Industry Nine 26" Gravity Wheels - Reviewed

Traditional steel spoked wheels will likely never go the way of the dodo, but Industry Nine believes that there is a better solution when it comes to assembling a wheelset, and that involves large gauge, straight pull aluminum spokes that thread directly into the flanges of their radical hubs. It doesn't end there, though, as they offer pre-built wheelsets that use their own rims, with our downhill oriented test wheels being built using their 530 gram Gravity rim in chrome, custom anodized blue spokes, and chrome hubs front and back. These things not only look incredible, they're also very light given their intentions at just 817 grams for the front wheel and 976 grams for the rear. That adds up to a 1,793 gram wheelset that I9 says is burly enough for everyday use on your downhill bike. Compare that figure to other DH specific offerings out there and you'll find that the I9s impress. Low weight is one thing, but reliability trumps numbers when it comes to what's required of a downhill wheelset, doesn't it? With that in mind, we put five hards months of riding in on the I9s to find out how they hold up to everyday abuse.

I9 Gravity wheelset details: • Intended use: downhill • Alloy rim, tubeless ready (530 grams) • Rim width: 33.5mm outer / 28.5mm inner • 20mm thru-axle front hub (QR and 15mm compatible) • 12 x 150mm rear hub (135mm QR and 12mm, 142mm, 152mm compatible) • 9/10 spd aluminum freehub body w/ 120 point, 3 degree engagement (XD version available) • 32 Aluminum 2.8/3.0mm butted spokes • Standard Colours: all red or all black hubs/spokes with black rims • Weight: 1,793 grams (claimed 1,750 grams) • MSRP: $1,210 USD base price

Construction

What makes I9's Gravity wheelset more downhill specific than their other offerings? It comes down to the rims and spokes, with both being burlier than what you'll find utilized in the rest of their lineup. The aluminum rims feature 33.5mm outer and 28.5mm inner widths, making them wide enough for use with proper DH tires (as you'd expect), and their height should help to fend off pesky flat spots that might come from speed miscalculations. I9 also says that they are "tubeless ready", although this refers to rim bed and hook shape, not a sealed rim bed - they do require sealing tape that comes pre-installed from the factory, along with a set of tubeless valve stems, to get everything rolling sans tubes. Black is the standard rim colour on tap, but the eye catching silver colour shown here can be had for an extra $50 USD should you be looking for a bit more flash. Have your own rims that you prefer? Not a problem, I9 will do that for you as well.



It's easy to spot a set of I9 wheels due to their large diameter, straight pull aluminum spokes that thread directly into the hub shell, often seen in flashy colours like the custom blue spokes on our test wheels. There are no nipples to be found here, either, with four wrench flats machined into the spoke at the rim end, as well as a shape to the end of the spoke that mates with the hole at the rim. While I9's standard spokes (featured on both their Trail and Ultralite wheelsets) use a butted 2.7/2.9mm diameter, they've gone with a heavier gauge 2.8/3.0mm version for their Gravity wheels that is said to improve strength while adding only minimal weight. Red and black are the two stock colour options, but silver spokes can be had for a $50 USD up-charge; or blue, gold, orange, pink, purple, turquoise, and green for $150 USD. Those who want to feel really special can combine two or more colours in their preferred lacing pattern for $260 USD extra, thereby ensuring that there is little chance of anyone out there having the exact same wheelset as you.

All those colours sure are pretty, but why go with straight pull aluminum spokes over the established standard steel spoke? It comes down to the two weak points found in a common spoke: the J-bend and the cut threads. Of the two, failure at the J-bend is far more common, since it is constantly being loaded and unloaded at the joint between the hub flange and the bend as the wheel rolls down the trail. As spoke tension lowers over time, slightly more slop can develop between the two, which can cause it to fail sooner than a wheel that can hold its tension longer. Not all steel spokes fail, obviously, and it seems that it happens less and less lately, likely due to quality control improving, but I9's straight pull aluminum spokes look to eliminate the issue altogether. The other talking point, according to I9, is the inherent rigidity in the design, with them saying that their ''stiffer spokes provide unrivaled cornering and tracking performance through the nastiest terrain,'' and that ''the added stiffness also makes tuning easier; eliminating the mushy, vague feeling most DH wheels deliver.'' Certainly some serious claims, but only trail time will reveal if they ring true.



