GT Avalanche in steel seatpost size

cold steel · Jun 17, 2019

I have just bought a GT Avalanche circa 93.

The non GT seatpost size on the bike is a 27 but is very very tight. Tight enough to scratch the post as I push it in.

I have carefully re sized the seat tube to ensure it's fully round and open but to no avail.

I'm looking at buying a new seatpost in black and obviously don't want to scratch it first time on.

Anybody know what size it should be?
Am I better off getting a 26.8?

Any advice appreciated

SeeingisBelievingGTMuseum · Jun 18, 2019

Any aluminum post that's been in a steel frame for 16 years is bound top be a little tight. 27.0 is the size providing you are talking about a 93 Team Avalanche since that's the only steel Avalanche that was available in 1993.

cold steel · Jun 18, 2019

Re:

Thanks for the reply gm1230126

I can't guarantee it is a 93, but thought so as it is the only blue one I can find in the GT archive catalogue. Same colour as the Team edition, but mine does not have the Team decals on it. It could be earlier as I know after then they went all aluminium.

The rest of the decals and paint look original though. The inside of the seat tube looks pretty clean, but will do the old metal coat hanger, wire wool and a drill trick to clean it up and see if helps.

Unfortunately there is not much left original to try and date the bike, and I bought it for the groove tube frame and the fact it was chromoly.

Does the frame number date the bike?

cold steel · Sep 26, 2020

Re:

Just an update.
After cleaning the seat tube, the 27 seatpost was still wrong.

For information, 26.8 is perfect

GT Avalanche in steel seatpost size

cold steel

Retro Newbie

SeeingisBelievingGTMuseum

Old School Grand Master

cold steel

Retro Newbie

cold steel

Retro Newbie

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