Mixing Materials - Testing Carbon and Aluminum Wheels Together 28

A year ago, I weighed in on one of mountain biking's burning questions: What is the superior rim material— carbon or aluminum? With passionate supporters behind each, I attempted to set the record straight once and for all with a simple head-to-head test. Oh, the naivety. Of course, things are never that simple, and both materials present strengths and weaknesses depending on terrain and rider preference. And while I don't think one material is superior, I understand the passion behind each.

Following that test, a new question emerged in our comments, forums, and on the trail: What happens when you run a mixed-material wheelset? Is there a setup that blends the strengths of both materials? Are the differences enough to present a real performance benefit? Many riders have rocked mismatched wheels (usually due to breaking and replacing a wheel with the easiest available option), and I've heard praise for both setups (carbon front/alloy rear vs. alloy front/carbon rear). 

After letting the idea marinate on a back burner most of last year, the launch of Roval's new Traverse collection offered the perfect opportunity for some mixed-wheel testing. After countless rotor, cassette, and wheel swaps, here is what I uncovered. Spoiler: there is so much more than rim material alone dictating how your wheels feel.

Roval's Traverse wheels are well-known because of their OEM presence on most Specialized mountain bikes. From the benchmark Stumpjumper EVO, to the full-power Turbo Levo, the Traverse lineup caters to a broad range of riders. The latest Traverse family was released last July and consists of two carbon and one alloy wheelset. For this test, I compared the HD Carbon and Alloy models because of these factors: 

• Similar intended use: trail, enduro, bike park
• Similar weight (~100g difference)
• Same spoke count, lacing orientation, and hubs 
• New rim designs on both models intended to increase durability and pinch flat protection (challenge accepted)
• Both have a lifetime warranty and a limited two-year crash replacement warranty
• Wheels are sold individually, so you can try this test, too

Left out was the Traverse SL II, Roval's lightest carbon trail wheelset to date (1,645g). Compared to the previous SL model, it is now more vertically compliant but also stronger and more resilient to pinch flats. A good option for those looking to shave additional weight or a more forgiving feel, you could also combine an SL II with a Traverse HD or Alloy. Ultra-compliant SL II front wheel with a stiff HD rear? That sounds like an interesting test for another day. 

Roval Traverse HD Details

• Available in 29" front and rear, 27.5" rear only 
• Front and rear-specific carbon layup
• Offset spoke drilling (28 count)
• Rim Dimensions: Depth: 24mm // External width: 40mm // Internal Width: 30mm // Bead width: 5mm
• Hand-built
• Lifetime manufacturer warranty
• 2-year "It Happens" crash replacement
• Weight: Front: 806g/ Rear: 995g/ Total: 1,801g
• DT Swiss 240 MSRP: $2,300 (Front: $925 / Rear: $1,375)
• DT Swiss 350 MSRP: $1,500 (Front: $600 / Rear: $900)

Roval dubs the Traverse HD as its strongest carbon wheelset. With durability and pinch flat protection weaved into the design of the front and rear-specific rim layups, the goal was to give riders a smooth, traction-seeking front wheel and a stiff, impact-resistant rear. The rims use an offset spoke drilling and hookless bead along with a unique 'Flat Top' bead profile that requires a claimed 85% more force to pinch flat than a typical round bead. The 5mm thick bead also gives the rims an extra wide 40mm external width.  

I tested the wheels with DT Swiss 350 hubs and Competition J-Bend spokes, which retail for $1,500. Riders can spend an extra $800 to upgrade to 240 hubs (with the same Ratchet EXP 36t internals and 10-degree engagement) and Aerolite spokes, which save ~75g. 

Traverse Alloy Details

• Available in 29" front and rear, 27.5" rear only (sold individually)
• 6013 shot-peened alloy 
• Offset spoke drilling (28 count)
• Rim Dimensions: Depth: 21.65mm // External width: 34.6mm // Internal Width: 30mm // Bead width: 2.3mm
• Hand-built
• Lifetime manufacturer warranty
• 2-year "It Happens" crash replacement
• Weight: Front: 897g / Rear: 1007g / Total: 1,904g
• DT Swiss 350 MSRP: $850 (Front: $350 / Rear: $500)

Like the HD wheels, Roval has pitched the Traverse Alloy as its most durable aluminum wheelset to date. The shot-penned 6013 rim features an asymmetrical design with offset spoke drilling, plus a bead shape that's supposed to bend inward upon impact, minimizing air loss or the chance of blowing a tire off the bead. 

