Crankbrothers Synthesis Enduro Alloy 2.0 I9

Now in its second iteration, the Crankbrothers Synthesis Enduro Alloy 2.0 I9 wheelset has a refined wheel-specific compliance formula with fresh rim profiles and new materials. The result is a very well sorted enduro wheelset that’s strong, yet comfortable. However, while the I9 hubs are nice additions, the £200 bump they bring over the standard wheelset means you’ve really got to want them.

Crankbrothers Synthesis Enduro Alloy 2.0 I9 – Technical details

The original Synthesis wheels were among the first to deliver front and rear-specific compliance profiles. The idea was to make the front wheel more compliant for grip and comfort, while the rear was stiffer for strength reduced rolling resistance. The overall formula here is the same, but it’s been developed further for this second edition.

The front wheel is still more compliant, and has a wider internal width for a broad contact patch and plenty of sidewall support. It uses a 30mm internal width and 28 spokes, whereas the rear gets a narrower 27mm internal width and 32 spokes for extra rigidity – all spokes are of the Pillar SR TB 2016 variety.

The rims are 6069 aluminium, which is said to provide ‘superior’ impact resistance (though in relation to what is not specified), and they’re laced to I9 (Industry 9)’s 1/1 hubs. With 90 points of engagement, the freehub produces a four-degree engagement thanks to a six-pawl driver and 45-tooth drive ring.

Both rims are 30mm high, and are available with six-bolt rotor mounts only. They’re finished with a shot-peened finish that strengthens the rim by creating a harder outer surface. Updated rim geometry also brings in thicker rim walls – again, for more strength.

The Synthesis Enduro Alloy wheelset is available with Crankbrothers Ratchet hubs for less money – they’re £200 cheaper at £699.98. There are downhill and e-MTB specific models available, too. As for freehubs, you’re looking at XD and Microspline only, and both wheels come in 650b and 29in sizes. The wheels are available in black or silver.

Our test pair (a 29in front and a 650b rear) weighed 2,030g, with the front tipping the scale at 941g and the rear at 1,089g. That’s a little off from the 935g and 1,152g claims, then, but not by much. As an enduro wheelset, that’s pretty much on the money.

Crankbrothers Synthesis Enduro Alloy 2.0 I9 – Performance

Pulling them from the box presented me with spot-on rim taping, and there are valves included, which is always welcome. Installing tyres was also super straightforward.

I went a little off-piste for this test and went with the flashier silver colour scheme. It’s a neat callback to old-school bikes but with a modern twist, and it’s given my bike a bit of a Colin McRae touch… I’m all for that! In fact, these wheels have received a good few compliments from other riders.

Looks are but a small part of a wheelset, but luckily, these have the performance to back it up. Over the past few months, I’ve ridden them through a vast breadth of terrain, from natural trails to fast and lumpy bikepark tracks. Throughout it all they’ve held up incredibly well.

The silver shot-peened finish doesn’t just look good, but it does an excellent job of hiding scratches you’ll naturally get after plenty of rides, and the wheels are still looking great after my test. In fact, durability in general is pretty darn good; the I9 hubs are still rolling beautifully smoothly, and there are no signs of play in the bearings after many kilometres.

While the wheel-specific stiffness isn’t immediately noticeable, these are certainly comfortable to ride. Over chattery, rocky terrain they do a commendable job of absorbing harsh vibrations and impacts, while totally shrugging off heavier impacts. I’m actually pretty good at dinging rims while haphazardly charging through rocks, but these – on a Cast Protagonist/Antagonist tyres – remained absolutely dent-free.

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I feel the ‘tuned’ rim width gains here lie more towards the marginal side. I didn’t notice any distinct improvement in rolling resistance at the rear, but I did feel the smoothness of the front, which helps to combat fatigue during long descents. The rear is certainly strong enough to put up with quite a beating – the strength-to-compliance ratio is more noticeable here than the relative rolling resistances.

It’s really tough to complain about the Industry 9 hubs. The rear has a snappy and near-immediate engagement that brings a spritely feel to pedalling, and they look great, too. Nevertheless, if it were my money I’d be inclined to save a bit with the Crankbrothers Ratchet hubs, but upgraded to the 54t ratchet ring. Though those only come in black…

Crankbrothers Synthesis Enduro Alloy 2.0 I9 – Verdict

At £899.98 these are up against some tough competition. Race Face’s Turbine wheelset is £818, for instance, and also features a front/rear-specific build in 6069 aluminium. Hubs are the brand’s own Vaults, and the end result is lighter at 1,895g for a pair of 29in wheels.

Hunt’s Enduro Wide V3 wheelset is well worth considering if you’re after enduro strength, and they’re only a little heavier at a claimed 2,096g. You don’t get fancy I9 hubs though, and Hunt’s H_Ratchet XL hubs are a little slower with a nine-degree engagement, but then it’s all considerably more affordable at £499.

The DT Swiss EX 1700 Classic enduro wheelset features asymmetric ‘usage tuned’ 30mm rims, the brand’s DF (Degrees of Freedom) anti-pedal-kickback device, a 72 tooth freehub and J-bend spokes for £699.98. Claimed weight is 1,916g, so it’s another good option.

Don’t go thinking the Synthesis Enduro Alloys are madly overpriced for the spec, though – if you want I9 hubs, the Triad Aluminium wheelset (the cheapest enduro option now the I9 1/1s have disappeared from the line up) starts at around £1,470. These Crankbrothers hoops are obviously way under that.

If you’re after flashy looks, a bombproof build and a fast-engaging freehub, this Synthesis wheelset totally fits the bill. Despite some hard times ours still look fresh and perform as well as they did out of the box. The snappy freehub and smooth, fatigue-resistant ride is hard to knock – assuming you don’t mind the price of those hubs.