Bicycle Mechanics - making a drop bolt (one sided?)
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10-15-10, 07:29 PM
can I make a drop bolt that is a single plane of metal or do I need to make 2 metal pieces come down and have washers of something in between?
I imagine the only issue with one peice of metal would be the torque on it during braking which wouldnt be shared by 2 peices of metal.
But it would be a lot easier to make... ill just use like a 1/4" peice of aluminum i figure.
10-16-10, 10:20 AM
You can do so as the factory ones I have seen photos of have been one piece of material. You need to make it thick enough so there is minimal flex and to me that means thicker than 1/4" aluminum IMO. I would use steel for thew added rigidity. Also you want it thick enough so that the caliper mounting nut can tighten against it.
Personally I would prefer to fit longer reach brakes as drop bolts indicate use of incorrect size parts for a bike build, at least to me.
10-16-10, 10:41 AM
As you can see on reply to your other post on this topic, drop bolts have a groove in them for anchoring the return spring.
As they replace that part of the center pivot brake,
it is more than a piece of metal with 2 bolts facing in opposite directions, in it.
As several have said, get a brake with a suitable reach.
10-17-10, 01:43 PM
Sheldon Brown offers one home-brew solution: http://www.sheldonbrown.com/home-drop.html
I made one out of a piece of electrical conduit:
10-17-10, 04:46 PM
I think we're talking about two different things. The traditional drop-bolt replaces the centrebolt of the brake with an offset one to lower the caliper arms (works well when you only want a modest-drop, like 10mm):
If you need more drop than that, then there's sufficient room to create a drop-bracket that lets you mount the same brake lower. In these cases, you MUST make them double-sided to deal with the single-shear cantilever forces:
Due to the wider bracing, you can use thin material, 3mm steel or 5mm aluminium. If you want to make a single-sided one, I'd go with no less than 10mm aluminium.
Here's one I did. Works nicely with no problems.
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