A silver spoon in a world of soup.
When you're a well-rounded rider, you tend to find pleasure in tackling all sorts of trails, from flowy all-mountain riding with pockets of rock gardens and gnarly roots to steep and trying XC climbs that test just how hard you can push your lungs and quads. With riding so varied, having a bike with restrictive geometry and suspension that can't support the trails you point it up or down can make you angrier than a man with a fork in a world of soup. Yeti Cycles offers us a spoon in this soupy world with the 2018 SB4.5 Turq mountain bike frame. Effectively finding the balance between a capable trail bike that can handle some chunky rock gardens, and a smooth-trail-loving, pedal-mashing XC bike, the SB4.5 features lighter weight, and more nimble handling to earn its spot as a true all-mountain bike.
With geometry that rides the line between trail and XC, the SB4.5 runs a 64.7-degree head tube, which is significantly slacked out beyond the 70-degrees we find on most cross-country bikes. This makes for incredible stability when descending, but because the seat tube angle remains steep you'll still be centered in your cockpit for laying down the power on climbs. In the back, progressive Boost spacing stretches the hub spacing to a wider 148mm that not only enables your hub to be laced up into a stiffer and snappier wheel, but also allows space for the rear wheel to be tucked in closer to your frame for a shorter chain stay for faster power transfers when you need to mash down on the pedals.
The guts of the bike, the Switch Infinity suspension, lie just above the bottom bracket, which helps maintain a low center of gravity. Tucked inside the bottom of the seat tube and the rear triangle you'll find two silky-smooth Kashima-coated stanchions with a slider that moves in conjunction with the 144mm of Kashima-coated Fox Factory DPS shock to soak up blows while balancing out pedal bob with linear travel and anti-squat technology. While it'll be happy to soak up some rough and burly square-edge bumps, it's important to note that the travel isn't bottomless the way the SB5 or 5.5 is, instead it prefers riders who like to clean descents with precise line choices and maneuvering rather than those who take the point-it-and-send-it approach to their rides.
With the claim of a much stiffer pedaling platform than Yeti's other bikes, the SB4.5 will be appreciated by XC enthusiasts and those who love smooth and flowy trails alike. It's capable of finding the neutral position after taking a hit, and the "dead spot" previously seen by some riders on the older Switch Link is nearly completely eliminated, so you won't experience wallowing in the travel. The stiff pedaling platform allows for minimal pedal bob and maximum power transfer on your climbs. With this in mind, the bike craves flowy and smooth XC and trail riding, pockets of rock gardens, and even consistently rough and rocky rides. Sequential hits from rocks and roots at high speed aren't the favorite activity of this bike, and on big drops the 114mm of travel won't offer the same bottomless feel it generously offers through isolated rock gardens and roots. Combined with the stiff boost-spacing and 29-inch wheels it does feel quick, supportive, and stiff.
Carrying through with lightweight stiffness, Yeti offers the SB4.5 in its top-tier Turq level carbon fiber as the building-block for a durable and responsive frame. Meticulously laid, the carbon fiber wraps around a mold to reinforce joints and high-stress points without adding excessive and bulky materials, landing you with a strong and exceptionally lightweight frame, claiming to come in at 5.28lbs—nearly 300 grams lighter than their regular Carbon series. With such stiffness and light weight it's no wonder the SB4.5 climbs with such ease while keeping its composure on descents.
- A roll-ready 29er for miles of pedal mashing and flow trails
- Hungry for rock gardens, 4.5in of Switch Infinity eats up hits
- Slacked out head tube offers stability where pure XC bikes suffer
- Snappy and nimble handling courtesy of stubby stays
- Intensely lightweight stiffness afforded by Turq level carbon
- Buttery-smooth Kashima coated shock smooths out blows
- Internal cable routing offers a clean finish