attaching a crank

[Mussels]

What tool do I need to reattach a crank to a BB? the dust cap has come off and the nut inside has come loose, it's recessed and there isn't room for a spanner - I don't think there is room for a socket either.
Is there a way I can bodge this or do I need a special tool?

 

[Danny-K]

What tool do I need to reattach a crank to a BB? the dust cap has come off and the nut inside has come loose, it's recessed and there isn't room for a spanner - I don't think there is room for a socket either.
Is there a way I can bodge this or do I need a special tool?

Yes, you need a special tool, something like this:

The Park Tool Crank Extractor

Park Tool Crank Extractor | Buy Online | ChainReactionCycles.com


Although I use the old fashioned, versatile, but much cheaper Universal Crank Extractor that looks like this -

Cyclo Pro Series Crank Extractor | Buy Online | ChainReactionCycles.com

Either of the two are available from the bike shop of your choice. I pinched the above photos from the ChainReaction retailer, so better mention them out of courtesy.

After the crank extractor has fully 'homed' the crank back onto the b/b axle I then use a socket where I've ground down the excess on the outside of the socket to fit the nut-head inside the crank opening. However my universal crank extracter has a reversible bolt just for this - you then apply a spanner to that end to tighten fully; but I prefer my home-made machined-down socket.

 

[flecc]

A ground down socket to make it thinner is the usual dodge as Danny says and I prefer that method.
.

 

[Mussels]

A ground down socket to make it thinner is the usual dodge as Danny says and I prefer that method.
.

The crank is wobbling when ridden, do I just bash it back on or does it need to be done a special way? Danny-K's post has got me worried about my brute force and ignorance technique.

 

[flecc]

No, just tighten with an appropriate spanner. It does have to be very tight to align and grip firmly on the square taper, but there's no need to get the hammers out.

The crank extractor is more necessary get a tight one off, but not needed to put the crank back on.
.

 

[Caph]

Mussels, I've never had a problem on either of my two bikes using a socket on the BB bolt. It looks like there is no room for one, but there is. Optical illusion maybe? I guess what I'm saying is give it a try with a socket before you write it off as not possible.

 

[Caph]

However my universal crank extracter has a reversible bolt just for this - you then apply a spanner to that end to tighten fully; but I prefer my home-made machined-down socket.

I'm intrigued Danny, are you saying that your extractor has a socket on one end for tightening the BB bolt? I'd be interested in getting one of those if that was the case, I prefer all in one solutions. Is it the exact same one you provided the link to?

 

[Blew it]

A ground down socket to make it thinner is the usual dodge as Danny says and I prefer that method.
.

Socket sets usually follow a similar pattern.

3/4" drive.. heavy engineering use

1/2" drive....car and motorcycle maintenance

3/8" and 1/4" drive... hobby use, including bicycle mechanics

Have a look at the small drive sets, they mostly have quite thin walled socket heads. Inexpensive as well

 

[flecc]

Mussels, I've never had a problem on either of my two bikes using a socket on the BB bolt. It looks like there is no room for one, but there is. Optical illusion maybe? I guess what I'm saying is give it a try with a socket before you write it off as not possible.

Many of the cheap socket sets use thick socket walls which don't go in and they have to be ground thinner. Best quality sockets are usually thinner, so it seems your socket is one of those.
.

 

[Mussels]

My sockets are mainly Halfrds basic ones so high quality is unlikely.
My high quality sockets are high impact ones so there's very little chance of them fitting, time to try the Dreaded Halfords.

 

[Danny-K]

I'm intrigued Danny, are you saying that your extractor has a socket on one end for tightening the BB bolt?

Yes; it's not clear from the original photo, (see my concerns below), here try this one:

Basically the Crank Extractor shown here, unscrews into two component parts, you can reverse and refit it together etc., depending on whether you're EXTRACTING the crank bolt, (and crank itself), or TIGHTENING it. It's an ingenious little tool, and you actually have to play with it to 'get it' as explaining in words doesn't always match up to the photos available, (need an exploded diagram) - but I assure you, once in your hands and the two parts unscrewed and refitted all becomes clear. (Pretty sure you get a little instruction leaflet with them too).

