After the bike industry woke up from its fever dream of futuristic mag wheels, Spinergy held on for one more go with their fiber-spoked SPOX lineup. Unfortunately, those first-generation SPOX would join the rest of those early carbon wheels to be remembered as educational, innovative, but ultimately failed experiments. But a lot has changed since then. Fiber technology has made huge leaps, and it’s now possible to weave a spoke that is stronger and lighter than steel. Berd spokes have been twisting our expectations for the past year, but Travis Engel was more curious about what Spinergy has learned in the past decades. Their MXX 30 mountain bike wheels, laced with their unique PBO spokes, make some bold claims. Travis spent a couple months on them to see if they delivered.
If you rode bikes during the ’90s, you were probably aware of The War on Wheels. Not like Jeeps and tanks and stuff, but like a war to end the wheel as we knew it. The War on Wheels was fought on multiple fronts. From outside the bike industry, by design undergrads and their sleek renderings of “bikes of the future.” As well as from within the bike industry, by Aerospoke, Specialized, Spin, and of course, Spinergy. They promised to finally free us from the tyranny of interlaced tensioned spokes.
Thankfully, cooler heads prevailed, but thirteen-year-old me was rooting hard for the underdog. I wanted my bike to look like a G.I. Joe toy. And though I’ve since put away childish things, I still get a little excited whenever a wheel manages to make a fashion statement. Like Industry Nine’s alloy spokes, or Race Face’s giant hub shells. There are still some exciting wheels out there, but only one seems to carry on the hubristic legacy of The War on Wheels. Spinergy’s PBO-spoke models stand out as being truly unique, while also making practical, functional sense.
Insert “Spoke” Pun Here
The material inside Spinergy’s spokes is an industrial fiber called polyphenylene benzobisoxazole (hence PBO). Though PBO is structurally similar to Berd spokes’ ultra high molecular weight polyethylene (UHMWPE), it is chemically unique. For one thing, PBO doesn’t like exposure to moisture or UV. That’s why Spinergy spokes are encased in a polymer material while Berd spokes bare their threads. Beyond that, comparing the strength, weight, and elasticity of UHMWPE to that of PBO is difficult because every manufacturer may have different specs for their own sauce.
And anyway, such comparisons would just be about their pure material properties, ignoring the fact that Berd and Spinergy use different quantities and configurations of their respective fibers. Until we staff up the Materials Research Wing at Radavist HQ, there’s no way to reliably quantify the difference between a Spinergy and Berd spoke … But fuck it, here’s something I randomly found on the internet.
These charts are published by Fiber-Line, a non-bike-industry manufacturer of both UHMWPE and PBO, as well as dozens of other industrial fibers. Again, the above information is not a comparison between Spinergy and Berd spokes. Just some distant background on the world of boutique threads. It’s worth including here because fibrous spokes might become the front line in a future War on Wheels. It seems like a logical step, given how “ride feel” has continued to be a talking point when comparing wheels.
Traditionally, spoke quantity, thickness, and lacing pattern have offered wheel makers control over ride feel, but the spoke material has remained static. Fibrous spokes like Spinergy’s PBO offer a whole other dimension of control. One of those dimensions, of course, is the all-powerful strength-to-weight ratio. Spinergy claims that a PBO spoke can offer three times the strength of a steel spoke. Though I couldn’t confirm that strength claim, I could confirm that a PBO spoke is less than half the weight of a steel spoke.
That’s compared to a 2.0/1.8/2.0 butted spoke with a brass nipple. Brass nipples seem to offer the most fair comparison. Although what technically counts as the PBO spoke “nipple” is alloy, it’s quite thick and burly. It just doesn’t work like you may think. There’s a spline at the spoke’s threaded tip, which is actually just to hold it in place as you loosen the nipple from inside the rim. A bit inconvenient, since you can’t true the wheel without removing the tire and tape, but there are other wheels out there with similar restrictions.
Plus, there’s a bonus for bikepackers thanks to the hub and spoke design. The spokes are easier to store, and their flexible, straight-end design mean you won’t have to remove the rotor or cassette to replace a spoke (though you have to pound out the hub bearing to remove the radial-laced-side spokes). Quick specs on that hub: This is Spinergy’s own design, with a straightforward three-pawl 108-point-engagement freehub and center-lock-only disc mounts. It’s reasonably quick and reasonably quiet.
