Cause of Loose Headset?
 

Hello all,

Just lately on my bike, I've noticed the headset (FSA Orbit C40 1 1/8 - 1.5) feels quite loose. When this first started I was able to pinch up the top-cap bolt, but the fix didn't last long before the problem returned.
It's now got to the point where even with the top-cap over-tightened, the headset is still loose.

By loose, I mean I can apply my front brake and feel movement of the stem in the head tube. To try and remedy the issue, I have removed the forks and cleaned, lightly regreased and replaced the components. Strangely both sets of bearings seemed okay to me, though I've not had the experience of comparing a worn set with new ones. In any case, the inner face of the bearing housing seems to rotate relatively smoothly, and there doesn't seem to be any play in either set of bearings.

My question: even though the bearings don't seem too bad, are these likely to be the culprit? I don't fancy spending £20 on replacements to find I then need to spent another £50 on a complete headset because the issue remains.

Thanks :thumb:

Forgive me if you are doing this correctly, but you are tightening the top cap with the stem pinch bolts loose, right? Have you checked carefully to see that the head tube hasn't ovalized or cracked, allowing one or both of the cups to move? Are these cartridge bearings, and if so, do they appear to rotate smoothly? do the cups appear to be in good shape? The races too? Just trying to get as much info from you as possible so that we can properly assist.

Yes, I am loosening the stem pinch bolts first.

Cartridge bearings, yes, and they seem to rotate fine. As far as I can tell, everything seems in good condition, though the upper bearing was a little corroded when I uncovered it. Not badly - just looked discoloured probably from the ingress of water. I think the upper race was in a similar state as well. I wouldn't have thought this would have caused the problems I'm having but... I wouldn't be asking if I knew the answer!

Thanks for the prompt reply.

New bike build? Did you have the headtube faced? It is important to have them free of excess paint and be parallel to each other. You do have a tapered steerer tube, correct?

not enough spacers, bearing cups and fork race still settling to their home position, or stem not clamping firmly enough/oversized

Not a new build, no. I bought the bike about 15 months ago and this is the first problem I've had with the headset. It is a tapered tube, yes.

The number of spacers has never changed since I bought it.

The spacers need to sit 2-4 mm or so above the top of the steerer tube so the cap can be tighten up, and then the pinch bolts on the stem tightened.

+1 If you don't have a gap between the top of the stem or top spacer and the top of the steerer, you can tighten the bolt all you want but the steerer can't move upward to remove the play.

But if I've always had the same number of spacers and never had a problem before? IIRC there is a small gap between the stem and steerer, but I'll double check just in case.