Stan's NoTubes Flow EX3 Wheelset

With a reputation for producing strong rims that can take a beating, Stan’s has become a staple in many a wheel builder’s arsenal over the years. With racers and gravity enthusiasts demanding ever more from their equipment, Stan’s embarked on a serious testing program to figure out how to design a new rim that would complement today’s highly capable enduro and downhill bikes. What they found led them to combine the characteristics of two of their previous models – the result is the all-new Flow EX3 rim and wheelset. We’ve had a set out on the trails for a few months now, read on to find out what we think of it.

Stan’s Flow EX3 Highlights

• Uses: Enduro & Downhill
• Internal Rim Width: 29.0 mm
• External Rim Width: 32.6 mm
• Rim Depth: 17.9 mm
• Optimal Tire Sizes: 2.35” to 2.8”
• Hubs: Stan’s Neo OS with Durasync
• Spokes: Sapim D-Light Black 2.0/1.65/2.0mm
• Nipples: Sapim Secure Lock Alloy Black
• Hole Count: 32
• Drilling Style: Symmetrical
• Rim Material: 6069 Aluminum Alloy
• Rim Color: Black Bead Blasted Finish (BBQ)
• Hub Color: Black
• Brakes: Disc only
• Wheelset Weight: 2,018 g (27.5") / 2,115 g (29")
• Rim Weight: 580 g (27.5") / 618,g (29")
• Front Wheel Weight: 932 g (27.5") / 981 g (29")
• Rear Wheel Weight: 1,085 g (27.5") / 1,134 g (29")
• ERD: 564 mm (27.5") / 602 mm (29")
• ETRTO: 584x29.0 (27.5") / 622x29.0 (29")
• ISO: 27.5"x32.6 mm / 29"x32.6 mm
• Tape: 30 mm
• Valve: 35 mm Presta
• Max Pressure Tire Pressure: 37 psi (2.4”), 26 psi (2.8”)
• Max Rider Weight: 250 lb (113 kilo)
• Max Spoke Tension: 125 kgf (1,225 N)
• Wheelset MSRP: $699 (Rim MSRP: $115)

Initial Impressions

The starting point for the new EX3 rim was the Flow MK3, which is made from 6069 alloy. 6069 alloy is 10-15% stronger than the more commonly used 6061. But Stan’s also found that their old EX rim did very well in testing, even though it was made from the weaker 6061 alloy. They concluded that this was mainly due to its internal reinforcement – an additional “bridge” that sits below the regular rim bed, as well as the short and stout sidewall design that is meant to help the rim resist denting. Stan’s combined design elements from the MK3 and the EX and the EX3 was born.

Stan's is responsible for several key innovations when it comes to rim design and tubeless systems. For example, the rim bed features Stan's "Bead Socket Technology" which allows the tire to easily slide up towards the bead and then lock in place for a secure seal. The overall profile of the rim is low, to provide a certain degree of compliance, while the short and stout construction of the sidewalls is meant to help avoid folding the bead under impact. All of these technologies were brought to bear on the new EX3 rim.

When specifying the new wheelset, Stan’s also took a look at their hubs, and came up with a new design that employs oversized bearings. The Neo OS hub uses Stan’s classic Neo freehub, which is available in either a 10-degree engagement version (via 6 pawls that engage simultaneously in a 36-tooth ratchet ring), or a 5-degree version where the pawls engage in an offset pattern to create 72 engagement points on the same, 36-tooth ratchet ring. The move to oversized bearings should help with durability, and there is also a chromoly axle in the rear hub to further improve the resilience of the EX3 wheelset.

To create the complete Flow EX3 wheelset, Stan’s laces the Neo OS hubs to the EX3 rims with Sapim D-Light, j-bend spokes. Sapim’s “Secure Lock” alloy nipples are used to help prevent spokes working themselves loose, and the complete wheelset comes with tubeless tape and presta valves already installed, ready to hit the trail. The 27.5” version tested here weighs in at 2018 grams.

On The Trail

Stan’s “Bead Socket Technology”, is meant to make mounting your tubeless tires easier, and we were indeed able to confirm this – several different tires went up on the rim with nothing more than a floor pump. The company’s website is literally “notubes.com” so this should come as no surprise, but it’s always nice when the thing does what it says on the box. The factory tubeless tape job was equally up to the task, holding air for the duration of the test (on the front wheel – the rear had a bit of an incident requiring a partial rebuild, more on that later). Cassette and rotors went on without a hitch, and all the tolerances were on spec.

Moving out, the first thing we noticed was the strictly average engagement offered by the “Durasync” freehub. With simultaneous pawl engagement on a 36-tooth ratchet ring, you end up with a fairly pedestrian 10 degrees of engagement. The reason is in the name – Stan’s wanted the Durasync option to be, you guessed it, durable. If you feel like exchanging a bit of durability for faster engagement, Stan’s “Speedsync” freehub can be swapped in (a $130 aftermarket upgrade that nets you 5 degrees of engagement).

The EX3 wheelset goes about its business in a solid, almost muted way.