I9's updated Torch freehub design delivers a quick 3° engagement via the 120 point drive ring set into the hub shell that mates with six pawls, with each of the pawls employing two edges that double the amount of bite. Rather than a single wound spring wrapping around the entire freehub, the layout employs separate coil springs to prop each of the pawls up. This should make for a much more reliable clutch system than if it depended on a single spring. The freehub body itself is aluminum, with a sealed bearing pushed into place at each end, and I9 says that their new sealing system helps to lessen drag compared to the previous design. Both the front and rear hubs are practically works of art, with machine work and detailing that makes them stand out from everything else. They're also compatible with pretty much any axle out there thanks to interchangeable end caps front and back - QR, 15mm, and 20mm up front; and 135mm QR, 12 x 135mm, 12 x 142mm, 150mm, and 157mm for the back. The caps also use an interference fit courtesy of O-rings, meaning that no tools are required to make changes. We love it when it's easy.




Installation

We ran our I9 test wheels with two different downhill tires throughout the summer and fall riding seasons, with Bontrager's new low profile G2 rubber fitted out back when conditions were dry enough to take advantage of how fast it rolls, while Kenda's 2.5" Excavator Pro downhill tires were used for the majority of the time. We went to a tubeless setup straight off the bat rather than muck about with tubes, and were happy to find that the rims' "tubeless ready profile" is an apt description given how easy it was. The I9s were painless in this regard, unlike some options on the market that require that their rim beds be artificially raised slightly with a few wraps of tape in order to provide a tight enough tire bead and rim interface to seal easily. This obviously might not be the case with every tire on the market, with some combinations requiring a bit more grunt than the floor pump we used in our shop to get the job done, but they were certainly among the easiest to set up tubeless in recent memory.



It was smooth sailing when fitting the tires, rotors, and cassette, but we ran into some rough water when we went to install the rear wheel onto the back of our GT Fury test rig, with the wheel refusing to spin when the bike's axle was tightened down. Slotting the wheel into the back of another bike showed that the problem wasn't specific to the GT and likely a tolerance issue within the rear hub that was causing the wheel bearings to be overly preloaded. We were able to get the wheel to spin freely by not tightening down the GT's thru-axle as snug as it should be, but that solution is obviously far from ideal. A replacement freehub body didn't solve the issue, either, thereby pointing the finger towards the hub itself.



Performance

Our chrome and blue I9 Gravity wheels saw quite a bit of action in the Whistler Bike Park, a location that can certainly highlight any shortcomings in a bike or component, as well as many shuttle runs on our local mountains. Our two main points of concern before testing kicked off centered on how I9's aluminum spokes would hold up, as well as their Gravity rim, an unfamiliar product to us. As it turned out, both proved to be non-issues, with neither giving us even a hint of trouble during testing. A handful of incidents that saw us coming up short failed to leave behind a single ding or dent in the rear rim, and we're not only talking about manicured jumps but some serious rock and square edge impacts - while obviously not indestructible, they certainly do appear to be quite robust relative to their 530 gram claimed weight. No dents or flat spots also went a long way to keeping the wheels from losing any spoke tension, something that didn't happen at all during our time on them. And not only did we never have to add tension, we also never had to true either of the wheels. That's pretty good in our books, and we now have more confidence in our Gravity test wheels than many much heavier wheelsets on the market. The rim's ability to shrug off our efforts to dent it is highlighted by the fact that tire pressures were often well under 20 psi, so it certainly wasn't like the Kenda and Bontrager rubber was shielding the rim from damage caused by our speed miscues. We did manage to burp a small amount of air and sealant from the rear wheel at those low pressures, although never once had an issue with pulling a tire off of the rim in a hard corner or awkward landing.



