SB4.5 T-Series GX Eagle Complete Mountain Bike

While Yeti may be known for their hard-hitting, long travel enduro sleds, one of the most capable bikes they've ever made is the SB4.5. The SB4.5 T-Series GX Eagle Complete Mountain Bike delivers XC-level speed with geometry and suspension that makes it competitive with top-level trail bikes when navigating technical 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 reliable, workhorse components that come straight from our inventory, passing savings on to you as the consumer. We started with SRAM's GX Eagle drivetrain with its smooth shifting, wide gear range, and 50t bailout gear for those seriously tough climbs. You can expect quiet operation, precise shifting, and unwavering chain retention from GX Eagle. It's an ideal 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 R brakes delivering plenty of power with an arguably more important feature: impressive modulation. We rounded out the build with sturdy e*thirteen TRS wheels that are ready for abuse and fit a wide range of trail rubber with their 30mm internal width.

• A highly-capable trail bike that rivals the speed of XC race rigs
• 4.5in of smooth and efficient Switch Infinity suspension
• Geometry finds the balance between stability and nimble handling
• 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 GX Eagle drivetrain offers a wide gear range, quiet operation, and impeccable chain retention