Bicycle Mechanics - bottom bracket
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09-04-08, 11:06 AM
So I have an old frame that I pulled out of the trash...I am wanting to take the bottom bracket out, can this be done without my LBS, my father has a wide range of tools available for use. Also how do I measure a bottom bracket, example: what does 68mm, 110mm mean? And can I re-install bottom bracket without LBS tools?
Second I would like to strip and paint the frame and fork, also I can do this with father's tools, but is it worth it? Is it just easier and better to take it somewhere for de-rusting and stripping then a paint job? The bike is nothing special, however it's a free frame that I would like to build up with my own style and labor.
Anything to help is appreciated...
09-04-08, 01:34 PM
68 mm mean the width of the bottom bracket,1110 mm is the width of the axle witch goes into the bb. is it worth it ? that up to you .
09-04-08, 01:41 PM
Rather than stripping the paint, I'd recommend sanding it a little and painting over it. You'll want to wipe it down with degreaser first. I stripped and painted a frame, and it took forever to get all the old paint off.
Regarding the bottom bracket, it depends upon what type it is. An old-school cup and ball BB can usually be taken out with a large channel lock wrench.
09-04-08, 03:24 PM
68 mm mean the width of the bottom bracket,1110 mm is the width of the axle witch goes into the bb.
and the axle is the spindle that connects to the cranks? so if I order a bottom bracket, i need to get cranks that will fit with the spindle size, right?
EDIT: I have only worked on bikes for a couple of weeks, I did a quick conversion and then a restoration that wasn't so major...so I am gaining knowledge as I move along.
09-05-08, 01:35 PM
yes to your questions .
09-05-08, 09:59 PM
You can use large Channel-lok pliers on the BB's fixed cup. Even use it on the adjustable cup's lockring. :)
09-05-08, 11:27 PM
68mm refers to the width of the BB shell, which is the part of the frame that the BB screws into. Other options are 70mm (Italian) and 73mm (mtb bike) or other rare sizes. 110mm refers to the spindle length which is the length of the axle the cranks attach to. Both dimensions are important but 99% of non-Italian road bikes will use 68mm. The 110mm part is also important so make sure you get a BB spindle that is the same size or else your cranks will hit the frame or be so far out the front deraileur won't work correctly. You can take these parts out with normal tools if you're lucky but if you found the bike in the trash there is a chance the BB cups are stuck and will be hard to remove. In that case you will want the 'right' tools. Some LBS have tools for free use and nearly any bike coop will lend tools for this as well.
Other useful information is that the drive side BB cup is left-hand threaded.Always make sure to grease the threads on re-assembly. Good luck and have fun.
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