Interbike Mtbr


Yeti SB4.5

The Yeti SB4.5 in brilliant nuclear green.​

Lowdown: Yeti SB4.5

I spent a good chunk of 2016 getting to know the SB4.5 carbon. Yeti's long, low and slack 29er trail bike offering features their usual reverse mullet suspension travel setup and is built around the unique Switch Infinity platform. The transition from my personal Yeti ASR-5 carbon 26" chassis to the 4.5 was surprisingly easy, handling seven-hour backcountry endurance adventures and some short course XC races with equal aplomb. The lightweight trail tamer can scoot uphill with gobs of traction and momentum, but can also descend with near reckless abandon. Could this be the Holy Grail one bike off-road solution?

Frame: Yeti SB4.5 (114mm travel) Cassette: SRAM 1180 10-42t
Fork: Fox Float 140mm KashimaChain: SRAM 1130
Shock: Fox Float Factory DPS EVOL Bars: Easton Haven Carbon 740
Wheels: DT Swiss XM401 Stem: Easton Haven 55mm
Hubs: DT Swiss 350Seatpost: RockShox Reverb
Tires: Maxxis Ardent 2.4/Ikon 2.2Saddle: WTB Volt[TD]
Brakes: SRAM Guide RSCHeadtube angle: 67.4 degrees
Rotors: SRAM Centerline 180mm/160mmChainstay length: 437mm
Shifters: SRAM X01Seat tube angle: 73.3 degrees
Front derailleur: NoneWeight: 26.5 pounds (w/XTR pedals)
Rear derailleur: SRAM X01Price: $6900
Cable routing: internalRating:
5 Flamin' Chili Peppers
5 out of 5
Crankset: Race Face Atlas
Stat Box [TD]


Pluses

Minuses
  • Low center of gravity with great maneuverability and handling
  • Frame broke at the seat tube due to relatively typical crash
  • Arguably best suspension platform on market
  • 30t chainring tall when paired w/29er wheels
  • Extremely comfortable cockpit
  • $6600 but no XX1 or XTR parts
  • Chainring swaps relatively easy
  • Maxxis Ikon rear tire light but fragile.
  • Bulletproof wheels
  • No room for bottle cage inside frame
  • Great looking frame
  • Knocking sound in front triangle
  • Benefits of boost 148 spacing
  • No clearance for piggyback shock
  • Minimal rear tire clearance (~2.35 max)

Review: Yeti SB4.5

I'm glad I gave the SB4.5 a second look. It was a leap of faith, actually, to eBay my favorite bike, swipe the debit card, and commit to that reevaluation. My own cash all in on the suspicion that this might be the one. The bet paid off.

At Outerbike 2015, the SB4.5 was Yeti's latest offering. I had decided prior to my trip to Moab that I needed to unload my beloved ASR-5 before the 26" wheels drained away the rest of its residual value. The newer Yeti ASR 29 geometry was lovely and I found the bike exceptionally fast, but it felt too race-oriented for the everyday riding I wanted to do. Looking at the Yeti SB4.5 specs, it was a lightweight trail-oriented carbon 29er paired with a Fox 34, and the new Switch Infinity suspension that had blown my mind on the SB5 the first time I rode it. However, when I tested the SB4.5, I found myself disappointed that the suspension felt overly-platformed, even a little harsh. It was not deep and controlled like the SB5, and not active and zippy like the ASR.

Yeti SB4.5 Shock

The XC Tune Fox Float shock spec'd at launch wasn't my cup of tea.​

A few months later, I started to hear via magazine articles and online posts that the Fox Float DPS EVOL had been overhauled with a higher volume air can and a new trail tune. Word on the street was the bike now rode like a big wheeled SB5.

Yeti SB4.5 Shock

Up-close with the Fox Float DPS trail tune shock.​

Well, I'm a Yeti fan. The geometry just works for me, and the ride quality combined with the close attention to the details makes me happy. But 29ers in general have been hit or miss. One of my ongoing issues has been that in order to get rear clearance for the wagon wheel, some manufacturers will slacken the seat tube angle. At full extension for my long legs, the seat is way out over the rear hub and it creates adverse handling characteristics.

Yeti SB4.5 Seatpost

A lot of seatpost to make my setup work.​

The SB4.5 approaches the problem differently, using boost 148 rear spacing and nixing the front derailleur to tuck the wheel in tighter. The effective seat tube angle is a reasonable 73.3 degrees. The travel is only 114mm (hence 4.5). Combined with a 140mm Fox Float 34, it's an over-forked setup that on other brands would suggest a rear squat tendency on climbs. The SB4.5 features a long top tube, has an increasingly mainstream 55mm stem, and a low'ish 13.1" bottom bracket. With the relatively slack 67.4-degree head tube angle, at least for 29er purposes, you get a long front center with a low center of gravity suitable for ripping. The boost spacing front and rear along with the stout linkages effectively minimizes the extra flex that leverage from larger diameter hoops can create.

Yeti SB4.5

55mm isn't as stubby as it used to be.​

Back to that shock changeover: The trail tune with the larger volume air chamber brings this bike to life. The supple, active feel is very SB5-like in execution, and yet the Switch Infinity link manages to maintain a decent snappiness while taking the technical route up the mountain. Unlike its SB95 predecessor, the suspension doesn't hang up at the translation point over square step-ups. It's truly seamless in the shuttle switchover from upward to downward motion on the twin Kashima coated switch rails.

Continue to page 2 for more of the Yeti SB4.5 trail bike review »


Yeti SB4.5

The heart of Switch Infinity.​

There's no discernable squat at 15mm of sag on a 7.5x2.0" stroke. For me, that translates to about my un-geared body weight at 168 PSI. The suspension design also allows me to run my fork with less sag (about 25mm) because I prefer to sit up a little higher into corners and minimize brake dive. While not bottomless, the rear suspension is supple, active, and shred-worthy.

