If you’re looking to soften things up, but still want performance on a budget, these might be a good option.

There’s something to be said for sticking to your guns, so to speak. 

Spinergy first introduced its PBO spokes to the world all the way back in 2006. Instead of being made of metal, each one is basically a bundle of polyphenylene bensobisoxazole fibers (over 30,000 strands in all, supposedly) that’s claimed to deliver “three times the strength of stainless steel at just half the weight”. They’re also supposedly impervious to kinking, and because those fibers need to be encased in a separate plastic jacket (both for abrasion protection and for UV degradation), you also get the option of fun colors. 

On paper — and in pictures — PBO has unfortunately also always just been … weird. Light as they may be, the spoke thickness and round cross-section were also anathema when aerodynamic efficiency was becoming a big topic on the road, and the unconventional technology just never caught on in mountain bike circles, either, partially due to that market’s reluctance to try out proprietary wheel technology, but also because the hubs at the time just weren’t that great.

But Spinergy may have finally found its calling in gravel. The GXX carbon wheels I’ve been riding for nearly a year don’t just offer a distinctly comfortable ride quality, they’ve also been impressively durable, they’re surprisingly attainable in terms of price (relatively speaking, of course), and they’re anchored by a hub brand with a legendary track record for longevity. 

Sounds like a decent combo, eh?

Those PBO spokes may garner most of the attention whenever a discussion of Spinergy wheels comes up, but the other pieces of the GXX gravel wheels are pretty noteworthy, too.

The carbon rims are tubeless-compatible, of course, with a healthy 24 mm inner width well-suited for wider gravel tires. The 29 mm external width, 26 mm depth, and subtle rounded V profile suggest some modicum of aerodynamic efficiency relative to a shallower and boxier shape, but that’s not really the point here. More interesting is how the carbon rim sports a urethane foam core. On the one hand, this helps on the manufacturing front by applying outward pressure during the molding process, but Spinergy also claims it helps damp vibration and boosts impact strength. 

Given the unusual spokes, it’s no surprise that the hubs are similarly unusual-looking and large-diameter star-shaped flanges. They’re CNC-machined in-house at Spinergy’s facility in Mexico and rotate on Enduro cartridge bearings, but Spinergy has wisely handed off the freehub duties to California company Hadley Racing Products.

Although the conventional three-pawl drive mechanism is standard-issue Hadley, the aluminum construction used in the Spinergy body differs from the titanium that Hadley usually features. Inside the body, Spinergy has also traded Hadley’s trademark needle bearings for a pair of Enduro radial cartridges. 

Spinergy uses just 24 PBO spokes per wheel, and buyers can choose between nine different colors for the jacketing on one of them. Front hubs are offered in quick-release, 100×12 mm thru-axle, or 100×15 mm thru-axle, while the rear are available in quick-release or 142×12 mm thru-axle, with the option of Shimano, SRAM, or Campagnolo freehub bodies throughout. 

Actual weight for my test set is 1,592 g (745 g front, 847 g rear), pre-taped for tubeless, and with a Shimano HG freehub body. That’s obviously not super light or anything, but retail price is quite remarkable at just US$1,099 / AU$TBC / £1,295 / €1,495 (including VAT for UK and EU currencies). 

Without the luxury of a test jig to objectively measure the stiffness of these things, I can only say that Spinergy’s GXX gravel wheels have a genuinely distinctive ride quality as compared to just about any other wheelset I’ve ridden — and I mean that in a positive way.

While some wheels can feel super stiff and responsive, and others soft and slow, these have a highly damped ride quality that’s hard to put into words. They’re quiet and muted, planted and calm. They don’t feel like they bounce around as much on choppy ground, but instead are more likely to glide across with minimal fanfare.

It’s important to note that I don’t think it’s flex I’ve been feeling with these, either, but just an awful lot of vibration damping. I can’t say how much is due to the spokes and how much is due to the rim, but the sensation is there regardless (and Spinergy owners who have reached out to me have offered the same feedback).

Is that a good thing? When it comes to gravel, I’d say yes. With so little casing volume to play with relative to mountain bikes, it’s critical for gravel setups to provide as much compliance as possible, not only for comfort, but for performance, too. In this genre, smoother bikes are faster bikes. 

On paper, the GXX wheelset isn’t especially light, but it does feel lighter than the numbers would suggest — as all good wheels do, in my experience. They’re snappy to accelerate and quick to change direction, and generally just come across as nimble and flickable underneath you. 

Kudos to Spinergy for going with Hadley Racing for the rear freehub, too. Hadley Racing isn’t exactly a household name even in cycling circles — the company has never even bothered to put together a website(!!) However, those in the know have long held the company in high regard for its legendary durability, and at least over the past 10 months, I can’t say I experienced anything other than a similarly muted click in the pawls and reliable engagement. 

Speaking of which, that engagement speed could be a little quicker than the 15° of my test set, but that’s a moot point now, along with whatever questions I had about Spinergy’s decision to trade the roller bearings Hadley normally uses in its freehub bodies in favor of radial ball cartridges. Spinergy has since updated the rear hub with a new Hadley design that features a larger driver body and 108-tooth ratchet ring that brings the engagement speed down to an ultra-responsive 3.33°. 

Wheel build quality has been excellent, too, with no truing required during my test period, and no weird pings or creaks. This is hardly as good as instrumented testing, but in terms of rim toughness, I should at least mention that a number of bottom-outs on nasty Colorado granite hasn’t even left a mark anywhere. 

