Those with decent memories might remember I got my dad a Carrera TDF on sale, etc. He swapped the stock stem for a slightly shorter one from a bargain prolight deal from crc.
Anyway I fitted the stem with him and there was abit bit a headset play when rocking the bike as the new stem wasn't quite as think as the old one. We added a thin washer as a spacer and that was enough to eliminate the play.
However, when he stands to ride uphill or similar there is a slight creaking from the headset - a thicker spacer will cue this perhaps?
Any other ideas in case I am missing the obvious? (saying the bike is from Halfords doesn't count )