I built up a bike from new recently and I just can’t tell if the top cap is on too tight. With all my other bikes, you put the front brake on, rock the bike back and forth and tighten the top cap until this headset play is eliminated. Even when the top cap wasn’t tight on there was no play. I’ve ridden the bike twice and there is still no play, I’m just worried that It may be overtight increasing bearing wear…
Any help would be appreciated. Regards, Rob

you are loosening the stem bolts first aren;t you?

Yep.

if it were me I’d loosen stuff of until there was play and then do it all up until there wasn’t.

easiest test for me has been;

bounce bike on back wheel with rear brake on – if anythign on the bars/forks rattles then the headsets loose.

put bike in stand and turn bars – if the sterring feels at all nothcy then it’s too tight.

The top bolt (other than to set the bearings), has nothing to do with how tight the bearings on the headset are. That is done with the stem. Once the bearings are preloaded, do up the stem, and you can take out the top bolt if you wished.

personally.

tighten it up as you would any other bolt
then back it off quarter or half turn
gently wiggle the bars to check its free
nip up the stem

The bike’s with me now. The stem bolts are loose, I’ve loosened the top cap so it can spin so no pressure, and still no play what so ever. The bearings aren’t knackered and the whole thing spins smoothly whatever the top cap bolt tension? Odd.

Then line everything up straight, nip up the stem bolts, and you’re good to go.

Sorted now. I rode the bike momentarily with the top cap very loose, this enduced some headset play, which I could then tighten as you suggested. Thanks very much for the advice people. Thanks again, Rob

Sounds like the wedgey part of the headset (that loads the bearings as you tighten the top cap) may not slide up and down the steerer very easily. Which isn’t a problem – it ensures that play shouldn’t come in too easily.