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What do you know about Bottom Brackets

Posted: Thu Jan 03, 2008 10:25 pm
by mikesbytes
Pulled the bottom bracket out of the OCR to figure out why its noisy. Cant find anything particular wrong with it, might be movement between the BB housing and the covers that hold it in place. I'll clean and grease everything and put it back in and see what happens.

Sticker on the BB says;
Power Pro
component
CARTRIDGE BB
7418ST
BC1.37x24T
L < 68 > R
099854

on the square taper is stamped A113

Any opinions on this BB ?

Posted: Thu Jan 03, 2008 10:50 pm
by europa
In what way is it noisy? It could just be that you've worn the poor thing out. If you've had water in there you might have grit in there causing a grinding noise.

Richard

Posted: Thu Jan 03, 2008 11:20 pm
by mikesbytes
europa wrote:In what way is it noisy? It could just be that you've worn the poor thing out. If you've had water in there you might have grit in there causing a grinding noise.

Richard


It's squeaked ever since it was band new, squirting some oil in each side seemed to stop the problem temporarily and after a while you got use to the noise and ignored it. But it irritates other riders. Basically its a fault with that particular model, as I've seen it reported time and time again.

Posted: Thu Jan 03, 2008 11:38 pm
by europa
Bung a new bb in there then, they're pretty cheap and it's not as though it owes you anything with the miles you do.

Richard

Posted: Thu Jan 03, 2008 11:40 pm
by kukamunga
Grease the threads real well. Otherwise, wear earplugs! :wink:

Posted: Thu Jan 03, 2008 11:44 pm
by sogood
Are you sure it's not the bearing in the cartridge that's gone? Examine the cups carefully and see if there's any wear marks.

Posted: Thu Jan 03, 2008 11:47 pm
by ez
I had a similar problem with a Power Pro BB, I just took it down to the LBS and purchased a new equivalent Shimano one for about $30.00. Of course the most impartant measurement is never on the bracket and that is the width of the thing from end to end, thats why you take the old one in(or measure it) when purchasing the new one.

Ez.

Posted: Thu Jan 03, 2008 11:47 pm
by mikesbytes
I could see wear marks in the cups and what appeared to be wear on the outside of the sealed casing.

Greased everything and put it back together. If it continues to squeak, I'll buy a new one rather than waste any more time on it.

Posted: Thu Jan 03, 2008 11:57 pm
by mikesbytes
ez wrote:I had a similar problem with a Power Pro BB, I just took it down to the LBS and purchased a new equivalent Shimano one for about $30.00. Of course the most impartant measurement is never on the bracket and that is the width of the thing from end to end, thats why you take the old one in(or measure it) when purchasing the new one.

Ez.


$30 is a bargain, can't get them that cheap mail order.

I suspect that "Power Pro BB" = <something I'd better not type>

I think its 113mm, based on the stampings. It is a triple and they are a little wider.

Posted: Thu Jan 03, 2008 11:59 pm
by sogood
Also suggest that you check the torque spec from Shimano. If components are not tightened adequately, your leg power may just be enough to distort it to cause problems.

Posted: Fri Jan 04, 2008 12:10 am
by sogood
mikesbytes wrote:I could see wear marks in the cups and what appeared to be wear on the outside of the sealed casing.

Could it be that there's something out of spec in terms of dimension eg. Cartridge BB? The other possibility is a bent axle.

Posted: Fri Jan 04, 2008 12:12 am
by Mulger bill
I'd go for a new one Mike, the old one would be flogged out in the 4 odd years you've had your OCR.

IIRC, 115mm is standard spindle length for a triple.

Shaun

Posted: Fri Jan 04, 2008 12:16 am
by mikesbytes
Mulger bill wrote:I'd go for a new one Mike, the old one would be flogged out in the 4 odd years you've had your OCR.

IIRC, 115mm is standard spindle length for a triple.

