In their 30th year of business, Yeti have introduced what very well could be their most versatile mountain bike ever. The all new SB4.5C — “4.5” denotes the 4.5-inches of rear suspension, the “C” stands for a carbon frame and the “SB” stands for “superbike” — is a hybrid of sorts, aiming to occupy the space between trail bikes with 140mm+ of suspension and XC bikes with less than 120mm of suspension. Designed from the ground up around the Switch Infinity platform, Yeti and Fox’s pivoting pseudo-suspension designed to improve pedal efficiency, the SB4.5C stands in a class all its own, a result of fine-tuning prototypes for over a year. After putting the SB4.5C though its paces we can tell you that it will dispel all of your preconceptions about 29-inch wheel bikes, and that the word “superbike” is more than just clever marketing.
The SB4.5C sits in a unique genre in mountain biking. While trail 29ers do exist, none approach the category quite like the Yeti. One look at the suspension numbers is enough to send most trail junkies and XC racers running in opposite directions. The standard for most enduro bikes, 29- and 27.5-inch alike, is suspension numbers north of 140mm in both the front and the rear. The SB4.5C, however, utilizes a Frankenstein-like combination of a 115mm Fox Float DPS in the rear and a 140mm Fox Factory 34 Kashima Coat up front. In most cases, that recipe wouldn’t work. Other bikes with those specs feel a little bit like the front wants to take larger drops, but the rear simply isn’t having any of it. Somehow though, Yeti makes it work. The bike feels stable and comfortable even when taking larger drops.
In the past I have been a large critic of the 29-inch wheel size for anything other than cross-country racing, and most hardcore enduro riders would scoff at the idea of riding a 29er. So when I heard that the SB4.5C was being marketed as a trail bike, I was skeptical. A trail bike needs to be nimble, and most of the time, the 29-inch wheel size simply doesn’t perform the way a 27.5-inch wheel bike does in tight technical sections. Those preconceived notions were shattered after I pointed the Superbike down the first steep test-piece. Although it didn’t descend with the uninhibited confidence of something like the Scott Genius Plus, it didn’t shy away from anything. Even with a handful of three-foot drops, the suspension felt nearly bottomless.
Wheel Size: 29
Suspension Travel: 140mm Front 115mm Rear
Frame Material: Carbon
Weight: 26.5 pounds as tested (w/ Crank Brothers Candy pedals)
Test Location: GP XC Test Loop and GP Enduro Test Loop
Bike geeks who like to get down to brass tacks with specs will have plenty to talk about with this bike. It has a dropper post, allowing riders to move their center of gravity lower and further off the end of the bike in steep downhill sections. The rest of the parts on the SB4.5C are impressive as well including a RaceFace Turbine 30T crankset, a Sram XO1 drivetrain, DT Swiss 350 wheels with boost spacing, a Maxxis Ardent TR tire in the front and a Maxxis Ikon tire in the rear. Were I riding the bike in Yeti’s state of Colorado, the tires would be ideal; however the trails at our test loop contained loose rock and dirt — conditions where the Ikon struggles.
The SB4.5C sits perfectly in the middle ground between the pure-bred trail bike and a cross-country hustler.
The bike I rode had Shimano XT brakes, which are excellent, but fine-tuning them to the ideal modulation can sometimes be an issue and they often feel soft. When the production model is released to the public, it will feature Sram Guide RSC’s, which are a better option and a vast improvement providing better modulation and braking power. The effective top tube on the SB4.5C is a lengthy 605mm which allows you to run a short stem and wide bars, putting you in an optimal trail-riding position. The top-tube geometry is paired with a slack 67.4-degree head-tube angle, which lengthens the bike and positions the front wheel and fork in a great position for attacking fast and steep terrain. In short, all of these degrees and millimeters make for a frame with very aggressive, trail-oriented geometry.
When riding a trail bike, the most important thing is how it feels — and this thing feels fast. I found myself carrying more speed through rocky technical sections due to the larger wheel size and with the benefit of the higher clearance, I made it over a number of downed trees that most bikes would normally struggle on. The speed handily makes up for what the SB4.5C lacks in nimbleness, and only a few times did I crave 650b agility. On drops and jumps, the 115mm of rear suspension was more than enough, feeling downright plush throughout the entire suspension curve.
The SB4.5C sits perfectly in the middle ground between the pure-bred trail bike and a cross-country hustler. For riders who like to do a little bit of everything, this workhorse will replace everything else in your stable. Don’t let the 29-inch wheel size deter you, this bike is rugged and will handle anything that you can throw at it.