Gravel Gear

Full-suspension vs. rigid gravel bikes

Salsa and Niner go head-to-head to determine which suspension set-up is ideal for riding rough-and-tumble gravel.

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For most gravel races, riding a hyper-stiff aero bike is jarring and silly, yet schlepping a fat-tire, full-suspension beast is overkill. So where is the middle ground? What is the ideal amount of compliance for a gravel bike?

Even the first production gravel bike — the Salsa Warbird — had design elements that tried to dampen vibrations. Now we have full-suspension gravel with the Niner MCR 9 RDO, as well as plenty of bikes that sit somewhere between the two, with frames flexing around pivots like Trek’s IsoSpeed system on its Checkpoint or Cannondale’s Topstone design. We have leaf-suspension Lauf forks and suspended cockpits like on Specialized’s Diverge. And then we have aftermarket suspension parts like Redshift’s suspension stem and seat post.

What is the ideal set-up? As with anything in cycling, the answer depends on who you are, where you live, and how you like to ride.

From Trans Iowa to today

Salsa Warbird rigid gravel bike
Salsa Warbird Carbon GRX 810 Di2 | $5,699 | Photo: Salsa Cycles

Salsa product manager Joe Meiser can trace the Warbird, launched in 2013, back to the 2009 Trans Iowa, an ultra-distance gravel race he won on a prototype frame built with a low bottom bracket, generous tire clearance and — critically — compliance, achieved with thin, bowed-out seatstays that flex under load.

So what’s the right amount of compliance? And how do you quantify that?

“‘Right’ is really dependent on the rider and course,” Meiser said. “We really see opportunity for damping like our Class 5 Vibration Reduction System for the majority of riders. We quantify it by taking measurements of vibration and events at the axle versus at the saddle or bars. We asked the question when developing class 5 VRS: ‘To what extent can we isolate the rider from what is happening at the road to minimize fatigue without making the bicycle unnecessarily heavy or more complex?’”

Relatedly, we here at VeloNews performed similar vibration measurements on various endurance bikes, also measuring at the handlebars and axles, back in 2011. While there were measurable differences between the bikes, the largest differences by far were achieved by simply putting on larger tires (at the time, 25 mm was a “wide” tire) and reducing pressure.

And, of course, Meiser and the team at Salsa built the Warbird with plenty of room for tires, now up to 45 mm.

I raced the Warbird at The Mid South this year and loved the bike.

Full-suspension fare

Niner MCR 9 RDO
The Niner MCR 9 RDO is a full-suspension gravel bike. Photo: Ben Delaney
Niner MCR 9 RDO 5-Star Shimano GRX | $7,000 | Photo: Niner Bikes

Niner showed off a plastic prototype at Sea Otter in 2018 of a full-suspension gravel bike. The cycling world freaked out. Last year, Niner had an actual bike, built with a 50 mm Fox fork and a 50 mm shock.

Niner Bikes marketing manager Zack Vestal said the bike came about after staff at Niner got into doing longer gravel rides out of their Fort Collins, Colorado, office and started asking why there were no suspended gravel bikes.

“The idea behind suspending the gravel bikes is about rider comfort for the sake of less fatigue, more fun on the bike, and a better experience riding on dirt,” Vestal said. “But it’s also really about control. A race like Crusher in the Tushar, it has some really high-speed sections but is a little sketchy on a rigid gravel bike. By adding suspension, you’re keeping the tires in contact with the ground, and giving the rider more control. That’s just a fundamental part of suspension, whether we’re talking cars, motorcycles, or bikes.”

Vestal disputes the idea that mountain bike suspension and gravel suspension are the same thing because gravel and mountain bike riders do different actions. “In mountain biking, a significant portion of the experience is about the downhill; you’re coasting, crank arms horizontal, weight evenly distributed front to back,” Vestal said. “Gravel is about covering distance and pedaling. The suspension needs are different.”

Niner is not calling the MCR 9 RDO a race bike. “That being said, it wouldn’t surprise me if people took it racing,” Vestal said. “Look at Grinduro, or Crusher in the Tushar.”

Choices are good

One of the many fun things about gravel right now is how wide open it is: the event formats, the bike designs, the whole scene.

For most amateur racers, gravel bikes that have some built-in comfort in the frame, seat post, and, of course, the tires will be adequate without any moving suspension parts. Low-slung seatstays and carbon posts with some built-in flex are fairly standard as a Goldilocks solution to the hyper-stiff vs full-suspension extreme ends of the spectrum. That said, if you have the option to test ride a gravel bike with a bit of suspension, we encourage you to do so.

 

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