Seatpost diameter 1983 Trek MTB?
01-31-11, 11:05 PM
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Seatpost diameter 1983 Trek MTB?
I need to replace the seatpost on my original Trek but the place on the post the states the diameter is worn away. Does anyone know the diameter?
02-01-11, 04:26 AM
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02-01-11, 05:58 AM
#4
a77impala
I think '83 was Treks first year for Mtn bikes. I have an '85 870 and the seat tube is 27.2 mm. I have six Treks and all have the same size post.
I just checked vintage-trek.com and the 850 was the first Mtn bike by Trek, in 1983. The only one in '83
I just checked vintage-trek.com and the 850 was the first Mtn bike by Trek, in 1983. The only one in '83
Last edited by a77impala; 02-01-11 at 11:37 AM. Reason: more info Trek mtn bikes
02-01-11, 11:39 AM
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02-01-11, 11:43 AM
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doesn't the current seatpost have the size stamped on it somewhere?
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk
“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk
Last edited by Bianchigirll; 02-01-11 at 11:47 AM.
02-01-11, 12:12 PM
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Call around and find a shop that has sizing poles(not sure what to call them) that they can insert into the seat tube to find out the exact seatpost size. You won't be able to eyeball the difference between 0.1 or 0.2mm when you line up seatpost. I tried lining up two seatpost because I had your same problem, turns out it was off by 0.4mm. It looked like they had the exact same diameter. It was only after I inserted the sizing poles that I learned I need a 26.8 vs. the 27.2 that I thought it needed.
Don't take the chance by inserting one that is too small because it will mess up your seat tube, maybe even cause it to crack!!!
See if you can find it on the vintage Trek website. Just google it. They have catalogs and a bunch of other info.
Don't take the chance by inserting one that is too small because it will mess up your seat tube, maybe even cause it to crack!!!
See if you can find it on the vintage Trek website. Just google it. They have catalogs and a bunch of other info.
Last edited by 531phile; 02-01-11 at 12:18 PM.
02-01-11, 12:16 PM
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Here's the Mombat page on it. No seatpost diameter listed, however. 
They claim it's Tange Champion MTB tubing.
Pic from Mombat:
They claim it's Tange Champion MTB tubing.
Pic from Mombat:
02-01-11, 12:22 PM
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Brochure at Vintage Trek says Tange also.
Brochure says it's an SR MTE 100 post, but still no diameter listed.
Crazy adjustability on that post!
I'm starting to think John's 26.8 is a good guess, as that's the only size I've seen that post in so far.
Brochure says it's an SR MTE 100 post, but still no diameter listed.
Crazy adjustability on that post!
I'm starting to think John's 26.8 is a good guess, as that's the only size I've seen that post in so far.
02-01-11, 12:27 PM
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Oops, velobase claims the post came in 26.6 - 27.2mm sizes.
02-01-11, 12:59 PM
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02-01-11, 01:05 PM
#12
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Wouldn't any bike shop be able to measure. Hell, I had a Performance shop do it once.
02-01-11, 01:17 PM
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Call around and find a shop that has sizing poles(not sure what to call them) that they can insert into the seat tube to find out the exact seatpost size. You won't be able to eyeball the difference between 0.1 or 0.2mm when you line up seatpost. I tried lining up two seatpost because I had your same problem, turns out it was off by 0.4mm. It looked like they had the exact same diameter. It was only after I inserted the sizing poles that I learned I need a 26.8 vs. the 27.2 that I thought it needed.
Don't take the chance by inserting one that is too small because it will mess up your seat tube, maybe even cause it to crack!!!
See if you can find it on the vintage Trek website. Just google it. They have catalogs and a bunch of other info.
Don't take the chance by inserting one that is too small because it will mess up your seat tube, maybe even cause it to crack!!!
See if you can find it on the vintage Trek website. Just google it. They have catalogs and a bunch of other info.
I ha thought these were made of a good polished stainless steel. the set I bought last year were alloy and I was a bit disappointed.
__________________
“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk
“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk
02-01-11, 05:00 PM
#16
a77impala
I bought a cheap plastic vernier caliper to measure seat posts from Harbor Freight in Austin for just couple bucks, sure saves a lot of time
trying to find the right post.
trying to find the right post.
02-01-11, 09:11 PM
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This is an '84/'85 850 and the seatpost size is 27.0. I have an '87 Stumpjumper Comp w/the same seatpost size. Awesome riding bike BTW
.
.
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'84 Trek 850--spinbackle-built, '85 Trek 670 Campy Nuovo Record--project, '87 Trek 560 SS/Fixed--project, '87 Specialized Stumpjumper Comp w/ Deore XT--Specialized-built, '87 Rossin Record, '03 LeMond Wayzata--commuter,
'?? TST Mtn Bike frame--project, '07 Tsunami Tandem--home-built
'84 Trek 850--spinbackle-built, '85 Trek 670 Campy Nuovo Record--project, '87 Trek 560 SS/Fixed--project, '87 Specialized Stumpjumper Comp w/ Deore XT--Specialized-built, '87 Rossin Record, '03 LeMond Wayzata--commuter,
'?? TST Mtn Bike frame--project, '07 Tsunami Tandem--home-built
Last edited by spinbackle; 02-01-11 at 09:16 PM.