Anyway, the bottom portion, (the bit where the syscycles.com name bleeds into it), is a socket head (14mm). And WILL fit the crank bolt easy-peasy, that is recessed in the crank. First unscrew the top part of the Crank Extractor, (although it can be left in situ if preferred), and simply fit the socket head part over the crank bolt. Look closely and you will see halfway up the Extractor where the socket head has 'flats' - these are provided for you to apply a spanner to it, and thus tighten the crank bolt. If you ask the Halfords bicycle staff, (or your local bike shop), to show you one, they might be able to demonstrate it too, if the above is unclear.

Is it the exact same one you provided the link to?

Upon reflection I'm not sure I like the one in the original photo in my original posting way up above in the early part of the thread - it may be one for the Shimano Octolink funny business. Mine's closer in resemblence to the photo in THIS post I'm writing now, (see photo in above para ie., this one from SJS, (b/brackets axles ending in a square taper):

Budget Cotterless Crank Extractor with 14mm crank

 

[Blew it]

Danny-K

What's needed is a slim walled socket to put the crank back ON!!

Please try to keep up!!

 

[Danny-K]

What's needed is a slim walled socket to put the crank back ON!!

Please try to keep up!!

Keep up? Oh alright I'll try.

Wasn't it clear, I was answering a query directed to me by another forum poster on a specific issue of a previously mentioned tool?

Anyone reading my post, will I hope, see that although it's got the word EXTRACTOR in it's name, the Crank Extractor shown above contains everything to put the crank back on too, as it contains a 'slim walled socket' that tightens via a spanner/wrench only, for those who can't obtain a slim-walled socket nor feel inclined to set up a grinder and grind an ordinary socket down to fit in the crank recess.

 

[Mussels]

LBS had nothing to help and Halfords had the right tool in their toolbox but didn't sell it.
None of the Halfords extractors had anything to put it back on. Instead I got a dinky y shaped socket thing that looks like it can't really do anything properly, but it is small and light and allowed me to do the nut over hand tight. I'll just have to stop at the roadside and reapply if it comes loose tomorrow.
I'm waiting for my Wisper toolkit to arrive at the moment and I'm hoping there will be something better in there. If not then I think Danny-K has the answer.

 

[wibble]

Keep up? Oh alright I'll try.

Wasn't it clear, I was answering a query directed to me by another forum poster on a specific issue of a previously mentioned tool?

Anyone reading my post, will I hope, see that although it's got the word EXTRACTOR in it's name, the Crank Extractor shown above contains everything to put the crank back on too, as it contains a 'slim walled socket' that tightens via a spanner/wrench only, for those who can't obtain a slim-walled socket nor feel inclined to set up a grinder and grind an ordinary socket down to fit in the crank recess.

You handled that very well. I would've hit him with my extractor.

 

[Blew it]

Now now Wibble, no violence please, we're British!!

 

[flecc]

Now now Wibble, no violence please, we're British!!

That's right, we only attack foreigners.
.

 

[Mussels]

Instead I got a dinky y shaped socket thing that looks like it can't really do anything properly, but it is small and light and allowed me to do the nut over hand tight. I'll just have to stop at the roadside and reapply if it comes loose tomorrow.

Socket thing that looks like it can't do anything properly has lived up to it's name, I had to stop 4 times on the way in to do up my crank nut.
I have a picture now, useless y thing looks like:

Time to order some more stuff from SJS.

 

[Lloyd_50cycles]

A Y-style drive isn't going to give you sufficient torque to tighten a crank bolt. And now you have an added problem. If it keeps working loose the soft alloy taper on the crank arm has probably worn slightly, which means the taper won't be a snug fit, and no matter how tight you do the bolt it will keep working loose. Take the arm back off and inspect the inside of the square taper. If damaged you will be able to see wear around the inside corners. If this is the case start a fresh with a new crank arm. When fitting it, you will find that some pedal spanners have a 14mm socket at the other end, recessed for snug fitment into crank arms. The ideal way of course is to use a torque wrench. Approx 40-45Nm will do the trick. And make sure the bottom bracket axle and the taper on the crank are spotlessly clean, and DO NOT apply grease. Some people advise you to, but it offers no benefit, only attracts grit and dirt.

I hope that helps

Lloyd

 

[Mussels]

Thanks. Strangely it seems to be getting a bit better as if the crank has been working it's way back on and causing the nut to loosen that way, I've been able to gradually do it up further and now it seems to be staying tight. With a bit of luck it will hold until I get something with decent leverage.