After a service my bike's steering has a "groove".

garnett

Yeah, as you might be able to tell, I know very little about bikes. I recently took my 5 year old Trek 1200 into a bike shop because the bottom bracket seemed to be "ticking".

They recommended a service as well as looking at the BB.

When I collected it, they said the BBhad apparently been fittred without grease, and that it had been cleaned and greased.

They seem to have worked a miracle and stopped the ticking but now my steering seems to stick in a groove going straight ahead. There is some new additional resistance when I turn the handlebars.

This resistance is pretty minimal.

What is causing the steering to behave like this?

Thanks for any help.

rhext

They've overtightened your headset. Either take it back, or have search on the internet for 'headset adjustment' and do it yourself. Takes about 30 seconds!

jomoj

to adjust your headset:

undo the two bolts on the stem, loosen the bolt on the top cap by a eighth to a quarter turn.
Hold the wheel steady and give the bars a wiggle to release the compression in the headset.
Straighten the bars up and test for stiffness in the headset.
If its ok then tighten the stem bolts up but not the top cap.
Check it's still ok once the clamp is tight. If yes, job done

If no, then loosen the top cap a bit more and repeat.

If you go too far and there is play in the headset, do the same thing but tighten the top cap gradually.

keef66

Alternatively they've preloaded your headset correctly but it's worn a little and self-centres due to false brinelling (sp?) where the ball bearings create tiny depressions in the races?

Monty Dog

I'd suspect that the headset is worn and that by cleaning / greasing it the notchiness is more apparent. Greaseless headsets and BBs are pretty common with Treks - they come that way from the factory IME.

Berk Bonebonce

Good quality grease is hard to come by in Vietnam.