Apart from the slow engagement, the EX3s feel crisp and direct on the bike. At 2018 grams, this wheelset is no lightweight, but it rolls well and we did not find it particularly sluggish when accelerating either. Trail feedback is certainly present, but without being overly jarring. In terms of precision, we found the EX3 wheelset really holds a line and responds well to rider input, never once feeling overwhelmed be it during braking, cornering, or when pounding through rocks. The EX3 wheelset goes about its business in a solid, almost muted way.

A couple of months into the test we had two fairly major incidents occur. After picking a bad line through a high-speed rock garden we took a massive hit to the rear wheel which resulted in burping half the air out of the tire, and a slight wobble in the rim. Given the violence of the impact, we were convinced the wheel was done for – but that turned out to be far from the truth. There was indeed a flat spot in the rim, but the sidewalls were nearly intact and the tubeless seal was unaffected by the incident. We had to re-true the wheel as at least 4 or 5 spokes had gone noodles on us, but after we worked the wheel over with a spoke wrench it was good to go again. Holding a perfect tubeless seal and spinning nearly straight after such an impact was impressive. A couple of weeks later we added further misery by somehow managing to get a big rock lodged into the rear wheel at speed. The result was 2 snapped spokes and a mangled rear derailleur as the rock ended up wedged between spokes and derailleur and carnage ensued. Once again we were able to rebuild the wheel (conveniently using a few j-bend spokes we had lying around), and we were back on the trail again. At this point we’re feeling pretty confident in recommending the EX3 wheels to anybody looking for a wheel that will take a serious beating. Looking at sponsored riders for confirmation is always a double-edge sword, since you don’t actually know how many wheelsets a race team might go through and the riders are paid to represent the product, but the fact that the EX3 can already be found on winning bikes under both the Athertons and GT Factory Racing is further testament to its ruggedness.

Things That Could Be Improved

We’ll mention weight in this section since 580 grams for a 27.5” rim is certainly on the heavy side, in particular for a wheel that is partially aimed at the all-mountain and enduro crowd. However, we did not find that the extra heft caused much in the way of sluggishness, and we certainly came to appreciate just how strong this rim is as described in the previous section.

When it comes to the hubs, we were not impressed by the 10-degree engagement of the Durasync hub. We’re all for durability, especially when it comes to hubs, but we’re pretty sure Stan’s can do better than 10 degrees without sacrificing much, if anything, in the longevity department. They do have a custom wheel builder on their site, but for some reason they are not offering the 5-degree Speedsync freehub as an option with the EX3 rim/wheelset, so your only option if you want better engagement at this point is to buy the standard wheelset and swap out the freehub at $130 of extra cost. There is also no official word from Stan's yet on the availability of a Shimano Micro Spline freehub option although we imagine it won't take too long before it's offered.

Long Term Durability

As we discussed in detail in the “On The Trail” section of this article, the EX3s did not have an easy life during our test period. The fact that they came through the ordeal with flying colors and ready for round two is testament to the strength and resilience of the new rim. In addition to being able to take a hit and keep on rolling, the new rim also features a shot-peened finish which helps it look fresh for longer as well. With only three months on the wheels so far, it’s hard to tell if the new oversized hubs will deliver significant lifespan improvements for the bearings, but so far they are solid and still spin smoothly. All in all, we’re confident that the new EX3 wheel will stand the test of time, pretty much regardless of what you throw at it.

What’s The Bottom Line?

Stan’s already had an excellent track record when it comes to the ruggedness of their rims, and by combining design elements from several successful predecessors, their latest creation looks set to pick up right where those left off. The new EX3 wheelset was made to answer the demands that today’s aggressive enduro and gravity bikes impose on the rolling stock, and to do so without breaking the bank. At $700 USD for the pair, this set of wheels is up for abuse and then some, and floor pump tubeless tire seating is always a bonus for those who wrench at home. The fact that it weighs in at just over 2000 grams means that it’s not for riders looking for an ultra-light build, but if you like smashing into stuff and want a wheelset that just keeps coming back for more, you should definitely put the EX3 on your list.

More information at: www.notubes.com.

About The Reviewer

Johan Hjord - Age: 46 // Years Riding MTB: 14 // Weight: 190-pounds (87-kg) // Height: 6'0" (1.84m)

Johan loves bikes, which strangely doesn’t make him any better at riding them. After many years spent practicing falling off cliffs with his snowboard, he took up mountain biking in 2005. Ever since, he’s mostly been riding bikes with too much suspension travel to cover up his many flaws as a rider. His 200-pound body weight coupled with unique skill for poor line choice and clumsy landings make him an expert on durability - if parts survive Johan, they’re pretty much okay for anybody. Johan rides flat pedals with a riding style that he describes as "none" (when in actuality he rips!). Having found most trail features to be not to his liking, Johan uses much of his spare time building his own. Johan’s other accomplishments include surviving this far and helping keep the Vital Media Machine’s stoke dial firmly on 11.

Photos by Johan Hjord