cut for his ktm out of mild steel and they worked fine and he rode motorcross and enduros on it so i cant see it being an issue

so thats what i will do ,one less problem fitting the portals to gu/gq axles

i was reading somewhere about a buggy that only has 1 brake disc, no brakes at the wheels, only one behind the gear box, i think it was a 6 spot brembo caliper with custom disc. by the owner it brake as good as any other buggy he had driven.

Im using lasercut plate steel for the front brakes on my buggy, it shouldnt be a problem.

talk to bubs, i had a mate tell me they were running some 6 stud rims on the STICKA truck that he was modding before tuff truck,

im not 100% sure on the info, but i was told they looked like nissan 6 stud hubs with nissan disca and calipers,

like i said not 100% sure on info, but always worth the question.

cast iron needs to be used as the steel will pick up when it gets hot

Yes I have heard of some odd problems with mild steel as brake rotor material. Apparently quite common on motorbikes - I was talking to someone who built some rotors out of mild steel (for the rear of an lj50 running a datsun 180B IRS and he had to get pads made up with a special compound.

Might work for a buggy, but they need a very high friction coefficient as all the braking is a very low speed/high torque

Steve.

i used steel plate as a e-brake... used it for years and it was fine.

mild steel will work on a buggy due to low speed (high torque though) but way less use...

you might want to use at least 8mm plate though or it will warp (due to the heat generated by the torque).. also it is cheap, so when it does wear out its not going to cost a huge amount to replace..

bloke at work who raced flat track used to make his out of boiler plate. made a few for road bike's without any problems.

may pay to look into different grades of steel, not sure off the top of my head but something with say more chromium or a lower carbon steel, heading down the coefficient of friction / metallurgy line here with regards to better head transfer/ dispersion if you get my drift!?!?!?!

the unbreakable luxtruxs wrote:may pay to look into different grades of steel, not sure off the top of my head but something with say more chromium or a lower carbon steel, heading down the coefficient of friction / metallurgy line here with regards to better head transfer/ dispersion if you get my drift!?!?!?!

I would think that a higher carbon steel would be better because the carbon will work as wear points in the microstructure? Like cast Iron drum brakes. Like krf_bb said Cast Iron would be better, but thats not the point of this thread. Just don't skimp here you want to be able to keep control of the vehicle.

I have seen blokes make patterns out of styrafoam, it would be quite possible to make up a basic pattern to what you want and get it cast and machine what you need all very cheaply

cut them out of bisalloy plate

Making a disc out of steel means that the steel has that "Hot worked" scale on the surface.
This scale is real hard, so hard that brake pads will not penertrate this scale & the pads tend to slide on the hard surface without getting a good bite.

So it feels like fade is happening, but it isn't.
Its that the pad cannot get a good bite & slow the disc down.
After all, brakes are about increasing the friction, not decreasing it.

If you bead blast the disc it takes off that layer of scale & brings the disc back to bare steel, now the pads will grip the surface instead of just skidding over that hard layer.

Instead of bead blasting you can also have the discs zinc plated.

The first process in zinc plating is to acid dip the part, this removes the scale.

Then the disc is zinc plated which puts a fine layer of zinc on the surface, it actually etches into the surface, not sit on the top like Chrome plating.

Thankx lads ill make them outta mild steel that has been acid dipped and thay should be fine.

Webbie wrote:Thankx lads ill make them outta mild steel that has been acid dipped and thay should be fine.

You'd want to get them turned.
I wouldn't trust steel plate to be flat enough to feel good at the pedal.

I wouldnt use mild steel plate

rust buildup during non-use periods
wont handle the high temps without warping "IF"the brakes get a work out
will score easily
could be bent from obsticles striking the disc



I'd go for a stainless disc..... the extra strength etc will suit ya needs far better

Old M/cycles have farily large disc's on the front, such as the Kawasaki S2 250 / 350 ( 3 cylinder 2strokers ), the front disc on one of these is almost the same size as a std 4x4 disc and is around 8mm thick.

