Bottom Bracket replacement

DODDYcp · June 2007

Hi,

After a long L2B!! my bottom bracket is a little gone[:(] it creaks more than me[:D]

The bike is an oldish Claud Butler Critirium and is so nice to ride that it deserves the new parts.........But what parts will fit.

The existing bottom bracket has the 'toothed' locking ring and the adjustable cup does not have the usual holes but a raised ridge approx 15mm wide and about 1.5mm high that you use to turn with a spanner to give the required 'play'

Can this all be replace with the modern equivalent?

What dimensions are required to purchase parts.

Cheers
CRAIG

Down the Road · June 2007

Yep and your local bike shop can do it for you very easily an d to the correct torques.

DODDYcp · June 2007

o.k. So new bits will fit.

What parts should I buy. I see loads of BB for sale but all have different numbers ie. BB UN52 or BB UN51 or ES32 what should I be looking at.

Quite happy to do the job myself but just need a little guidance.

Cheers
CRAIG

monty_dogcp · June 2007

Your BB will be English thread, 68mm shell and the only other number you need is the length of the spindle, from end to end - probably around 110-115mm. It can get a little bit more complicated because there are two different types of tapers- an ISO taper for European chainsets and a JIS taper for Japanese and almost all others.

DODDYcp · June 2007

O.K. Thanks for the help, what of the other numbers UN, EN etc

Cheers
CRAIG

DODDYcp · June 2007

Hi again,

Just a quick warning and update.

Bought the new bottom bracket system and set about the insallation. Everything cleaned and tools ready.

Once the BB was started into the housing it started to get tight...backed it off, started again. She was going in at an angle!!![:(!] looked through from the other side and sure enough, everything was off-centre. Tried a number of times and no way was this going in.

Just as I thought about packing it up and taking it to LBS it hit me[:I] Holding the cable guide to the bottom of the frame is a small pop rivet. The inside part of the rivet protrudes into the area where the BB fits (only a little bit but enough to interfere with the BB!!!) I took my trusty Dremmel and ground the rivet down. Low and behold the BB fitted no problem.

I hope this helps if anyone has the same problem..or is this soooooo common that only a fool could have not seen the forthcoming problem.

Cheers
CRAIG

gkerr4 · June 2007

well done on fitting your first BB - I did my first last week - a bit simpler though in that it was a hollowtechII setup with external bearing 'cups' rather than an integrated axle / bearing unit.

there is some strange obsession about taking things to your 'LBS' around here but no only would I not trust my LBS anywhere near my bike with a spanner but also I find tinkering with my bike very theraputic.

I think BB's and headsets are the most complex things on a bike - everything else is pretty simple to remove / install and setup - but lets face it - even the fanciest bike isn't exactly complex - it's not as if we are bulding nuclear submarines here is it! Having done the bb last week with some advice on here I am feeling confident enough to try and do my own self build bike project.

Down the Road · June 2007

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by DODDY

Hi again,

Just a quick warning and update.

Bought the new bottom bracket system and set about the insallation. Everything cleaned and tools ready.

Once the BB was started into the housing it started to get tight...backed it off, started again. She was going in at an angle!!![:(!] looked through from the other side and sure enough, everything was off-centre. Tried a number of times and no way was this going in.

Just as I thought about packing it up and taking it to LBS it hit me[:I] Holding the cable guide to the bottom of the frame is a small pop rivet. The inside part of the rivet protrudes into the area where the BB fits (only a little bit but enough to interfere with the BB!!!) I took my trusty Dremmel and ground the rivet down. Low and behold the BB fitted no problem.

I hope this helps if anyone has the same problem..or is this soooooo common that only a fool could have not seen the forthcoming problem.

Cheers
CRAIG
<hr height="1" noshade id="quote"></blockquote id="quote">

What torque setting did you use?

romans · June 2007

Changed my BB last year as it was creaking in one spot with only a little play. Noticed that the screw holding on the gear guide plate was too long and had been schaving the OD of the bearing housing causing swarf to get into the bearings. How I hadn't noticed anything before I don't know unless the bearings had worn and the eccentricity of the BB impacted on the screw. Anyway, I used a shorter screw.

Romans

I asked the telephone speaking clock lady for a date but she doesn't have the time.

gkerr4 · June 2007

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Down the Road

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by DODDY

Hi again,

Just a quick warning and update.

Bought the new bottom bracket system and set about the insallation. Everything cleaned and tools ready.

Once the BB was started into the housing it started to get tight...backed it off, started again. She was going in at an angle!!![:(!] looked through from the other side and sure enough, everything was off-centre. Tried a number of times and no way was this going in.

Just as I thought about packing it up and taking it to LBS it hit me[:I] Holding the cable guide to the bottom of the frame is a small pop rivet. The inside part of the rivet protrudes into the area where the BB fits (only a little bit but enough to interfere with the BB!!!) I took my trusty Dremmel and ground the rivet down. Low and behold the BB fitted no problem.

