bbaker22

Any options out there for putting a stoker stem on a 31.8mm seatpost (not handlebar diameter)?

Thanks,
baker

Ritterview

The Calfee stoker stem fits a 31.8 seatpost. They make it from a conventional aluminum stem and leftover sections of Edge frame tubing. Mine weighed 261 grams.

Chris_W

If you want to use a standard stem, for a 1 1/8" steerer, then get a 27.2mm seatpost plus two shims - one for the seatpost-to-frame (27.2 to 31.8mm) and one for the seatpost-to-stem (27.2 to 28.6mm). The stem can then weigh in the region of 150 grams, maybe less, but you are limited to the 140mm maximum length of stock stems.

bbaker22

I was hoping to avoid shims, but may end up having to go that route.

The stem will be for toting people on the back deck of my Yuba Mundo. I don't really care much about the weight, the frame is already 27.6lbs alone!

The Calfee looks nice but is way outta my price range.

Chris_W

Tandems East have a new Control Tech stoker stem that fits 31.6mm seat posts (see here). Hopefully, the 0.2mm difference won't be a problem.

bbaker22

I bet that would work.

I cheaped out and ordered a regular stem that is for 31.8mm bars and a 1-1/8" steerer. The stem is adjustable in angle, so I can set it at 0 degrees. I'll have to use a shim for the bars.

I started perusing pics of the Mundo w/ a stoker bar and it doesn't look like I need the extension ability of the stoker stems (crossing my fingers).

zonatandem

You can make your own shims out of alu beer/pop cans.

bbaker22

Yes, you can. I raced for years on a pop can shimmed seatpost. :-) Gave the bike to my bro-in-law who rode it the same way for another pile of years.

In this case, I have the appropriate 1-1/8" -> 1" shim just sitting around.

PMK

10-4 on that, my poor stoker has her bar to stem clamp surface shimmed with a Barqs Root Beer can. Just right for a 25.4 bar in a 26.0 stem.

PK