The Sum of Its Parts
The other thing I liked about the spokes is that there are 28 of them. I accept that 28 is the new 32, but there are way too many 24-spoke “trail” wheels out there. When weight is of real concern, 28 spokes just seems like the safest bet. Bonus points if those spokes weigh half as much as normal spokes. Across 56 spokes, that’s just over 200 grams lighter than butted steel spokes with brass nipples. To put that in context, 200 grams is more than double the difference between ENVE’s XC-oriented M-525 wheelset and their lightweight-trail M-630 wheelset. Basically, the PBO spokes offer a full category’s worth of weight loss at apparently zero cost to durability.
The MXX 30 rim is pretty traditional, with one noteworthy exception that I’ll save for the next section ’cause it’s a banger segue into my ride impressions. The carbon itself isn’t anything groundbreaking like Fusion-Fiber. And the shape isn’t as unique as Zipp, Nobl, or WTB. It’s 26 mm deep and 30 mm wide internally, with 2.5 mm bead walls. Those bead walls are pretty thin by 2023 standards. Santa Cruz Reserve wheels launched in 2017 with 3.5 mm bead walls. Most trail-oriented ENVEs measure about 4 mm, as do most Fusion-Fiber rims. Plus, MXX 30 bead walls are hooked.
That’s a bit of an odd choice. I could see it on a high-pressure road rim, but carbon mountain rims have been predominantly hookless for a while now because they work great with low-pressure tubeless setups and do a good job withstanding straight impacts. Another odd quirk is the MXX 30 valve hole. Spinergy has already widened it in forthcoming MXX 30 production runs, but on my test set, the hole in the inner wall is not big enough for the wedged base of most conical-based valve stems to sink into. My first setup with some no-name valves refused to seal, though the Stan’s valve pictured above held just fine.
Although several brands offer lifetime no-questions-asked warranties on carbon rims, Spinergy’s warranty is limited to manufacturer defects that arise in the first two years of ownership. That said, they do offer a $300 crash-replacement program. You just pay shipping and they will re-lace your damaged wheel with a new rim (no questions asked). With a few exceptions, most of those other boutique wheel warranties are only for the rim, so you’ll be paying for a re-lace on your own. Just something to consider when comparing the price of Spinergy’s full-service crash-replacement to that of a rim-only warranty. On a similar note, Spinergy also offers a trade-in program that will get you 25% off one of their carbon wheelsets and 20% off alloy.
Normally, that only applies if you’re trading in a Spinergy wheel, but at the time of writing this, they’ve opened the door to all brands of wheels. You can get the details here. And if that’s not enough, they also offer a 30-day money-back guarantee, allowing you to try out the wheels and return them for a full refund if they don’t meet your expectations. Point is, Spinergy still offers a number of innovative incentives, even if one of them isn’t “free rims for life.” I’d just recommend running a tire insert if you know you’re a little abusive.
And I am a little abusive. I’ve killed more than my share of carbon rims, and recently had to replace a two-year-old alloy rim because the dents were so bad it would no longer reliably seat a tubeless tire. Nevertheless, I did not pinch any tires or crack any hoops during my two months on the MXX 30s. To be fair, I often go several months without a big enough mistake to kill a tire, much less a rim. But the point is, despite my concerns, I had no durability issues while testing, and I did not run an insert.
Speaking of inserts (segue incoming), Spinergy fills the MXX 30 rims with a vibration-damping foam. Years ago, I did some back-to-back testing on alloy Spank handlebars with and without their foam filling, and I would call the difference “very subtle.” I don’t have that type of apples-to-apples comparison with the MXX 30s, and even if I did, it would be hard to feel something “very subtle” through all the variables that surround a bicycle wheel. I did feel something though. And it was very good.
I split my time on the MXX 30s between a few bikes. They started on an enduro-ish Scott and an XC-ish Yeti, but most of their mileage was on my aggressive-mid-travel Canyon Spectral 125. The whole time, they donned a 27-PSI 2.5-inch Maxxis DHR rear tire and a 23-PSI 2.5-inch Assegai front, both with standard EXO casing and 3C tread compound. I consider my setup to be aimed at “enduro trekking,” where I cover a lot of ground, but with the specific purpose of getting a lot of remote, often primitive descending. So, I want my wheel configuration to be nimble and encouraging when I’m trying to make good time on an uphill, but I willingly accept that this means I can’t ride like Baby Huey on rocky descents.
