OK what is it with GT seat post sizes?

[trxrincon]

Right I'm building my lopes frame up at the min and bought a nice "as new" 31.6 (the right size) post for it, it goes in about an inch then jams and it wont move, this also happened with my 98 zaskar, whats the crack? Can any one tell me what I can do? Oh its took all the paint off the bottom of the post now and I'm not happy. grrr! :evil: :evil:

 

[cyfa2809]

Hmm thats annoying!. Maybe its actually where the seat tube has been 'stretched' or whatever when a seatpost was removed as thats the bit thats flexible. 31.4?

 

[Magsy]

Same 'ere, I have two GT Lobo's on the floor, one takes the 31.6" an inch or so, the other takes it all the way

Same frame, same date, both paint stripped, both holes appear round and I've cleaned them inside the tube.

I have two seat posts, same problem.

My guess is in a previous life someone put a slightly narrow post in there and clamped it up

 

[trxrincon]

So what do I do? sand the inside of the seat tube?? Just dont want to buy another seatpost.

 

[cyfa2809]

Hmm if you can get down far enough that may work. Just dont take too much off, and grease lots too

 

[mikee]

take it to a good bike shop and get it reamed
an engeneering shop would be a good place to try too
you need someone with adjustable reamers

 

[coomber]

Buy a smaller post. Only real option if the tubes are clean. If it goes in the first inch cant be overtightened at the top of the seattube.

Offer a swap on here, someone might fancy it.

 

[the great roberto]

My M2 stumpy had a similar problem.Turned out teh seat tube was bent.Most likely from a crash.Wasa bit pist that my new shiny seatpost would not fit. Got a reamer from work and carefully reamed it out to teh corect 30.9mm.Everything was then fine.