Stan’s NoTubes Unveils Strongest Rim Yet – The Flow EX3

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Sick of trashing rims? Then you’ll be eager to learn more about the brand new Flow EX3 from Stan’s NoTubes – a super tough alloy rim designed for enduro, downhill and e-MTB use.

As the newest mountain bike rim to come from Stan’s NoTubes, the Flow EX3 shares a lot in common with the existing (and very popular) Flow MK3 rim. They’re both made out of 6069 alloy, which Stan’s claims is 10-15% stronger than comparable 6061 alloy rims. They also share a 29mm internal rim width, which means they’ll fit 2.35in to 2.8in wide tyres.

Look a little deeper though, and you’ll start to find the differences.

stan's notubes flow ex3
The Flow EX3 is a brand new, super-tough alloy rim from Stan’s NoTubes.

Triple Cavity Profile

For a start, the Flow EX3 rim is a little taller (17.9mm vs 16.1mm), and the external width is also wider (32.6mm vs 32.3mm). This is because the alloy walls are thicker on the EX3 rim, and they’re also reinforced internally by what Stan’s refers to as its ‘Tiebeam’ construction.

stan's notubes flow ex3
The walls are thicker, and there’s a triple cavity profile called ‘Tiebeam’.

Tiebeam creates a triple-cavity design, by placing an additional alloy bridge that sits between both sidewalls. According to Stan’s NoTubes, this Tiebeam construction, along with a thicker spoke bed and a new shot-peened surface treatment, creates the strongest and most impact-resistant rim the brand has ever tested.

The Flow EX3 will be available as a rim on its own, in both 27.5in and 29in diameters. The weight is on the porky side at 580g (27.5in), but when you realise that this is a rim designed to handle World Cup DH courses and multi-day enduro races, that figure is actually pretty impressive.

stan's notubes flow ex3 martin maes
Martin Maes has been helping Stan’s with development of the Flow EX3.


For easy tubeless setup, the Flow EX3 utilises Stan’s BST internal rim profile, which means a layer of yellow tubeless tape is all you need to seal it up and ditch the tubes. The shallow BST sidewalls not only allow for a more rounded tyre profile, they’re also supposed to be more fold-resistant, with the goal of maintaining tubeless air pressure even under heavy impacts.

stan's notubes flow ex3
Short and thick BST sidewalls are designed to resist folding.

Complete Wheel Options

As well as standalone rims, Stan’s will be offering the Flow EX3 in complete wheelsets built around new Neo OS hubsets. The Neo OS hub features larger diameter bearings than the standard Neo hub, while the rear Neo OS hub gets a tough steel axle and a fast-engaging 6-pawl mechanism.

The Flow EX3 wheels in most popular hub configurations, including the new-school ‘Super Boost’ 157x12mm rear spacing, and 20mm Boost front spacing.

stan's notubes flow ex3 neo hub
The Neo OS hubs feature burlier internals over the standard Neo hubs.

Wheels will be assembled with Sapim D-Light double-butted J-bend spokes and Secure Lock alloy nipples, which should make things easier when it comes time to find a replacement.

Stan’s NoTubes Flow EX3 Specs

  • Super tough alloy rim for enduro, downhill & e-MTB use
  • 6069 welded alloy construction
  • Tiebeam triple-wall profile
  • Shallow 17.9mm depth
  • 32.6mm external rim width
  • 29mm internal rim width
  • Designed for 2.35-2.8in tyres
  • BST tubeless ready
  • Available in 27.5in and 29in diameters
  • 32 hole drilling only
  • Rim weights: 580g (27.5in), 618g (29in)
  • Complete wheelset weights: 2,018g (27.5in), 2,115g (29in)
  • Rim RRP: £90 / $115 USD
  • Complete wheelset RRP: $699 USD (UK pricing TBC)
stan's notubes flow ex3
You can get the Flow EX3 as a standalone rim, or in a complete wheelset.

You can get more information about the new Flow EX3 rims and wheelsets via the Stan’s NoTubes website, and if you’re in the UK, head to for pricing and availability.

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