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help - GT Vengeance, 25.0mm seat post(5 posts)

help - GT Vengeance, 25.0mm seat postvenga venga venga
Nov 17, 2003 11:27 AM
hey all. i just picked up a GT veangeance TT bike (from the classifieds) and the bike is in good working condition. no cracks, plenty of paint chips but still very rideable. one thing that was missing, however, was the proprietary seatpost/seatfairing. the previous owner (2nd maybe third owner) said that it came this way and he didn't have it. anyway, he had it set up with an american classic 25.0mm seatpost with standard setback.

to make a long story short, do any GT Vengeance owners (Akirasho) know the exact post diameter? i want to replace it with less to zero setback as the original had too much. the only post i could find was the look ergopost 25.0mm. are there any other posts out there?

thx
Thomson makes a 25.0 (nm)TJeanloz
Nov 17, 2003 11:42 AM
that must be newcollinsc
Nov 17, 2003 12:13 PM
I was sure they didnt, but, sure enough...

http://www.lhthomson.com/SPpartslist0.asp

SP-E156 * 25.0 diameter by 330mm long
I've been edjumakated...Akirasho
Nov 17, 2003 12:01 PM
... sorry vengaX3... but it's been a long time since I've been inside that post... and since it's proprietary, I never bothered measuring it... indeed, I didn't even know that you could shove a 25.0 in there!

How does the current post fit? My suggestion would be to set a caliper on the frame's internal post and go from there... it would seem that you've got few options in the 25.0 range.

FWIW, the original post... or moreso, the saddle interface can be a bit finnicky to dial in... which might explain why it disappeared... and why I'm reluctant to pop mine off for a measure!

Be the bike.
the 25.0mm post...venga venga venga
Nov 17, 2003 12:48 PM
...feels like its a good fit. there seems to be just a tad of wiggle which leads me to believe that the seat tube may receive a 25.4mm. i tried getting some calipers down the seat tube but it is kinda deceptive. around the collar of the seat tube i measured 26.0mm but if you look further down, there is a shim and a thin curved plate that binds the seatpost when you tighten the 3 set screws (i only have 2, the lower most screw threads were stripped out). i can't get the calipers down far enough to get an accurate reading.

the bike screams speed! but man it is the loudest bike i've ever been on. it seems the frame transmits all the drivetrain noise. i get loud CLUNKS whenever i shift. who cares though. i 'll be only doing, at the longest, 40K TTs anyway. i've already made a fairing out of some thin black polycarbonate from TAP plastics to cover the void.

thx