stan's notubes flow cb7 carbon wheelset
02 Jul 2020

The new Stan's NoTubes Flow CB7 wheelset comes with a unique carbon rim design that's said to be stronger and more reliable

Best known for its popular tubeless sealant and standalone rims, Stan’s NoTubes also offers a vast selection of complete mountain bike wheels. Though most of those models feature alloy rims, NoTubes has been steadily growing its carbon fibre offerings, which at present includes the Podium SRD, Crest CB7 and Arch CB7. Joining those are NoTubes’ widest and toughest carbon mountain bike wheelsets to date; the new Flow CB7 and Baron CB7. Both of these wheelsets are built with brand new carbon fibre rims that feature a very shallow and asymmetric rim profile – a first for NoTubes. To find out what that means, here we’ll take a closer look at the NoTubes Flow CB7 wheelset we’ve just received for review.

stan's notubes flow cb7 carbon wheelset
Stan’s NoTubes has brought out a carbon version of the venerable Flow rim – this is the new Flow CB7.

The Flow Goes Carbon

The Flow CB7 is the first ever Flow rim to be offered in carbon fibre. Compared to the Flow MK3 alloy rims, the new carbon version offers notable weight savings of 60-72g per rim depending on the diameter. Claimed weight for the Flow CB7 rim is 420g (27.5in) and 455g (29in).

Being the next step up from the Arch CB7 wheelset, the Flow CB7 is of course wider and tougher. Inner rim width grows to 29mm, which NoTubes says will accommodate tyres between 2.35-2.80in wide.

Like all NoTubes rims, the Flow CB7 features super-short sidewalls and the BST (Bead Socket Technology) tubeless profile. Each bead is 3mm thick, which isn’t quite as fat as the 3.75mm beads on the Zipp 3Zero Moto wheels, or the 4.64mm beads on the new Bontrager Line Pro 30 wheels. However, because the sidewalls are so short, NoTubes says they’re both stronger and less vulnerable compared to taller sidewalls. They’re also not meant to ‘pinch’ the tyre’s sidewalls as tightly as a conventional rim, allowing for a more rounded profile that effectively emulates a wider rim bed.

To mitigate this, NoTubes uses a shallower and more blunt rim profile, which it calls RiACT. The idea is to allow the rim to compress radially for a more forgiving ride, while still offering the lateral stiffness benefits of a carbon rim.

Less Depth, More Compliance

Ever since NoTubes released the original Valor and Bravo carbon wheelsets, radial compliance has been a big consideration for the company’s rim designs. While carbon fibre rims offer weight savings, handling and durability benefits over alloy, they can also create an overly stiff wheelset that feels harsh on the trail.

To mitigate this, NoTubes uses a shallower and more blunt rim profile, which it calls RiACT. The idea is to allow the rim to compress radially for a more forgiving ride, while still offering the lateral stiffness benefits of a carbon rim.

On the Flow CB7 rim, the depth is just 18.3mm, which is the shallowest of any carbon fibre rim from NoTubes. To put that in perspective, it isn’t quite as shallow as the Zipps (14.8mm) but it is a lot shallower than the Bontragers (27mm).

stan's notubes flow cb7 carbon wheelset
The Flow CB7 rim has a super shallow rim depth that encourages radial compliance for a smoother ride, and greater impact resistance.

Off-Centre For Better Balance

Additionally, the Flow CB7 is the first rim from NoTubes to feature an asymmetric profile, with the spoke holes drilled 4mm from the centre of the rim. The offset spoke drilling allows for wider spoke bracing angles at the hub, which results in more balanced spoke tensions and, in theory, a stronger wheel. On our 29in test wheelset with Boost hubs, it also results in the same 292mm spoke length for both the front and rear wheels, drive and non-drive side.

Many rims on the market already use an asymmetric rim profile – there’s nothing new there. However, NoTubes has apparently invested a load of development time into coming up with an asymmetric rim design that would provide the same ease-of-inflation and security of its existing tubeless rims. According to NoTubes, one of the challenges with an asymmetric rim profile is that during inflation, the beads don’t pop into place simultaneously. We’ve experienced this with Race Face and WTB rims, which have presented their fair share of frustrations with tubeless tyre setup, especially when you’re fitting a used tyre without a compressor on hand.

We’ve experienced this with Race Face and WTB rims, which have presented their fair share of frustrations with tubeless tyre setup, especially when you’re fitting a used tyre without a compressor on hand.

So, does the Asymmetric BST profile do the job? Well, we’ve only setup our test wheels with one set of tyres so far – a 2.6in Specialized Butcher and Eliminator combo. Both tyres fitted to the rims without levers required, and both inflated easily with a floor pump, which is what we’ve come to expect from Stan’s NoTubes rims. We’ll be trying out many more tyres on these rims over the coming months though, so we’ll see if that experience carries on.

These feature CNC machined alloy hub shells, sealed cartridge bearings, tool-free end caps, and a 6-pawl freehub mechanism with 10° engagement.

Nothing Weird About Those Spokes

While the Flow CB7 is offered as a standalone rim, NoTubes also offers a complete wheelset option too. Refreshingly, the wheels are built with external nipples and regular J-bend Sapim stainless steel spokes, which are laced in a conventional three-cross pattern. Also nice to see is that the rims come pre-taped and are fitted with tubeless valves.

At the centre you’ll find NoTubes own Neo hubs. These feature CNC machined alloy hub shells, sealed cartridge bearings, tool-free end caps, and a 6-pawl freehub mechanism 10° engagement. Our test wheelset arrived with a SRAM XD freehub body, though at the time of ordering you can choose a Shimano HG or Micro Spline freehub body. If you need to change down the line, spare freehub bodies are available separately for $179 AUD.

stan's notubes flow cb7 carbon wheelset
You can get the Flow CB7 rims on their own, or as a complete wheelset built with Sapim spokes and NEO hubs.

Stan’s NoTubes Flow CB7 Wheelset Specs

  • Available in 27.5in & 29in sizes
  • Asymmetric BST carbon fibre rims
  • 18.3mm depth
  • 29mm internal width
  • Designed for 2.35-2.80in wide tyres
  • Neo hubs w/CNC machined hub shells
  • 6-pawl freehub mechanism with 36pt engagement
  • Available with SRAM XD, Shimano HG & Micro Spline freehub bodies
  • 32x Sapim Laser double butted J-bend spokes per wheel
  • Sapim Secure Lock alloy nipples
  • 113kg rider weight limit
  • Available with a 7-year warranty and lifetime crash replacement
  • Claimed weight: 1,674g (27.5in) / 1,761g (29in)
  • Actual weight: 1,822g (29in, Boost hubs, including tape & valves)
  • RRP: $2,199 AUD
stan's notubes flow cb7 carbon wheelset
The Flow CB7 differs from NoTubes’ alloy rims in its heavily offset profile. This allows for wider spoke bracing angles, and in theory, a stronger wheel.

We’ll be riding the Stan’s NoTubes Flow CB7 wheelset over the coming months on a variety of bikes to see just how well they hold up to their claims. Stay tuned for the full review, though if you’ve got any questions in the meantime, give us a hoy in the comments below.


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