disc brakes?

Ok, I've been doing my research, and I hear a lot of people talking about massive kits and massive speeds, and even some suggestions of disc brakes, but for the life of me I can't figure out how to do it.

If I were ever going to go faster than 50 on a moped (which I've been reading is plausible on these kits) I would never trust my drum brakes to do the job of saving my ass.

If I wanted to upgrade just my front brakes (which, of course, are the important ones), how the hell would I get a disc brake setup to work? Buy a kit? Steal a motorcylcles wheel? Does it need an electrical system? (my electrical is working hard enough just to power my headlight!)

Thanks in advance for the help, this should be interesting.

Hank

Re: disc brakes?

John Joedicke /

Find a wrecked Revival or Streetmate and do a transplant of the front fork setup. Simple and easiest way to get a decent disc brake.

Re: disc brakes?

Yup, and no electrial required but you will have to get the handlebar control that goes with it.

Re: disc brakes?

yeah it just used disc brake fluid which you can buy anywhere. The only "easy" way to do it is to find a whole front end of something that has disc brakes and just transplant it in.

It is too time consuming and expensive to try and modify your forks and rims.

Re: disc brakes?

how did dan do his?

Re: disc brakes?

Luke Evans /

okay search the picture section for mb5's ive Heard that the whole headstock bolts on to a puch maxi front end, you change of the headstock (where the handle bars fasten) stations (top bit of the leg) dampener (bottom bit of the leg), caliper (bolted on to the dampener) wheel mudguard etc. the brakes dont use electrical assistance at all, you have your reservoir on your handle bars and the force of you squeezing the lever squashes the pads onto the disk. (with you thinking electrical, im not sure if think this will be power assisted or have abs, but mopeds are usually lucky to have a disk) other ideas on this site so far have been to use bicycle forks with the cable disk break, but to be honest cable disks dont have the haul down power, also they tend to seize up (but they have been used on production bikes (honda cb100))

luke

Re: disc brakes?

with those kind of speeds I would be more worried about your front fork holding up to the forces put on it when you try to stop, and the forces put on the frame.

bicycle forks, and disks are most likely going to be pretty high quality, as there aren't a whole lot of low end disk brakes for bicycles, and the ones I've seen have been hydralic as well, but a good triple clamp, and disk brake and everything, and you are going to be coming close to what alot of people paid for their moped.

Re: disc brakes?

Hanky B /
hank OP

I don't think I would ever trust a brake made for a bike on a kitted moped. Those brakes are designed to stop just a rider, not a rider plus 150 lbs, let alone at the speeds a kitted moped could be traveling.

Re: disc brakes?

Luke Evans /

your right i would Never Trust my weight on a disk break designed for a bicycle, a bicycle stops from ...... 30mph max? more often 10mph. i would have thought it would have trouble with cooling. P.S. compair the size of a bicycle disk with a motorcycle disk motorcycles are alot bigger and wider therefore more surface area-stop

luke

Re: disc brakes?

I'm working on a disc brake project, pretty much starting from scratch. I'll be finishing it up in a few weeks. Hopefully the results will be good.

WillyT

Re: disc brakes?

Luke Evans /

what are your palns? are you using an existing caliper or are you making one? what about wheel? are you replacing the whole wheel or grafting a disk onto your existing wheel?

luke

Re: disc brakes?

I'm using a rotor from a Honda C125, along with some metal machining, it will attach to the rim directly. I'm then going to use a pipe clamp. In the screws from the clamp will be an upside down "L" bracket. I've got a pair of brake pads, I'm going to drill two holes. Bolts will go through the "L" bracket and through the brake pads. Then I'll just make a hole in the middle of the brake pads where the brake cable will run. I am also thinking of a strong spring in between the brake pads so that the discs will return. If not, I might not have a return spring, I don't think you really needs it that much, the movement of the rotor will push the brakes away or I can manually push the brake lever back. I hope it works. We'll see.