The Traverse Alloy is only sold with DT Swiss 350 hubs and Sapim D-Light spokes. Unfortunately, the rim doesn't use a TreadBed valve but rather a standard tubeless valve. 

Before diving into on-trail performance, I want to address two things. The first is price. Usually, the warranty accompanying carbon wheels helps justify the high price—that's not the case with the Traverse lineup. The $650 extra you have to cough up for the HD 350 wheels doesn't buy you extra peace of mind, but instead, 103 grams saved and a different (stiffer) feel. This is something to consider if price is the motivating factor behind your next set of wheels. 

The second is internal rim shape and how that affects tire profile. Both rims have a 30mm internal width, but the HDs are 2.35mm deeper with double the sidewall thickness. This translated into more sidewall support and was quite noticeable through corners. Riders around my weight or heavier and those who ride hard will definitely benefit from the dimensions of the HD. 

On The Trail

To minimize variables, I tested the wheels at two spots in San Diego over three months before spending a day riding each setup back-to-back (to-back-to-back). Riding both wheelsets before comparing mixed setups allowed the spokes to settle and tire casings to break in. It also allowed me to test Roval's claims of superior durability. 

I mounted 2.3" Specialized Butcher tires in their GridTrail casing with 25 psi in the front and 27 psi in the rear. All testing happened aboard a SCOR 2030. Its combination of relaxed geometry and minimal travel (120mm rear/140mm front) meant that my average speed was high down trails, but the margin for error was slim, and there wasn't much suspension to drown out the feel of the wheels.

I know the point of this review is to test carbon and aluminum together, but let's start by summarizing how each wheelset performed individually.

Traverse HD Performance

The Traverse HDs offered a nice blend of stiffness and responsiveness with adequate damping. They weren't the stiffest carbon wheels I've ridden, but they weren't the softest. The key is that it was methodical when they were stiff or compliant, creating a precise, supported ride. 

They excelled at holding firm through high-energy corners that translated into forward momentum. Pumping my weight into the pocket of berms was met with an immediate, snappy redirection that was predictable and fast. Over small bump chatter and moderate compressions, I did feel bumps more than through my hands and arms. On the one hand, this meant my arms had to withstand more abuse on long descents; on the other hand, there was no slop or vagueness in how the wheels responded to the ground. Since I wasn't lapping long downhill tracks, I enjoyed the definite feel. I never struggled to find traction, and the HDs had great compliance when taking impact straight on. When blitzing rock gardens, the wheels didn't deflect much at all, and I was able to keep tracking where I wanted. 

Traverse Alloy Performance 

The Traverse Alloys delivered a soft, smooth ride that took the edge off trail vibrations and impacts. They were noticeably more comfortable than the HDs, which kept my bike calm and planted through rough sections. The downside of this comfy damping was a lack of support when I really started pushing the wheels. 

Comfort was quickly replaced by moments of squirming that made it hard to predict how my bike would respond. Corners and harsh landings highlighted this instability, and the experience was worse with the rear wheel. While the HD carbon rear wheel would stand me up through turns and push back against my efforts, the Alloy rear wheel would flex and wind up as the tire would roll on the rim, and then the wheel would rebound, shooting me out of corners. Sometimes, I was able to rip a corner and use that flex to my advantage, while other times, it was tough to gauge where the wheel would send me. 

In a straight line smashing into rocks and braking bumps, the Alloys felt nearly identical to the HDs, remaining firm and exact with enough give to absorb impacts and not deflect. Overall, the Traverse Alloy wheels were enjoyable for day-to-day cruising on familiar trials and are damn strong when it comes to impacts. If I were to keep riding them, I'd toss on tires with a stiffer casing to help alleviate the instability I felt in high-energy moments. 

