Anyone know of a good on-line guide to help me through the process of removing and replacing the bearings on a Hollowtech II bottom bracket?
Thanking you.

Whack 'em out, whack 'em in!

http://www.enduroforkseals.com/sitebuildercontent/sitebuilderfiles/hollowtech2a.pdf

Unscrew the old ones. Screw in the new ones. Make sure you've got the spacers in the same places as you had originally.

Simples

Your options are:

Replacement Enduro Bearings from BETD…

Bin the crappy Shimano BB and buy a Hope (or CK if you’re feeling flush)…

Go back to Square taper cranks…

That is all…

the new Pace ones look quite interesting – Hope pricing but with a grease purging facility.

This is the way to go if you don't have the proper tool:

http://www.mountainbikerides.co.uk/fettling/hollowtech2bb.htm

I also came across this with some interesting stuff about MAX bearings:

http://www.peterverdonedesigns.com/bikebottombrackets.htm

I bought a deore BB for under £20 and a set of replacement bearings off fleabay for £5 to rebuild the XT so I got a spare.

I got a deal from BETD where you bought 5 sets of bearing s and got the removal tool free…. you need to supply your own sledge hammer though!!

Easy – have a look on the Hope website – in the tech section there is a video showing you how to fit and adjust etc

Found this last night, which is just what i was after:
http://www.mountainbikerides.co.uk/fettling/hollowtech2bb.htm
Sorry that i wasn't clear enough in my OP, but some of you got what i meant anyway 🙂

Ah, Duncan, yes… You were already there with that site. Thanks 🙂

I used eBay bearings for a fiver. Been going really well for me and it'll take a lot of these before you paid back a CK/Hope, or XT even.

I used a thin blade to carefully life the black flanged spacer out, then a splayed headset cup removal tool to get a purchase on the inner race and tapped them out as you would a headset cup. Tapped new bearings in. Job's a good 'un!

ebay bearings for £5?

I've got an old shimano that could do with being re-conditioned for use as a spare…

link please?

Am I right in think it’s a 6805-RS (25x37x7mm, single rubber seal) bearing?

cookeaa is right google or ebay search 6805 2rs (also known as 61805) the bearings are 25 X 37 x 7 , better off with rubber seals on both sides. The only problem is that shimano/raceface/fsa and others use the 0.5 mm plastic spacer which is dead easy to break on removal. The crankshaft is 24mm so the 0.5 mm spacer takes it up to 25 to suit the bearing. I have thought about why shimano did this, why didnt they make a 25mm crankshaft? I cant convince myself if its sensible or not. Maybe its becuase the plastic wears out before the crankshaft so its just new bb on bearing failure rather than new crankset – and its a lighter shaft, maybe they didn't want to commission a new bearing size just to suit their needs. Or maybe they are just mad..

Enduro bearing is 24 x 37 x 7 bearing so no spacer, and there is no bearing number for this (at least not that I can find) its some kind of speciall that norm,al bearing suppleirs cannot get. But a pair are on BETD for 20 smokes. I think the hope and pace ones use a 24 id bearing like enduro and maybe phill wood, but I'm not sure.

toys19 – yes, the idea is if the bearings seize that the crank isn't knackered too.

wwaswas – Premier Member

toys19 – yes, the idea is if the bearings seize that the crank isn't knackered too.

Shock horror shimano acts to save punters money!

One thing that troubles me, is the enduro bearings dont have top hats, so wont the crank arms not sit too close to the bearings / bearing shell?
Oh and how the fxck do you get the plastic top hats off shimano bearings without breaking them?

bigyin, i was thinking of soaking them in hot soapy water first. Thought this might help?

Yep pretty sure my Hope doesn’t have the 0.5mm plastic spacer so must be a 24mm OD, same thing I think with the Enduro replacement bearings…

Is there any way of sourcing a replacement for the plastic axle spacer? I don’t need one but just interested like, no part No shown on any of the Shimano Crank exploded diagrams, is there a separate data sheet for the BBs?

I'm sure I looked at all of this a year ago…

enduro supply spacers with each bearing kit to suit.

clicky

I looked for the plastic spacers too, no joy.

I think the crank wearing thing could be a non issue.. I mean spacers are not present on any other cartridge bearing installation – like hubs.

Personally I've got shimano hollow tech on my FS that have lasted 3 years so far and had race face on my HT that failed in 3 months. Just about to fit the enduro ones so I'll tell you how long they last..

Guess what I looked on crc for the new pace BB – this close up shows a lovely enduro bearing in place pace rc80

The Phil Wood ones use top hats for the very reason above. Lots cheaper than a new chainset if the bearings seize.

You can replace the bearings on one of these (if they wear out).

Phil Wood OBB

Group buy on one of these:

bb bearing tool

I don't supose anyones tried THESE yet?

BETD also have a tool similar to that.

A quick squizz at the phil wood website shows that they do replacement top hats too.

Sideways tim are you going to start stocking the top hats and the phil wood tool?

I don't supose anyones tried THESE yet?

Yup, I have. Been in 12 months now. Never been touched, and still running nice and sweet. From my experience I'd say they are very good.

toys19, cant find it on thei website… you got any info?

toys19, cant find it on thei website… you got any info?

It's not on the website, you have to ring them.

why would you buy that overpriced tool just to change some cheap bearings the whole object of the excercise is to save money I will be using:

+

+

+

fair enough, will do.

Yeah, give 'em a ring. I've got one, it's not quite as "full featured" as the Enduro one, but has all the basic tools you need

BETD also do a little extra clip that catches the inside edge of some bearings which are harder to get access to – like raceface. Of course my experience on this is theoretical, I've just ordered the tool today and haven't used it.

BTW as turneround mentioned if you order 5x set of enduro bearings then they will give you tool for free. Which is what I've just done so potentially I'm gonna ruin 5 sets of cranks if the bearings seize 😀

I'm not overly worried about the bearings seizing problem :

1) Keep an eye on them check for play etc..
2) I'm fairly sure the plastic sleeve is made from a glass fibre/partice reinforced polyamide such as grivory, this is about the only injection moulding polymer with enough stiffness to do the job. These glass reinforced polyamides are abrasive as hell, injection mould tools do not last long when using this stuff. So if it does seize then it might do just as bad a wear job on your crank. My raceface ones which failed quickly polished the living daylights out of the crank arm so I'm not sure.

Lets find out what happens…

I changed the bearings in my KTM motocross bike's engine a while back. The advice I was given was to put the engine halves face-down in a hot oven (over 200 deg C) for a while as aluminium expands faster than steel. The bearings literally dropped out of the aluminium onto the floor of the oven.

I reckon heating a HTII bearing shell should do the same. Have the replacement bearings in the freezer at -20 so they should just drop straight in while the ally shell is still hot.

Much kinder than hammers, sockets and the like.

TBH you can bodge the removal tool tool fairly easily using sockets etc, although the Enduro Collett tool might be worth a punt for $10, could save a lot of grief trying to get behind the shoulder in the shimano cups to push the old bearing out, shame they're out of stock tho.

@ shedfull, that sounds interesting and potentially very useful info indeed. I presume 200 degrees wouldn't harm the ally BB shell?

check this out for the ultimate Shimano BB mod, a STW forum user, stand up and take a bow David!!

http://s282.photobucket.com/albums/kk243/covehustler/?action=view&current=gresaeports1.jpg

A section cut through what he had done.

http://s282.photobucket.com/albums/kk243/covehustler/?action=view&current=halfBB.jpg

out of interest how much is the bearing too from betd…

I dont need 5 sets of enduro bearings… I get the 6805's for 1.20 each.. (skf ones)