Yeti SB4.5

Hot from any angle.​

Even zipping up and around switchbacks, it feels like the rear wheel is motoring underneath me and the suspension is seeking out traction. While I prefer to use some compression damping found on the medium platform settings for climbing, I'll switch the front and rear suspension into full open on some very techy sections to maximize that welcome tendency to bite in and go. One stretch in particular is steep, loose, rooty, washed out, and rocky all at once. It is almost a 90% sure thing for me to clear with the SB4.5. My prior success rate was about 10%.

Yeti SB4.5

Steeper than it looks. Photo by Cameron Prickett​

I'm not overly effusive regarding shiny new bikes. If one stinks or just doesn't work, I'll admit it, unload it, and move on to the next thing. That statement out of the way, this is the best bike I've ever ridden. One of the things that puts it at the pinnacle of my bike experience is the sheer versatility. I've taken the SB4.5 on 7-hour backcountry treks navigating by map, and ridden short course XC races on it. It blew my Strava PRs to pieces both up and down, and grabbed a few all-out KOMs along the way. My exceptionally good DW link Turner 5 Spot sat nearly unused for most of last year.

Yeti SB4.5

Abominable snowman gets shreddy.​

So what are some of the negatives? Every bike factors in compromises. The hope is that the sum of them serve the overall execution for the intended purpose. The 114mm rear travel is on the short side. Honestly, though, it feels more like 130-140, and the excellent travel quality makes me pause to consider piggyback shock options to manage lengthy descents even better.

The SB4.5 also lacks the room inside the frame for a bottle cage given the shock placement. With the Switch Infinity design, I don't know if there is any way around it. Perhaps the shock could be mounted to the top tube, instead of the downtube while maintaining the same leverage rates? I carry flip-top bottles on the underneath downtube mount when I don't want to use a hydration pack.

Yeti SB4.5

Water bottle placement not quite optimal.​

I do wish the rear triangle had more clearance for a wider tire. Right now, I'm running an Onza Canis 2.25 rear after tearing out the fragile OEM Maxxis Ikon. I would be uncomfortable mounting up anything much larger for fear of tire rub. For those whose wish list includes wider rubber, the SB5+ should be on your short list, albeit with somewhat less attractive frame lines.

Yeti SB4.5

Rear tire clearance is somewhat close with an Onza Canis 2.25.​

Even with the relatively wide range offered by the 10-42 X01 rear cassette, the 30t front chainring didn't quite do it for me from a gearing standpoint. The larger diameter of 29er wheels dictate that the riders is effectively pushing a higher gear ratio than an equivalent gear combo on 26 or 27.5 wheels. To get a low enough gear for hour-long switchbacking climbs on my local trails, I swapped to a 28t. I'll be trying an Absolute Black oval 28t ring this spring after having excellent luck with a 26t oval ring on my fat bike.

Other changes from stock that I made include ESI grips (because they are comfy), Slik Graphics custom decals (because they are pretty), my Yeti edition WTB Volt from my ASR-5 (because it has Kevlar corners and fits my backside), and an X.0 grip shift (because it enhances my ability to dump handfuls of gears on an 11-speed cassette with no front derailleur). The RockShox Reverb dropper post failed out of the box with an audible clunking sound, and was replaced at no cost under warranty.

Yeti SB4.5

Grip Shift helps de-clutter things and blends in with the ESI grip.​

In the interest of full disclosure, I did crack the frame at the seat tube in June in a crash (about four months after purchase). It was a shock to me, because I'd never broken a bike, and because the crash was a relatively un-catastrophic over the bars maneuver when the front wheel hit an unseen buried rock on the tamest of my local trails. Yeti handled it expediently and had a replacement front triangle to me within a couple of weeks. My local shop, Two Wheeler Dealer in Hayden, Idaho, did a fantastic job getting me up and running again asap.

Online, I have seen another SB4.5 and an SB6 break in this same location, which strikes me as an unusual place for breakage. With the protection of the seatstays on either side, it has to be a leverage break and not an impact. Whether this signals a design or carbon lay-up problem, I have no idea. If you'd like more info, feel free to message me, but suffice it to say, I was more than pleased with Yeti's warranty service and resolution.

Yeti SB4.5

Broken toys.​

One unexpected result of the frame swap was that an occasional knocking sound that would arise under repeated hits while descending went away with the new frame. My best guess is that the internal cable routing was the culprit, and the full rebuild with the new front triangle inadvertently solved this problem.

For the price, I also wish my best bike ever came stock with XTR or XX1. My outgoing ASR-5 carried full XTR at its $6600 price tag. This SB4.5 approaches $7000 bike with three inch taller wheels and does add a dropper post. My best guess is the premium price with the lower tier X01 spec reflects the additional cost of the Switch Infinity partnership with Fox. It's worth the tradeoff in terms of ride quality, but I do miss the XTR componentry. For 2017, you can get a "Turq" premium carbon frame with XX1, but it comes with ENVE wheels and will leave your bank account $10,500 lighter.

Yeti SB4.5

Adventures await. Photo by Shaun Gonsalves​

It's obvious I'm sure, but I would absolutely buy this bike again. I'm extremely happy with what it offers in terms of all-around capability combined with some ridiculously good suspension technology and progressive geometry. Despite positive experiences on other bikes from several manufacturers last year at Outerbike 2016, the Yeti SB4.5 remains my nuclear green weapon of choice for my local trails.

For more info visit www.yeticycles.com.