Cutting off granny gear mounting tabs

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Cutting off granny gear mounting tabs

Postby john_galt » April 22nd, 2013, 8:04 am

I have some XT (M770) cranks that I want to run 1x with an E13 LG1+ chain guide. The granny gear mounting tabs on the crank spider interfere with the chain guide mounting plate. I'm going to remove the mounts and am weighing my options. So far these are the processes I'm considering:

1) Cut them off with a hacksaw
2) Grind them down with a grinder
3) File them down by hand
4) Drill them out

The drill method seems like the cleanest and least amount of chance I'd error/ef up. I'm concerned that they'd get too heated with a grinder. The other ones require a lot of elbow grease.

Anyway, anyone have any other ideas or experience? Without needing special tools or taking it to a machinist.

Thanks
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Re: Cutting off granny gear mounting tabs

Postby MediumRB » April 22nd, 2013, 8:12 am

A metal file should do the trick pretty quick. I had to "adjust" my cranks and chainring for fit, file did it with ease and control.
Everything I ride makes sense.
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Re: Cutting off granny gear mounting tabs

Postby okeja » April 22nd, 2013, 12:57 pm

How much needs to be removed? If just a little bit, hand file will be easy.
If you have a drill big enough, agree that method would be most simple to remove whole mount boss. Use light oil as cutting lube
Otherwise a cutoff wheel in an angle grinder (or Dremel type rotary tool) will zip them off quick.
Then clean it up with a hand file.
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Re: Cutting off granny gear mounting tabs

Postby john_galt » April 22nd, 2013, 1:47 pm

At least 5mm needs to be removed to clear and for gap. The whole boss will likely be removed. Filing is a good choice but I imagine would take much longer than drilling.
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Re: Cutting off granny gear mounting tabs

Postby john_galt » April 23rd, 2013, 12:29 pm

Done. Took about 2 minutes per mount with a medium duty drill bit. Finished them off with a fine file. Looks pretty clean.
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