Kingy

V8Patrol wrote:I wouldnt use mild steel plate

rust buildup during non-use periods
wont handle the high temps without warping "IF"the brakes get a work out
will score easily
could be bent from obsticles striking the disc



I'd go for a stainless disc..... the extra strength etc will suit ya needs far better

Old M/cycles have farily large disc's on the front, such as the Kawasaki S2 250 / 350 ( 3 cylinder 2strokers ), the front disc on one of these is almost the same size as a std 4x4 disc and is around 8mm thick.

Kingy

I wouldn't use stainless, I'd look for an austenitic steel plate. I can't recall right now whether bisalloy is austenitic or not.

Bisalloy is ferromagnetic.

I would have thought it might make a fairly good material if you could get the pad composition right.

Steve.

I agree with Kingy they kwaka's used 8mm stainles disks for about 15 years on all bikes from 100 to 1300cc (KH100 to Z1300) these lasted for years. People have to remember that cast iron is shit it is only used cos it is cheap to cast, mild steel will be fine and should not warp unless it is to thin and over heated n rapidly cooled but the same applies to std cast rotors. Late modle bikes use a 4.5mm mild steel or stainless rotor n they flex very easy. I would look at using an off the shelf rotor for cost n availability or stainless wear plate remember a calipers piston will fall out if the rotor is to thin and/or pads will fall out. other advantage of std type disks is the ventilated ones reduse the inertia of the disk therefore less rotating mass, less weight to have to stop turning and better braking efficiency.

nastytroll wrote:I agree with Kingy they kwaka's used 8mm stainles disks for about 15 years on all bikes from 100 to 1300cc (KH100 to Z1300) these lasted for years. People have to remember that cast iron is shit it is only used cos it is cheap to cast, mild steel will be fine and should not warp unless it is to thin and over heated n rapidly cooled but the same applies to std cast rotors. Late modle bikes use a 4.5mm mild steel or stainless rotor n they flex very easy. I would look at using an off the shelf rotor for cost n availability or stainless wear plate remember a calipers piston will fall out if the rotor is to thin and/or pads will fall out. other advantage of std type disks is the ventilated ones reduse the inertia of the disk therefore less rotating mass, less weight to have to stop turning and better braking efficiency.

The stainless that's used in disc rotors is martensitic (400 series). High strength, high hardness and high cost.

People have tried making mountainbike disc rotors out of 304 and 316 stainless (the commonly available grades), they scoured out quite quickly.

As the discs are also the means of attaching the wheels to the portals they will just be mild steel and ill have them drawn in cad so i can get them laser cut and should one warp or anything just get a newy,remember buggys dont go real fast maybee 20kmph if your lucky or unless your Mooney

i work for a disc brake importer for motorcycles, im told that the steel in our discs is high carbon, i dont know alot about metalergy so hope im helping.

eldo wrote:i work for a disc brake importer for motorcycles, im told that the steel in our discs is high carbon, i dont know alot about metalergy so hope im helping.

I'm not very thorough on my material properties knowledge, however I do know that in allot of Iron-Carbon alloys, the carbon often forms into clumped nodes, and will then act as wear points. This is why grey cast iron is good, because it wears well, and uniformly. Steel is a bit different (has allot less Carbon to begin with), but I think that high carbon will work similar, of course dependng on cooling and heat treating as well.

Do an image search on google for 'Cast Iron microstructure', and 'Low/High carbon stell microsturcture'. And you'll see plenty of images of the microstuture. Do read the associated text, unless your a materials engineer, and you'll get the gist of what I'm saying.

Webbie wrote:newy,remember buggys dont go real fast maybee 20kmph if your lucky or unless your Mooney

KiloMilesPerHour?

If you want to use standard pad materials than use cast iron.

Have found out the hard way that mild steel isn't all that suitable for automotive friction materials especially for road applications. ( bikes use different materials ).

what about 3cr12 very cheap and common