Electric Bikes Conversion Kits EMTBS eRoad/Commuting What's New?

Crank removal

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matthewslack

Esteemed Pedelecer
Nov 26, 2021
2,522
1,643
Try heat as well, and a big socket not a spanner. If necessary drill a hole through the spanner flats for a bar, or reshape them with an angle grinder to get better purchase with a smaller size spanner.

Or clamp the tool in a big vice and use the bike frame as the spanner.
 
guerney

guerney

Esteemed Pedelecer
Sep 7, 2021
12,108
3,383
The issue when trying to remove my BB was galvanic corrosion seizing it up. I don't think the BB on my aluminium alloy framed bike had ever been removed, bike manufactured April 2006. In desperation after many hours of bashing soaking in WD40 etc, having had damaged the thread of the first extractor tool, I telephoned the bike shop dude, who suggested placing the axle on a metal butt and bashing the frame closely around the BB area. That worked to unseize - I used the damaged extractor tool as a butt, hammered it's fatter end vertically into a horizontal piece of pallet wood with a hole drilled exactly the diameter of the extractor tool, because there are no vertical metal butts available to buy from hardware shops. Installing my awesome BBS01B mid-drive was a breeze thereafter.
 
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guerney

guerney

Esteemed Pedelecer
Sep 7, 2021
12,108
3,383
saneagle said:
You're not supposed to connect your battery to the bottom bracket. There should be a connector on the motor for it.
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I didn't have to. Galvanic corrosion happened ragardless. There's salt on them thar acid rain soaked roads.
 
V

volt x

Pedelecer
Apr 26, 2025
73
2
Sparksandbangs said:
If you are talking about removing the bottom bracket then if it has been there for a long time then it will be almost impossible to get any purchase with the standard tool. Every time that you apply any pressure the tool will slip off and chew the ring. Trick is to soak the thing in penetrating oil and have an adaptor that clamps onto the square taper. This ensures any pressure will be exerted onto the threads and no sideways movement.
You can make your own adaptor with an M8 fine thread set screw (probably, can't remember)and a couple of washers or buy one.

Left-hand side is a standard thread, right-hand side is reverse thread. Left side needs to be slackened off first.
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Will WD40 be okay for that?. I went for a ride without removing the crank. Just put the crank arms back and no noise from bearings. I will soak it with some penetrating oil and try your adaptor idea . Good idea as it happens. Cheers
 
guerney

guerney

Esteemed Pedelecer
Sep 7, 2021
12,108
3,383
saneagle said:
Do you know what galvanic corrosion looks like? If your BB was stuck and there was white powder on the aluminium, that's crevice corrosion, which is much more likely than galvanic.
difference between crevice and galvanic corrosion - Search
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I should have taken photos but I wasn't on this forum then, so there was no need to, plus there was the red mist factor. My bike's frame is aluminium and the BB is steel. There is a weak electrolyte and there was rather a long period of time. Bashing it against a metal butt broke up whatever the heck it was enough to get the damn thing out. Blimey, anvils are expensive.

https://www.ebay.co.uk/itm/304565442976
 
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S

Sparksandbangs

Pedelecer
Jan 16, 2025
144
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