Hi,
My first post, am hoping someone can help as I have become bamboozled.
My friends has a not too good mountain bike & the bottom bracket is shot. Being the helpful chap I am I said I'd replace it for her.
Having checked the BB & seeing it was a square taper one I thought it ought not to have been more than a 5 min job. However upon removing the crank bolts I have been met with this:
So nowhere to screw my crank removal tool into & not a crank type I have encountered before. It's the same on both sides & I have no idea how to remove them (other than maybe just finding a screw the right size to fit the brass looking thread & screwing it it?)
Any thoughts or input greatly appreciated.
Regards
DM
Crank removal issues
Re: Crank removal issues
I think using a big bolt in the brassy coloured screw thread is what you are meant to do there. But I've not removed one like that myself.
cheers
cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Re: Crank removal issues
It looks to me like a steel crank with a plastic "overcoat", so that thread may not be too fragile.
Worth a try to put a bolt in and torque it up, if nothing happens, give the bolt head a sharp crack with a one pound hammer.
Worth a try to put a bolt in and torque it up, if nothing happens, give the bolt head a sharp crack with a one pound hammer.
Bike fitting D.I.Y. .....http://wheel-easy.org.uk/wp-content/uploads/bike-set-up-2017a.pdf
Tracks in the Dales etc...http://www.flickr.com/photos/52358536@N06/collections/
Tracks in the Dales etc...http://www.flickr.com/photos/52358536@N06/collections/
Re: Crank removal issues
Brucey wrote:I think using a big bolt in the brassy coloured screw thread is what you are meant to do there. But I've not removed one like that myself.
cheers
Would it need something to press against so as not to damage the axle threads?
Although if the axle is U.S. then probably doesn't matter.
You'll never know if you don't try it.
Re: Crank removal issues
That looks like a Thun chainset to me, or one of a similar design. IIRC you need a standard bolt which you screw into the chainset which then pushes against the axle, 15mm springs to mind for the bolt size but I might be wrong.
Re: Crank removal issues
Removed cranks where the extractor threads have been stripped by inserting short flat tapered wedges between the arm and BB flange. Insert a scrap bolt into the spindle, apply heat to the crank arm boss and hammer temporary bolt.
Can be awkward inserting wedges if the inner ring is heavily dished.
Caution with the arm inner flange. These can be quite soft material.
Depending on the BB type/design??? Try working from the other side first.
3-leg puller is ideal. You maybe fortunate, space permitting, to use a vehicle forked ball joint separator.
Unable to quite see if the small rectangle recess near the boss, is for removing a protective cover?
Or…. Removing an outer seal…???
Can be awkward inserting wedges if the inner ring is heavily dished.
Caution with the arm inner flange. These can be quite soft material.
Depending on the BB type/design??? Try working from the other side first.
3-leg puller is ideal. You maybe fortunate, space permitting, to use a vehicle forked ball joint separator.
Unable to quite see if the small rectangle recess near the boss, is for removing a protective cover?
Or…. Removing an outer seal…???
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- Joined: 1 Aug 2013, 3:56pm
Re: Crank removal issues
Thanks for all the input!
I have dug out a couple of big bolts & shall see if either of them fit the bill. If not then it's a trip to the hardware store for a three-legged puller! (Sounds like some kind of hideous sci-fi beastie!)
Shall keep you all posted.
Cheers
DM
I have dug out a couple of big bolts & shall see if either of them fit the bill. If not then it's a trip to the hardware store for a three-legged puller! (Sounds like some kind of hideous sci-fi beastie!)
Shall keep you all posted.
Cheers
DM