I have to applaud Roval for making both rims extremely capable of taking a wack with grace. As I say in all my wheel reviews, testing wheels is the best because it gives me the okay to deploy a plow-and-pray mentality. In the spirit of product testing, I did my best to hit some shit, but the HD and Alloy rim weren't phased. This isn't to say they're unbreakable (what wheels are?), but their resilience was commendable for 28-spoked, all-mountain wheels.  

After months of testing and a dizzying day of laps comparing each setup, here is how they stacked up from least to most favorite: alloy rear/carbon front, alloy front/rear, carbon front/rear, carbon rear/alloy front. 

Least Favorite Setup - Alloy Rear & Carbon Front

Pairing the Alloy rear with an HD front wheel was the least enjoyable because it was the most unbalanced. The difference in lateral stiffness front to rear, combined with the tendency for the tire to roll on the shallower aluminum rim, caused my bike to squat out in corners. The rear wheel would wind up and step out through a corner while simultaneously, the front wheel would continue to track on a constant path. It was a very disconnected feeling and led to a lot of oversteering and a few rear tire burps.   

Outside of turns, the stiffness of the carbon front wheel felt amplified compared to the aluminum rear's muted feel. Even though the vertical compliance felt similar between the wheels when I rode them as a unified system, mixing them seemed to highlight their differences. I was still able to ride at a fun pace and could hit compressions, drops, and jumps with the same aggression, but the lack of consistency through corners placed this setup at the bottom of the list. 

Favorite Setup - HD Carbon Rear & Alloy Front

If the goal of this test was to see if a mixed material wheelset could combine the strengths of both materials into one, then this setup achieved that initiative. The asterisk is that it barely beat out carbon front and rear. 

I enjoyed the carbon rear with an alloy front because I got all the benefits of having a stiff rear wheel to manage cornering forces and impacts, matched with the vibration management from the Alloy front wheel. The difference between the carbon and aluminum front wheels was slim, but the Alloy ultimately won because of the added comfort offered throughout a ride and the extra control it gave me through rough sections. The carbon front wheel did hold a line better in corners, but it took more energy and focus to steer where I wanted in other sections. For my abilities and trials, I picked control over cornering feel.  

What's The Bottom Line?

Is there a superior wheel setup that blends the strengths of carbon and aluminum? Within the confines of this test: yes. The caveat? There are a multitude of factors dictating how your wheels feel, and rim material alone doesn't tell the whole story. I know most riders understand this, and it's why you can have two wheelsets of the same rim material that ride very differently.

The main takeaway from conducting this test is that targeting the performance of your front and rear wheels is beneficial but can be achieved with or without a mixed material wheelset. I enjoyed having a stiffer rear wheel paired with a more compliant front, and I think most riders will, too. However, achieving this setup doesn't require a carbon rear and alloy front wheel. If you know what ride quality you are chasing, there are many ways to achieve that beyond rim material. With most brands selling wheels individually or front and rear-specific, it's worth being intentional with your wheels. 

The other takeaway is that the best wheelset is probably the one you already have. I urge anyone who thinks their wheels are too compliant, stiff, flexy, dead, deflecting, or whatever to try new tires first. They're cheap and can drastically change how your bike responds to terrain. If nothing else, you can check that box before cashing in on some new hoops. 

Finally, look at the big picture when analyzing how your bike is performing. Don't assume that new wheels or rim material alone will solve your problems. Rim width and depth, spoke count and material, tire choice, air pressure, cockpit setup, suspension setup, and body position are just a few of the pieces that make up the puzzle. Experiment with your setup, and don't be surprised if the answer to your problems is much simpler than needing a mixed-material wheelset. 

For more information on Roval's Traverse wheels, please visit specialized.com

Photos: Tanner Stephens

Reviewed by: Jason Schroeder - Age: 29 // Years Riding MTB: 16 // Height: 6' (1.8m) // Weight: 180-pounds (79.3kg)

A once-upon-a-time World Cup downhill racer turned desk jockey, Jason has spent years within the bicycle industry from both sides of the tape. A fan of all-day adventures in the saddle or flowing around a bowl at the skatepark, he doesn't discriminate from any form of two-wheeled riding. A SoCal native who doesn't spend too much time in any single place, you can find Jason camped out in his van most weekends somewhere on the West Coast.