Seatpost Diameter for 1984 Trek 400
01-13-19, 11:02 PM
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Seatpost Diameter for 1984 Trek 400
Have an '84 Trek 400 frame and cant figure out seatpost diameter...tried a 27.2 and would start to go in but was really tight. then I tried measuring with my digital calipers but measurements were between 26.6 to 27.1 (cheap Harborfrieght one). Also, checked Vintage-Trek, but could only find info for '89 and newer 400 series which varied between 26.6 and 27.2.
So is it a 26.6 or 26.8 or 27 ???
Thanks!
So is it a 26.6 or 26.8 or 27 ???
Thanks!
01-13-19, 11:16 PM
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My 87 should be 27.2 by all accounts. It is perfect at 27.0.
01-13-19, 11:59 PM
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Flex ball hone?
If it goes in part way and stops it sounds like it needs cleaning
https://www.rockymountainatvmc.com/p...nder-Ball-Hone
01-14-19, 12:36 AM
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That bike, that year: dunno.
But about 1/2 the vintage bikes I find in my shop were, at sometime, pinched down to fit a smaller seatpost and take some spreading and honing to make right again. It's absurd how common this is. I guess I get a lot of bikes that were stripped at some point? And then re-assembled by an indifferent builder?
But about 1/2 the vintage bikes I find in my shop were, at sometime, pinched down to fit a smaller seatpost and take some spreading and honing to make right again. It's absurd how common this is. I guess I get a lot of bikes that were stripped at some point? And then re-assembled by an indifferent builder?
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● 1971 Grandis SL ● 1972 Lambert Grand Prix frankenbike ● 1972 Raleigh Super Course fixie ● 1973 Nishiki Semi-Pro ● 1979 Motobecane Grand Jubile ●1980 Apollo "Legnano" ● 1984 Peugeot Vagabond ● 1985 Shogun Prairie Breaker ● 1986 Merckx Super Corsa ● 1987 Schwinn Tempo ● 1988 Schwinn Voyageur ● 1989 Bottechia Team ADR replica ● 1990 Cannondale ST600 ● 1993 Technium RT600 ● 1996 Kona Lava Dome ●
01-14-19, 10:10 AM
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'87 used a 531 main triangle in its 400 model. My seatpost is 27.2.
But the '83 and '84 400 models used tange 2001 db mangalloy.
But the '83 and '84 400 models used tange 2001 db mangalloy.
01-14-19, 12:51 PM
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an excerpt from the vintage trek site...
Seatpost Diameter - Nearly all road Treks prior to the mid 90s have the standard seatpost diameter of 27.2mm. Exceptions are Models TX200 and TX300, which have a diameter of 26.8mm, and the Model 170 at 27.4mm. Additionally, a 1985 Model 2000 (aluminum bonded frame) with a 27.4mm seatpost has been reported.
01-14-19, 03:38 PM
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IIRC, the 1984 model 400 was a Japan-brazed frame, and may have used a 26.8mm post. Most of the Waterloo production (except the off-road frames) used 27.2mm posts.
01-14-19, 08:44 PM
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I have an '84 400. 27.2 seat post and it's pretty snug. I honed mine. fit's fine.
