By the way - on the 650A rim availability tangent, I almost forgot one recent development: The second-generation Spin dockless bicycles use 26 x 1-3/8" drop center rims with machined braking surfaces (and solid tires). I believe they're dual wall and hooked bead too; I've got a rough Gen 2 in my office right now (donated to our program; read on) as a gopher bike and may convert it to tubes, so I'll know eventually.

https://bikesharemuseum.com/bikes/2017-spin-gen-2/


I know this is an extremely obscure opportunity for many C&V'ers, but there are a few markets where Spin has left (or renewed contracts only for scooters) and may have donated them. Case in point, I recently worked with Spin to get these two donated to the Bike Share Museum, along with a number of others to the non-profit that I work at.

There's also the possibility abandoned examples may wind up at co-ops eventually in cities such as Seattle, where Spin pulled bicycle a year ago. Pays to be sure though; San Diego just got 500 bikes from the former Miami fleet - apparently there's a market where dockless analog bike share remains popular.

EDIT, two years later: Yes, they're dual wall. These rims also shed beyond belief. Machined brake surface or not, these particular rims don't do well with rim brakes (even though that's how they're config'ed on the Spins). Highly recommend relegating these to drum or disc applications.

-Kurt