Rear Disk brakes

[Drunkskunk]

I've got the Disk mounted on my Clyte, the clearance issues sorted out with mounting the wheel in the frame, and everything set to mount the brake caliper.

Only one problem. The caliper is way to thick to go between the disk and the motor. I have 1/2 an inch space, but the Avid BB7 is 1/4 inch thicker.

Anyone know of a thinner Disk brake calliper?

 

[johnrobholmes]

What is the measurement from the bolt holes on center to the motor? Basically how much room do you have from the center of the disc mount?

XT disc calipers were really thin, but they might have changed that.

 

[Drunkskunk]

you mean on the mount side? probably 1/8th an inch. The caliper won't fit on the normal mount, but I have the ability to make a mount that will work, one that bolts to the outside of the bracket.


Do you remember what year modle of XT you had seen? if nothing else, I can hit up Pinkbike for used ones.


this is going on a Kona Stinky. A Downhill frame, but it only has 135mm dropouts on the back. the disk its self only fit after grinding out 1/16th an inch from the inside of the suspension arm mount. Its all a tight fit.

 

[johnrobholmes]

it is probably a 2002 XT disc caliper.


I am asking for the measurement from the disc mount to the motor, on the inside of the swingarm. I assume you aren't using Hayes type mount then. Since you had to clearance the swingarm for the disc you probably shouldn't move the caliper and disc out any further.

 

[Drunkskunk]

Disk to motor is just shy of 1/2 inch.

it is a Hayes type mount, but I can build a mount that bolts from the outside, not the inside.

 

[Trumpet]

Have been following Mark W's build and have gone for Avids myself (still building) as easy retrofit, well rec'd brake and prefer a non-hydraulic brake.
http://endless-sphere.com/forums/viewtopic.php?f=6&t=1533&p=21702&hilit=+jamis#p21702

What size disk are you using? 203mm looks a must with most hub motors.

 

[ngocthach1130]

Yeah i use avid bb5 and i had to move up to 203mm rotor to clear the hub.

 

[Ypedal]

You can use up to 2 of those " freewheel ring " spacers on the threaded collar to distance the rotor from the hub ( not always enough on some bikes ) .. more than 2 i fear may not leave enough threads for the adaptor

 

[Mark_A_W]

I had to remove the inner adjuster knob to mount the 2005 model Avid BB5 mechanical caliper on my front hub motor. The 203mm disc is mounted directly to the side of the motor, with spacers pushing the disc to within about 1mm of the fork. I adjust the inner adjuster with a pair of bent pliers.

A Hayes MX-3 mechanical caliper will fit, it is very narrow on the inside, but you will have to remove it to tweak the inner adjustment (you can't get an allen key in there).

I just picked up some Shimano M-485 hydraulic brakes, and they won't fit very well at all. They are very wide. If I mount it up as is, with a custom adapter, I will only be using a bit over half of the pad.

I'm looking for a 220mm disc. I might get a custom one lasercut (easy for me, my job is CAD).

 

[Drunkskunk]

The guy at my LBS grabbed a calliper and we went through his inventory, and what they had out on the floor. the thinnest we could find was a shimano hydrolic at 0.6 inch. i need > 0.5

i have one of Ebike.com's spin on adaptors as well, but its too thick. as it is, the disk hit the A arm, and the A arm had to be ground for clearance on the 160mm disk. and its riding close to the swing arm. Even a 180mm would cut through the A arm, and be grinding on the swing arm

Has anyone ever shaved down the outside of a BB5 or a BB7? I have one of each now to experiment on.

 

[Mark_A_W]

Pictures please?...

Hayes MX-3 is the thinnest one I've found so far.

 

[Drunkskunk]

yeah, took some pics.

 

[Mark_A_W]

If you either:

1. Countersunk the disc and fitted countersunk screws, then flipped the disc adapter over...or

2. Cut the centre out of the disc and bolted it straight to the side cover of the motor, maybe with some thin spacers (this is what I did).

And used a 203mm disc (maybe a 200mm), then I think it will work. You absolutely need a bigger disc, closer to the motor, so it clears the frame.

As it is now there's no way you will get a caliper in there.

 

[tailwind]

Like Mark said. First thing is to make sure that the rotor clears the frame.

The pictures look a lot like the ones from Steveo's build.
He solved the problem by flipping the wheel over.
The freewheel side had more space for the disk rotor and disk adapter.
I think his controller had a reverse switch.

If your controller doesn't have a reverse switch, would it be possible to change the wiring order of the phase and/or hall wires so the motor reverseses direction.

Heres a picture of a Hayes So1e hydraulic disc brake

Greg

 

[Drunkskunk]

Wow. Thanks! that brake would solve all my problems.

 

[monster]

you could grind you way out of this situation with a bench top grinder ?

 

[Drunkskunk]

you could grind you way out of this situation with a bench top grinder ?

Maybe, but it remains to be seen if the BB5 or BB7 brakes can be ground down that far.

 

[marty]

Here is bad idea? Spreading dropouts might cause caliper to not line up with rotor.

Read - Bicycle Frame/Hub Spacing
at http://www.sheldonbrown.com/frame-spacing.html

 

[Microbatman]

Hayes MX 2 will work with the the 1/2 in adapter from ebikes.ca

I had the same problem that the 3/8 adapter would not give enought clearance and
then had to buy a 1/2 adapter.

http://endless-sphere.com/forums/viewtopic.php?f=6&t=4014


The 1/2 inch is on the bike and it fits.

Check out the price of the MX2 and let me know how it compare to others that you are considering.

 

[Microbatman]

Like Mark said. First thing is to make sure that the rotor clears the frame.

Greg

Yep had to solve that problem also.
Had to spread out the dropout with wood shims and make custom spacer.
See post a few down for pics of spacer.

 

[Johnbear]

I am using Avid bb5's on a KHS AM2000 full suspension, - they were a bit of a nightmare, I had to grind and space, grind and space for hours. All bikes seem a bit different, My Giant Warp I just had to add a couple of spacers and they dropped right in. They finally work great now.

 

[Drunkskunk]

the problem with spreading the dropouts is the Kona uses a forged Aluminum piece in both the trailing arm and the support arm. I might try bending an all tubular aluminum setup, but not forged.

@Microbatman. Your thread was one of the inspirations to get this project going.
For me, the 3/8 wouldn't fit, and I'm using the stock spacer that came with the Clyte brand disk. I think it may be 1/4. total spacing ends up being 13mm from disk to the motor side, and 1mm clearance disk to frame on the other side. Its a tiiiiight fit.

@Johnbear. I'd love to see some pics of that BB5. what did you end up doing for fine adjustment?


I've got Expiriment 1 in the works. I had a BB5 and BB7 for the bike. the BB7 was a little thinner in the areas i needed to cut, so i startd with it. I've managed to get it sawed down to 10mm with new pads in place. that gives me a whole 2mm clearance.

the only problem now is building a custom bracket. the brake won't fit on the stock mount, its too close to the disk

 

[Johnbear]

I used washers between the frame and disk brake and I used spacers on the disk to hub side. I will have to take a picture and post it.

 

[Microbatman]

Here are some pics using a Hayes MX2

Sorry for the sloppy typefonts had to hand write using mouse pad in Microsoft paint.

Will try to hunt down the Fastnal part # for the collar.
****update found the part # Fastenal part #0403085****
12mm Metric collar

About 2mm of clearance between caliper and motor.

About 3-4mm of clearance between frame and rotor/disc.