|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
Industry Nine's jewel-like hubs, with their threaded spoke flanges and easily interchangeable end caps, are the highlight of the wheelset.
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.
With a 33.5mm outer and 28.5mm inner width, Industry Nine's own Gravity rim is certainly ready for true downhill tires, and it weighs a competitive 530 grams.
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.
Industry Nine's wheels use proprietary, straight pull aluminum spokes that thread directly into their own hubs. Wrench flats have been machined into the opposite end to facilitate truing.
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.
Six freehub pawls, each with two biting edges, and a 120 point drive ring, add up to a quick three degree engagement system.
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.
We tested the Gravity wheels on our GT Fury test bike that saw plenty of action in the Whistler Bike Park.
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.
Rough enough? Day in, day out, the Gravity wheels rose to the challenge and performed well.
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.
Light and sturdy, they were only brought down by a bearing issue within the rear hub.
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:
|I9 is adamant that the binding we experienced in the rear hub is the first time that they've come across such an issue, and also pointed out that their wheels come with a three year warranty (many competitors only offer a single year warranty) that covers all of the parts that they machine in-house - had our wheelset been with a customer, it would have been looked after. Binding issue aside, I9's Gravity wheelset did everything we asked of it without any objections. If you're looking for something a bit different - perhaps even a custom colour combo - and don't mind the proprietary spokes, then the I9s are worth looking at. Their relatively light weight and unique construction does carry quite the price tag, though, so it'll be up to you to decide if they're worth the extra coin. Are you building your downhill bike on a budget, or are you assembling a one-of-a-kind dream rig and want something a bit unique? - Mike Levy|
Proprietary technology that solves a problem nobody has? Pass...
timkoerber, and that should make you wary of their claims. If they say the j-bend is a problem here, yet they are still selling j-bend spokes, then they obviously don't fully believe their own hype, and they see the claimed benefits are very limited.
If people want to continue to downvote me that's fine, but I've spent hours and hours in a lab breaking hundreds of spokes from various brands/styles of spoke in a tensile machine, under static and dynamic loading conditions. I trust that a lot more than marketing hype.
i built a set with ZTR FLOW EX and 2mm spokes (single gage) , with 16mm nipples - the full build is under 1,900 gr....
ofcourse u can make it lighter with DB spokes and "regular" 12/14 mm nipples
YES you can melt 7075 and YES you can add a filler material, but you break down the chemical composition (Thats the part that makes 7075 so strong) to the point where you might as well have pure aluminum (dog shit). It is considered unweldable because it is made structurally unsound when welding.
I don't believe that alum spokes are that bad after all
There are definitely more economical wheels out there (hopes to stans duh) but these are rad.
I don't believe that alum spokes are that bad after all
Have their gravity wheels-I love them.Marvelous review and test.Thank you!
Spokes are in tension in a wheel. Tension stiffness of a spoke is proportional to Area (A) x Modulus (E).
For a 2.8mm aluminium spoke, AE is proprtional to 2.8mm^2 x 70 GPa = 548 E6.
For a 2mm steel spoke (non butted usually used on DH wheels), AE is proprtional to 2mm^2 x 200 GPa = 800 E6.
Steel spokes build into a stiffer wheel. i9 is lying!
Yes they are pretty and sounds like they are good, but please no lies inb the marketing. Can we have a name a shame section on Pinkbike.
The most important thing is to regularly maintain and check on your wheels. Don't let them get out of true or let tension in the spokes get very uneven, and watch for wear around the spoke head and nipple corrosion or deformation (if aluminum nipples). Do this, and the only time your spokes should be breaking is if your derailleur hanger breaks and the derailleur rips through your wheel.
Phutphutend, higher spoke tension does not equal more stiffness. + I would assume the stiffness comes from the thickness of the spokes and the material.
More info (with experimental data) on wheel/rim deflection vs. decreasing spoke tension
I'm not having a dig at the article - I'm just really interested in the mechanics of bike construction and want to know more !!
Edit - I should have replied to MTBLegend92's thread below...
the spoke thread on those is rolled not cut ( as is the case with every decent steel spoke too ). I'll spare the details but rolled threads are much stronger due to the material being cold worked... only downside is in manufacturing as it takes roughly 1/3 hp more to complete instead of cutting it ! Also that infamous J-bend is done cold too so again not much of a factor with quality spokes, I guess I'll have to bring spokes to my school and test them out !...
I have these wheels and have had huge problems since day 1 with them - as have loads of other riders - checkout MTBR to see the woe being caused to riders who have forked-out a huge amount of money on a very unreliable set of wheels.
Bearing problems, spoke detensioning problems, freehub problems, freehub falling clean-off the wheel when fixing a puncture - pawls and springs popping out and getting lost in the mud - crazy!!
Revised spacer design, revsed freehub design....etc....all of these problems should have been fixed in their QA process and never have reached the customers.
I've never ever had such issues on my Hope Pro 2's on Stans Flow rims, and they're less than half the price!
These wheels are great to look at, but put them into real riding riding conditions and their poor reliablility shows-up very quickly.
And it's all well and good poeple saying "Oh, I9 were so good at sending me replacements etc.." - well, you never should have needed those replacements in the first place if they had made a good quality product.
I got a warrantied freehub from them and they were so mean they didn't even include the pawls or springs with it - that's just lousy service for all the time my bike has been off the hill waiting for them to send me a part that should have never failed in the first place.
I wouldn't buy straight pull again either, stronger or not. I've got a set of hope spam4s and while they work flawlessly, they are too big of a pain in the neck to clean properly. You just can't get in without taking the disc off and using a tooth brush, and who's got time to do that? It's standard flanges and centrelock discs all the way for me now.
The freehub pickup sounds rude though. I wish my hope and shimano hubs had quicker engagement.
At $6 apiece, that's a serious concern, if one's bike is inclined towards taking bikepark abuse. But I'd happily run them on my enduro bike. A 100 gram penalty for a wheelset that would serve my enduro needs without requiring constant spoke replacement is a very attractive proposition. And given the weight, the price isn't all that steep either. Hmm...
Tried Superstar (£130 wheels), Hope, Saint etc - all fit fine with no issues...
Something like a precision bearing, on the other hand... yeah no. That needs to be exact.
wow - what a bold faced lie - the people on MTBR would beg to differ!