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-   -   Trek Multitrack 750 Seat post size? (http://www.bikeforums.net/classic-vintage/928394-trek-multitrack-750-seat-post-size.html)

Bicycle Addict 01-03-14 03:17 AM

Trek Multitrack 750 Seat post size?
 
Hey all, Paul here I have just got a Trek 750 frame, which came with no seatpost, can someone check theirs for me? Thanks

rhenning 01-03-14 08:53 AM

I believe it is 26.6 but a cheap caliper is a better answer. Roger

rumrunn6 01-03-14 09:03 AM

I don't have a caliper but I think my son's multitrack is a 750. if I remember I'd be happy to eyeball it with a standard ruler, if that would help. but then you can kinda do that with the frame ... there must be a Trek Spec web site out there, no?

surreal 01-03-14 10:08 AM

What year? Googling has suggested 27.2, but it wouldn't surprise me if earlier examples were narrower....

kaliayev 01-03-14 10:35 AM

I have a 1990 750 and it uses a 26.8 sp. Congrats on the find, pretty sweet frames. 90-93 the 750 used TT lugged steel. After 93 the frames were tigged so might have changed sp sizing.

rhenning 01-03-14 12:31 PM

Surreal that site lists the seatpost for the earlier road bike from the 1970s called 750 not the newer 1990s hybrid 750s which this is. Roger

Lascauxcaveman 01-03-14 03:39 PM

Quote:

Originally Posted by rhenning (Post 16378548)
I believe it is 26.6 but a cheap caliper is a better answer. Roger

+1

Seriously, OP, go to the big online auction house and invest $5 on a cheap caliper. You'll use it on all your oddball seat post, quill, spacer etc, questions.

kaliayev 01-03-14 04:11 PM

Personally I think the caliper idea is not very good. Unless the caliper is calibrated and you are very proficient at measuring inside diameters, being off by just .2mm means the difference in a sp working and not working. Best to go to your LBS if you are unsure and let them determine the sp size.

rhenning 01-03-14 06:33 PM

For $10 your can buy a digital caliper from Harbor Freight (most of the time it is on sale for that) that will be accurate enough for your needs. It can be set for for both inches and metric measurement. I have high end calipers but use that one the most because I don't worry about breaking it

surreal 01-03-14 06:43 PM

I saw info on 750s' seatposts on a few sites, including this one. Google is awesome that way; buncha results. The 27.2 was for late 90s models...

Many shops have a tapered rod that they can insert into your frame to determine the size.

If the OP tells us the year, or hits up his LBS, we'll be closer to solving this, although even at this point, we can prolly narrow it down to 3 different sizes....

Hummer 02-17-14 08:18 PM

The seatpost diameter varies from year to year for this trek model. 1991: 27.2; 1993: 26.8.

My advice, if you do not know the year of your bike, or you do know the year but not the diameter for that year, then you will need to use trial and error. Start with 27.2.

bikeroader 06-11-15 06:07 PM

Quote:

Originally Posted by Bicycle Addict (Post 16378087)
Hey all, Paul here I have just got a Trek 750 frame, which came with no seatpost, can someone check theirs for me? Thanks

I'm sure by now you've already found the right seat post but if it helps anyone else, I found these pretty specs pretty detailed:
Trek, Fisher, Klein, Lemond bike catalogs, bicycle brochures
I recently came across a 1993 Trek Multitrack 720 with a wrong seat post size (using a dodgy shim), the manual/spec says it should be 26.8mm. Although I found that trying to fit a smaller 26.6mm was way too hard. The seat tube doesn't look too dirty or distorted but going to try to clean it out so see if that helps or just stick with whatever works I guess.


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