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-   -   Bottom Bracket / Crank Questions (https://www.bikeforums.net/bicycle-mechanics/947168-bottom-bracket-crank-questions.html)

Swen 05-09-14 03:24 AM

Bottom Bracket / Crank Questions
 
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Hi all,

After riding Linda (my Peugeot Performance 3000) for a little than 2 years (she was standing in a garage for 10 years before that), my bottom bracket is not turning around properly anymore. This could, according to me, be rust or anything else.
Because the BB is a Shimano BC-1.37 (Loose-bearing, square-taper spindle) I was wondering if I could replace the BB with something like an ISIS cartridge?

Second question is regarding the cranks, this is a picture of them:

http://bikeforums.net/attachment.php...hmentid=379195

According to what I have read Campy cranks can be pulled out with Parks CPB puller. Obviously I am not planning to do this on a regular basis, so can I use the BBB BTL-14 instead?

Thanks for a having a look at this in advance,

Swen

dabac 05-09-14 03:47 AM

You can't replace a square taper BB of any kind with an ISIS BB unless you also replace the cranks. But you can replace a square taper cup & cone BB with a square taper cartridge BB and keep the cranks.

A bit of a warning here that your Campy crank may have a ISO spec taper, while most BBs will be JIS spec taper. Means that you might not get the chainline that you expected if you inadvertently end up switching tapers as you replace the BB.
It's usually manageable by deliberately choosing another BB length, but can be a hassle if you buy the parts on line.

The BTL-14 should work fine - assuming it engages the threads in the crank. Haven't handled enough Campy stuff to remember offhand. But you may need to remove the "button" on the plunger so that the plunger will engage the BB spindle instead of pushing against the crank.

SkyDog75 05-09-14 06:45 AM

A standard square taper crank puller will take those crank arms right off. I use a Park Tool CWP-7, but that BBB one should work just fine.

You may be able to simply service your bottom bracket without having to replace anything. Remove the crank arms, remove the NDS (non drive side) bottom bracket cup, pull out the spindle & bearings, and inspect. If the races are smooth, put in some new bearings and grease, assemble, adjust, and ride.

If the bearing races are worn or damaged, you may need to buy a new bottom bracket and a square taper sealed cartridge unit is an option. As mentioned above, Campagnolo uses an ISO taper for their square taper interface, so you can't (or preferably shouldn't) use one of the common Shimano bottom brackets. Normally, you'd just need to find something Campagnolo-compatible with a spindle length that matches the original one. But since you said you're using Campagnolo cranks with a mismatching Shimano bottom bracket, there are a few variables and possibilities.

zacster 05-09-14 06:47 AM

Shop around for a Campy square taper cartridge BB. It is guaranteed to fit your Campy crank. I saw Chorus for $130, but I think you can find cheaper if you look.

But the question is why doesn't your current BB work? If you are ready to pull it out, why not at least try repacking the bearings before you take the fixed cup off? And another question, you already have a Shimano taper with a Campy crank, which while they work are not 100% compatible because the taper is different. Do you have issues with the chainline as it is now?

Skydog beat me to the same answer while I was typing.

Swen 05-09-14 07:02 AM

Hi all,

First of all thanks for the replies, these are one by one very helpful and gets me a better idea of what I am up against.

2 years ago I bought this bike online, unfortunately it was badly maintained, my ex-LBS, worked on it and screwed things up when changing the back hub. Long story short, that was the last time I went there. (I live as an expat in Czech Republic).

Based on the advice above I will start inspecting one side of the BB as described by @zacster and see where that will lead me.

FWIW the problem lies in the fact that in order for you to rotate the cranks you have to place some force. This isn't the case on my MTB so hence the reason for me to post the questions and beside that this situation didn't occur a week ago.


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