warrenroadie

Does anyone know torque spec on Trek carbon fiber frames on seatpost clamp? I have a 2002 model 5500. Never had any movement until I purchased and installed a Thomson seatpost last night. I torqued to 70 in/lbs and post can still be moved by bumping with hand. Never had any problem with Bontrager C/F post torqued at 70 in/lbs. I cleaned seatpost with degreaser below insertion point before installing. There is 150mm exposed post above seatpost clamp on a 250mm seatpost.

my58vw

Ask your trek dealer?

msheron

You may need a seat post shim.

patentcad

There is no greater weenie indicator than using a torque wrench to tighten down a seatpost clamp. I hope it's electronic : ).

55/Rad

I have an '03 5500 that had the same problem with a Thomson Elite. I solved it by going to a skewer on the seat clamp - incrementally tightening it just a hair more until it held.

55/Rad

cydewaze

Funny you guys mention this. My old OCLV was fine, and when I got the new frame, I got this snazzy Campy seat post clamp. It was also fine, until I got my nice new smooth-n-shiny black seatpost. The thing dropped 1-1/2" in the first hour I rode it.

I've since cleaned it, and have tightened the clamp a bit more. So far so good, but I'm keeping an eye on it, because the clamp seems really tight.

TomMc1

The road bikes I'm looking at are carbon and have carbon seat posts... I asked one guy at my LBS about lubricant and he said that it was needed on carbon. I don't think he is an expert but you may want to check with your Trek dealer or the seat post vendor to be sure you aren't damaging the materials by using an degreaser or a lubricant.

alanbikehouston

"Cycling Plus" recently tested a road bike with a carbon frame and carbon seat post. The seat tube had a crack, and the entire frame had to be replaced. The editors concluded that someone (NOT someone at CP...no way) had tightened the seat clamp and did NOT use a torque wrench.

The Trek web site has links to PDF's of the owner's manuals that include the torque wrench specifications. But, there is no need to follow Trek's procedures. Only a "weenie" would actually bother to assemble a bike correctly, right?

kahn

As someone mentioned Trek's site or the cd that came with the bike has the specs:

Seatpost binder:

Alum seatpost: 85-125 lb-in/ 9.6-14.1 Nm

Carbon fiber seatpost: 65-80 lb-in/7.3-9 Nm

This was for my Trek Madone but it might be applicable across models**********?

Sheesh, they don't make it easy to re-find the link. No search functions.....

https://bike-manual.com/om/trekbikes/...ifications.htm

Trek Torque

warrenroadie

Thanks for information. I called Trek dealer and spoke with mechanic. He said just to use good judgement and not over tighten. He also said he did not know of a specification on seatpost torque. I'll be sure to pass along information to him.

nsiegel

Do not use lubricant on a seatpost going into a carbon fiber seat tube! Universally, carbon bike manufacturers and tech experts (do a search under the Velonews website tech contributions written by Leonnard Zinn) do not advocate using a lubricant. Your seatpost will slip, and you will not be able to tighten the clamp enough to prevent this.

wagathon

I had the same problem with the stock Bontrager post but a FSA CF post that I already had--and had used on a steel bike--apparently, the FSA post was not as slick and worked fine.

warrenroadie

Just for your info, Thomson recommends to clean posts and stems before placing them in service. They are shipped with greasy/oily substance on parts.