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

Crank removal

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matthewslack

Esteemed Pedelecer
Nov 26, 2021
2,539
1,646
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
12,155
3,394
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
12,155
3,394
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
100
3
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
12,155
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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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Sparksandbangs

Pedelecer
Jan 16, 2025
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V

volt x

Pedelecer
Apr 26, 2025
100
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Well if it could go wrong it most likely will do it in the worst way possible. As you can see from the pic , I've sheared the thinginmebob. The remainder is still in the frame, how do I remove it. Please don't ask for an explanation as I'm not in the best frame of mind as you might understand.
 

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Sparksandbangs

Pedelecer
Jan 16, 2025
189
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volt x said:
Well if it could go wrong it most likely will do it in the worst way possible. As you can see from the pic , I've sheared the thinginmebob. The remainder is still in the frame, how do I remove it. Please don't ask for an explanation as I'm not in the best frame of mind as you might understand.
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I would have to see the bit that remained in the frame. Does the other side unscrew?

Best advice I can give is don't rush into bludgeoning it. Cup of tea, have a think before taking action.
 
guerney

guerney

Esteemed Pedelecer
Sep 7, 2021
12,155
3,394
Best way to get good clear shots in dark places (such as BB interiors) using a Pentax K1 (gleaned from your pic metadata), is to use manual settings, holding it steady using a tripod, F8-ish, with low ISO and low shutter speed. They're excellent cameras, but because they use a CCD sensor rather than CMOS, less sensitive to light. Much nicer colours though, with good exposure, on Pentaxes of that era because they made efforts to make digital look like film. I do miss my *IST, Pentax make proper photographer's cameras.
 
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volt x

Pedelecer
Apr 26, 2025
100
3
Sparksandbangs said:
I would have to see the bit that remained in the frame. Does the other side unscrew?

Best advice I can give is don't rush into bludgeoning it. Cup of tea, have a think before taking action.
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Yes I can remove the crank spindle , the broken part is on the non drive side. I could try to take a photo of the piece but it involves going macro trying to get some light in there and generally becoming a major pain. Essentially the remainder of the piece needs to be screwed out.
 
S

Sparksandbangs

Pedelecer
Jan 16, 2025
189
56
Four ways off the top of my head.

Bike shop

Nipple extractor if you can find the right size. Penetrating oil soak night before attempting. Luckily the left side is a standard thread.

Internal pipe wrench. Need the right size again. Penetrating oil soak.

Third way, the one that I would probably go for because I'm too tight to buy the above or go to a shop.
Junior hacksaw. Split it. Blade through the opening where the bottom bracket went. Reconnect the saw and then cut just over 3/4 of the way through in 2 cuts then prise out with a flat bladed screwdriver. Would work better with a junior that has the knurled tension ring rather than the bend the frame to get the blades in type.

All of these are likely to damage the threads a bit so would need a quick run through with a tap if it does.

Wait to see if anyone comes up with anything better.
 
V

volt x

Pedelecer
Apr 26, 2025
100
3
guerney said:
Best way to get good clear shots in dark places (such as BB interiors) using a Pentax K1 (gleaned from your pic metadata), is to use manual settings, holding it steady using a tripod, with low ISO and low shutter speed. They're excellent cameras, but because they use a CCD sensor rather than CMOS, less sensitive to light. Much nicer colours though, with good exposure. I do miss my *IST, Pentax make proper photographer's cameras.
Click to expand...
What we have here is a frame with a sheared piece left inside. I do have all the gear to get a good picture but what more info will it provide. I'm not meaning to be awkward but it is a lot of hassle to set this up and like I say I'm not in the best frame ( excuse the pun) of mind.

If it's really required then I'll make the attempt. The pic here is taken from the drive side does it help. Hand held 50mm lens not bad even if I say so myself.
 

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Sparksandbangs

Pedelecer
Jan 16, 2025
189
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volt x said:
What we have here is a frame with a sheared piece left inside. I do have all the gear to get a good picture but what more info will it provide. I'm not meaning to be awkward but it is a lot of hassle to set this up and like I say I'm not in the best frame ( excuse the pun) of mind.

If it's really required then I'll make the attempt. The pic here is taken from the drive side does it help. Hand held 50mm lens not bad even if I say so myself.
Click to expand...
I'd definitely go for the saw looking at that but I do have a habit of using brute force and ignorance. There may be a better way. Cut carefully though if you do.
 
guerney

guerney

Esteemed Pedelecer
Sep 7, 2021
12,155
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volt x said:
excuse the pun
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Puns are always welcome.

Personally, I'd try a junior hacksaw as already suggested (or triangular microfile), sawing or filing most of the way through, then I'd shove a straight thin pointy awl under the cut in order to make it bend or (hopefully) break, then I'd shove a flathead screwdriver into any available newly created space to further deform or break the thang enough to drag the thang out.
 
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V

volt x

Pedelecer
Apr 26, 2025
100
3
Sparksandbangs said:
Four ways off the top of my head.

Bike shop

Nipple extractor if you can find the right size. Penetrating oil soak night before attempting. Luckily the left side is a standard thread.

Internal pipe wrench. Need the right size again. Penetrating oil soak.

Third way, the one that I would probably go for because I'm too tight to buy the above or go to a shop.
Junior hacksaw. Split it. Blade through the opening where the bottom bracket went. Reconnect the saw and then cut just over 3/4 of the way through in 2 cuts then prise out with a flat bladed screwdriver. Would work better with a junior that has the knurled tension ring rather than the bend the frame to get the blades in type.

All of these are likely to damage the threads a bit so would need a quick run through with a tap if it does.

Wait to see if anyone comes up with anything better.
Click to expand...
I like the way you think and your solution though very risky might be the way forward. Like you say wait for more replies. The other problem is as you can see in the pic the removal tool attached to the spindle is not wanting to be removed. It's tightened to the extreme, I've used some penetrating oil and just left it. Any ideas on how to remove this. It's not the 13th today is it, it just feels like it .
 

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