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I have been working on a 26" folding MTB, and its coming together slowly. The rear wheel has a band brake and for the life of me I can't get it to work well.

I have no experience with this kind of brake. Nearest I've worked with is a drum brake on a tandem, and drum brakes on a car.

Band side - own work Band side of brake. When actuated, the silver lever on the upper left rotates, and the band is pulled up and right. Since the other end is fixed by the rusty rivet, the band has to take a shorter path and decreases in circumference thereby tightening on the drum.

Drum side - own work This is the drum which is attached to the wheel hub. It is threadded onto the non-drive side.

So when braking under no-load this brake works perfectly and stops the suspended rear wheel quickly. When riding, this brake has a barely-perceptible slowing effect, and absolutely nothing if its a downhill grade in any way.

I have tried a light sand of the drum to remove any glaze. I've also sanded the band lightly but its soft so didn't want to tear it.

Also I've applied an electrical cleaner spray called Contact60 That also made no difference to braking. The band appears to absorb the spray

So far I have not applied "brakleen" because the band is soft and am worried about it absorbing into the band, rendering it contaminated permanently.

What else can I do to improve this brake? Or should I simply replace the whole thing with a conventional rim brake ?

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    I'd probably opt for switching to a rim brake if possible.
    – Batman
    Oct 1, 2017 at 3:06
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    They're known to be mediocre at stopping. I believe all you can do is try to sand or otherwise refresh the band to get its CoF back up. Remember that despite being weird elsewhere, they are a staple component in East Asia, and you can just order a whole new one for very cheap.
    – Nathan Knutson
    Oct 1, 2017 at 5:30
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    Contact cleaner often contains ingredients that linger, to deter corrosion. These could make things worse. Not knowing exactly what the band is made of it's hard to know what to clean it with, but that's probably what you need to do (unless you replace it)
    – Chris H
    Oct 1, 2017 at 8:09
  • @ChrisH yeah its not metal, its a vaguely spongy lining with a thin sprung steel backing. I've just finished sanding both sides more, and it feels better without really being any good.
    – Criggie ♦
    Oct 1, 2017 at 9:41
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    Virtually any brake will seem to work "fantastically well" with no load, even if it's virtually useless at actually stopping the bike. Probably you need a different brake lever with a different pull ratio, so that LESS cable is pulled (but with more force) when you apply the brakes. (IOW, not a V-brake lever.)
    – Daniel R Hicks
    Oct 1, 2017 at 21:54

1 Answer 1

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In the end I improved this brake's operation manyfold, but its still pretty mediocre.

While working on it, I found the brake pad (strip?) was slick. So I presume some idiot applied oil to the brake in an attempt to make it quieter.

  1. The main fix was to extract the band, and use a hot air blower (a workshop version of a hairdryer) to warm the band and I could see the oil running out of the band and dripping off.
    I used a non-contact IR thermometer to make sure the top of the pad didn't exceed 150 degrees C and kept the hot air moving to not overheat one spot.

  2. After a while the oil stopped dripping, so I had to use a blotting method; I'd heat the brake pad and then quickly wrap it in a couple of paper towels. The oil was clearly visible wetting the paper. It helped to massage the brake pad by hand, so I wore some decent leather gloves as heat protection.
    There were at least a dozen head-blott-massage cycles, and I stopped when the paper towel did not get wet.

On reassembly, the brake was okay when free-spinning in a stand. There was a lot of fiddling back and forth with the cable tension and the two standoff screws that set the band's resting position, close enough but not so close that it rubs on the drum.

However when the bike is loaded, it absolutely screeches when braking. This is what makes me think an earlier owner oiled the brake, which certainly quietened it, but at the expense of function.

I did lightly sand/scour the drum and the inside of the brake pad, and it really made little noticeable difference.

A better solution would be as Bruce suggests, and fit a rim brake caliper. While this frame has a brake bridge, the rim lacks a braking track. Given this bike is literally a shopper / dunger / beater, I'm loathe to throw more money at it. However I did replace the fork to get canti mounts, and the front wheel has functional and effective V brakes on it now.

Own photo

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  • Apologies for delay in adding this answer - it completely slipped my mind that I'd posted this.
    – Criggie ♦
    Oct 19, 2020 at 10:54
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    I used to have a beater bike with good front brakes and effective but really noisy back brakes. For riding round a city where people often step into the road without looking it's ideal. Band brakes just are rubbish though
    – Chris H
    Oct 19, 2020 at 14:27

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