I just want to keep my bike flickable. Probably my favorite bike-review buzzword, “flickability” is generally more valuable to me than all-out speed. And it’s what I scrutinized first on the MXX 30 wheels. My test set weighed in at 1,885 grams with valves and tape. That’s somewhere within the “average” spectrum for a trail-oriented carbon wheelset. Forge+Bond EM30 wheels are a bit over 1,920 g. Reserve’s 30 SL wheels claim 1,725. Of course, both of those retail for hundreds of dollars more than the MXX 30. And the MXX 30s are doing something that those other wheels can’t quite match.
See, when I went into this review, I brought some skepticism with me. Fiddle around with one of these PBO spokes, and you can slightly twist it, like a taught piece of string. But that’s because you’re twisting woven fabric, not solid steel. Still, I assumed that would translate to lateral flex. And I knew just where to test it. There’s a right-hander on one of my top-three trails, where a rutted-out fall-line chute transitions from ridgeline to traverse. The trick is to ride a little inside where the V-shaped tread base will naturally push the rear wheel outward. The rear end then gets safely caught by the high side on the left as you exit off the ridge and onto the traverse. It’s like a big dirt waterslide. You can almost do no wrong, so I always hit it hard.
When I rode it with the MXX 30s, they had an interesting reaction. The jolt that usually signifies the maneuver has been completed successfully, somehow wasn’t so harsh. It was subtle, but those lateral chatters that come with rear-end steering were significantly less severe. Here’s where I’ll use the rather eye-rolling bike-review buzzword of “damped,” but I’ll combine it with that other buzzword to create something entirely new: The MXX 30 wheels have a damped flickability. The harshest points of my favorite types madness were somehow softened. Not dulled, exactly. It simply makes entering or exiting lateral moves—like dropping into a rut, hopping onto the highside, or responsibly skidding—a bit less chaotic. I’ll say it again, this effect is subtle, but that’s the nature of high-end wheels today. Nothing’s going to blow your (or my) socks off. But what it is going to do is make my beloved flickability a bit more predictable.
The other side of this “damping” debate is about straight-line traction. Now, I don’t doubt that the phenomenon I felt during lateral hits was also present in some small way during non-oblique direct hits. But if it was, it must have been even more subtle than the effect I feel on Fusion-Fiber rims, for example. I mean, Spinergy’s wheels do handle straight-line speed better than the early days of carbon, where first-gen ENVE and Reynolds wheels were distractingly chattery in straightforward chop. And of course, chop is rarely just straightforward.
When careening through oddly shaped boulders, that lateral damping stood out by allowing me to stay just a little more focused on the many last-second decisions I had to make to stay upright and maintain speed. But try as I may, and with confirmation bias in my back pocket, I still couldn’t point to any memorable moments where the MXX 30 wheels softened the repeated spikes of head-on hits. In those moments, the magic inside those spokes wasn’t doing much more than, ya know, reliably holding a mountain bike wheel together with barely three grams of material each.
I probably shouldn’t be surprised that those spokes turned out to be the main characters in this movie. Sure, I’d like to see a 6-bolt hub, and I’d give up some grams for fatter, straighter bead walls. But the fact that those even count as criticisms on a wheelset this unique shows just how far we’ve come. Not only does the MXX 30 (and the rest of Spinergy’s PBO-spoked lineup) prove that there’s still room for new ideas in wheel design, and that those new ideas can meaningfully raise the bar in performance. It proves that it can be done without raising the bar in price.
Most wheelsets with innovative new tech use it to justify numbers well north of $2,000. But the MXX 30s retail for $1,649. And at the time of writing this, you can get them at a very bike-industry-in-2023 discount, making them an insane deal at $999. It gets me stoked in the same way I was stoked in 1995 when I wanted a pair of 4-spoke (8-spoke?) Rev-X wheels. But now I’m older and wiser. So, I can tell people I’d pick these because of the material properties of polyphenylene benzobisoxazole. But somewhere deep down, I just think they look cool.
See more at Spinergy
- Added calm and predictability through chaotic terrain
- Light, lively ride under foot
- Spokes are truly half the weight of steel spokes, and promise to be even stronger
- Easier to store and replace spokes
- Head-turning design
- Reasonable price
- The dream of the ’90s is alive
- Warranty doesn’t cover as much as some other carbon wheel warranties do
- Narrow hooked bead walls don’t inspire confidence
- Truing requires removing tire and tape
- Centerlock rotor-mount only