Headtube is standard - 1 1/8" Mine was 1040 wheelbase. I've owned an Orange Zero, a Koxx Levelboss 1040, a Base TA26 '04 and a Leeson Clear 660. The Saracen was probably one of the better riding frames out of that group, especially considering the price. I loved mine for the short while I had it. Was easy to get on the backwheel, bunnyhop, manual, you name it. Just a shame I got given it with a crack in it, and I practically destroyed it in 2 rides ...and welcome to full membership Lisa