Internal brakes without fork mounts?
 

Hello mechanics,

Are there any non-rim brake types that can be installed onto bikes that do not have mounting points on the front fork? I'm aware that they all require some kind of reaction arm, but do they all have to be bolted to some kind of fork attachment?

Specifically I'm wondering if it's possible to after-market a Shimano roller brake system to a folding bike, since I can't find a folder with both internal gears and anything other than rim brakes.

Thanks,

M.

Doable, yes.
Sensible, not always.
A humble hose clamp will suffice to hold the reaction arm to the fork leg.
But there are no guarantees to what the fork will think of being exposed to the bending load introduced by a hub brake where one wasn't expected.

Band clamps have secured hub brake reaction arms for many decades and millions of bikes. From cheap coaster brake hubs, through classy SA drumed hubs to many tandem drag brake drums. There's no difference between a chain stay or a fork blade as far as the clamp sees it. I do agree with the concerns of blades not being up to the task to handle the bending forces that some brakes and riding styles can place on them. But that's a different question.

IME roller brakes don't have very high initial stopping forces and are usually found on transpertation bikes which usually don't see the speed/stopping extreems that a sport or off road bike might. Also the smaller wheels of many folder bikes will have less leverage over the brake then a 26 or 700 wheel will.

I look forward to reading what the smart posters have to say. Andy.

I'll wait and see what others have to say. This will be transportation (commuter bike; planning ahead for winter), and I'm not very swift at cycling. Now for the leverage - would that be a good thing, having smaller wheels?

M.

I used P-clamps to hold the drum brake reaction arms on this bike when I built it up in 1988:

http://www.os2.dhs.org/~john/commuter/05.jpg

http://www.os2.dhs.org/~john/commuter/08.jpg

No problems so far, including several years hauling my kids around in a trailer when they were young.

Interesting; is it only disc brakes that require specialized mounts, or can those be rigged up too?

I think keeping the rear brakes as a rim might be useful as well, as others have mentioned these aren't the most powerful brakes (don't know if wheel size has a factor in that). Together I figure they're more than enough, and it isn't like I'm racing. Other than roller brakes, what then would be better? I only have experience with rim brakes and haven't had anyone tell me about anything else in practice (just theory).

M.

AFAIK there are no ready-made bolt-on adapters for forks, but I've seen a few who've managed to make adapters using the lowrider mounts and the wheel axle as attachment points. For steel forks, brazing in a set of caliper mounts is usually possible. Although on some forks the legs come together too quickly to leave enough room for the rotor.

People keep saying that as long as you can achieve wheel lock, then braking s as good as it's going to get. I think that's a huge simplification. (decent) discs offer more braking for the same amount of hand force, and IMO that's just about always a good thing.
And even if you aren't racing, who would ever turn down a real shot at getting a significantly shorter stopping distance?

For fit & forget, drum brakes are the kings. Also very little bothered by different weathers.
Roller brakes are a good second, but do need more maintenance than drums.
Then there are band brakes, but that's almost always only found on tandem rears.
SS/IGH rear hubs can have coaster brakes, which are basically a kind of drum brake.
Then there's the infamous spoon brake, a lever pushing against the tire.
And then there are rim brakes. Magura even makes a hydraulic one that has a very good rep.

Sturmey-archer drum hubs would work fine for a folding bike. The rear hubs come in a variety of configurations: internal gear hubs, freewheel and cassette hubs. I've used 70mm and the 90mm drums on large wheel bikes and they allow me to lock up either wheel. I've never worried about bending the frame and I've used them on hi-tensile steel frames and chromoly frames. The only downsides to the drum brakes is that it takes a while to "break" in the system. My only complaint about the Sturmey drums is how all the hardware has cheap chrome plating but the 2014 catalogue seems to show a lot of stainless steel options for that stuff now. A lot of frames also won't have the cable guides for drum brakes so you'll need zip-ties to set up and the proper sized clips if you want it to look nice.

Been using S-A drum brake Hubs on my bike since the mid 80's.. now as my Studded tire winter MTB.

I'm going to go out on a limb here and suggest that if you're looking at hub brakes then likely the forks are not the lightest and thinnest wall racing forks. More than likely they are heavier and thicker walled with sufficient room for fenders. With this in mind I'm going to say that P clamps will do just fine for the reaction arm and that the fork blades won't even so much as give off a slight complaint about the point loading.

If I'm wrong and the forks are something a little more exotic then I'd suggest that you can still use the P clamp. But you would likely want to cut and shape a3 to 4 inch section of tubing to produce a load spreader for the load bearing point at the clamp. Or you could bend a piece of decent quality flat aluminium around the leg to do the same thing. By "decent quality" I mean something that has some sprinyness and fight to it for shaping to fit. Not the "soggy cheese" stuff which bends all too easily and has no springiness.

The comment about "if it has enough power to lock then it's good" is true. But it hardly speaks the full story. As a long time wet weather commuter I can say that having good brake modulation is at LEAST as important. If you have to go all white knuckled for every stop or if light pressure is enough to almost do a stoppie it's tough to modulate the right pressure in questionable traction. Such a bike CAN be ridden, but it's just no fun to do so. Having all the systems in balance so the efforts are matched and suitable makes for a lot more smiles.

Alright, so next step is to figure out if I want to go the folding bike route first or if I want to squirrel away for something more "utlity" like - either way I can use this information for either decision, so a big thanks to all!

(And the P-clamp tactic will also work with a drum brake, should I opt for that instead, correct?)

M.

Yep. Anything that uses a reaction arm can be attached with a P clip. Just always use the clip such that the arm is compressing the clip instead of trying to pull it apart. And finding a clip with some steel in it that is better than the usual "overcooked noodle" soft steel isn't a bad idea either. Or perhaps even make your own from something suitable and then wrap it with shrink tube or some other solution. The arm clips that typically come with such things are often made from 18Ga or heavier steel.

Yep. As shown in my post above.

They will come in the kit when you buy the Hubs .. in the case of the fork , measure the blade
there are a few different ones vor various diameters of blade(tube)..

Well this is all good news. Now the hard part is deciding which bike I want next! The folder or the utility roadster...

M.