All in all, these are mighty impressive, particularly given the price. 

As good as these wheels have been, there’s always room for improvement.

For one, the ride quality is maybe a little too muted, almost to the point of being completely dead. There’s not a lot of information coming up through to your hands, and although Spinergy insists otherwise, I couldn’t shake the sensation that handling precision suffered a bit due to excessive lateral flex under cornering loads.

“I don’t have any recent data,” admitted Paul Cusick, Spinergy’s VP of sales and marketing. “Way back when when we first started doing the fiber spokes, we ran some tests against the at-the-time industry standard wheels (Mavic Ksyrium, I believe), and we came out right in line in terms of lateral stiffness.

“I just had this conversation with another journalist in regards to moto wheels. He told me that for years he had used the stiffest wheels he could find assuming that was a good thing, then he rode a bike with the stock wheels which according to the manufacturer were flexier than what he was on. He said his cornering improved dramatically and he was turning faster lap times. We have always said the same thing about our wheels: the softer feel is a good thing, like lower tire pressure even though it feels like it’s flexing more.”

In fairness to Spinergy, I didn’t do any timed testing so I may very well have been going faster through corners. That said, I still could have done without the vagueness, and some sort of middle ground might be nice.

Riders concerned about aerodynamics will also invariably be put off by the PBO spokes’ 2.5 mm-thick, round profile. However, does aerodynamic efficiency even matter for general gravel riding? Probably not, but it’s something to consider if you’re looking for reasonably priced performance wheels for long-distance gravel racing. Round cross-sections are pretty awful for cutting through the wind, and there are 24 of them per wheel here to consider. 

“On our road offerings, we do a bladed version of the PBO spoke,” Cusick explained. “Our feeling on gravel wheels is that with the large knobby tire hitting the air first, spoke drag is not a very significant component of the overall wheel drag. The round spokes pick up less dirt and mud, so that’s why they are standard on gravel as opposed to the bladed versions.”

Fair enough, but Cusick also pointed out that while it’s not listed on the company website, aero-minded riders also have the option of requesting those bladed spokes for Spinergy’s gravel wheels for a US$50 upcharge per wheel.

As good as the freehub is reputed to be, some other aspects of the hub design give me pause. Three of the four outboard bearings have no supplemental shields or seals, leaving them perilously exposed to the outside world. The Enduro cartridges that Spinergy uses are generally pretty well regarded, and two of those exposed bearings are at least sheltered behind the rotor lockrings. However, while I didn’t have any issues myself here in arid Colorado, prospective buyers in wetter climates should maybe consider this before typing in their credit card info.

As far as service goes, it’s a good thing I didn’t need to true these as it would have been a royal pain to do so. From the outside, Spinergy appears to use exposed nipples, which is sort of true. However, what isn’t so obvious is that there are two tools required for truing: one to keep the “nipple” from turning, and the other to actually turn the real nipple that’s hidden inside the rim. It’s a slow process that I thankfully haven’t had to do in over a decade, and now that tubeless is a thing, it’s important to remember that tubeless tape can’t be reused once it’s peeled off the rim, which then adds cost on top of hassle. 

I have to say that I find the way the spokes are secured to the rims to be pretty ugly, too. There’s too much thread exposed for one, and the amount of thread exposed varies from one side of the wheel to the other. Maybe this is my wheelbuilder roots coming out, but this asymmetry in particular just grates me, especially since these spokes are presumably made in custom lengths to Spinergy’s specifications. On the plus side, at least replacement spokes are available directly from Spinergy, and at reasonable cost.

“We have had only a handful of actual broken spokes in 20 years,” Cusick said. “The last one I remember was due to a horse stepping on the customer’s wheel — not joking. Spokes are US$8 each and include the nipple.”

That’s reassuring, but I’m still a little disappointed by Spinergy’s warranty coverage. Many carbon wheel brands have moved to no-fault policies that cover just about any possible riding scenario, if perhaps only to ameliorate concerns over carbon rims’ impact durability. However, Spinergy’s policy is more traditional, sticking only to manufacturing defects and the like, and limited to two years for the original owner. This is supplemented by a “No Fault Replacement Program” where new wheels are sold at a hefty discount in the event of something like a crash. 

“Our warranty is more traditional, I guess, but we have also worked really hard to get the price down to a really competitive level for carbon wheels,” Cusick explained. “You know how it goes with buying extended warranties: you can pay up front and probably never use it, or pay less up front and a bit more if you ever do need it. I get the feeling based on pricing that some of our competitors are including the cost of the ‘extended warranty’ in their pricing. We are really confident in our carbon rims and have had very few issues. Replacement rims are US$200.”

So, do the pros outweigh the cons here? I’d say they do, yes. 

They ride exceptionally well, they’re very reasonably priced, construction quality seems excellent, and you can’t do much better than Hadley in terms of freehub reliability. The aero thing isn’t a big deal — especially since there’s a workaround — and although truing is a major headache, at least it likely doesn’t have to be done very often. And are those exposed bearings a deal breaker? They aren’t for me, but they’re certainly something I’d think about seriously were I living somewhere like the UK or the US Pacific Northwest.

That all said, I’m still of the opinion that being smooth matters more than being stiff when it comes to gravel bike performance, and I dare say these would be on my short list if I was looking to buy some new wheels for myself. 

Sorry for having these so long, Spinergy. Parting will be such sweet sorrow.

More information can be found at www.spinergy.com.