I hope this helps if anyone has the same problem..or is this soooooo common that only a fool could have not seen the forthcoming problem.

Cheers
CRAIG
<hr height="1" noshade id="quote"></blockquote id="quote">

What torque setting did you use?

<hr height="1" noshade id="quote"></blockquote id="quote">

'tight' probably - who cares?

Down the Road · June 2007

Vital for bearing preload. Too loose or too tight shortens your bearing life. That is why there is a specified torque.

Basic Engineering and mechanics.

Unknown · June 2007

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Down the Road

Vital for bearing preload. Too loose or too tight shortens your bearing life. That is why there is a specified torque.

Basic Engineering and mechanics.
<hr height="1" noshade id="quote"></blockquote id="quote">
Doesn't matter on sealed bottom brackets. Over or undertightening has no effect on bearing pre-load.

Nobody ever got laid because they were using Shimano

msb123 · June 2007

dtr - do you work in a bike shop?

andy_wrx · June 2007

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Smokin Joe

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Down the Road

Vital for bearing preload. Too loose or too tight shortens your bearing life. That is why there is a specified torque.

Basic Engineering and mechanics.
<hr height="1" noshade id="quote"></blockquote id="quote">
Doesn't matter on sealed bottom brackets. Over or undertightening has no effect on bearing pre-load.
<hr height="1" noshade id="quote"></blockquote id="quote">

Agreed, that's what I was thinking.
All you're doing is screwing the thing into the BB shell.

why is it sunny all week yet rains at weekends ?

Down the Road · June 2007

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Smokin Joe

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Down the Road

Vital for bearing preload. Too loose or too tight shortens your bearing life. That is why there is a specified torque.

Basic Engineering and mechanics.
<hr height="1" noshade id="quote"></blockquote id="quote">
Doesn't matter on sealed bottom brackets. Over or undertightening has no effect on bearing pre-load.

Nobody ever got laid because they were using Shimano
<hr height="1" noshade id="quote"></blockquote id="quote">

Wrong wrong wrong wrong

Neither cup is fixed and ALL bearings require Pre load. It is a basic engineering principle. If you don't know don't assume. Yes I have 20 + years experience with bearings

Unknown · June 2007

Sorry DTR, can't see that at all.

The races are sealed inside the cartridge and the right hand cup does not come into contact with the bearing, it is just a slide fit over the cartridge and all it does is to hold the unit in place.

Try it yourself if you have a cartridge bb, remove the r/h cup completely and see how much play is on the axle. None.

Nobody ever got laid because they were using Shimano

Down the Road · June 2007

And the left and there is a spacer between That's why a torque is specified It's not done for fun. Get it wrong and shorten the component life.
Ever wondered why once you get a little play soon after you get loads.

Or do we not pay attention to these details and wait until it is completely worn out and slag it off on forums for not lasting.

Unknown · June 2007

So what happens if the shell is 10 thou oversize and it has a thick layer of paint on the faces, that throws your torque setting out a bit, doesn't it? The bearing torque is pre-set inside the sealed cartridge at the factory and the removable cup is tightened onto the face of the shell, not against the cartridge.

Nobody ever got laid because they were using Shimano

Down the Road · June 2007

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Smokin Joe

So what happens if the shell is 10 thou oversize and it has a thick layer of paint on the faces, that throws your torque setting out a bit, doesn't it? The bearing torque is pre-set inside the sealed cartridge at the factory and the removable cup is tightened onto the face of the shell, not against the cartridge.

Nobody ever got laid because they were using Shimano
<hr height="1" noshade id="quote"></blockquote id="quote">

What paint Surely the BB shell was faced as is proper procedure.

phelim · June 2007

not all LBS are dodgy.sure u can enjoy tinkering with ur bike but what happens if u strip the threads on your bb you'll have to get it rethreaded. wheras lbs should know what there doing.[:D]

pjmcg

msb123 · June 2007

you haven't answered my question dtr but if you do work in a bike shop and are as determined to regard mechanics as a black art not to be shared with the masses as you seem to be on here then you and people like you are part of the reason so many of us avoid bike shops. mechanics isn't that complicated and the people who pretend that you can't do anything without a torque wrench are wrong. i have had many thousands of miles from bottom brackets tightened by feel.

Unknown · June 2007

Torque settings are given so that you get the cups tight enough to prevent them coming loose without overtightening and damaging the threads. As msb123 says a competant spannerman can do that by feel on most componants.

Nobody ever got laid because they were using Shimano

DODDYcp · June 2007

O.K. The job is done and I am happy with the result but am now a little confused as to if it is correct.

I am in fact an engineer, I have a great deal of bearing knowledge and have built cars and other engineering item over the last 40 years but I can't get my head round this BB bearing thing. It is sealed, it requires no adjusting, it is fixed. Yes it requires torque to stop it coming out but how will this effct load. Just out of curiosity could DtR explain as I do not want an 'I TOLD YOU SO' later. Better get all the facts before I panic![:I]

Cheers

Bottom Bracket replacement

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