Tech Q&A

BB External bearings - The cheap rebuild

greatwhite's Photo greatwhite 02 Aug 2008

I got a price from SKF when DR 1st posted this how to at under R20 each. Figured I'm busing working on my MTB today, so I'll do a bearing swop, called the local bearing man branch and they quoted me R118 ex VAT each. I can get complete XT assembly from CWC for the price bearing man want for 2 bearings Posted Image
 

Bearing man has yet again proved to me they want to rip the unsuspecting average man off (they quoted one of my guys in Richardbay over R7k the other day for a coupling half that I got from my usual supplier in JHB for just over R2k - my local guys even couriered it down at no charge)

Speed Devil's Photo Speed Devil 20 Aug 2008

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OK - thanks DR and others who gave tips! I have now 'resurrected' 2 BB's in the last 2 weeks. In both cases the existing bearings were not damaged in any way but were devoid of all grease.

 

I simply removed the bearings, carefully removed the seals and cleaned them out with Paraffin and then re-packed them with grease. Put it all back together and they are good to go.

 

Just as a matter of interest we are talking a Truvative GXP and a Raceface X-Type. Pretty much the same as the Shimano ones shown .......

 

Interesting that in both cases the non-drive were dry, is that cause it is 'more exposed' to the cleaning 'forces' me wonders?


 

Some bearings have a metal cap with a circlip on the one side and a plastic cover on the other side. They would be a better bet so that when servicing the bearing you can open them to clean and re-grease. Just make sure you put the bearing in the cup with the plastic cover to the outside.

 

On a NCR topic, I had to replace the bearings in the wheels on my gate last December and bought a set at Bearing man. When I tried to fit them they were about 0.02mm bigger in diameter and didn't fit. I eventually had to ream the hole out to accept the new bearing. It seemed that the wheels had non standard bearings in. Not even SKF or Timken could help.

 

ALways take a sample with when buying so that you match the bearing 100%. But I'm sure Shimano will only use standard bearings.

Bike Mob's Photo Bike Mob 09 Sep 2008

Has anyone fitted Ceramic bearnings into their OEM cups?
 

I'm specifically asking about Dura Ace

Dustbin Dog's Photo Dustbin Dog 28 Nov 2008

[quote name='dirt-rider]Here follows instructions on how to rebuild your Shimano External BB's at a cost of R30.00 (your labour excluded ) I did not use the Press' date=' puller or any other funny tools as I know most people only own a hamer and a screwdriver . OK I also used a knife but a steak knife should also work .

Tools :
1 x medium size Flat tip screwdriver
1 x rubber mullet (half a brick will also work)
1 x Knife

Spares :
2 x 6805.2RS-DYZ @ R15.00ea[/QUOTE']
 

Hi dirt-rider,

 

I am in the process of replacing the bearings of my external BB, but having trouble in locating  bearings at your quoted price R15.00ea.  I can get them @ R88-53 each.  Do you perhaps know where I can get cheaper??
sandstone2008-11-27 23:00:40

davetapson's Photo davetapson 29 Dec 2008

Zhou's Enterprise - R10.95 ea

Bearing and Conveyor Supplies - R30 for two.



You're looking for chinese cheapies (although I got Japanese cheapies) not skf etc which go for anything between R90 - R120 odd...

bduplessis's Photo bduplessis 08 Jan 2009

Where do you get the bearings?


Bearingman asks R165 for 2.

Stryder's Photo Stryder 11 Jan 2009

The owner run bearing shops sometimes have a Chinese bearing range, those prices are normally cheaper. SKF and INA bearings are good quality. 

Stryder's Photo Stryder 11 Jan 2009

It is nice to rebuild something yourself rather than buying new all the time or sending to bike shops. I stripped my Reba race the other day to take out the spacer clip and now I have 115mm stroke as apposed to the 100mm it came with.

dirt-rider's Photo dirt-rider 18 Feb 2009

After a lot of questions about the difference between LX, XT , XTR , Race Face and all kinda other cups I decided to try and get a few different ones and see if there is a difference . (Big Ben I am not referring to your funny bearings) . Since I have only bothered with LX/XT I assumed they all would be the same . Well it turned out they not the same , here follows a pictorial of what I found .

dirt-rider's Photo dirt-rider 18 Feb 2009

Lets look at the cups first . The XTR , Race Face seems to have a deeper thread .Posted Image

dirt-rider's Photo dirt-rider 18 Feb 2009

But the cavity that holds the bearing is the same

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dirt-rider's Photo dirt-rider 18 Feb 2009

So is the OD of said hole

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dirt-rider's Photo dirt-rider 18 Feb 2009

Now this means that we can use our standard chinese bearing , but there is a problem with the inner plastic sleeve if you do this . This sleeve will not fit properly into the bearing because .....

dirt-rider's Photo dirt-rider 18 Feb 2009

The ID of the bearing is smaller by .5

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dirt-rider's Photo dirt-rider 18 Feb 2009

And another interesting thing is that these bearing are thinner .

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dirt-rider's Photo dirt-rider 18 Feb 2009

That is why the plastic insert got the little lip on these things

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