When Yeti introduced the SB5c last summer it was clear the company was heading in a new direction in terms of suspension design. Yeti replaced the eccentric main pivot previously used on its Switch Platform with a new sliding tube design dubbed Switch Infinity.
This suspension overhaul indicated that many of the company’s other models would soon be replaced. The SB4.5c is the successor to the well-regarded SB95c. On paper at least, it doesn’t quite measure up to its predecessor.
The SB95c had 127mm of rear travel, while the SB4.5c sees a decrease in suspension travel to just 114mm – so does this matter on the trail? Two BikeRadar testers have been hammering an SB4.5c apiece – one in Colorado, one in the French Alps – to try to find out…
Yeti SB4.5c highlights
- 4.5in / 114mm via Yeti’s Switch Infinity suspension system
- Designed around 130-140mm suspension forks
- 5.4lb / 2.45kg claimed frame weight
- 25.94lb / 11.76kg weight as tested (medium X01 build)
- BB92 bottom bracket
- 148x12mm rear axle spacing / 110x15mm front axle spacing
- Frame with shock will retail for $3,400 (UK and Australian pricing TBA)
- Compete builds will range from $5,599 to $10,449 (UK and Australian pricing TBA)
Design details
The SB4.5c borrows heavily from the Enduro World Series-proven SB6c in the shortest-travel incarnation of the Switch Infinity suspension system to date.
While the SB4.5c sports just 114mm of rear suspension travel, the familial resemblance to the rough-and-tumble SB6c is readily apparent. It shares the same clean lines, with an extremely low top tube, giving the rider ample standover clearance and internal routing through ports on the sides of the down tube.
The SB4.5c has a similar silhouette to the longer-travel SB6c
Like the SB6c, the SB4.5c sports a BB92 bottom bracket shell (the SB5c and ASRc use PF30 shells). Yeti opted not to build the SB4.5c with ISCG-05 tabs. While this undoubtedly shaves a few grams from the frame it does seem like a misstep for such a capable short-travel machine.
The SB4.5c is designed for 1x drivetrains
According to Yeti president Chris Conroy, the SB4.5c is the stiffest bike the company has ever made. The seat- and chainstays are absolutely massive and the front end really does looks like it was borrowed directly from the SB6c.
Ruthlessly efficient
“Sport-tuned suspension” is how Conroy described the SB4.5c’s rear end. Yeti’s Switch Infinity suspension system is ruthlessly efficient in terms of making the most out of every millimeter of travel.
With a 140mm Fox 34 the SB4.5c’s head angle is a well-rounded 67.4 degrees, and a substantial amount of anti-squat makes it an easy bike to pedal uphill. It requires a bit more attention to keep the front end tracking on steep climbs than 29er trail bikes with longer rear ends, but the 17.2cm / 436.9in chainstays keep the SB4.5c refreshingly nimble the rest of the time.
Despite applying a liberal amount of sag (30 percent) and setting the shock with minimal compression damping, our UK tester Seb Stott found pedal-bob impressively low even when stamping hard on the pedals. This is due to the bike’s high main pivot point, which rises even higher as the Switch Infinity link cycles through its travel.
The effect of this is that the chain tension is used to counteract pedal-bob, keeping things efficient. This allows the shock to be kept open on technical climbs, affording impressive traction and comfort without suffering from ponderous bobbing and wallow. It was only worth flicking on the shock’s firm mode for long, smooth efforts on surfaced roads, where fast-rolling tyres, stiff frame and locked-out suspension allowed it to eat up the miles with effortless speed.
There's plenty of squish upfront with just enough travel in the rear to keep you tracking true
Split personality
While the geometry of the SB4.5c gives it a composed feeling in nearly any situation, the unequal suspension numbers give the bike a split personality – a bit of a reverse mullet, if you will: party up front and nothing but business in the back.
A 140mm fork with 114mm of rear travel can feel felt a bit imbalanced if you’ve been accustomed to riding bikes with suspension numbers that are in relative parity from front to rear. It’s not bad though, just different – the very capable Fox 34 soaks up impacts with ease while the EVOL-equipped Float DPS rear shock ramps up quickly, skimming over the trail and providing just enough movement to maintain traction and take the edge off hits. The setup seems to suit a more aggressive, off-the-front, moto-inspired riding style.
According to Conroy, Yeti plans to offer a second, more forgiving tune for the SB4.5c, which should suit lighter riders and those wanting a bit more plushness out of the rear end.
The Fox Float DPS shock continues to impress us with its performance
There’s a lot of tactile feedback from the rear end when charging down rocky descents, but the slack angles and easy-rolling 29in wheels mean the SB4.5c can be pushed as hard as 27.5in many enduro rigs, so long as you’re willing to take on a bit of discomfort in the process. The stiff frame and relatively rigid DT Swiss XM401 Boost wheels keep the bike feeling sharp and direct when cornering hard or charging over rough terrain, yet make for rapid acceleration out of the bends.
While the bike is incredibly capable, we really wish Yeti would have given more thought to the rolling stock. The specced Maxxis Ardent / Ikon combo can't keep pace with the SB4.5c's capabilities. A High Roller II in the front with an Ardent in the rear would be a much more appropriate choice of treads.
One thing's for certain though – after logging approximately 300 miles on the SB4.5c on our proving grounds in Colorado, and four days' thrashing it in the Alps we have no reason to doubt Conroy’s claims that this is the stiffest frame Yeti has ever made.
This unyielding chassis combined with boosted front and rear axles adds up to a 29er that is incredibly responsive. The frame is willing to be snapped in and out of corners and transitions through berms and tight switchbacks with a sense of grace not often found in big-wheeled bikes.
Verdict
The SB4.5c is the latest member of the new guard of incredibly capable short-travel 29er trail bikes such as the Kona Process 111, Transition Smuggler and Evil's The Following that make up for their meager millimeters with refined suspension designs, slack head angles and long front centers.
The Yeti impressed both of our testers with its climbing prowess and downhill chops. It makes the most of its 114mm of rear travel and proves that suspension numbers alone do not make the bike.
