SB4.5 T-Series X01 Eagle Complete Mountain Bike
Yeti Cycles is well known for its big hit, big travel enduro sleds, so it should be no surprise that its shorter travel bikes bring a bit of that heritage along for the ride. The SB4.5 T-Series X01 Eagle Complete Mountain Bike blends a focus on XC speed with geometry that pushes its capabilities into much larger terrain. This particular bike also carries the Turq designation, which provides strength where you need it, and lightness where you don't. For the SB4.5 Turq, that means a more precise carbon layup, carefully molded to reinforce key stress points along the frame without adding bulk and claimed to reduce weight by 300g compared to Yeti's Carbon-series frames.
Yeti claims that the SB4.5 has a stiffer pedaling platform than most of its other bikes. While we don't have numbers to verify this claim, it's definitely a responsive go-getter when the going gets mashy, and we think the inclusion of a Boost 148mm rear axle is at least partially responsible for the bike's eagerness on climbs. Coupled with the innate aggression of 29in wheels and the stiff, collet-style hardware, the boosted rear triangle certainly feels every bit as stiff as any of Yeti's other models.
The frame's aggressive speed is not to be outdone by its slack front end and surprisingly capable Switch Infinity suspension, though. Its 67.4-degree head tube is fairly slack for an XC-leaning 29er trail bike, and it makes for a boost of confidence while picking lines across terrain that would make XC-race bikes stumble. The Switch Infinity suspension is equally confidence-inspiring, and its linear travel hits the sweet spot of anti-squat to keep pedaling sharp across rocky climbs, while remaining smooth and supportive as you move deeper into the travel.
While some riders might scoff at the 114mm (4.5 inches) of rear travel on the SB4.5, the 140mm fork that Yeti chooses to pair it with is a better indication of the bike's capabilities. The SB4.5 is for the trail rider who demands that their machine flattens big hits with the same tenacity that it cleans excruciating climbs—a machine that covers ground quickly, efficiently, confidently, and without ever feeling like too much bike. Compared to its bigger sibling the SB5.5, the SB4.5's Switch Infinity suspension isn't quite as soft off the top, and you might fight the bottom of the travel if you overshoot the landing. That being said, the SB4.5 has much sharper handling and rewards technique while picking lines, making the SB4.5 more fun if you're into finesse over just bombing terrain with your eyes closed.
This Turq-series SB4.5 is an in-house build we've put together with components focused on performance and longevity, using parts from our inventory to pass on savings to you as the consumer. We started with SRAM's reknowned XO1 Eagle drivetrain for crisp accelerations across the entire wide range cassette and a 50t bailout gear to help you scoot up steep climbs without needing to dismount. This 1 x 12 Eagle drivetrain is precise, quiet, and provides infallible chain retention—even in rough terrain. It's a perfect match for the top-of-the-line Fox Factory suspension with durable low-friction Kashima stanchions and Fox's flagship internals, keeping your wheels tracking in all conditions so you can charge ahead with confidence. Your newfound speed is kept in check by SRAM Guide RSC brakes with notable power, modulation, reliability, and adjustability. We rounded out the build with a carbon handlebar, carbon crankset, and sturdy e*thirteen TRS wheels that are ready for abuse and fit a wide range of trail rubber with their 30mm internal width.
- A speedy trail machine that pushes the boundaries of 29in wheels
- 4.5in of smooth and efficient Switch Infinity suspension
- Geometry straddles the boundary of slack and moderate
- Steep angles (for Yeti) reward a surgical approach to terrain
- Turq carbon construction drops weight and bolsters stiffness
- Boost axle spacing transfers power more efficiently on climbs
- Top-tier Fox Factory suspension with Kashima stanchions
- SRAM XO1 Eagle drivetrain for precise shifting, a wide gear range, and infallible chain retention