Carbon seat post - what length is worth it?

ne0sk

Hi folks

Just bought an old Cannondale CAAD4 R500 as a winter trainer to keep my carbon baby happy.

58cm frame which is slightly bigger than I would usually get (56cm) but it has a more relaxed headtube and fits perfectly.

Expecting a hard ride so I'm considering a carbon seatpost to take the sting out. However, there is 140mm of seatpost exposed above the seatclamp (measured to centre of saddle rails) so wondering if a carbon post is worth it, ie will this exposed length be sufficient to give adequate flex?

This may be a daft question but thinking the "physics" through it has got me thinking.........

Thanks in advance

Bar Shaker

A carbon seat post has a very thick side wall to cope with high compressive loads and high lateral loads. It will not absorb any vibration at all.

Save your money and buy some Assos shorts.

imposter2.0

or some wider tyres...

foggymike

I have a caad5 as a trainer (also 14mm seatpost exposed) which is the same frame with an integrated headset. It's not harsh, just a little firmer than a good carbon frame which I like as you feel very connected to the road. Save your money and just stick on a cheap alu post. I agree the saddle/shorts/tyres will all make more difference to comfort than a seatpost anyway.

garethclarke

I had a CAAD 4 R500 as a winter trainer for a few years. With a fairly cheap FSA alloy seat post and 25mm tyres it gave a fairly smooth ride even over some very poor road surfaces (better than the Planet X superlight I had before it). In the end it was the lack of mudguard clearance and incredible amount of BB flex that meant it had to go.



p.s. also worth noting that some of the tubes on those old cannondale frames are wafer thin, I ended up with a dent on the top tube after the bike fell against another bike in my hall.

cycleclinic

Carbon seatposts do not improve ride comfort. I have a quite a heavy aluminium Pinarello Monviso with a cheap heavy alloy post but 27mm tubular tyres. the bike glides over lumps and bumps well it glides as much as a bike can. Wider tyres (vittoria open paves) and lower pressures will help a lot more.

ne0sk

Thanks everyone.

Money well saved......