Ritterview

For a while now, the premier suspension stoker seatpost has been the Thudbuster®. It is seen on a lot of tandems.



You don't have to be a far gone weight weenie to have some pause before installing a Thudbuster®. There are two models, the 570 gram Long Travel (left), and the 450 gram Short Travel (right). In comparison, the captain's Thompson seatpost on the depicted DaVinci weighs 193 grams. The Thudbuster ST and LT thus adds 257 and 377 grams (9 and 12.6 oz) respectively.



There are two new seatposts becoming available that may provide some stoker relief without a significant weight penalty.

The 220 gram Ergon CF3 Pro Carbon, which is listed as not yet available at Bike24 for 250 euros.

Edit: News about availability--



And the $200, 250 gram Specialized COBL GOBL-R carbon seatpost.




Don't laugh - the strange-looking Specialized COBL GOBL-R really works, and quite well in fact. The benefits vary depending on saddle positioning but even in the forward-most setting, it takes the sting out of bigger bumps in the road.

The COBL GOBL-R isn't available until September as an order item, but newer Specialized bikes are equipped with it. I rode one last Saturday, but it was difficult to compare on a different bike. The LBS offered for us to borrow the COBL GOBL-R, and I hope to put it to the stoker test on our ride on Saturday.

mwandaw

Maybe it's just me, but that thing looks scary! I experience macabre visions of injuries that would require the attention of a trauma center proctologist.


For some reason, this looks much more reasonable.

joe@vwvortex

We've run the old Specialized Pave Zertz in back since we bought the tandem. Tried a thudbuster and my wife absolutely hated it. This thing actually works really well. Tough to find nowdays. The updated S-works version didn't work as well.

Ritterview

We visited Mike's Bikes, who lent us a demo Cobl Gobl-R,

It turns out to weigh 257 grams, whereas our 27.2 mm, zero offset ENVE weighs 169 grams. So, an additional 88 grams (3.1 oz).





How it looks mounted.





We road the tandem around the block a few times (it is very bumpy, and is slated for repaving) first with the ENVE seatpost, then with Cobl Gobl-R. The ENVE post ride was much more punishing for the stoker, Mrs. R estimated it dimished the magnitude of the uneveness by 40-50%. With the ENVE she clammed up, anticipating bumps, but with the Cobl Gobl-R kept chatting about the house's landscaping through the bumps.

We'll see how it fares on tomorrow's ride, which features over a mile on dirt/gravel trail, and some fairly rough roads.

mstyer

Eagerly awaiting a full ride report. I've been eyeing one of these for our Cannondale build.

Sprout97 

+1. I added a Pave post for my wife 3-4 years ago. (Both of our then-single bikes -- Roubaix and a Ruby -- had them and my wife thoroughly loved her post, so a Pave post was one of her Christmas presents.) The Cobl Gobl-R does look interesting, though. Bizarre looking in any case.

Ritterview

We rode the Cobl Gobl-R today on a ride in the Santa Cruz mountains. In the Santa Cruz mountains, there are smooth roads with high traffic, and rough roads with little traffic. Our descent, SJ-Soquel and ascent, Mt. Charlie, are respective examples of the former and latter. So, this was a good test for the Cobl Gobl-R.

Mrs. R really liked the Cobl Gobl-R. It smoothed out the many bumps for her a lot. She felt it was like having a cushier seat, or an extra chamois. That made it a lot easier to be a captain, as I found myself not tiptoeing around every little bump, but more inclined to keep my line and run over road irregularities. I think it helped with stoker confidence and morale, and lessened fatigue. So, I think what I dub the Stokr Coddl-R® to be well worth the price and extra grams.

I'd like to compare the Ergon CF3 Pro Carbon, but alas, it doesn't appear to be available until September.

Here's a video from Interbike 2012 at which both are discussed.

ReedCycle

It would be interesting to find out how the Cobl Gobl-R compares with the Thudbuster ST.

Werkin

What the ST can do that the CBR can not, is maintain seat plane in relation to the handle bar. Also, the rear of the bike pivots on the front axle axis, the seat travels in an arc relative to that axis, a bump encourages your bottom to follow that arc and pitches body weight forward. A saddle on an ST moves rearward countering the forward pitch. To keep things relative, the arc is tighter on a single than tandem, so the benefits are greater on a single. The majority of the CBR's deflecting movement is downward only.

Tookool

I agree ^^^^^^^^ can you get a demo Thudbuster ST and have your stoker compare the ride??

Ritterview

Hmmmm... I'll have to ponder this. That would be a useful comparison. My Calfee might rebel, however, at the indignity of sporting a 440 gram seatpost, if even for just a demo.

DubT

With the disc brake, the 28mm tires and the new seatpost what does your bike now weigh?

ReedCycle

My Calfee, and my stoker, are quite happy with the Thudbuster SL. I would be nice to have a comparison, though.