WillyT

Re: disc brakes?

Hanky B /
hank OP

How are the brake pads being held parallel to the disc so they make full contact? I just can't see how this rig will communicate enough force through that one cable to the disc to slow the bike more effectively than the drum brakes that are already in place.

Re: disc brakes?

Yeah, that's where there's a short fall. The brake pads are up vertically. So I'm really only using about a third of the brake bad. It's probably not going to work, but atleast I know I tried.

WillyT

Re: disc brakes?

Luke Evans /

:) its nice to see you people trying new things, good luck with it,

i think you will have problems with the amount of force exerted, if you look at any sort of cable brake they use an arm and a pivot mechanism, this basicly acts as a lever, (physics principles) and improves the force placed on the pad, any way im not here to critisise you let us know how it goes,

luke

Re: disc brakes?

If it doesn't work, I'll just get some new front drum brakes.

WillyT

Re: disc brakes?

I talked to 1977 mopeds today, and they told me that they plan to have a disk brake kit for the Targa LX's in about 3 weeks. (no promises though).

If you can get the disc fitted to the rim the battle is 90% over. you can snag some good hydraulic calipers from many different places.

things to consider:

Amount of mechanical advantage (you need force)

keeping the pads parallel

Keeping the disc from being warped

Designing a sliding mechanism for the pads (the back pad must push just as hard as the front). I've seen these sliding mechanisms lock up on cars, and when it does the braking power goes down, plus it put all the wear on 1 pad, and heats the disc unevenly.

What if the rim is not strong enough to handle the braking force? The spokes would fold up, and the wheel would collapse at 50+ MPH. I think that's why The mopeds that I have seen with disc brakes use spoke wheels and not mag wheels.

I'm not saying that it can't be done... but make sure you do your homework!

Re: disc brakes?

did you ever get my email about making that adaptor ring? I'll still do it for free, but i need better specs from you. Drop me an email.

I've always thought this kit would work

Re: I've always thought this kit would work

Hanky B /
hank OP

That link didn't work, but they're on this page:

http://www.bmikarts.com/gokarts-minibikes-chopper-parts.shtml

I think it looks promising as well, does anyone else think these might bolt on to our systems?

guarentee it won't just bolt on

dude no way it'll just bolt on, you'd have to fabricate spacers so mounts etc etc but i definitely think it's doable by a halfway competent machinist/fabricator

only potential problem i can see is...

they're mechanical discs as opposed to hydraulic. another idea i had was to find some 100cc class d bike and rob the front brake assembly and the master cylinder.

Re: only potential problem i can see is...

For a hydraulic disc brake system, are these the only parts you need?

Rotor, Caliper, pads, hoses and master cylinder?

WillyT

Re: only potential problem i can see is...

Luke Evans /

yeah the only problem is mounting the calipers to the fork leg, usually you have to mount them with high tensile bolts.

luke

far as i know

not a fabricator/machinist myself but as far as i know yeah that's the entire system

Re: only potential problem i can see is...

Luke Evans /

:) mounting points, the master cyclinder and lever assembaly clip on to the handle bar, the cable can be fastened to the fork leg with tie wraps, the disk is fitted to the wheel using high tensile bolts(x5+), and the caliper is mounted to the fork legs..............usually they have manufactered lugs to mount the calipers on (dont forget the high tensile bolts)

luke

Re: only potential problem i can see is...

I was wondering about putting on the lever assembly and wires that run through it. How does a brake lever even work with the brake light?

WillyT

Re: far as i know

John Joedicke /

Well there is a switch!!!!

Re: far as i know

This is the main concept for my disc brakes. This is how the brake pads are going to be situated. I've drawn in where the bolts will go for support and where the brake cable will go.

WillyT

1143392932_rotor.jpg

Re: far as i know

This is a little bit better description of how I'm going to do it. I hope.

WillyT

1143393384_rotor2.jpg

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account