Jackmen

I have started doing some gravel riding and have had back issues in the past and was looking at the possibility of using some type of suspension seat post with my gravel bike to eases the pounding on my back. Gravel road in middle Missouri are sometimes very rough and punishing on my body.

I have looked at several types and eliminated the pure spring tube type as the stiction issues as well as the varying height doesnt work very well.

I like the thud buster st but its kind of heavy and has a minimum length of 100 MM which may be an issue on my gravel bike.

Other types included split post carbon style that are a somewhat passive movement.

I would like to get input from other gravel riders if they have used any of these or have other options that have worked on your gravel rigs to smooth out the ride.

chas58

I love the thudbuster, but it does require a compact frame. I bought one for a tandem and liked it so much I bought a couple more for my road and gravel bikes.

the body float looks to be the best out there, but given the cost I'm not sure it justifies the advantage over the thudbuster for me:
First Impressions: Cirrus Cycles BodyFloat Seatpost | GRAVELBIKE

Suntour one seems to get a lot of good comments by people too:
SR Suntour SP12-NCX Suspension Seat Post Review | Tour on a Bike

overview:
https://www.electricbike.com/suspension-seat-posts/

I do have a specialized cg-r. but that thing is about worthless (unless maybe for weight weenies)

chas58

What tires and PSI are you using?

Between running softer PSI (34-50) and a good saddle (brooks or something with carbon rails), that helps a lot too!

dabac

I've got a thudbuster ST on my XC MTB. It works well to ease saddle hotspots on long choppy rides.
Not so sure if it'd soak up enough to ease back troubles too.

ksryder

Spesh designed the CG-R seatpost specifically for the gravel version of the Crux. Like all things spesh it's $$$$

https://www.specialized.com/us/en/co...eatpost/105098

KonaRider125

Have you looked into the Niner RDO carbon seatpost? Designed to flex enough to improve comfort while riding, next on my list of bike upgrades.

Kopsis

I found that going to a Brooks Cambium saddle on a conventional seatpost made a huge difference in comfort on rough roads/trails. With the Cambium you're basically sitting on a thick rubber hammock. The saddle feels nice and firm on smooth roads while offering plenty of flex to smooth out the rough stuff. With the Brooks saddle and a set of 43mm tires at 25/30 PSI, I've ridden many miles of pig-rutted grass trails where the *only* things that didn't hurt at the end were my back and butt Good suspended leather saddles offer similar, if not better, performance if you can live with the break-in, protection, and upkeep.

Werkin

I have the CG-R and Thudbuster ST. The Thudbuster has better compliance of the two, but the downsides are ballistic return and increased bounce at high cadence. The CG-R performs well with few drawbacks.

chas58

my CG-R didn't seem to soak up any bumps. The Thudbuster ST does great. Never had ballistic return or increased bounce problems (although I spin up to 150 rpm, and that requires me to be pretty smooth).

Henry III

I've had and really liked the LT Thudbuster on a previous bike. Though I run an old RockShox suspension seatpost on my Bianchi single speed gravel bike but it was dirt cheap and adjustable. No hating here on suspension seatposts. Heck they don't come on "Comfort" bikes for nothing. Lol.

phatfree

I also use a Cambium on my GG and highly recommend it if you can ride one. If you have a saddle that already fits you the Thudbuster will not change that contact point. I would not worry too much about the weight of the Thudbuster if you decide to go that route. Would the extra weight be justified if you are pain free after a ride?

dgodave

What drawbacks do you notice?

I have a CG-R on my AWOL, and I'm quite happy with it so far.

Werkin

Drawbacks: high initial cost, limited max insertion, must accept setback, and while the threshold is higher, I still experience bounce with high cadence in low gear. Of course it's all relative, the Thudbuster is also limited on how low it can go, setback is not as much as Thudbuster's, and cadence bounce could be user dependent.

The ballistic return I mentioned for the Thudbuster refers to being pitched forward following a high amplitude bump or dip while seated. It is especially bothersome when the bike is pointed downhill, and the bump occurs unexpectedly.

I'm also pleased with CG-R performance. It's been effective for me. I saw a slow motion video capture of racer Tony Martin crossing a finish line over rough pavement with a CG-R post; significant saddle movement could clearly be seen.

FYI, my dropper post is far more useful than a suspension post. As a side benefit, there is a minor amount of saddle deflection rearward due to bushing give within its lower tube.

chas58

1) For some reason it doesn't seem to move at all. It's like a straight carbon post. The original you-tube video showed it flexing, but with my 175lbs it is as solid as a brick. I'm confused.

2) it needs a shorter seat tube than my thudbuster ST. So it doesn't fit my bike. I can put a thudbuster on there, but not the CG-R. It needs something crazy like 5-6 inches of post sticking out the seat tube.

3) it clamps from the side. Thus it does not fit a carbon seat with squarish tall rails - it needs rounded metal rails (where my carbon railed seat needs top/bottom clamps).

#1 really gets me though. Does yours have any flex to it where the insert is? Mine doesn't move at all.

Werkin

Yes, the post flexes at its elbow. I have two, one is under my co-rider who weighs less than 140lbs, and it flexes for her too.

On the same frame, my ST was inserted to its max with clipless pedals, the CG-R was higher than its max with clipless pedals. The CG-R currently is at 2 5/8 inches from rail to seat tube with low profile flat/platform pedals, which is near its max insertion height.

My CG-R post(s) came with an additional saddle rail clamp(s) designed for taller profile carbon rails, plus installation instructions.

chas58

Thanks. I'll have to go back and look in the box now for those adapters. Good idea!

I'm also wondering if there is something wrong with mine as there is some flex in the 27.2mm diameter post, but nothing at the elbow.

chas58

Well, I got her working and road to work today.

CG-R and a carbon seat and supple tires feels very nice on a stiff aluminum frame. Bike has the responsiveness of a stiff frame, but the ride quality of a high end carbon bike. Very nice.

Thanks for the heads up about the separate clamps. I was struggling to find a solution, while you gave me the easy way out.

I don't know what is wrong with my CG-R, but it needs 5.5 inches below the seat rails to be exposed. The bike I had last year only had about 5" available, and I couldn't insert the thing deeper. There is an amost invisible black rubber coating around the top 5.5" of the seat post preventing anyone from inserting the seat post deeper. Although the Specialized CG-R would not fit on my Specialized Allez (old school non compact geometry) because of the tall seat tube, it does fit on my off brand Aluminum cyclocross bike and works well.

Thanks to your help, I'm able to use this seat post for the first time since I bought it 18 months ago.

chas58

It is hard to see here, but there is an extra rubber coating on the seat post that does not allow insertion deeper than the end of the measuring tape here. Odd that it needs 5.5" of seat tube exposed below the seat rails...