Tech Q&A

BB External bearings - The cheap rebuild

greatwhite's Photo greatwhite 20 Feb 2008

[quote name='Edman]Greatwhite: the 61805 is the same size as the 6805. It appears to have a lower speed rating' date=' but since your cadence is unlikely to hit 11 000, this is probably not going to be a problem. [/QUOTE']
 

The speed rating is as a result of the 2RS1 seal arrangement, not the bearing itself (which is 24000) - reading between the lines this suggests SKF have slightly tighter seals than others - better for MTB keeping crap out, worse for drag (for those that buy into the whole ceramic bearing thing etc) - all pretty academic in the end I suspect though.

 

The highest I've ever had my cadence was just over 200, so 11000 is definately no problem...

Johan Bornman's Photo Johan Bornman 20 Feb 2008

[quote name='dirt-rider]I am not to sure about that SKF bearing size ' date=' going to bearingman this afternoon and will get info . Like Thug said I know somebody with a road bike but its got Campy . I am sure the bearing caps are the same i.e LX - 105 , Ultegra-xt etc . Maybe Johan can help .[/QUOTE']
 

Sorry, I can't help here. My bike still has old-fashioned BBs and I hardly ever get to replace other people's BBs.

 

But if someone comes up with the correct bearing size, I'll list them on my website for future reference. I have no doubt lots of people are reading this and planning on doing their next BB overhaul themselves. At least that way there will be a resource listing the replacement numbers.

 

May I also suggest that anyone contemplating doing their own BBs next time they break, keep one backup BB in stock. This way, when your BB packs up (Ialways on a Sunday), you replace it with the one you've recently overhauled and fix the old one in good time when the shops are open.

 

 

 

dirt-rider's Photo dirt-rider 20 Feb 2008

I went to my LBS yesterday and asked the mechanic for old bearings . He got 4 outta bin for me .

AndreZA's Photo AndreZA 20 Feb 2008

Look at the top Google ads for this thread.
 

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Racer X's Photo Racer X 25 Feb 2008


Brilliant post!Posted Image


 


As anybody tried this with a ISIS BB?


 

Yes I've done it. Takes a little longer as there are more seals and bearings but it is quite easy.

The Guy in Pink's Photo The Guy in Pink 25 Feb 2008

erm, not related, does anyone know where i can get el- cheapo bevel gears? just to play around with


 

The guys who make taper lock pulleys - Fenner I think they are - also make gears and sprockets. Ask your local bearing shop if they have a catologue .

GoLefty!!'s Photo GoLefty!! 26 Feb 2008

[quote name='dirt-rider]I am not to sure about that SKF bearing size ' date=' going to bearingman this afternoon and will get info . Like Thug said I know somebody with a road bike but its got Campy . I am sure the bearing caps are the same i.e LX - 105 , Ultegra-xt etc . Maybe Johan can help .[/QUOTE']
 

The Xt and XTR bearing cups are a size unto themselves. LX, 105, Ultegra and Dura Ace are the same and marker "Road"

 

XT and XTR are marked "Mountain"

 

LX is also marked "Mountain" but it's the "ROAD" cups width which is 1mm wider than the "Mountain".

 

also when you replace the bearing make sure that they are caged and sealed bearing. Full complement bearings will not last very long.

greatwhite's Photo greatwhite 27 Feb 2008

 

also when you replace the bearing make sure that they are caged and sealed bearing. Full complement bearings will not last very long.


 

thats what the .....2RS at the end of the designation means

 
greatwhite2008-02-27 02:27:21

GoLefty!!'s Photo GoLefty!! 27 Feb 2008

Yes you know that, I know that but there are many people who won;t read this and will hear by word of mouth and will ask for "bearings"
 

Knowing the generic term is often less confusing for the layman

greatwhite's Photo greatwhite 27 Feb 2008

Yes you know that, I know that but there are many people who won;t read this and will hear by word of mouth and will ask for "bearings"

 

Knowing the generic term is often less confusing for the layman


 

Hmmmm.. Posted Image Maybe I should have worded differently - as long as someone orders the bearing with a 2RS designation they'll get seals both sides (this is aimed at others who didn't know)

 

Pocketbikes's Photo Pocketbikes 27 Mar 2008

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push the rest of the bearing . If you have not got a vice then two pieces of wood and a g-clamp works just as well . Use the old bearing to push the new nearing in untill it seats .


A great step by step "how to" Posted Image

Another small tip to try... if you are nervous with pressing and hitting (you shouldn't) on the new bearing. Place the bearings in the fridge before you start stripping. This will let them cool down nicely and shrink slightly.Place the caps in a pre-heated oven at 100 deg for about 10 mins. If you line the bearing up nicely, it will just slide all the way in. Done. Once you have placed the bearing, push it all the way in one movement. Don't hesitate, as the bearing will expand with heat and the casing will shrink as it cools, and it will then sit half way.

NotSoBigBen's Photo NotSoBigBen 12 May 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?

dirt-rider's Photo dirt-rider 12 May 2008

Deposit some money into the relevant bank account

paulvs's Photo paulvs 21 May 2008

Thanks or the tip...

What BB sizing do we use here in SA - British or Italian?

paulvs2008-05-21 13:30:40

halliburton's Photo halliburton 21 May 2008

What have you been painting green?

Matchstix's Photo Matchstix 13 Jun 2008

I redid my FSA ceramic bearings. the only problem was that the plastic cup was worn through. you can get them from FSA through a bike shop. and shoul fit on normal shimano. the difficult part is to ge the right part code. mine was not the correct ones but with some modification with a carpet knife and a o ring, they are working 100%