wphamilton

Not very clear, since "more vibration damping" and "more flex" doesn't quantify anything. My conclusion is that their "more" means "a tiny bit more" or more likely "imperceptibly more".

chaadster

What are your conclusions about climate change? No, wait...I don't care.

wphamilton

Climate change is also largely unaffected by the choice of seat post material.

colnago62

That was very funny.

f4rrest

Thread is making me thirsty!

woodcraft

I'm a fan of the Specialized carbon post w/ zert insert.

Have them on two bikes, & shopping (ebay, etc.) for one for the latest bike.

The one bolt style is kind of a PIA, but OK once set up & tightened as much as you dare.

I think it only makes a difference with a setback post, & if a fair amount of post is showing.

As far as beer, anything bottled & shipped is an alloy post compared to the smooth carbon coming from the tap at (one of) the local pubs.

jaxgtr

I love the carbon post on my CrossRip, removes a lot of the roadbuzz off my back. For $80, you got a great deal on the SL-K post. I picked up one for my ALR for $105 and thought I got a great deal, would have been nice to get it for 80.

79pmooney

I am a fan of seatposts that offer: setback to center the clamp on the rails, ease of seat adjustment and ease of replicating settings and reliability. After those requirements (which are core to tuning the engine for maximum power and efficiency), details like vibration damping, stiffness and weight come a distant second. Half of my posts are custom to get the right setback. All but one have 2-bolt clamps, allowing systematic adjustment of saddle tilt and ease or returning to the original tilt. (And can be easily done on the road, no tools needed except the Allen key.) I have two seatposts with titanium shafts.

There is noticeably less road shock felt than with the aluminum posts. As above, I have never tried to quantify that and wouldn't go far out of my way to get ti posts. It happened that the builder of these posts was also the builder of the two titanium bikes they were put on. Guess who "just happened" to have on hand 27.2 mm titanium tubing? And on ti bikes, it looks nice.

Ben

79pmooney

duplicate post

KonaRider125

I recently installed a Ritchey carbon seat post on my bike, and honestly its worth it. It really smooths out the ride and absorbs vibrations better than my old alloy post. I don't regret spending the money on this upgrade.

Campag4life

A lot of myth here. I have owned a lot of Al and carbon posts and ridden the highest end of both. I would say in a blind test, impossible to tell. I still ride both. The best current AL and carbon posts have designed flex. By contrast, the heralded Thompson post rides like a brick s&&& house compared to other softer Al posts that come from OE bike makers like Specialized. I have an excellent 2 bolt AL post that came with my new Secteur and no reason to change because it is excellent.

I find most here don't know anything about seatposts. What makes a good one? Yes flex is a big factor. But the clamp is arguably most important. Lots of crappy one bolt rotory interference clamps out there including from the OE's like Cervelo, Trek and Specialized. They basically all suck if you weigh over 150 lbs. Even my girl friend's which was torqued to spec...she weighs 115# slipped when she hit a pot hole the other day.

Best clamps are 2 bolt. Best carbon post on the market? For my money is the FSA Kforce Lite carbon 2 bolt...available in many offsets or straight.
The FSA SLK 'sucks' compared to the Kforce...same company...very different clamp design...the SLK clamp basically sucks almost as bad as a common single bolt rotory interference clamp found on OE bikes.

Blue Belly

I was merely referring to the dampening qualities of CF vs Aluminum, considering the longer length of seat posts, these days. I don't know if it's something I would feel, either. Though, it doesn't help that I ride a level top tube bike with a short seatpost. However, if you have 10-12" of seatpost above the frame the leverage & dampening difference should be, at least, minor. Enough in cycling terms...

Campag4life

Well...we just don't agree. I am sharing my experience...I do ride a lot of post. I can't feel the damping qualities of carbon thru my bum personally....and I ride both... one the Kforce carbon...one of the nicest flex carbon posts compared to an AL OE post from Specialized. Actually the saddle matters more for damping.
Btw, same with carbon versus Al handlebar...even put stem in the mix. I ride both of those as well. Can't feel any damping difference. Even new Al framesets have damping rivaling that of carbon...I have also become a believer in this regard as well. But seatpost....nope. Flex diff is more discernible. In fact, on one mountain bike I was riding, I removed the carbon handlebar because I found it less comfortable than an Al handlebar...relationship of flex to damping...flex wins the day hands down.

redfooj

bicycling is funny. one day consumers are convinced they want the stiffest seatpost. next day theyre convinced they want the most compliant post.

they've got a saddle that strains (=deflects) when pressed with a finger.
they've got saddle rails that strains when pressed with a palm.
then they've got a 30mm diameter post supporting the saddle longitudinally... but even so wouldnt bend even if they stomped on both ends along the weakest direction...

