BB questions.

[Mariner]

Straying into an area I know nothing about but as I am accidentally bikeless at present thought I would build something out of the parts box.
Spare frame has a PF92 BB but as its Hope that would be PF41. Would seem an ideal opportunity to service the used BB which costs circa £75 complete if you shop around while 'Bearing World' offer replacement BB bearings and Outer Seals for circa £30 for a full set. There are no details of size of which there are two available for 30mm and 24mm crank size. The Hope page only gives their bearing part number which does not include the bearing dimensions which should be something like ID+OD+Width+a code for Sealed and a code for material type ST, STST or Ceramic and possibly an angle code if any.
Does anyone know what the dimensions and codes are for Hope replacement PF41 24mm bearings and where I can get them from without paying the ‘bike tax’? My LBS has the bearings for £23 each. Same spec bearings via an engineering bearings monger should cost around £4 or 5.

Can anyone point me at the chainline information for an XT Crankset double and single in a PF92 BB with 12 x 142 rear axle spacing please?

[psling]

Sorry for the totally useless and crap response but... things used to be so simple!!
I know I'm an old curmudgeon; even though I try to service and maintain my own bikes, stuff goes way over my head these days

Sorry

[RIP]

You and me both Peter. And stuff definitely lasts way shorter time than it used to. I'm pretty sure I've only had one new BB on me old Dawes Cougar over 30-odd years, same chainrings(!), same wheels, same brake gear (yes alright new blocks obviously), same front mech, etc.

[ctznsmith]

142 chainline is the same as 135.

[fatbikephil]

The bearings in a PF42 / BB92 bottom bracket are the same as those in a threaded external BB - 24mm ID 37mm OD x 7mm deep. There are two types angular and radial. Angular:- https://simplybearings.co.uk/shop/p2000 ... backstep=1 I think this is what hope use and they require a bit of pre load. Some BB's use plain radial bearings (Like you will find in your hub) https://simplybearings.co.uk/shop/p1528 ... backstep=1

I've tried both in a hope BB and never noticed any particular difference but the radial bearing should not be preloaded at all - just nip up the pre load ring on the crank until it takes up the slack and no more.

Enduro bearings are OK ish. I always pop one of the seals and squeeze a bit more moly grease in.

[Mariner]

ht

I found the same here for £5.99
http://www.wychbearings.co.uk/MR24377-2RS-Enduro.html

[Mariner]

142 chainline is the same as 135.

Thanks but the question I was trying to answer was to do with the spacers for double and single rings.
On threaded BBs the spacer is inboard.
On press fit the only place it can go - if required - is between the crank arm and the dust cover which means its rotating?

[ctznsmith]

Looking at the dealer manual* if you have a frame with a 92mm bb shell then you shouldn't need a bb or spindle spacer.

If you have a frame with a 89.5mm bb shell then you put a 2.5mm bb spacer on the drive side but still no spindle spacer.

*M8000 dealer manual fyi

[BreninBeener]

Mariner,
Many thanks. I needed a pr of those, just ordered them.

They are for a Trek Elite 9.8 carbon ht. When i removed the bearings, the bb shell area had about 10ml of water. There is no central tube keeping the bearings free of this water, so they just sit in it.

It seems that its probably coming down the seatpost? What can i do to alleviate this?

Thanks

[Bearbonesnorm]

What can i do to alleviate this?

Drill a tiny hole in the lowest point of the BB shell.

[fatbikephil]

ht

I found the same here for £5.99
http://www.wychbearings.co.uk/MR24377-2RS-Enduro.html

Nice one - good find

Middleburn and sram do spacers that can go on the spindle to tweak chainlines

[Mariner]

Hope just replied to my enquiry

The part code for the a single bearing is BBSP108:S and retails at £18.71 each, and the outer seal is BBSP104 retailing at £1.22 each.

Just hope (no pun intended) the wych bearings are not copies made of putty.

[BreninBeener]

Im reluctant to drill a drain hole in BB shell....frame is carbon and im the original owner...so it still has a warranty.

I guess i should have ordered more bearings!

On another note, how do i remove the seal to add more grease to bearings? It it just pop them out with the corner of a stanley knife blade?

Thanks

[ScotRoutes]

If it's a standard BBII then you should be able to get a tube to fit it. They come with every BB so it's likely folk would have a spare for your model.

[BreninBeener]

When i press the bearing in, what grease should i use?

[Mariner]

Just run across the Rotor PF41 BB.
Not seen this before but it has steel bearing cups as opposed to the Hope plastic ones.
All the reviews are positive and its half the price.
My only query is over the frame machining as plastic would more accommodating of machining tolerances
and steel would require precision limits and fits.
You not only have to press the bearings in but you also have to get them lined up or am I being too picky?
Anyone used one or replaced plastic with steel bearing cups?

[sean_iow]

Not seen this before but it has steel bearing cups as opposed to the Hope plastic ones.

The Hope BB has aluminium cups, or mine certainly does. This is the one I have in my BB92 frame

http://www.hopetech.com/product/press-fit/

Have you got a 24mm axle on your cranks? If so the Hope centre tube should fit, which is also threaded and holds the cups in the frame and prevents any creaking. A special tool is needed to install the cups and this needs for be done before fitting the non-driveside bearing. I fitted one of these BBs to my On One as the frame was a bit slack in the BB area and the original cups creaked. The central tube will stop and water that comes down the seat tube from getting to the bearings.