Wheel rigidity is something that is talked about often, and it would be easy to assume that the I9 wheels would be stiffer than a more traditional wheelset given their large diameter aluminum spokes and tall rims, not to mention the claims made by I9 themselves. That very well might be the case, but we couldn't pick it up when they were bolted to a 220mm travel bike with wide tires deflated to around the 20 psi mark - there are just too many other variables that mute any expected gains when talking about rigidity, despite the fact that they likely are stiffer than a traditional wheelset. If you can't pick it up when pushing hard, is it still an advantage?

And what of those fancy aluminum spokes? None broke, which is always good, and they were also free of creaks and groans that we thought might pop up over time, especially at the cross where they make contact with their neighbor. The one caveat is that we didn't put any serious dings or gouges into any of them, which is obviously a good thing, but it also means that we weren't able to see how they fared after being damaged. Maybe the answer was to pick one unlucky spoke to intentionally sabotage in order to see how it held up afterwards, but damn, these things are simply too beautiful to do such a thing.



The wheelset's chrome rims and blue spokes obviously caught people's eyes, but the real jewels of the I9 setup has to be its hubs. These gems at the center of it all are so pretty that you almost want to unlace the wheels and set the hubs on your desk simply to stare at for a few hours everyday. The sound emanating from the rear hub when coasting should be enough to keep you from ever wanting to do such a thing, though, and the loud metallic buzzing is also unique enough that at least a few other riders asked what sort of hub we were running on the back of our Fury test platform. The relatively loud humming won't be for everyone, and there feels to be a touch more freehub drag when turning it by hand than a less aggressively designed clutch system, but it also makes for a damn quick 3° engagement when it's time to jump forward. That's quick enough that it feels instantaneous underfoot.

Bearing life on our test wheels seems to be on par with anything else on the market, with the rear hub now feeling just a touch rough after five months of abuse, although it should be noted that our binding issue may have accelerated bearing wear in this case. The tool-free hub end caps do make accessing internals quite easy as well, but the inference fit with the front hub's O-rings was just loose enough for us to sometimes knock one of the end caps out of place when sliding the wheel into the fork. Have you ever arrived at the mountain to find that one of your hub end caps has been left at home on the driveway? We have. Small issue, no doubt, but worth mentioning given their $1,210 USD base price.


Issues

After a close examination it was discovered that the rear hub's non-drive side bearing bore was out of tolerance by 0.25mm, which turned out to be enough to add both excessive bearing preload and cause the freehub body to come into contact with the hub shell when the bike's thru-axle was tightened down properly. It's a bit of a shame for this beautiful wheelset to be taken down by what turned out to be a machining error that measured just a quarter of a millimeter, especially when we know that there are countless I9 wheelsets out there running smoothly, including the one that we originally reviewed back in 2008. This left us a bit deflated, regardless of their otherwise flawless performance, and we'd hope for more from a $1,210 USD wheelset. However, I9 did tell us that they have taken steps to prevent the issue from popping up again: ''We have added two quality control measures since we shipped this wheelset in order to preclude this happening on wheels and hubs in the future,'' I9's Operations Manager, Jacob McGahey, explained. "A more precise bearing bore check, as well as a final wheel and hub check where a high force is applied to the hub end caps to check for correct bearing preload and freehub drag.'' The other updates include the addition of a double-row inner freehub bearing, a change that should take bearing longevity to even higher levels, as well as added clearance to the backside of the freehub body to prevent any contact with out of tolerance components.

We had absolutely zero issues with I9's proprietary aluminum spokes on our current test wheels, but previous experience with a different I9 wheelset showed that they can be a bit more prone to failure when damaged compared to a common steel spoke. I9 owners should be aware of things like pedals from other bikes going into their spokes during shuttle runs, as a good sized gouge can lead to a spoke needing to be replaced. It's not terribly uncommon for standard steel spokes to break, of course, usually at the J-bend or the threads, but we're willing to bet our last cookies n' cream Clif Bar that regular spokes stand up better to general neglect and abuse that I9's aluminum version.


Pinkbike's take:

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