...yet theyre convinced the post makes a difference in their perceived comfort...

rpenmanparker 

I agree with having enough setback to be a able to position the saddle where it is needed on the rails, but I don't see the need for the saddle to be centered on the rails. Common 25 mm setback posts allow me to get the position I need BUT with the saddle all the way back. To center the saddle on its rails I would need about a 40 mm setback. No sense looking for that. What difference does it make if the saddle isn't centered?

dvdslw

Not for me, I tried a Bontrager xxx lite post last week that was on sale for $100 because it looked nice and weighed 140g compared to my stock Cannondale C1 post @ 225 grams, but after several attempts to tighten and apply carbon paste I couldn't get the height or tilt adjustments to stay put. I did get two rides in on the post and didn't feel that it did much in the way of dampening compared to the aluminum post.

chaadster

The FSA SLK clamp has been 2-bolt for several years; perhaps you're recalling when it was a single bolt, like back in '07/'08. I don't recall when it changed.

The 2 bolt SLK SB20 is excellent in my eperience as I mentioned earlier. I run a ton of extension, and have a lot of leverage on the post from the SMP saddle. Check the pic; if I can slam my 220lb mass against that setup and not have the clamp budge in 3 seasons, that's a pretty good indicator it's a solid choice for most riders.

RollCNY

Was the Breezer not available in your size?

f4rrest

@chaadster that saddle setback plus stem spacer stack seems like the frame may be undersized for you.

chaadster

No, they don't offer custom service, but this setup is very close to perfect; maybe an extra 5mm in front-center...maybe?? I dunno, but it handles awesomely, so I don't really think about it.

chaadster

SMPs have about 20-25mm more rail run than most saddles, so it's a visual trick; a properly positioned SI Flite clamps about mid-rail.

The stem spacing is similarly deceptive, as the head tube has virtually no rise above the top tube, whereas most metal frames (or at least steel ones, which are what I'm interested in) do. Factor that in, and the spacing is not unusual.

My main concern when selecting this frame was with handling crispness and responsiveness. I wanted a point-and-shoot bike (in steel), one that jumps, carves and cuts with alacrity, which this does. This bike nails it for me, being tighter, steeper, and just racier than anything I could find.

As I mentioned earlier, were I doing a custom build, depending on the tubeset, I might consider spec'ing an extra few-to-five millimeters in reach, maybe, but I'd be scared to mess up the brilliant handling of this frame.

chaadster

Of course perceptible flex is not the unique component of perceived comfort. Material properties, and designing to its strengths, make the greatest differences. Knock a chunk of iron on a cement floor and compare that to a similarly sized piece of wood...you'll perceive a difference. Same thing if you've ever hit a baseball with an aluminum baseball bat compared to a wood bat, or swung a metal handled ball pein hammer compared to a fiberglass or wooden one: no perceptible flex, but very different feels due to the way the materials transmit vibrations and how they're designed.

redfooj

Neither hammer nor bats have anything designed to combat shock. They have padding first and foremost for grip.

The impact of a hammer or bat strike isn't in the same order of magnitude, and isn't dampened by pneumatic tires and the chain of rim spoke fork headset frame.

I appreciate there are intrinsic material differences b/t alum alloy and carbon fiber. But it seems like the bike manufacturers could sell you guys new box springs when you complain of a stiff mattresses.

Campag4life

Hi Chad,
No I meant your design. Sorry, not a fan. A design created for cost and not design integrity. Not microadjustable...have to loosen both bolts and scoot the cradle front or back. Sounds like it has been effective for you which is all that matters. Laterally positioned bolts can't be as stable as fore/aft position bolts as principle saddle loading is fore aft. Pretty basic. Yes, your design is probably more solid than a single horizontal bolt saddle that takes a full 10 ft-lbs to keep in place...Specialized spec for their design.
But the FSA K force light is simply outstanding...light, mid flex, and rock solid 2 bolt clamp design which can be easily tweaked 1/4 of a degree by simply changing bolt torque fore/aft...no scooting or guessing.

chaadster

It may seem one way to you, and you may be right about susceptibility, but that does not obviate differences in materials performance. Carbon fiber transmits vibration differently than aluminum.

Read people who love their Thomsons; they say things like "didn't think I had any flex before replacing the FSA [carbon] seatpost, but I must have." It cuts both ways, some preferring one attribute over another, but perceptible differences remain.

RS seatpost flex -