D Brake vs frame mount

Brake squeaks like mad when using D brake, regardless of which brake, rotor or pads I use. Soon as I put the exact same brake, rotor and pads on a frame mount, squealing and noise is instantly gone. And I’ve tried using a reinforcement rod on the D brake, but still squeals and squeaks loud enough to wake the dead! I wonder if it’s just the different angle that the brake attaches to the frame mount that makes the difference. Btw, I’ve also tried both D brakes versions, beefy and thinner, made sure pads were centered and rotor was true, but still didn’t make a difference. Any thoughts?

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The d’Brake bends under load and thus, swings / vibrates. A proper Hugo Strut (reinforcement rod) can often stop it from doing so, especially when preloaded in the opposite direction (pressure on the rod). But it still isn’t as rigid as a frame mount. There are only three things that can stop vibration: rigidity, mass and dampening.
The d’Brake isn’t a perfect solution. It’s a nice problem solver but still has its downsides. A proper frame tab will always be the superior solution.

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Thanks for the quick reply Eric. Yes, I suspected this was the main reason, but I also can’t help but think that the difference in angle could have something to do with it as well.

Brazed on Frame disc mount which instantly eliminated squeal/noise. But on my 36er, since I didn’t want to remove powder coating to braze one on there, I made a short reinforcement bracket which directly counteracts braking force, and is much more rigid due to the short length, and works in combination with the longer, lateral support.


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How did you find brazing the aluminium frame?

I just have this image of a big hole in the frame and a blob of aluminium burning a hole in my bench if I were to try that :slight_smile:

I practiced on scrap pieces first, making sure both frame and part were sufficiently heated to fuse together, without reaching the melting point of either frame or part. The rods are flux cored so no separate flux was needed, and I made sure everything was clean to reduce oxidation. The melting point of the rods is much lower that of aluminum, but I wanted to make sure the braze would penetrate and fuse, and not just sit on top, so I let the part and frame get hotter than the rods require.

That’s pretty impressive. I wouldn’t have seriously considered it before, but I’ll maybe give that a try at some point – thanks for showing it is doable.

Actual welding would be the best choice, but I don’t have the equipment or skill for aluminum welding (only steel), and local aluminum welders have minimum charges, even for very small jobs like this, and rather than spend $100 - their estimate - I wanted to at least try brazing.

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For sure welding would be best, but like you I don’t have a suitable welder. I’ve got an old scratch-start DC TIG welder and always wanted to get a decent one to do aluminium but it hasn’t happened yet. It is good to see this is an option.

Hopefully this stands up to the force and vibration from the brake and doesn’t crack – you’re probably the first person to ever try it on an ali frame :slight_smile:

This idea was basically just to stop-gap until I could replace the frame with the current version, which comes with a disc frame mount. Unfortunately I couldn’t find any KH frames available, so I ended up buying a Mad4one frame, which has disc frame mounts on both sides.

So far, I’ve taken it on three Muni rides, and ridden down some pretty steep sections with the brake on full, and and it seems solid. But as an added reinforcement, just in case, I put two steel cable ties around the tab and frame, so if it does crack, it won’t fly off during downhill braking.

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