Cycling UK Forum

531colin wrote: ↑9 Aug 2024, 7:18pm With cable disc brakes you must take up pad wear using the pad adjusters.
If you only adjust using the cable barrel adjuster you will run out of the slope the tiny ball bearings run up, as Brucey says

Cyclothesist wrote: ↑9 Aug 2024, 8:42pm I agree with 531colin. The caliper lever arm looks to be operating very close to the barrel adjuster with only a short cable throw. The pads do not look worn out. As Colin says if you haven't used the pad adjuster screws to move the pads towards the rotor as they wear, and instead shortened the cable it results in the lever arm being at the end of its stroke on braking.
It's concerning that this brake caliper will pop the ball bearings off the end of the ramp towards the limit of the brake arm range. Its not exactly a fail safe design. Some early Spyre brakes were recalled because of this issue. The brakes pictured are single mechanical piston type so definitely not Spyres. They may be faulty or just a bad design. Personally I'd take the bike back to the retailer for assessment. If it's a bad design I'd replace it, and the back one too with something more robust and reliable.

Brucey wrote: ↑9 Aug 2024, 6:35pm some mechanical (cable operated) disc brakes are notorious for doing exactly this; all such brakes use an actuator that comprises three balls on three ramps, which is fine provided you don't run out of ramp. If you do, the result is usually that the brakes start to come on, before you get the click/no brakes thing. A whole load of tektro brakes manifested this behaviour, and were consequently recalled.
However, even in bad brakes, this only happens when the pads/disc are badly worn. E-bikes can be pretty hard on brakes, and pads don't last long anyway, so......

DevonDamo wrote: ↑9 Aug 2024, 5:42pm Without photos/video, it's a guessing game, but my guess (assuming it's a hydraulic system) would be that there's a fault with the lever mechanism. It's a simple mechanical system whereby the lever pressure is translated (via a pivot) into a short, hard push on the master cylinder. This can have any number of linkages and actuator rods, often held in place with little bits of plastic - one of which I reckon has broken. I had a similar problem on one of my bikes, and the only solution was to replace the entire lever assembly - I couldn't find spare parts. If this is the case, then regardless of whether you can diagnose the problem or not, you're still going to need to get the bike provider to swap out this part.

AndyK wrote: ↑9 Aug 2024, 5:38pm Is it a hydraulic or cable-operated brake? (From your biker avatar I'm guessing you know what a hydraulic brake looks like. )
Any visible damage to the cable/hose between the brake and the lever?
Normally for videos people stick it on YouTube or somewhere then link to it. If you can't provide the video then some photos would help, including a close-up of the brake calliper.
If it's less than a year old this sounds like something the shop should be sorting out under warranty.

PT1029 wrote: ↑22 Apr 2022, 8:24pm The asymmetric lower jockey wheel, the side that is notchy/lumpy near the teeth has the notches on the spoke/LH side and the smoother side on the RHS.

cyclop wrote: ↑22 Apr 2022, 8:19pm If you look at the removable plate,the bottom pulley position has a sort of shroud,which will interfere with the thicker side of the pulley,so most bottom pulleys can only be fitted one way round.

rjb wrote: ↑22 Apr 2022, 4:27pm When you've got it all back together make some bread. The kneading lifts all that grime out from under your fingernails. Hands will never be cleaner, and you can sit down with a well earned slice of toast.

cycleruk wrote: ↑22 Apr 2022, 4:36pm

trogg wrote: ↑22 Apr 2022, 3:19pm Picture of bottom wheel

There may be a direction arrow embossed on the pully side. That shows the direction of rotation required.
I once put mine in the wrong way and it was noticeably noisier.

mattheus wrote: ↑22 Apr 2022, 2:37pm
p.s. I could really use these:

trogg wrote: ↑22 Apr 2022, 2:02pm

do you use some unicode magic? Are others available on this platform??