Does this look correct BB and fork/head bearing gap

[Tommy2]

Hi everyone, a little help please.

I am putting a new BB on to a ribble frame, it had campag mirage but they don't do that anymore, so got a centaur one which I was told was compatable, but should there be that bare metal face around the BB or should there be a washer/cover around it?

Also fitted a new headset which should also be compatable but the gap between the fork and head tube seems a little bigger than I've seen before, the lower bearing seems to be seated as far as it will go, any opinions?

I have probably done something glaringly obvious to an experienced bike builder so any help is appreciated.
Cheers

 

[accountantpete]

I'll pass on the BB but you are right - the headtube is sitting too high.

Did you change the crown race?

 

[Tommy2]

By crown race do you mean the metal 'shim' that slides on to the fork? If so then yeah.

 

[accountantpete]

It looks like an integrated headset so

It could be

1) crown race not fully pressed down (I take it you took the old one off).

2) Bearing not fully seated in headtube.

If you have the old bits you can pop them back in to see where its going wrong.

 

[Tommy2]

looks like I'll have to whip it to bits and check if its seated fully, think I binned the old one too.
Cheers Pete.

 

[e-rider]

there should be a small gap between the fork crown and the head tube - but, are you using the correct angular bearings? e.g. 45 deg bearing on a 45 deg crown race etc.? There are at least 3 common sizes. 45 being a common one. Almost impossible to tell by looking - usually it's stamped on the bearings, or colour coded seals - you'd need to know what crown race you fitted.

 

[Tommy2]

Its a 45x45 hidden headset, Crown race came with the bearing.

 

[Bob Orbell]

Hi everyone, a little help please.

I am putting a new BB on to a ribble frame, it had campag mirage but they don't do that anymore, so got a centaur one which I was told was compatable, but should there be that bare metal face around the BB or should there be a washer/cover around it?
View attachment 21771

Also fitted a new headset which should also be compatable but the gap between the fork and head tube seems a little bigger than I've seen before, the lower bearing seems to be seated as far as it will go, any opinions?
View attachment 21772
I have probably done something glaringly obvious to an experienced bike builder so any help is appreciated.
Cheers

HI Tommy2, the BB is correct, but not shure about the headset.BOB

 

[Tommy2]

Thanks Bob,
Do you think I should coat the bare metal with some form of paint or grease?

 

[Bob Orbell]

Thanks Bob,
Do you think I should coat the bare metal with some form of paint or grease?

Yes, it will look much better with some paint on it, did you put grease on the threads before fitting the BB bearing? they can be a sod to get out latter if you haven't, I have seen many with the threads compleatly trashed because of no grease, only on ali. frames.

 

[lpretro1]

The bare metal looks to me like where the frame has been (correctly) faced for extenral cups. Did you previously have these and replaced with square taper/splined? On headset looks definitely like crown race not seated properly. It should sit flat on crown - you may need the right tool to ensure it is pushed right down - you often can't get enough force just doing it by hand.

 

[Tommy2]

Yes, it will look much better with some paint on it, did you put grease on the threads before fitting the BB bearing? they can be a sod to get out latter if you haven't, I have seen many with the threads compleatly trashed because of no grease, only on ali. frames.

I was in 2 minds whether to grease it or not as it had threadlock on it so felt it might defeat the object of the threadlock to grease it as well but now I think of it I don't want the remaining threads that don't have threadlock on to seize in.

I have another frame with a campagnolo mirage BB that wrecked a tool trying to get out (and is still not out) so I think I will grease this one (not that I put the BB in the other frame).

Right so BB back out and grease, coat bare metal and remove fork to check crown race seating, should keep me busy for a bit.

Cheers people.

 

[simon.r]

Copper grease on bottom brackets has always worked for me.

 

[Tommy2]

Just took took the fork down and looked at the race, turns out it is flat in the centre but the underside is chamfered(sp?) upwards which makes it look like the outer edge is not seated properly.... Odd.

 

[accountantpete]

Having a look round my guess is that the forks/headsettube were designed for a flat bottomed crown race.

A lot of modern crown races have a lip underneath so that they can be removed without damaging the carbon.

I'd try and pop a thin seal around the base just the narrow the exposed bit.