Pressfit BB swap - home job or LBS?

larkim

Son's Canyon Nerve has developed play in the bottom bracket, which I'm fairly sure is a pressfit one. I will remove the crank at the weekend to have a better look, but assuming my memory is correct from the last time I looked at the BB, how challenging is removing and replacing a PF BB for someone who hasn't done any pressed fittings work previously?

I'm not utterly incompetent, but obviously don't have the tool at home (nor have I experience in making one with a threaded bar etc, though I might do this at some point for a headset press) and seem to remember potential for horror stories of removing and fitting these.

So, LBS or have a go myself?

larkim

Googled and found myself asking this previously (I knew I had some recent recollection of the BB being on its way out).

viewtopic.php?t=13079116

larkim

Continung the theme of answering my own thread...

Its a BB92 pressfit BB I need (and have ordered one). This tool http://www.chainreactioncycles.com/x-to ... d|567747UK seems to suggest it only does BB86 but I thought the 86 was effectively the same (just not as wide) as the BB92? For £32 will not be far off the labour charge from LBS.

Alternatively this http://www.ebay.co.uk/itm/BB86-BB92-bot ... DNuNF6i1Hw is cheaper and appears to be spot on in terms of the spec that I need. I could of course make my own, but the shaped press ends appear to be "advised" (if not necessarily necessary).

Thoughts?

trek_dan

BB92 easy enough to do without any specific tools. If the old ones already knackered just bash it out with a hammer and chisel. New one should press in a decent way just using pressure from your hand then use a wood chock to distribute pressure evenly and send all the way in with some careful hammer action.

larkim

Thanks Dan - I've read that applying pressure flat to the face of the BB is possibly a "no no" which seems to be what necessitates a tool. Is that just excessive caution do you think? Don't want to end up with a misaligned BB and then knacker the cranks too as that would be bit more expensive.

Lookyhere

trek_dan wrote:

BB92 easy enough to do without any specific tools. If the old ones already knackered just bash it out with a hammer and chisel. New one should press in a decent way just using pressure from your hand then use a wood chock to distribute pressure evenly and send all the way in with some careful hammer action.

get the park tools bb90 tool, similar money to the CRC tool but it will remove as well as fit the bearing, you just need a bit of threaded bar, the cups used to press the bearing in are shaped to avoid pressure on the new bearing.

On the Grand Canyon i ve got, i use silicon grease, which is what Canyon recommend, otherwise, it creaks.

swod1

Cant you use a large socket from one side to gently tap out the cups or even the bearings and just change those?

figbat

I did the BB30 on my 'dale with no special tools. Getting the crank out of the bearings was the hardest part and needed a very persuasive tap from my big hammer (shielded to prevent damage, of course). After than I just drifted the old bearings out and then use the outer race of the old bearing as a drive to drift the new ones in. Took it steady and tapped all around the circumference and both sides went in square. I'm sure a bearing puller and press tool would have been quicker/easier but I didn't have any and the method I used was identical to how I had done motorcycle wheel bearings in the past, with no issues.

I had thought I would freeze the bearings and heat the BB shell to aid re-entry but in the end I forgot (and never needed to).

ryan_w-2

I bought this: http://www.chainreactioncycles.com/park ... d|546369UK

Perfect for removing the existing BB, and comes with BB cups which I used on my DIY threaded bar install tool, which I made for £7 from B&Q.

larkim

Crank comes out OK already so not concerned about that. Bearings are in a plastic surround, so I don't think just sorting the bearings would do it. And for £23 for the XT BB I might as well remove the lot.

Can't use that parktools set I don't think as it isn't sized for a BB86/92 is it? BBright isn't quite the same as the 41mm BB92 I'll be fitting if what I've read is correct.

I think I'll try the hammer and chisel slow but steady approach to remove the existing, and then the £17 kit to install from ebay if step 1 goes OK! I'll try to remember to take pics and post here if successful just in case its helpful for others in the future.

ryan_w-2

My bad for not reading the post correctly... This one should do the trick and comes with the correct cups: http://www.chainreactioncycles.com/park ... prod142345

Lookyhere

larkim wrote:

Crank comes out OK already so not concerned about that. Bearings are in a plastic surround, so I don't think just sorting the bearings would do it. And for £23 for the XT BB I might as well remove the lot.

Can't use that parktools set I don't think as it isn't sized for a BB86/92 is it? BBright isn't quite the same as the 41mm BB92 I'll be fitting if what I've read is correct.

I think I'll try the hammer and chisel slow but steady approach to remove the existing, and then the £17 kit to install from ebay if step 1 goes OK! I'll try to remember to take pics and post here if successful just in case its helpful for others in the future.

http://www.parktool.com/product/press-f ... t-bbt-90-3

larkim

I always resent paying more for the tool than for the part - particularly as I don't have any other pressfit BBs in the household, so money spent on this could be for a one off job (the existing BB has lasted over 2.5 years and in 2.5 years time the owner of the bike can pay for this stuff himself!). But I will mull over the very sensible suggestions!

ryan_w-2

It'll cost more to get done by a LBS than buy a tool you'll have forever.

larkim

Probably true, but it could well be that I only ever press in one BB in my lifetime! Still waiting for the LBS to give me a price on installing it for me, mind you.

Shelled out for the cheap BB tool in the end for the fitting. On the basis that the BB is knackered already, chisel and soft mallet will have to do for removal.

larkim

BB is out. At first took a fairly narrow wood chisel too it, as that sat nicely on the back side of the cup, but after a few significant whacks it started to disintegrate as the chisel was too sharp and the plastic too easily damaged. So had a quick rethink, and ended up with a 10mm (I think) socket mounted on an extender bar so the impact was more broadly spread, and that soon pushed out the first side, and the second side was much quicker and easier once the socket had been settled on as the tool of choice.

Cleaned everything up, and now just waiting for the postman to deliver the BB. Ordered the XT one -
http://www.chainreactioncycles.com/shim ... prod135902 - no idea if it is any better or worse, but at £23 they all seemed to be the same price point. Mixed messages seem to be available as to whether to use a small amount of grease when installing to prevent creaks etc but will err on the side of caution and use some, even though with plastic on metal there can't be any corrosion issues to worry about.

larkim

All fitted easily last night. The BB had some excess grease around the cartridge (factory grease) so I smeared a thin film of that around the outside of the cups before pressing in with the ebay too. 5 minute job, crank took a small amount of persuasion with a rubber mallet to move home, but all back together and running smoothly.

So in summary, simple job even for a numpty. Just take care to ensure that the BB shell isn't damaged if removing the BB with a non-specific tool, and whilst I'm sure the more expensive tools to fit it would be "better", the one I used seemed perfectly fine.