Author Topic: headtube & headsets diameter sizes (Read 867 times)

20to26 · « **on:** July 17, 2009, 02:09 PM »

I've noticed on some of my GT frames that some headset cups fit very loosely (like they're 1.1/8"...) and I need reducers to fit a 1" headset. Strangely I just removed a Hatta MX-II from one to fit an Epoch headset and I need reducers... $:-\$

anybody know what gives? Are there 1" headsets with different cup size diameters on the OS bikes?

thecrooch · « **Reply #1 on:** July 17, 2009, 03:23 PM »

it may be (and dont quote me on this) a road 1" headset - BMX headsets have a different size to road even though both are 1"

Chris King do an explanation that ill try and dig out in a mo....

here: http://www.aspirevelotech.com/Reference/CupSkirt.htm

20to26 · « **Reply #2 on:** July 17, 2009, 04:13 PM »

thanks for that Si, it seems odd that in this particular case I'm fitting a GT Epoch style headset into a GT BMX frame and it's not a snug fit. About 1mm out each side as the chart in the link shows. So perhaps GT made some narrower cup diameter headsets too for some reason.

thecrooch · « **Reply #3 on:** July 17, 2009, 04:16 PM »

Shim it with a coke can - always works!

tobybrown35 · « **Reply #4 on:** July 17, 2009, 07:05 PM »

had same problem dans comp do a shim 7 dollars and about 40 dollars postage

oldtired · « **Reply #5 on:** July 17, 2009, 07:13 PM »

brass sheet to make a shim,from hardware shop , comes in different guages so you can get it a snug fit, couple o quid at the most for the amount you need, failing that

Quote from: Crooch on July 17, 2009, 04:16 PM

Shim it with a coke can - always works!

+1 on that

Gary72 · « **Reply #6 on:** July 17, 2009, 11:40 PM »

I have a odyssey pro headset, and it needs a shim for BMX. Only ended up using the locking nut as that fits the threaded part fine. I think Crooch dug out the chris king thing when I asked this question.