Five years ago, if someone asked me if I'd prefer to run a coil shock on my trail bike my response would have been, "Hmmm, doubtful." Times have changed. Today's incredibly versatile mid-travel bikes have become mountain biking's Rally cars, regularly ridden up and raced down technically demanding terrain by enduro racers and weekend warriors alike. Ironically, as more air-sprung suspension is being spotted on elite downhill race circuits, the serious enduro crowd has embraced coil-sprung shocks.
Bike brands have different philosophies, but generally downhill bikes are designed with a premium on impact absorption and controlled suspension movement through the stroke of their eight inches or more of rear-wheel travel. In this application pedaling efficiency can take a back seat to high-speed stability and traction. Conversely, a versatile 130 or 160-millimeter-travel trail bike is designed to pedal well, yet also be capable when descending technical terrain. Regardless of how pedaling performance is achieved, bikes designed to pedal efficiently usually have less small-bump absorption and traction on fast, chunky terrain. Air shock suppleness has been greatly improved across many brands by implementing negative air springs that help shocks more easily bypass the static pressure inside the air spring canister and activate rear-wheel movement. However, today's popular enduro events regularly have descents three times as long as a downhill race track or standard bike park trail. During fast and rough descents conventional air shocks can heat up and squander damping and control. Simply put, coil shocks can offer shorter-travel bikes improved traction and small bump absorption, plus maintain cooler internal temperatures. With my shock usage speculation out of the way, let's dig into how Ohlin's coil shock performed on my trail bike.
Ohlins TTX 22 M Shock Details
Following a decorated history in motorsports, the name Ohlins has become synonymous with premium performance suspension. In recent years, their strides in the mountain biking segment have been largely rooted in a partnership with Specialized. Currently, Ohlins suspension is available on the Specialized Stumpjumper, Enduro, and Demo lines, plus offered aftermarket for those models directly through dealers. What if you don't ride a Specialized but are interested in Ohlins suspension? The TTX shock ($800) is available in seven sizes to fit the majority of trail and all-mountain bikes on the scene, and can be found at shops carrying Ohlins goods or through Ohlins USA directly. The Ohlins shocks designed for Specialized bikes are tuned specifically for those models, while tunings for other brands' frames are available through Ohlins dealers.
The TTX features user-friendly, externally adjustable tuning options - 16 clicks of low-speed compression, seven clicks of rebound adjustment, and a three-position high-speed compression adjustment lever. The foundation of the TTX shock is its twin-tube design, which uses an inner tube to house the piston and shaft, while the outer tube and adjusters direct the flow of oil between the tubes. Ohlins says their unique Twin-Tube design ensures consistent damping performance over varying terrain. Unlike most mountain bike suspension brands, which offer shock springs in 50-pound increments (250, 300, etc.), the TTX's steel coil springs are offered in 4 Nm increments, which relates to 23 pounds per spring. Therefore, Ohlins' springs can potentially offer a more precise setup per individual rider weight. I'm 5'9" and weigh 150-something pounds, and the spring suggested for the dimensions of my meat wagon was Ohlin's 502-pound option.
TTX 22 M's On-Trail Performance
Like most riders, my trail bike (in this case a Stumpjumper) came equipped with an extremely capable air shock. The stock Ohlins STTX featured nearly all of the same external adjustments as the TTX coil shock; and for an in-line air shock it seemed to handle the heat generated during long, rough descents better than other in-line shocks I've run on the same bike. For as capable as the STTX was, I was in search of better rear-end traction, more rebound damping, and improved high-speed stability.
On a human-powered machine, one of the pitfalls facing coil shocks is the inherent weight difference compared to an air shock. Coil springs alone can weigh as much as the entire air shock. Weight weenies will likely stop reading at this point. However, adding weight to a bike inside the frame's front triangle at the shock absorber (sprung weight) may not be as noticeable while riding than if the weight had been added directly at the wheels (unsprung weight.) For reference, my stock STTX air shock weighed 386g, while the TTX 22 M coil shock I replaced it with registers 750g (with spring.) The Ohlins spring itself weighs 310g.
I set up the TTX with the minimal preload required to keep the spring neatly in place. One of my gripes with the stock air-sprung STTX was the inability to get the rebound damping slowed to my liking. On the Ohlins air shock I ran the rebound fully slow (six of six clicks,) and still then it was often too fast. With the coil version, I found a rebound sweet spot one click away from fully slow. Before installing the coil shock, I was more concerned about unwanted suspension movement than I was the additional weight. However, once I dialed in my high-and-low-speed compression settings unwanted movement hadn't re-entered my mind until, well, I mentioned it in this sentence. Low-speed compression can help filter out rider-induced input on the suspension and help a bike feel balanced. The 16 clicks of low-speed compression are adjusted by way of the small blue dial. My best results came when running five to six clicks of low-speed compression in conjunction with the high-speed compression adjuster set in the second of three positions. In this configuration, the shock seemed efficient, yet supple, and also provided plenty of mid-stroke support during repeated chunky rear-wheel impacts.
The TTX has three high-speed compression settings. Position 1 is the most "open" setting and provides a plush, comfortable ride. Position 2 seems to be the most versatile setting, as it provides initial-stroke plushness along with more mid-stroke support for aggressive riding. Oddly, Position 3 on the high-speed compression adjuster is the shock's "pedal mode," and would only be utilized on extremely long, smooth uphills. After doing countless all-day rides and never once thinking about flipping the lever into position 3's "pedal mode," I personally can't find much use for the third setting.
After three months of exclusively riding the TTX coil across demanding terrain in California, Colorado, Nevada, and Utah, the most noticeable factor was how my trail bike felt to have more usable travel, but didn't wallow or feel sluggish. I also found the bike to have more traction on loose and chattery terrain. Additionally, the TTX felt as though it provided more mid-stroke suspension performance through repeated harsh impacts, like massive braking bumps or speedy sections of trail stacked with drops and g-outs. Sure, the coil shock setup weighs nearly twice as much as the stock air configuration, but for how I like to ride I'd rather save those grams by skimping on the midnight nachos, rather than on how my suspension performs.