Cycling Equipment · Public discussion

Newbie in need of bottom bracket help

Started by AaronHorn · · Last activity · 4 posts · 1,079 views

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Cycling Equipment
Published
11 July 2007
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11 July 2007
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AaronHorn
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  1. Hello,

    Just found this site and figured I'd see if anyone knew the answer to my problem... Bit of background: I have a cheap(ish) Raleigh P2000 bicycle that I found in a skip. It worked well after I'd cleaned it up a bit. After a long time of not riding it, I decided to overhall it for the summer. The pedels had a bit of a lateral knock so I removed the crank arms (square cotterless). I was able to remove the adjustable cup (which had a raised 'rectangular area'😉 using a big adjustable spanner... I removed the fixed cup in a similar fashion... On inspecting the fixed cup I found a crack running halfway around the inside propergating to the outside (meaning the cylindrical shape of the cup when sat on a bench made it look bent)... I don't know how this happened but suspect it could be to do with a missing ball bearing and hills in my area 😄.

    Now obviously I don't want to stick this back in but would like to replace the pieces.. I've found a suitable replacement cup and bearing set at freemanscycles.co.ukproduct2.asp I'm guessing this would just work but it means that I'd likely have to buy the two tools needed to adjust and fit this... I also guess there'd be some mucking about in adjusting this so another option would be to buy a 3 piece thing like a UN54... I've found this one: cyclexpress.co.uk.%2fproducts%2fDeore UN54 Bottom Bracket.aspx. My axel is marked 03/03A which means it's 117.5mm (which it is by measurement) and my frame is 68mm so I assume the above would work if I brought the 118mm version or do I need something more exotic? (does .5mm make a difference to chain line?)

    The other question is that between the fixed cup and the frame I had a 2mm piece of metal that help a mud guard in place... I don't want this there anymore so I assume that the absence of this spacer could affect chain line? Will it be notable or not?

    Any thoughts or advice... I'm only tinkering for something to do with my holidays and don't want to spend a vast amount of money on something I found in the skip!

    Thanks!

  2. Get the cartridge UN54. The tool to install it is pretty cheap and those BBs last a long time. The 0.5mm difference won't matter between 117.5 and 118. The chain line without the 2mm from the mud guard will probably not be a big deal. You can always get a 1mm or 2mm spacer from a local bike shop if needed to adjust the chain line a bit.

    The issue that may come up is that the old spindle may be asymmetric, whereas the newer one is symmetric. If so, the new one will work, but the left side crank will be a bit farther out--probably not enough to be problematic though. See Sheldon Brown's website for discussion of bottom brackets.

    http://www.sheldonbrown.com/bbsize.html

  3. Turns out it's a good thing I double checked, the spindle is 122mm long.. Shouldn't matter I guess... The 'A' part (from Brown's site) is 32mm where as the C part is 36mm... A 4mm difference; will that matter?

  4. AaronHorn said:

    Turns out it's a good thing I double checked, the spindle is 122mm long.. Shouldn't matter I guess... The 'A' part (from Brown's site) is 32mm where as the C part is 36mm... A 4mm difference; will that matter?

    Get the 122.5mm and you will be good to go.

    The same link that you provided for the UN54 has the 68-122.5 listed as available.

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