Author Topic: Headset + Seatpost for GT Pro Series (Read 950 times)

~nomad~ · « **on:** October 24, 2014, 12:31 PM »

Hi guys, just trying to put my GT Proseries back together, and I am a bit stuck with the headset. The 1inch threaded type I have ordered is too small, and a 1 1/8 seems too big.

I am also short a seatpost, does anyone know what size is used?

Any ideas?

That Swan Guy · « **Reply #1 on:** October 24, 2014, 12:34 PM »

What year is it?
Investing in a set of verniers will sort these problems out, they're cheap from good tool shops or even bad tool shops

~nomad~ · « **Reply #2 on:** October 24, 2014, 12:38 PM »

Its a 92.

That Swan Guy · « **Reply #3 on:** October 24, 2014, 12:43 PM »

If it's threaded it should be either 1" or 1 1/8" there wasn't any other. Have you tried the bigger one?

~nomad~ · « **Reply #4 on:** October 24, 2014, 12:46 PM »

yeah the bigger one is miles out. Verniers say 1 1/4? The seattube is 22.1mm inside measurement. Would that make sense?

~nomad~ · « **Reply #5 on:** October 24, 2014, 12:52 PM »

ok, research tells me 1 1/4 threaded headset and 22.2mm seatpost!

That Swan Guy · « **Reply #6 on:** October 24, 2014, 12:58 PM »

22.2 is normal not heard of 1 1/4"? Curious

20to26 · « **Reply #7 on:** October 24, 2014, 01:32 PM »

I think you need 32.5mm diameter headset cups - there are a lot of 1" headsets out there for narrower road bike & mini head tubes that are sold as '1" old school bmx' - but in fact they need shims to fit.

nosepickben · « **Reply #8 on:** October 24, 2014, 02:48 PM »

Ok, seat post first, a 1992 gt will take 22.2mm post. That is often referred to as a 1" post as the seat tube is 1" outside diameter.
If it has that sized seat tube/seat post, then it will need a 1" threaded headset. 1 and 1/4" is not used for bmx so either the headset you got is " not what it says on the tin " or you've not used enough force to tw4t the cups in!!