Freerojo

Hi, wife and I just inherited a 1995 Cannondale RT2000
tandem so I will be asking some questions about upgrades, for example, installing V brakes.

Right now my question is, is this stokers seat post a “dropper” kind? It’s not original to the bike. I would like to know if there are any instructions about this seat post. It doesn’t push down smoothly. Not sure if it even works.

Carbonfiberboy 

I can't answer your question, but I'd sure try to find a different post which will work your this frame and your stoker. Those saddle rails look really odd, too. I wonder if that post is homemade, cobbled together because the previous stoker's legs were way too long for this frame and a long enough seatpost couldn't be found at that time.

surak

I had a similar seatpost with my Santana. Posted it here and people said it's likely a U.S.E. suspension seatpost.

lichtgrau

This is an old suspension seat post and it's technically somewhat outdated. You could try to bring some life into that poor old thing by disassembling/cleaning/lubricating/assembling it (be careful in case the spring is pre-loaded) but I really doubt if it's worth the effort.
Those "stick style" suspension seat posts were rarely quality products. In most cases there are problems with unwanted lateral rotations of the saddle (just a little bit, but enough to give you an annoying, unstable feeling), an inappropriate spring power and a suboptimal responsiveness.

If you want to do your stoker a favour, invest in a parallelogram type seat post (we use the Cane Creek Thudbuster LT, there are others too). With this setup (and in our case in combination with a very satisfying working suspension fork) we ride smoothly on rather rough kinds of pavements where I wouldn't even think to ride on with my race bike...

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Freerojo

Thank you for the responses. Looks like a new stoker seatpost is in order.

merlinextraligh

Personally, I'd try a conventional, non suspended seat post first. Many teams do not find the need for a suspension seat post. (We don't use one on either our road or offroad tandem)

And there a number of downsides to a suspension seat post including: 1) cost; 2) weight, 3) complexity, 4) alteration of your pedaling position as the seat post moves, and 5) some decrease in efficiency.

Whether a comfort benefit from a suspension seat post outweighs the drawbacks is a subjective, and personal judgment. I wouldn't start out with the assumption, however, that a suspension seat post is a must have item.

Carbonfiberboy 

^My thinking also. If your thinking runs along these same lines though, you might do what we did and run a carbon Specialized CoblGobr post. This post takes the buzz and small stuff out but not the big hits. Stoker likes it a lot. No bouncing at all.

lichtgrau

Agreed. That’s my only criteria too. During the ride nearly everything is captain’s decision, but when it comes to hardware for the stoker compartment: I’m out. Happily, she’s fairly undemanding. Actually the “Thudbuster” is the only component that can’t be discussed. But since we do more than 100 Kilometers at the weekends: I’m more than willing to sacrifice another pound of extra weight for happy Ms. Stoker.

Leisesturm

Agree on going hardtail for stoker. Ideally it would be the big hits that the seatpost would deal with, but since they can't, I for one don't see why they are worth the weight and hassle. I call out 'bump' for the hits I can see coming and I get verbal abuse (mild) for any that I miss. Sadly, in 2019, state of the art suspension still looks like large section clinchers at less than MAX pressure on the sidewall. Even electric assist bikes that can afford to waste some available torque heating up the suspension elastomers are instead using 2.0" clinchers as low unsprung weight passive suspension. Simple, cheap and effective enough. For road use anyway.

jim_pridx

Well, in our 34 years of tandeming, we've tried going with no stoker suspension at all to nearly every suspension post out there, and my wife won't settle for anything less than the Cirrus Bodyfloat (Kinekt these days). It's undoubtedly heavy, but once we got it set up properly, she claims that it handles a vast majority of the bumps in the road that we encounter. As the captain, I honestly don't think that I'm in any position to argue. We have yet to try the Specialized version, though.

Tom M

Our tandem won't fit a Thudbuster. My wife started with a padded seat, which helped with the bumps, then, with the help of our LBS, switched to a Selle Royal saddle, which has a bit of suspension built in. Lighter than her padded seat and a better fit. Also, relatively expensive (<$70).

Tom