I recall the first 29er I rode back in the day. It was an aluminum Bianchi SOK singlespeed with Avid Juicy brakes that never quit and a 100mm RockShox Reba fork. What a whip. I transitioned from 26″ to the big hoops without spending any significant time on 27.5″ bikes, and when I test bikes from the middle size now I can appreciate a lot of the platform’s unique character traits. So when the opportunity came up to test out this mixed-wheel bike I was more than a little excited. Would it really hold all of the best bits of both 29″ and 27.5″ bikes?
The Define AL Race 160 from Poland’s NS Bikes is a long travel enduro race machine designed around today’s modern gravity courses. With a 170mm fork and 160mm of rear travel, mixed wheels, and that blingy beer-colored Kashima coating, it should help riders find their limit on nearly any race track.
I’m going to kick this review off in reverse, with the less tangible “felt” elements first. The burning question I had for this bike was “what’s special about mixed wheels?” The lukewarm answer is that I’m still not sure. While the bike performs well on a variety of terrain, I don’t have the sense that it rips out of corners faster than a similar 27.5″ bike, or flattens rock gardens like a full fledged 29er. Instead, It rides really well in a variety of situations but doesn’t necessarily outshine a symmetrical-wheeled bike in any of them.
I rode this bike for a few laps at La Thuile Bike Park, and on super rough terrain the front end does roll with the impacts a little easier than a full 27.5″ setup would, but the rear tire occasionally hangs up on larger holes where a 29″ circle can more easily roll through. These properties pushed me to position my weight further forward, similar to how I would ride some single pivot bikes or a hardtail that can get hung up and slowed down. With the right position, this issue is largely mitigated, but it does take time to grow accustomed to.
On the more rhythmic sections of bumpy trails, the Define glides nicely, aided by the smooth Fox Factory suspension and thin Maxxis EXO tire casings that absorb trail chatter well. Anywhere a 27.5″ bike would fair well, it does, with one surprising bonus.
The main place that the Define AL Race 160 feels exceptionally good is in steep turns when the bottom of the rear tire is rolling above the front hub. It has a sweet carving sensation like that of fat parabolic skis in fresh snow. I can’t guarantee that this is due to the mixed wheels, or the bike design more generally, but it feels fantastic. If you like to fly through steep turns without muscling the bike, or really thinking about it at all, this whip is worth a close look.
Enough about the mixed wheels. The Define AL Race 160 is a great bike in its own right. Setting it up is a breeze if you are familiar with Fox suspension, though it does ship with tubes in the tires so that will cost some time and sealant. I had to pump about 20 PSI more than I typically would into the shock to achieve the support I was looking for, but once I hit the right number the Fox DPX2 shock worked as splendidly as it does on any other bike. Apart from that most of the settings were quick and easy to sort out.
At 32lbs (14.5kg) on the nose for a size medium, this alloy bike isn’t the heaviest enduro sled out there, and there are multiple components that could be swapped out to shed a little heft. With a moderately steep 76° seat tube angle, the Define climbs better than some of its enduro racing peers. There is little pedal bob to speak of, and with a forward saddle position, the front wheel tracks well enough considering its slack 64.3° headtube angle.
The medium frame’s 457mm reach is somewhere in the middle of the current enduro geometry range, and paired with its 438mm chainstays this bike feels neither playful nor planted, but somewhere in between. The slack head tube has saved me from more than one poor line choice, and overall the bike feels well balanced on rowdy descents despite the occasional rear tire snag. Apart from the cornering sensations mentioned above the Define has a largely unremarkable descending character. It descends well, and there isn’t much that stands out about how it does so. Maybe that’s a really good thing?
Finally, enduro bikes must be sprintable. Racers have to put all their breakfast into the pedals to exit corners and tricky rock gardens with a hard sprint, and this is where the Define AL Race 160 could really use a few volume spacers in the shock. While the bike feels decently supported through the mid-stroke on descents given its long 160mm of rear travel, it soaks up a lot of throttle when I stand up and try to turn my lungs inside out. I tried adding low-speed compression to the shock, but with enough compression to improve mid-stroke performance it becomes too harsh. This bike is a prime candidate for a volume spacer or two.
The alloy frame
The frame uses a down tube channel to hide the cable housing and brake hose, and along with the external bottom bracket cups this bike is a home mechanic’s delight. A lot of long travel frame manufacturers have gone away from mounting cables below the down tube where they can be damaged by rocks. While there is a small plastic cover near the BB, I would be concerned about severing a brake line if this were my personal bike.
The rear triangle has ample space for wide 2.5″ tires and their requisite mud, and the main pivot hasn’t managed to collect an abundance of mud on wet rides. NS lengthened the seat stays to make the frame mixed-wheel compatible, which lifted the BB and put the head tube angle back to the same place it would be with symmetrical wheels. The company makes an identical 29er model in both alloy and carbon fiber.
The chainstay is well protected, and along with the SRAM derailleur clutch it keeps the bike surprisingly quiet. A dependable four bar suspension design makes things simple throughout, and this bike should be an easy one to maintain for privateer racers and hard charging trail riders.
The shock mount can be flipped to adjust the BB height up and down by 5mm, and riders can also purchase a different mount that cuts the bike’s travel to 130mm. Two bikes in one? Yes please.
It’s no secret that the Fox Factory 36 fork and DPX2 shock on the Define Race AL are a fantastic piece of kit. The suspension on this bike works flawlessly, despite potentially needing a few spacers, and it certainly feels like the right balance for the frame’s leverage curve and intended use.
The control center on this build is also well suited to a good day out on the race course, with a set of SRAM G2 RSC 4-pot brakes and a 12-speed X01/GX Eagle mixed drivetrain. I managed to blow through brake pads with this bike for some reason. After trying several different brands I landed on a set of Alligator semi-metailc pads that have held up far longer than the original SRAM set.
The house brand 35mm carbon handlebar is as stiff as any. Maybe a little too stiff for my taste. The rest of the house brand kit has a scathed-copper look that matches the frame well, and most of it is right in line with the bike’s gravity race focus.
My primary complaint about the Define is the same as nearly every other enduro bike that I test; the tires are useless for anyone who wants to race an enduro or ride similarly rough trails. I won’t digress here, as we all know Maxxis EXO casings are nowhere near tough enough for gravity bikes. I flatted the rear tire twice and the front once before changing both. In short, this bike needs a downhill casing on the rear wheel and at least a heavier gravity casing up front. Tires are a terrible place to shave weight.
At €5699, the Define AL Race 160 has a great component spec and a decidedly comfortable ride quality. Though it didn’t sell me on the mixed-wheel platform just yet it does ride very well and would undoubtedly be a fun bike for racing enduro. I want to re-highlight the steep turn love for this model, as it truly is something special. On a good day, I love to push traction speed in the turns and this bike was a pleasure to lean over.