Carbon Seatpost on Aluminium Frame

Cee-Jay-Cee

I picked up an FSA K-Force carbon Seatpost for my alum framed bike. I have a few questions about fitting it:

1. Do I need assembly paste to fit it?
2. Do I torque the seat post clamp to the same torque setting as with a metal Seatpost.
3. Anything else I should or shouldn't do before or after fitting it.

Holyboy

CJC999 wrote: »

I picked up an FSA K-Force carbon Seatpost for my alum framed bike. I have a few questions about fitting it:

1. Do I need assembly paste to fit it?
2. Do I torque the seat post clamp to the same torque setting as with a metal Seatpost.
3. Anything else I should or shouldn't do before or after fitting it.

I hate when people quote a post in the first few replies but I'd forget what you asked if I didn't:)

1. It's a very good idea.
2. Yes, it should probably be about 5-8nm unless said seatpost says different.
3. With an Alu frame and carbon seatpost you should really use a carbon seatclamp otherwise the edges of the gap in the seat tube could damage the seatpost but you can always slightly turn or even turn the seatclamp 180 degrees without any problems and I would think it would be fine but don't blame me if it breaks:rolleyes:

I've actually not ever seen a carbon seatpost break before not even Happytramps from on here and he's done EVERTHING wrong to it!

Cee-Jay-Cee

Thanks for the advice. I don't really mind if it gets marked, once fitted and adjusted I wont have any need to move it again so any marks on it will be hidden.

I'm just thinking, I don't have an allen key that fits on a torque wrench for tightening the seat clamp, can they be bought?

BubbleBalls

Hi C,

I picked up a bargain priced Bontrager carbon seatpost intended for my alu frame - should be here in a week or so.

Just wondering how you got on with yours? Did you use paste (if so which one)? Any tips?

Brads locks

About 5-8nm, that's a big difference to a 4mm bolt, caution is needed I reckon, just saying!

Popoutman

I shattered a carbon seat tube on an aluminium frame, but that was a heavy impact from my ass onto the saddle on my hardtail mountain bike! The tube was at its insertion limit, and I just landed wrong from a small jump No injuries to my backside but I defintiely needed a new tube of the correct length at that stage.

The paste will increase the grip that a patricular torque will give, so for something that isn't moved often on a road bike, it'll do no harm at all once the correct position has been determined.

BubbleBalls

The carbon post I ordered is for a roadbike. It is 400m in lenght (max for the model) and, as I am not tall, I will not be maxing on extension - and once in place I hope it will stay there for years.

I will use carbon paste as most of the posts/advise I have read recomends it, though some have not used paste and had no issues. Another tip I read was to avoid aligning the join (running up the seatpost) with the clamping side of mechanism - how practical this is (if possible at all) I don't yet know!

Nearly everything I have so far read maintains that torque should be less than that used on alu seatposts - hence the recomendation for carbon paste - but I expect the seatpost packaging will state torque required.

Any advise on what Carbon paste to use?

edit. popoutman - I replied earlier (on my phone) but think I reported the post instead of replying with quote to your post. I hope mods/admin realise.

Cee-Jay-Cee

I fitted this the other day. I used fibre paste to fit it and a torque wrench, however the recommended torque was 27-45ft/lbs which seemed way too loose and so i gave it another quarter turn or so to be sure.

The post I bought is an FSA K-force post with zero set back (couldnt get a comfortable seating position with 25mm set back and saddle full forward) Its only marginally lighter than the Deda Zero100 it replaced (230gr v 275gr) but it looks soooo nice and matches the bikes red/white/black color scheme.

Anyway I absolutely love it. I had read reviews on wiggle CRC etc etc on various CF seatposts and how they dampened road buzz and made for a more comfortable ride but thought that it was a placebo thing and that they wouldnt have had much effect on ride comfort but i was so wrong! It really does dampen road buzz on rough surface roads. I was out for a spin last night along my usual loop/route and there is one particular section of very rough tar/chips section which i normally get off the saddle for as it resonates through the saddle and spine but i decided to sit through it, just to see...and was pleasantly suprised, the post really does help on rough surfaces, there isnt the same resonance up through the seatpost/saddle anymore and more importantly, i've now got a comfortable saddle position after a year of fiddling with saddle height, pitch, position and changing the stem twice!