Stan’s No Tubes has an all-new lighter generation of Flow & Baron carbon rims that take a completely re-engineered look at how to optimize a tubeless rim to build better wheels. While we’ve seen plenty of asymmetric rims over the years, Stan’s is known for just making tubeless easy and doing that with an asymmetrical rim profile was surprisingly more complicated than it sounds.

Stan’s Flow & Baron CB7 carbon asymmetric tubeless MTB rims

Stan's Flow & Baron CB7 carbon asymmetric tubeless MTB rims mountain bike wheels

Talking to the specialists at Stan’s, it’s easy to see them getting almost lost in the tiny details, but in the end that’s what has made their rims work, often taking the hassle out of setting tires up tubeless.

So what’s wrong with most asymmetric tubeless rims?

When you first put a tire on an rim that is asymmetric from the outside but not optimized for asymmetry on the inside, the tire doesn’t sit in the middle of the rim. Then when you try to inflate it, one bead has a shorter or easier path to snap into place first. Because of that, mounting a tire can be more difficult, often times requiring a large burst of air (think: air compressor required). Even then, once you get it to work, the rim & tire are both subjected to uneven forces that need to be accounted for, somewhat negating some of the benefits of asymmetry in the first place. Riding them the situation is the same, with most asymmetric rims delivering uneven tire & structural support, even durability side-to-side. So it often would actually be easier to burp a tire or even smash a rim into a rock in righthand berms than in lefthand ones.

Stan's Flow & Baron CB7 carbon asymmetric tubeless MTB rims mountain bike wheels

So Stan’s went completely back to the drawing board (several times apparently) to get the inside asymmetry perfectly complementing the outside. So there new Flow & Baron rims get an asymmetric spoke bed to build stronger more balanced wheels AND an asymmetric tire bed & bead that delivers optimal tubeless tire mounting, inflation & removal. And of course as Stan’s likes to say, always with just a standard floor pump!

So where have we seen this before?

The new carbon Stan’s rims aren’t 100% new. Ibis has been making their S-wheels using the same tooling (albeit a different layup), and we covered those wheels back in the Spring.

Those were the fruit of this development process, but Stan’s took their own rim construction even a bit further. The Flow & Baron rims are slightly heavier (~20g extra) compared to the Ibis editions which share the identical profile, as Stan’s wanted to offer even more impact resistance & durability. That said, the new Stan’s rims are still more than 70g lighter than the previous generation making them a killer lightweight option for some proper trail trashing.

Tech details, pricing & availability

Stan's Flow & Baron CB7 carbon asymmetric tubeless MTB rims mountain bike wheels

The new asymmetric Bead Socket Tech carbon rims are available in Flow CB7 (29mm internal) and Baron CB7 (35mm internal) versions sharing all of the same tech, and same $600 per rim pricetag. The new high-strength Flow CB7 rim is still just 420g for the 27.5 & 455g for the 29er, and is designed to be ridden with 2.35-2.6″ tires. The wider Baron CB7 actually comes in at exactly the same weight, which although somewhat surprising, makes sense as they are designed for use with more burly 2.5″ and bigger tires that offer more tire volume & reinforced sidewalls for added rim protection.

Stan's Flow & Baron CB7 carbon asymmetric tubeless MTB rims mountain bike wheels

In addition to rim-only options, Stan’s also offers complete wheelsets hand-built internally in NY around CNC-machined Neo hubs (with 6-pawl, 10° engagement) and J-bend Sapim spokes/Secure Lock nipples. Stan’s wheels are all about simplicity and long-term durability, but at 1674g for 27.5 & 1761g for 29″ in either Flow or Baron, they still are quite light.

The new Baron CB7 rims & wheels are already available now, with the Flow CB7s arriving in November 2019.

Stan’s is also offering a new seven-year warranty and lifetime crash replacement on all newly & previously-registered carbon rims for the original owner. Registering also gets you a lifetime no-fault crash replacement offer, too.


  1. Johnny on

    The mounting struggle is real on asymmetrical rims. Many times, I find with my current (non-Stan’s, asymmetrical, carbon) rims, I have to mount a tire with a tube and then carefully break the bead, but only on the side opposite of the spoke offset, pull the tube, and then finish setting it up. It’s a total PITA. I hope what Stan’s has done here works because that would be awesome!


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