Carbonfiberboy 

We're using a telescoping post that's fairly stiff and has a good bit of internal friction. Stoker likes it. Advantage is that it doesn't bounce with Stoker's pedaling, like I've observed with Thudbuster's on other tandems, yet it yields to larger hits. I know it's not light. Always been tempted to go to a carbon post, but the ones in this thread are a bit pricey when what we have works. OTOH, Stoker gets a sore butt after 80-100 miles and I wish she didn't. That's been a distance limiter for us. Could be the internal friction on the little stuff. So maybe worth the money . . .

zonatandem

Stoker Kay does not use any type of suspension seatpost on our last five tandems.
Been tandeming since 1975.
Did do roadtesting for a few companies (including the original Thudbuster and a few others). What she liked the best was the old Allsop beam setup.
However our standard setup on our c/f Zona is Thompsons for both pilot and stoker.
Works great for us.
Pedal on!
Rudy and Kay/zonatandem

Chris_W

We've already done the Thudbuster ST vs. Cobl Gobl-R comparison on the back of our tandem. Here's the full story:

We've had a Thudbuster ST on the back of our Co-Motion Speedster since it was new, about 4-5 years. The stoker liked it, with the only complaint being a pogo-stick effect on certain sizes of speed-bumps, where the post would compress as we hit the front of the bump and then launch her upwards as we went over the top of the bump - this was much worse on certain kinds of speed-bumps, especially those in France (Swiss ones are built quite differently). It did fine at absorbing regular bumps/irregularities in the road, and my stoker was generally happy with it, but would occasionally complain when she had an uncomfortable pogo experience.

I had her try riding with a rigid carbon post a few times a couple of years ago because of the extra weight of the Thudbuster. Despite riding regular road bikes with rigid seatposts and a hard-tail MTB without many complaints, she couldn't live with a rigid post on the tandem and wanted some extra comfort.

When the Cobl Gobl-R seatpost was announced last year, my boss at the bike shop where I worked immediately wanted one for himself, so I asked him to order one for our tandem, also. They finally arrived in mid-June, but we've been riding MTBs and road singles a lot this summer so haven't logged too many tandem rides - maybe two or three 2-4 hour rides since the post change. So far, my stoker is sold on the Cobl Gobl-R, and actually PREFERS it to the Thudbuster. Apparently, it's about as good at soaking up small bumps and doesn't have the pogo effect on speed bumps, so she is happy. I'm obviously happy because of the significant weight loss. She's so convinced that she won't change her mind that she's already given me the all-clear to put the Thudbuster on e-Bay.

My boss is pretty obsessed with seatpost comfort and has ridden MANY different carbon posts on his road bikes, and until now found the Alien post by USE to give him the most comfort of any that he'd tried. But now that he has his Cobl Gobl-R I don't think you will ever be able to separate him from it, and he's promoting it to anyone who wants to listen and isn't totally turned off by the look. For the first week or so after he got it he kept riding over every bump he could find just to test it out, and kept coming back from his rides raving about how wonderful the post was. It has just the right amount of comfort while generally being stiff and solid according to both him and my stoker.

Availability is certainly still a problem, but hopefully that should be improving soon.

Artmo 

I sold our Thudbuster because of its weight and installed a USE Alien, which my stoker likes.

Ritterview

Ergon has finally gone into production with their CF3 Seatpost, and so it should be available soon.

At Interbike, Ergon will be showing their setback version of the CF3 Seatpost. This looks to me like it would have more suspension than the straight version of the seatpost.



Someone at Twitter got a chance to try out a CF3:

Matthew Page (@mattpage24)
9/14/13, 7:50 AM
It took less than 1km riding for me to decide I want a @Ergon_Intl VCLS seatpost on every bike. Wow, that's a comfy perch!

@AndyWaterman very impressive. It's like loosing 50psi from a tyre but still motor along on the tarmac. Light too, sub 200g.

jnbrown

We have been using a Specialized Pave and it seems to work ok.
I would be interested in the Cobl Gobl-R but I can't find anywhere selling it.
On specialized web site they are now calling it CG-R and they don't have any, says coming soon.

Ritterview

Hey, you're right, the name was changed to something more conventional. The ungainly name and appearance must have been too much.

CG-R CARBON SEATPOST

The seatpost that we trialed was cannibalized from demo at the bike shop. When they checked, it was to be available in September. So, it must be soon.

Now that we are back to our conventional carbon seatpost, the stoker says it is just fine, but it isn't just the stoker that benefits. The captain is in more control on, say, a descent on a rough road, if the stoker has less vertical movement.

Turbotandem

We like our Cobl gobl-r acquired about a month ago. Not too deep an offset to work for us, and a shockingly tight dimension between bottoming out the seat post into the frame and the seat rails. Necessary on our cross tandem for getting the seat low enough. Even with a bit more post showing on the road bike, I've not noticed a change in handling given the .25 to .375" vertical movement of the post. Maybe less under my 104# stoker. But she says it is working well.

Ritterview

The Ergon Setback seatpost is not yet available, but it does now appear on the Ergon website (though not to purchase), so its availability appears to be drawing nigh.

CF3 Pro Carbon SetBack

seth10015

The Ergon web site claims no sleeve can be used with this seat post. I called Ergon & that's there company policy, but couldn't tell me why. My Co-Motion is 29.6 I believe. Any thoughts to why this might be dangerous & not approved. We now use a Cobl Gobl & my 102 pound stoker claims it does not help with bumps at all.

twocicle

Calfee is one mfr that uses the 27.2mm standard. Bet he would be surprised his bikes are not "modern". I certainly was. With this breaking news coming to light, now I'll need to send our frame back for a seat tube modification to 29.6mm so we could also start using shims :/

There has been some mention that Specialized would have different density elastometers available to tune the CG-R. OOTB it is likely setup for a 150-180lb rider. Maybe give them a call to find out.

seth10015

Ouch.....I meant no disrespect whatsoever. Calfee is surely perhaps the most modern tandem bike there is. I've only been in tandeming for 3 years, and am simply trying to learn about the Ergon CF3 seat post & why it won't work on my frame.
I did call Specialized & told them about my issue, but they had no advise.
Have a great day & I hope Craig doesn't send the Calfee police after me. I like Calfees