FSA headset replacement advice

[JoeM]

Howdy!

Can anyone help out with a problem I've encountered with a (self installed) new headset? Story is...

My old headset (FSA Orbit IS) was getting loose, so nipped it up only to find it was indexed. No probs I thought - it's integrated and by all account they're easy to replace! Which it was, but...

I got a new one of these, swapped out the upper and lower bearings (even compared them to the old ones and they were identical in size and shape) and rebuilt the whole stack. The problem now is that if I tighten the top bolt enough to stop any play when I have the brake on and jiggle the bike, then it's too stiff to steer! If I loosen it off so that the steering is ok, then there's play in the fork!

It's really odd - all I replaced were the two bearing units and the compression ring. All the other stuff is the same; I didn't want to use the new style upper bearing cover that came with the new headset as I wasn't sure it'd fit my steerer length.

Is it a case of book into the LBS or does anyone have any ideas?

Thanks!

 

[accountantpete]

I can think of 2 causes (the second is a tad more complicated) so the first is:

Sealed bearings have an angled bevel on the outside and inside.

These must match the angled bevels of the crown race (at the bottom) and the compression cap (ring with split in it at the top).

The usual angles are 45x45 and this is printed on the side of the bearing.

The ones you link to are 36 x45 but they also do Orbits in 45x45 - so it may be these that you need.

 

[JoeM]

Cheers Pete. Unfortunately I binned the old sealed units after I (thought I) checked that the new ones were the same.

Will most likely drop it off at the bike shop this weekend - was vaguely hoping that there was something numpty that I was missing!

 

[BimblingBee]

Blue or red seals? I'm sure you need the blue ones.

 

[JoeM]

Blue or red seals? I'm sure you need the blue ones.

The old and new sealed units were both blue if that's what you mean...

TBH I'm just going to drop it off at the LBS this weekend - could do with getting the steerer cut too (dropping the stem was the secondary reason for messing with the headset!)

 

[accountantpete]

A further check - the Orbit IS does have 36 x 45 bearings so if you had an Orbit IS before then the new one should work fine.

The only two things I can think of are

a) You have left the compression ring and seal off - these fit on top of the upper bearing and then that conical cap goes on.

or

b) The bearings are slightly less deep than the old ones

if either of the these are the cause then that top conical cap will remain still when you turn the handlebars.

 

[JoeM]

A further check - the Orbit IS does have 36 x 45 bearings so if you had an Orbit IS before then the new one should work fine.

The only two things I can think of are

a) You have left the compression ring and seal off - these fit on top of the upper bearing and then that conical cap goes on.

or

b) The bearings are slightly less deep than the old ones

if either of the these are the cause then that top conical cap will remain still when you turn the handlebars.

Thanks again Pete!

I was pretty careful to replace everything that came out of the original headset when I replaced the bearing units, so maybe they have changed the depth of the units or the ring & seal. I'll give it a look this evening and try putting all of the new gubbins that came with the new headset in. I didn't do this in the first place as I thought it might not align properly with my steerer length.

Now you mention it, I did notice that the conical cap wasn't moving particularly freely, but thought that this might be due to over-tightening so maybe that's the problem.

 

[BimblingBee]

The old and new sealed units were both blue if that's what you mean...

TBH I'm just going to drop it off at the LBS this weekend - could do with getting the steerer cut too (dropping the stem was the secondary reason for messing with the headset!)

Yep, the blue and red seals differentiate between the angle of bearing. I think you've just made a basic error somewhere. Have another go!

 

[JoeM]

Yep, the blue and red seals differentiate between the angle of bearing. I think you've just made a basic error somewhere. Have another go!

Now THAT is well within the realms of possibility! Will give it a crack.

 

[accountantpete]

Now you mention it, I did notice that the conical cap wasn't moving particularly freely, but thought that this might be due to over-tightening so maybe that's the problem.

What should happen is that the very top of the compression ring and seal should raise the conical cap so that it doesn't touch the top of the headtube.

But if either the bearing or compression ring are slightly less deep then the conical cap bottoms out onto the headtube when you tighten the star nut.

So when you tighten up everything you will find that the cone stays put but the spacers above it turn - so you are effectively using their meeting point as the top bearing (ie it will be hard to turn the handlebars!).

 

[JoeM]

Hooray - it now works!

FSA must've slightly changed the upper bearing cover; all I did was to put the new one on & tighten everything up and everything's now free and easy just like it should be!

Cheers for the help