RADBMX.CO.UK
Technical & Reference Section => Tech and Restoration => Topic started by: cozi70 on August 22, 2013, 02:37 PM
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Hello folks.
I've got a 2002 haro shredder lhs crank bike.
(http://i962.photobucket.com/albums/ae102/cozi70/25B8E9DA-DA18-4097-9515-2A5FFB142481-2439-000000B6988CC418.jpg)
Problem is I need a new bottom bracket as one off the inner bearing threaded parts is damaged.
It's a three piece crank,centre bit being 150mm long and its got very similar BB to the one piece type apart from the 2 inner bearing threaded parts are threaded the wrong way,meaning the Lh thread is where the RH thread should be and vice versa.
Here's some specs
(http://i962.photobucket.com/albums/ae102/cozi70/F1138F03-3BF8-43D4-B00C-C7CC14EADB87-2439-000000B9771959BC.jpg)
(http://i962.photobucket.com/albums/ae102/cozi70/FD1834A3-044D-47C8-B3DF-EEDC837B013E-2439-000000B983A9978D.jpg)
(http://i962.photobucket.com/albums/ae102/cozi70/8C839A4C-7A94-44B1-AA29-98F665F9FD87-2439-000000B99007135F.jpg)
(http://i962.photobucket.com/albums/ae102/cozi70/5CA8A31D-D7E0-40B8-97E7-19BD95130623-2439-000000B99DF615B6.jpg)
(http://i962.photobucket.com/albums/ae102/cozi70/D95E07B9-1FFB-4828-A4CE-1AA4D2BF10B9-2439-000000B9AB286203.jpg)
Any help would be greatly appreciated as most off my local bike shops are not interested in helping out with bmx's.
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Anyone?
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Looks like a standard american bottom bracket set up. If your axle is ok what fits to the cranks, then pop into a bike shop with the axle and ask for an american bottom bracket and test fit the cones what go on the axle. If the fit, then jobs a good un. Use plenty of lithium high melting point grease.
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I'd be tempted to ditch the lot for some better cranks with a sealed BB
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Yep - you'll be hard pushed to find replacement threaded cones for a caged-ball LHD crank. Do what Pickle says and splash some cash on a secondhand pair of Profiles or (dare I say it) Redlines. You can pick em up on eBay for around the £50 mark with bottom bracket.
Only problem is is you want em LHD. You can get em, but they'll be more expensive than the RHD counterparts - just get a RHD pair, flip em and then swap your pedal cages over.
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Cheers folks for the input.
I'd tend to agree with the comments about getting a sealed bearing arrangement sorted.
Think I have a cheap solution to the current problem though,just to get this lad back out again.
I've purchased the standard one piece BB(£6),which looks ultimately identical,and I'll lathe out the new bigger cones internal threads and tack it on as the adjustment is from the other side,and I can reuse that undamaged internal part along with the new bearings and cups.
Can anyone advise/direct me on going down the sealed bearing/new crank route,or possibly just transforming it into a one piece assembly. Will one piece require new pedals and sprocket?
Cheers
Colin J
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love to see a pic of youre swap 8)
Can anyone advise/direct me on going down the sealed bearing/new crank route,or possibly just transforming it into a one piece assembly. Will one piece require new pedals and sprocket?
... think so, yeah - "Multi-piece cranks have a 9⁄16-inch (14.2875 mm) hole with 20 TPI (a diameter/pitch combination fairly unique to this application). One-piece cranks use a 1⁄2-inch (12.7 mm) by 20 TPI hole."
(http://en.wikipedia.org/wiki/Bicycle_pedal).
...with the spider/disc ... beats me "help"
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You'll need 1/2" axle pedals for a one piece. You wouldn't need a new sprocket though as they're standard - they'll fit 1 or 3 piece cranks.