JSNYC

yep thomson's are nice. i've had one. great micro-adjustability.

the moots' ease of use, simplicity & adjustability--best i've ever seen, it'll blow you away.

...but so will the price, unfortunately.

(i got mine used from a pal at a very good price, otherwise i would def. choke at paying the $340 msrp for a new one.)

waynesulak

Yep - lighter than the Enve and no paste needed to hold it in place when clamped.

TandemGeek

I should probably ask the nice folks at Thomson if they'd be willing to make an extra-long, fixed-length stem to replace our adjustable carbon stoker stem...

I always worry that it's a matter of when, not if that stem will need to be replaced.

That would be the nutz, but would probably cost as much as a Calfee BarStem for a one-off. Still, it would make for an awesome set-up given we already have Thomson seatposts and a Thomson stem on our Calfee.

tredlodz

Anyone figure out how to attach a stoker stem high on a Thomson setback post? The unique Thomson setback design is the reason I went with Ritchey for mine.

TandemGeek

Yeah, add a link to the sync chain to bias the eccentric so the front BB is well forward and use a zero set-back Thomson with a slightly longer stem.

JSNYC

If Thomson made one, count me in. Black ano please.

Dean V

On our C'dale which has a 30.6mm seat post I use a Specialized multi position stem which has a 33mm bore. I then made a sleeve to get it to fit the post.
Anyway, you would have to try it but the 33mm bore might be big enough to slide over the bend in a Thomson set back post and then you would just need a split sleeve to make it fit where you want to clamp it.
I was actually wanting to go to a set back post on our bike as even with the BB forward as T'Geek suggested I still can't get my usual amount of set back with a straight post.

waynesulak

If you can get that done then I would love two of them. Specs: 180mm length with mountain bike like 40 degree rise. Currently use a stoker stem at 260 grams so lets aim at less than that.

To make this economic for Thompson it can be made with a 1.125" vertical clamp so it can be used as a mountain bike or trials stem as well as a stoker stem. We can shim it to a 27.2 seat post.

zonatandem

TG:
We have no worries about our Zona adjustable c/f stoker stem. It's been in use for 34,000+ miles.
Have never had issue with any adjustable stoker stem.
Rudy/zonatandem

Dean V

I guess the loading on a stoker stem would also be something that is very variable between teams. A stoker that isn't especially strong wouldn't load it much at all compared to a strong stoker that liked sprinting or cranking up hills out of the saddle in big gears.

TandemGeek

Yeah, well we're on our 2nd one and I'm hoping the cracks are simply stress cracks in the paint. We beat the hell out of our equipment and Debbie wrenches on those bars, so we're really talking apples and rocks when we compare the amount of wear and tear that y'all put into your equipment vs. what we put into ours. Of course, at a mere 280lbs and being weekend warriors, our wear and tear pales in comparison to those average teams of 350lbs who truly do have to deal with significant loads.

waynesulak

Look at. Trials. Stems. Very strong. Aluminum and shim to 27.2 seatpost.
WWW.tartybikes.com.
surprizingly light.

TandemGeek

+1

This is the problem with tandems. No two teams are exactly alike. We have friends who top out at 600lbs and we tip the scales at 270lbs. When I bought them a new wheelset as an anniversary gift I had our friend Mel at Tandems East build a bomb-proof 48 spoke wheelset using robust components because that's what they needed... not what they thought they wanted. It was a long, long time and several hundred pounds ago when they could get away with those OEM C'dale 36° XTR hubs and Sun rims that I rebuilt twice before putting them on the right wheels that I knew they needed.

Folks need to be honest with themselves when making equipment decisions. I'd like to think I'm still a hard core 30-year old cyclist like I used to be. Sadly, I'm now a card-carrying member of AAPR who can only dream of pushing the big gears and running at the front of the pack. Reality is, I work 60 hours a week and feel fortunate to get in 60 miles of riding on the weekends... not 600 miles a week a like I used to ...and am just barely able to run with the B-Teams when we attend rallies. Sure, we'd like to ride every day, but when you go to work at 5am and get home at 7pm, it just ain't happening. Call it poor vocational choices: should have taken a gov't job.. I'd be retired by now and living large on the tax payers backs.

waynesulak

That is something many like about bikes. Upper middle class folks can buy pro level high tech equipment as good or better than the pros and pretend they need it. Nobody drives a. Formula 1 car but many have a bike like Lance even if it makes their Back and backside hurt.

I try to keep from falling into that trap but still find myself succumbing once in a while.

JSNYC

If I were to go with custom stem route (which I'm considering), do any of you experienced tandem folks have a view of the purpose of the generally steep rise on stoker stems?

Assuming there's enough captain post, is there any shortcoming of having a stem with minimal rise that gets to the right end point for stoker bars (c-c measurement)?

Assuming the clamp is appropriately sized to distribute the load, would the strain on the captain seatpost be any more than a typical stoker stem with a 35 degree rise?

DubT

I think you see the steep stoker stems are installed in order to get the stoker in a comfortable position. The angle used would be determined by what makes the stoker comfortable. We are using a standard stem on the rear in order to save weight, I do not understand an adjustable stoker stem. Determine what length stem is required and then buy a regular stem, i had to use a spacer to get the correct fit between the stem and the seatpost but it works perfect and saves weight and money.

Wayne

JSNYC

How long is your stem? I'm probably needing something in the 160-170mm range. The only "mass produced" (as it were) stem that comes close that I found was a Thomson Elite at 140mm with a 15 degree rise.

I am really just trying to understand why stoker stems like the Control Tech were designed like they are (with the steep rise), as though it caused less strain on the captain post with that design. If instead it's simply to account for ease of mounting (i.e., less exposed captain post to work with) and makes up for reach via steep rise and adjustable tubes, ok.

Put another way, I just don't want a near zero rise custom stem to act like a giant lever that busts the captain post. If the clamp height (call it 50-60mm) is sufficient to distribute the load, it shouldn't be an issue--or at least i would hope so.

DubT

Our stoker stem is a Ritchey Pro that is 120mm long and it has 30 degrees of rise. The link to the trials stems shows some stems that are longer.

Wayne

JSNYC

Thanks for the suggestion to check out trials stems! I would've never thought of that one.

mrfish

The angle of the stem makes no difference to the load which the captain's seatpost 'sees' where it is clamped into the frame, whether it clamps at the top, bottom or somewhere in between. If you think of the stoker stem and bars as a system, the forces put into the system by the stoker's hands must always to be balanced by the forces which the frame exerts on the captain's post.

There is only one good reason not to clamp the captain's seat post at the top - if you're using a very light carbon post it probably won't be designed to be clamped there. But other than that, there seems no good reason to use an adjustable stoker stem or one with 40 degree slope in my view. Cheaper, lighter and more efficient to use a long road stem.

I'm fortunate that my hips are narrow and my stoker likes a long stoker compartment, so we use a 120mm road stem and shim to clamp it to our Thomson Masterpiece captain's seat post. It's held in the frame by a Thomson clamp as well. The clamp and seat post are both highly recommended as they are reasonably light and are fit and forget reliable.

diabloridr

Components don't fail due to *loads*.

They fail due to *stresses* (load/area).

Stresses will change based on where you choose to load a component.