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KoolKat
02-19-2013, 08:14 PM
"Hi Zombies. I finished the basic frame and running gear on my Kyoto Cruiser and used your disc brake hub adapters. I find that, when I rotate the wheel, there is wobbly movement of the cassette and brake disc on both sides. The discs rub due to what I would call "out of radial plane alignment". Have you folks received any other comments about possible miss-aligned hub adapters? These are new cassette so, it's probably not them. Comments appreciated. Thanks. Frank."

charlie_r
02-20-2013, 07:45 AM
Assuming the axles are indeed cold rolled steel, did you put a divot in the axle for a setscrew or did you through drill for a bolt?

If using a setscrew, the axle and adapter can deform slightly when tightened, giving you that wobble. If through bolt, any misalignment of the bolt hole will also do this. If setscrew is given a small divot to set in, this deformation can be reduced a significant amount, by not requiting as much torque to hold the adapter in place. Use of loctite becomes necessary in this scenario, but really should be used anyway for rotating parts.

The problem becomes worse if the axle is hot rolled steel. Hot rolled is much softer, and deforms quite readily when stressed.

The adapter should fit fairly tight to the axle, but not so tight you have to use force to slide it on. Any looseness between the adapter and axle will also cause the wobble -radial alignment- issues. Even as small as .001" can allow this.

That being said, my experience with my DIY adapters says that some radial miss-alignment is tolerable, just means a little bit of drag for the brakes, not enough to worry about. The freewheel is a different matter, though. any more that 1/4 chain width will cause shifting problems.

There may be a solution, if the problem is a loose fit to the shaft. Shim stock can usually be found at automotive machine shops fairly cheaply. This can be used to fill the slight gap between the axle and adapter, and adjusted by position to reduce (doubtful to eliminate) any radial miss-alignment.

Charlie

Ticktock
02-20-2013, 10:14 AM
Hi
I have not tried this, but if you have any loosness in the adaptor, after shimming, as Charlie suggests, you could try loctites bearing fixer.
Not the right words, I can't think what they call it right now. But it sets more firmly than most other of their products.
I have just done some calculations for another project, and amazed my self that we can generate over half a ton stress on a bike chain, so you do need more than basic loctite!
More than 2mm wobble on a rear hub will definitely annoy your derailer to extent that it will annoy you!
Steve G,
beijing

charlie_r
02-20-2013, 12:36 PM
Steve,

Is that half ton tensile through only one gearset? Think about the multiplication of double reduction such as what we use in our mid drives......

bluemax
02-20-2013, 02:28 PM
Charlie and all,
I drilled through the hub into the 1st wall of the axle then inserted a 1/4" bolt temporarily, then drilled the other side so, the alignment should be pretty good. I plan to remove the bolt and check exactly how much play there is and go from there as to shims. Regarding Locktite, Ticktock did you mean using the stuff between the axle and the adapter or were you talking about the through bolt?