cbr2702

Has anyone had success getting a modern front drum brake (like the sturmey archer SBF [1]) to work with roller levers (like on a dl-1 or other roadster)? It sounds like rod activated drum brakes were used in the netherlands at some point, so it might be possible. The main issues should be something like:

1) Strength of rods -- probably ok
2) Length of pull. Not sure. I can measure how far the lever is capable of moving the rod, but I can't find specs on how far the drum's lever needs to be pulled to be activated.
3) Rod routing. I would think the hub can only be mounted to spin one direction if it's not to slowly loosen. If the drum needs to be pulled from the left, the rod routing from the left hand brake (which would normally go to the rear stirrup brake) should be workable. If it needs pulling from the right, that's harder, but I may be able to get the right hand brake to do it.

I could also consider putting on a cable brake, but that would look pretty silly. (Three brake levers on the handle bars). There's room for it there, though.


[1] https://www.sturmey-archer.com/hubs_fh_SBF.php

Doohickie

Intriguing.....

cbr2702

I just found the technical manual for the hub I'm considering on the SRAM website:

https://www.sram.com/en/service/sram/...Y08_E_RevA.pdf

It looks like they do go on the left side, which should make rod routing easier. And they give the numbers for operation, too:

* leverage must be 1.9 to 2.1
* cable pull of at least 25mm

Now I need to take off the current brake and measure to see if this is the same range.

Am I correct in reading "cable pull" as a hard requirement and "leverage" as a weak one? I think it's saying the brake won't function if it can't be pulled 25mm but if leverage is wrong it will either be more difficult to engage or prone to overengagement (locking and maybe flipping the bike)

The prohibition on brake arm clamps confuses me, though. Brake arm clamps (maybe I have the name wrong? the things that attach the brake arm to the frame with a clamp) are standard for coaster brakes. Why wouldn't they also be suitable for front drum brakes?

repechage

Not rod controlled but:

https://www.pashley.co.uk/

I want the roadster with the drum brakes, 531 frame and the white tires.

cbr2702

So yeah. If I could afford it I'd totally buy a pashley. They look awesome. My hope is to get something I like almost as much at about a third of the price (counting the shipping from the UK).

cudak888 

Raleigh had a rod-operated drum brake variant - used a single-pivot leverage arm in place of the rod-brake stirrup, which controlled the drum, IIRC.

-Kurt

cbr2702

Kurt: when you say "single pivot", I'm not sure what you mean. Do you mean that there was a lever coming off the drum parallel to the road and the rod lifted it instead of a stirrup? (So the "single pivot" would be at the front hub) Or was the pivot somewhere else?

cbr2702

Got my new hub (SA XFDD) yesterday, put it in last night. I managed to hook up the front drum brake with only the parts from the rear brake linkage (which I took off, as I have a rear coaster now). It works great. Doesn't look that great, though, so I may make a new linkage at some point.

Just the brake area:


The linkage:


The whole system:


So now the bike has a rear coaster, a front drum, and a front rim brake. Now I just need to build an LED headlight so I can use the generator to it's best.

cudak888 

Is that Never Seize lubricant that I spy on the headtube from the rod linkage?

-Kurt

cbr2702

To tell the truth, no. It's just paint I put on to cover some scratches that I didn't want to rust. It's amazing how visible it is in the camera flash. In normal lighting I can't see it at all, but I guess it's much less reflective than the other paint.

3DCityGal

I've been thinking of doing the same to mine. Been working on a solution for months. THANK YOU!!!

Reynolds 

Once I saw a Swedish bicycle which used a length of chain to connect the lever to the drum brake, through the fork. But the owner said it wasn't a good idea, too much drag.

mickey85

This reminds me of the Rat Rod guys that used a coaster brake on the front and a suicide gear shift to ratchet in the chain...

I'd consider using a suicide shifter as a front brake on a Mixte that had a coaster brake on it. The only problem as I See it with that would be that you wouldn't be able to put out as much force, because you'd be pushing on one side of the handlebar as well. That's why I'd want to use it with a coaster on the back.

Coreyk

What you want is one of these. I'd love to get a few made. I believe this one is a vintage Raleigh part, though the modern Gazelle "Toer Populair" models use something similar.


(All credit to the original picture poster, if I could only find out who that was.)

This works with the Raleigh-style front and bottom rod brake linkages. The Phillips or Italian ones would need a different configuration. The rod from the brake lever goes to the center hole. The clip affixes to the right fork or seat-stay, and the rod continues on to the drum brake lever.

You can probably have a few fabricated if you know a good hot-rod or motorcycle shop near by. Maybe somebody is a machinist?

Corey K

windup capybara

you have no idea how big a problem you just solved for me

(rebuilding an ancient gazelle for work, took all the rod brake components apart thinking they'd be easy to reassemble, got totally lost, put project aside, boss isn't happy. but i think i get it now!)

David Newton

I'm on the verge of ordering a SA X-FD brake for my DL1, and appreciate this thread.
My plan is to fabricate a single rod to make the trip to the actuating arm, and do the adjusting at the actuating arm with a slip bolt. That, or fit replacement North Road bars with a regular brake lever & cable setup.

NormanF

My Pashley Guvnor roadster and Raleigh Superbe both have front and rear drum brakes.

Reliable, sealed all weather stopping power.

cpingenot

I have a 1971 DL-1 (Ladies) which I'd like to make into more than a fair-weather friend. I actually tuned the rod brakes so that they stop about as well as it's possible for rod brakes to stop. However, I can't count on them in the rain, and would like to make this bike one I can take out even if there's a threat of light rain without worry.

So I built up a wheel with the S-A XFDD generator-brake hub that others have used, Long term I'd like to rig a rod system similar to that shown in CBR-2702's system, but for the moment, I used a cable and attached it from the action arm to the brake stirrup. I actually removed the shoes to allow the stirrup to travel further, and used the shoe attachment hole to fasten the cable to.

My problem is that even though I pre-compressed the action arm what felt like a fair bit, I'm still not getting enough leverage to really feel like I'm stopping the bike. Do I need to create mechanical advantage to increase the actual pull beyond what I'm getting from the lever travel?
It looks like that might be what the L shaped piece at the end of the rod is in CBR-2702's photos.
Also, if CBR (or anyone else who's done this) can weigh in on the advantages or disadvantages of leaving the front brake shoes on while (apparently) using part of the front stirrup as a pivot point.

The good news is that the light works GREAT. I'm using the IQ Cyco, which isn't terribly antique looking, but man does it have a lovely beam spread. I've been using the Edeluxe on the bionic Raleigh Sports that I ride daily, with the same optics, and they're great lights.

Advice, especially from anyone who's actually done this, would be MUCH appreciated.

cbr2702

The L-shaped piece in the pictures was just so that I could connect the two bits of rod I had to make something long enough. I've since replaced it with something smaller. As it's not pivoting, there's no way it could have been doing anything.

I suspect your problem comes from the front brake lever not having enough pull. On my bike I used the left lever, designed for the rear rod brake, which pulls the rod a little more than twice as far as the right lever. Mine has a phillips-style design, so this is possible, but if yours is a raleigh design then I think both levers are the same length. You could try making the lever on the hub shorter by connecting closer to the pivot. Or if you didn't precompress the brake to the point just before braking, you might need more compression. (Actually, I think that may be the answer: just trying on my bike, I only need about 3/8-inch pull to engage the brake fully)