It took a while for Yeti to get on the 29-inch wheel bus, but man, the American brand is making up for lost time in a big way. We were impressed with the Yeti ASRc Marathon/XC race bike we tested previously and appear to have been swept away by the SB4.5c.
By the TREAD Testers
Photos: Dino Lloyd
There’s a bit of confusion which Yeti models fit in where. Well, the ASR models are Yeti’s take on pure Marathon/XC race models with 102mm of rear-wheel suspension travel and 120mm up front. The SB (Super Bike) models are more Trail/Enduro orientated. The SB4.5 has 4.5 inches (114mm) of rear travel. Yeti isn’t afraid to use different suspension designs and technology for different models. The ASR models have the single-pivot with Loopstays design while the SB models use the Switch Infinity design.
It’s a concept unique to Yeti that has received widespread acclaim on Yeti’s bigger-travel 650b wheel models. Switch Infinity is essentially a combination of Yeti’s Rail and Switch systems, designed in partnership with Fox. The original eccentric system relied on an eccentrically shaped bush with a bearing, where as the Infinity system makes use of two opposing piston based shafts that are Kashima coated, using a patented translating pivot that is free to move and switch direction as the bike moves through its travel. The aim of the system is to provide improved anti–squat characteristics for superior pedaling performance, while maintaining responsive suspension characteristics throughout the travel.
Yeti’s own video rendering provides a real time visual idea of the suspension movement;
But that’s what every suspension design claims to achieve. So what’s different? Well, the design is very different to everything else out there, and that’s attention grabbing, even before you start riding it…
The frame is full carbon fibre with beautiful lines. What are beautiful lines? Those that make the bike look stable, yet sleek; robust, yet swift. It has huge seat and chainstays and a low top-tube with plenty of standover space. The one niggle though is the placement of the shock. It’s only a niggle if you’re bottle-carrying rider, which is about 90% of South African mountain bikers.
The SB 4.5c is intended more as a trail-tamer/Enduro style bike, leaving the ASR models for the race-minded riders looking for a Yeti ride (and a bottle cage mount in the frame).
Having said that, before we even rode it, we did suspect that the SB4.5c would be an ideal bike for less-competitive marathon riders and stage-racers looking for a bit more comfort and control. And fun!
We did consider that the design of the rear suspension might make it difficult to clean and service, but learned subsequently that the Switch Infinity shock mechanism is rather well protected from mud and grit and servicing it is as simple as injecting Heavy Duty Molybdenum grease into the available ports with a needle-style grease gun.
Our test bike came with a Fox Factory 34 fork with 140mm of CTD adjustable travel. Matched to 114mm of rear travel makes that seem a little out of kilter. Until you start riding it…
The wheels are DT Swiss XM401 Boost rims with DT Swiss 350 hubs, wrapped in Maxxis rubber – a 2.20 Ikon at the back and a 2.40 Ardent up front. Yeti uses the wider Boost platform on both wheels – just that wheelset alone begs to be ridden hard!
There’s a Rock Shox Reverb dropper seatpost with remote adjustment and a SRAM X01 1×11 drivetrain matched to SRAM Guide hydraulic disc brakes with 180mm rotors front and rear and Easton Haven handlebars (740mm) and stem (55mm) with a Yeti/WTB saddle.
The Fluro Green may not be to everyone’s liking, especially die-hard Yeti disciples, but it’s certainly bold and eye-catching. This bike just looks stable and able. And we actually couldn’t wait to ride it!
We were particularly interested to see how this Switch Infinity design would improve climbing as claimed. Well, it’s undoubtedly the most efficient we have ever felt on climbs on a dual-sus 29er. We’d put the new Specialized Camber pretty close though. Even with the shock set in Descend mode the SB4.5 just clawed its way up and over any trail obstacles with incredible composure. We actually found ourselves either climbing familiar technical climbs faster, or with less effort at a slower pace. If the designers at Yeti were looking for climbing efficiency in this design, they found it. We had to stomp on the pedals super hard on a flat road with the shock in Descend mode to see/feel any kind of pedal induced bob – it’s that effective.
Why is climbing efficiency so important on a Trail bike? Well, nobody likes to push a bike up a climb, right? Even steep, rough climbs should be within everyone’s reach. If you can’t conquer them on the SB4.5, it’s your mind and body that need work, not the bike…
Descending was, as expected, excellent. The ‘eased-up’ geometry and shortish chainstays along with the Boost width axles, grippy tyres, wide bars and short stem made downhills a cinch.
Cornering was also incredibly sure and predictable although we did have to shift forward a little more on some turns to ensure optimal front-wheel weighting for maximum traction. This could have been due to the 140mm travel fork, which gives the front end a slightly higher default position in relation to the rear.
The rest of the time we never really felt an imbalance though. Of course we were really railing the turns because that’s what this bike begs for. Less aggressive riders may not notice any front/rear nuance.
Braking was really good! The SRAM Guide brakes are spot on for this kind of bike where predictability and control are critical. In fact our experience on the SB4.5 raised our respect for the Guide model brakes. Shifting was sure and crisp and we felt we had ample gearing for even the steepest climbs. The SB4.5 has been designed for only one chainring though, so chainring size needs to be carefully considered. Our test rig had a RaceFace 30-tooth blade.
The inability to carry a bottle inside the frame could well be an issue for many. So too could the price (it is available in a more expensive Shimano XTR build, or a cheaper SRAM GX build). That said though, every one of our testers almost wept when this bike had to be returned. It was unanimous that the SB4.5c is one of the best bikes we have ever ridden. Not just Trail bikes, ALL bikes! It’s an incredibly versatile bike that continually impressed us on any terrain, gradient and at any speed. We’d race an Enduro on it, we’d not feel uncomfortable taking it into a stage race, especially a technical event like Tankwa Trek or 3 Towers; and we’d have a permanent grin just riding it on trails for hours and hours…
SIZES: S, M (tested) , L, XL
HEADTUBE ANGLE: 67.4 degrees
SEATTUBE ANGLE: 73.3 degrees
CHAINSTAY LENGTH: 437mm
*PRICE: R124 000 (as built). Frameset R61 000
COLOUR: Fluro Green
FRAME: Carbon fiber
WEIGHT: 12.00Kg (without pedals)
FORK: Fox Factory 34 with 140mm CTD adjustable travel and Kashima coating
SHOCK: Fox Float, Extra Volume, CTD, Dual Piston System
SHIFTERS: SRAM X01
FRONT DERAILLER: N/A
REAR DERAILLEUR: SRAM X01
CRANKSET: RaceFace Turbine 30t
BRAKESET: SRAM Guide RSC
WHEELS: DT Swiss XM401 Boost rims with DT Swiss 350 hubs
TYRES: Maxxis Ikon 2.20 rear and Maxxis Ardent 2.40 front
OTHERS: Rock Shox Reverb dropper seatpost, Easton Haven handlebars (740mm), Easton Haven stem (55mm), Yeti/WTB Saddle
CONTACT: www.cyclic.co.za; 081 755 9462
*Originally published in TREAD Issue 39, 2016 and can be found on Zinio– All rights reserved