Shaun


So A113 must refer to 113mm

Posted: Fri Jan 04, 2008 12:42 am
by Mulger bill
Could be Mike :? Why not just take it to the LBS and ask for a replacement. At least it's not Italian threaded :roll:

Shaun

Posted: Fri Jan 04, 2008 9:43 am
by europa
Mulger bill wrote:Could be Mike :? Why not just take it to the LBS and ask for a replacement. At least it's not Italian threaded :roll:

Shaun


That's what I'd do. After stuffing about with bbs a bit this year, the easy way is to walk in with a frame in one hand and a set of cranks in the other.

Richard

Posted: Fri Jan 04, 2008 11:31 am
by mikesbytes
I'll take it for a test ride soon and see if the noise has gone away

Posted: Fri Jan 04, 2008 3:13 pm
by mikesbytes
OK, took it for a spin and it still squeaked like hell, so while I was out I picked up a bottom bracket for $35. The sticker says;

Sealed Cartridge Unit
SHIMANO
BB-UN26
VIA SINGAPORE
68 FD
BC1.37x24
L<- D-NL ->R

and on the box is hand written 112.5

Think I can survive the 0.5mm reduction

Of more interest is that the thread on the (right) drive side is part of the unit rather than being a separate component, so the unit is fixed in better. On the (left) non drive side, there's a plastic threaded cup - interesting. BTW the bolts are going to be chucked they are simply hex bolts, I'll use the exisiting allen key ones with rubber washers, I've had nothing but trouble with hex bolts in the past.

Posted: Fri Jan 04, 2008 3:51 pm
by sogood
Did you measure the axle length on the original unit? My understanding is that triples require 115mm axle length too.

Check out Sheldon Brown's page and the numerous tables. Maybe you can make something out of that. I am having difficulty. :shock:

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

Posted: Fri Jan 04, 2008 5:14 pm
by LuckyPierre
I think that Mike should be OK - there are 109, 113 and 115 'length' bottom brackets and (I think) they are for dual chain ring (road), triple chain ring (road) and triple chain ring (mtb) respectively.
ps. after another check, the UN26 comes in lots of other lengths too. :?

Posted: Fri Jan 04, 2008 6:57 pm
by mikesbytes
OK after a mammoth effort I have fixed the squeak. Those of you who have ridden with me know what squeak I'm talking about.

1. Put the new BB in. Test ride - the squeaks still there UH!!!!!! OK, it still squeaks if I stand and it still squeaks if I ride no hands, it only squeaks when I pedal. I fix 2 other known squeaks, that being the seat post and the other being the steam, just to make sure that their noise is not confusing the issue.

2. Swap the pedals. Still squeaks. mmm, it might be a broken frame.

3. Inspect the frame carefully. No visible cracks. Can't be the cleats, as the don't squeak on the beast and the squeak has survived 2 pairs of pedals.

4. Ride with no shoes on, just to prove its not the cleats. OK whats left, it only happens with pedalling, only the chain and the rear wheel left.

5. Pull the rear wheel out, take off the cassette, try in vain to get to the sealed bearings. Grease the skewer. Put engine oil on every possible crack and seal. Reassemble and test. AND VOLA, the squeak has gone.

BTW, I don't feel bad about replacing the BB, it was crap from day one and had squeaking problems from day one (different rear wheel in those days), its done a stack of K's and was probably long in the tooth.

Posted: Fri Jan 04, 2008 7:13 pm
by sogood
So what was the source of the squeak? Are you suggesting it came from the rear hub all along? Engine oil in the hub? It'll be a dirt magnet. :roll:

Posted: Fri Jan 04, 2008 7:35 pm
by mikesbytes
sogood wrote:So what was the source of the squeak? Are you suggesting it came from the rear hub all along? Engine oil in the hub? It'll be a dirt magnet. :roll:

Yip, it was coming from the rear hub when power was applied.

Your've heard the noise, sounded like bottom bracket didn't it.

Posted: Fri Jan 04, 2008 8:04 pm
by sogood
If that's the case, then is it possible that the rear hub bearing is shot? A bit of engine oil may be just temporary. Well, just glad that you've sorted it all out. Maybe there's a new wheel in the near future. Anyway, can now look forward to riding next to you again. :wink: