It arrived

StuartsProjects

Esteemed Pedelecer
May 9, 2021
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My Bafang rear hub motor kit has arrived, its a freewheel hub, time to start work I guess.

Rear droputs need widening a little bit, a not uncommon issue I believe. They are around 9.5mm and need to be 10mm for the bafang axle.

Never filed titanium before.
 

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Scorpio

Esteemed Pedelecer
Apr 13, 2020
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Portugal Algarve (temporary)
Hi, I've had to "square off" the bottom of the slots on a couple of rear dropouts, not had to widen any (or fitted a Bangfang, or worked with titanium).

Maybe wait for advice from one of the more experienced folk on here before deciding the best way forward.

Hope it works out the way you want it :)
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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West Sx RH
Yes don't square off the drop out seat completely otherwise you will over time induce metal fatigue at the corners, the radius needs to match the hub axle. One won't die due to compressive explosion like a Comet 1 but one doesn't want to see the wheel pass you.
 

Scorpio

Esteemed Pedelecer
Apr 13, 2020
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Portugal Algarve (temporary)
Poorly worded on my part but it sounds like you've already worked out - you just need to square the drop out enough to match the profile of the axle, making it fully square would introduce a stress riser / weak point.
 

Scruffydroid

Pedelecer
Dec 12, 2020
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Titanium is not an easily worked metal. I'd be more inclined to convert an aluminium bike, rather than file out the dropouts, or fit a crank motor to a Ti frame.
 

StuartsProjects

Esteemed Pedelecer
May 9, 2021
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The corners, of the dropouts were not affected. On close inspection the problem appears to have been some surface burrs on the edges of the droputs, perhaps caused by the threads of the original rear wheel.
 
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