Coker Brake

I’ve added a Magura brake to Marvin the Coker (a standard Coker), I’ve tested it with a short (5 1/2 mile) ride with several hills (not any thing really steep or long, mind you, but hills) and decided that it’s defiantly successful :smiley: :D. It works smoothly with no apparent grabs and all I need do now is to shorten the line to the handle and lengthen the line between the slave cylinders.

What I did was I went to a LBS and got a V-brake mount (a D.N.A. mount, but any brand should work) and modified it and the Magura mount. The reason I had to modify them was that the arms on the Magura were to close to the tire (yep, I’m a Yank - a Connecticut one at that :sunglasses: ), so I cut two slots in the V-brake mount for them and cut the arms shorter so that they would not protrude from the mount. The only work I had to do on Marvin the Coker was to drill a hole at the junction of the tubes for the V-brake mounting bolt.

There wasn’t much adjustment left on the positioning the angle of the slave cylinders - it would have been better all around if the V-brake mount were made for a wider tire, then I probably wouldn’t have had to modifiy it - but it works fine. The only part that my legs touched was the hose from the handle to the brakes and that just needs to be shortened as it was for the rear wheel of a bike.

Pictures at Coker Brake (link)


The advantages of a Magua over cable operated brakes are:

1 That it’s smoother (better modulated).
2 You can set it as a drag brake :sunglasses: (if you have the newer handles) and not have to have your hand on the lever.
3 There are no arms that move or stick out.
4 You don’t need to adjust it after you set it up. :smiley:


The V-brake mount cost $29USD new at the LBS and the Magura $30 :astonished: on eBay.


If you look closely at the first and third pictures - Marvin the Coker Brake and Marvin the Coker Brake right side - you can see the mounting bolt for the V-brake mount at the top of the adapter, that’s the only mount needed as when the brake is being used it is held against the frame (mount brakes on the BACK of the frame so they push on the frame instead of pulling on the mounting assembly) and when it’s not being used there are no forces on it. The mounting bolt goes through the frame of Marvin.

The V-brake mount also came with hose clamps that I took one look at and laughed at, although if you didn’t want to drill a hole in the frame they’d work. I’m glad I didn’t use them because the wheel is not centered in the frame, and the clamps would center the brakes.

The handle and master cylinder are temporarily mounted on one side of a GB handle - it’s temporary because the Magura itself is broken (one half of the thing is broken off, that’s why it was cheap - $30 for both front and rear brakes on eBay) and because I didn’t have any of the mounts I’ve seen in other threads . . . Yet.

Brian - sounds great. Can you post a photo showing the “newer” handle that allows use as a drag brake? I’m very interested. What model brake are you using? If at all possible can you post some photos showing the mounts and everything on your Coker?


HS 33 is the model that can be set as a drag brake

The red knob can be adjusted so that the brakes are dragging with no hands on the brake.

I have HS 11 - no red knob.:frowning:

My pictures are here

I’ve up-dated the brake on Marvin, the Coker, because U-Turn (Dave Stockton) has created, just for me, a very, very nice wheel. You need an Airfoil rim if you have a brake on a Coker, the standard rim has bumpy welds. Now it’s got a beautiful HS 33 red Magura, which matches the red seat.

Note that the brake is mounted on the rear of the frame, many posts about brakes mention hitting the brake and/or mount with legs, is this why I don’t have this problem? Anyway, always mount your brake on the rear of the frame; it’s structurally better that way

I’ve also added some more lights (I ride to work between 11 PM and midnight) including a yellow Xenon strobe, note that red flashing lights are not legal in most places.

My pictures are here, the ones with the red brakes are the new ones, but the mount is still the same.

Did I mention that the new brakes are RED? :astonished: :smiley:

Nice going, Brian!

Have you tried using your HS-33 as a drag brake? I found a while ago that it took quite a few turns to engage it, many more than I thought would be acceptable for a good drag brake.

I need to revisit that impression.

I have done some investigation into modifying the handle to improve the engagement time but haven’t yet developed anything that is substantially better.

Dave, how about taking a bolt with a coarser threading than the stock lever bolt onto which the red plastic knob is set (which bolt controls the plunger depth in the lever), grinding a 4-sided area to stick out of the lever into which the red knob can be pressed & glued? That way the plunger acts in the same manner only it takes fewer turns to activate it. Yes it would require machining of a bolt and the part between the bolt and the plunger inside the lever, but it does change the rate of the knob actuation.

Hey Pete, I actually did that about 3 years ago, but two things: one, I had to develop a new insert piece as well, and real life intervened, and two, the geometry went away with the 2005s. I used a larger knob as well, but it proved to be a little bit of a finger trap. All in all, it was a little clumsy.

Unless you meant the 2005 design?