To Switch Infinity and Beyond: A 27.5″ Yeti SB135 with SRAM Transmission Review

Curiosity. It’s a great trait to have as a cycling journalist. An inquisitive nature is what first prompted me to throw a leg around subculture-spawned bikes, like steel full-suspension 29ers and titanium hardtails, years ago. Sometimes, you have to pedal something for an extended period to whet that appetite for the occasional oddity that arises. If you’re lucky, those experiences challenge your preconceptions, too.

Working in bike media, it’s pretty easy to get cynical about all the marketing hype and the constant push for model years by the bigger brands, particularly regarding ever-changing drivetrain technologies, incremental gains, and complex suspension designs. I still value riding a rigid 29er as much as riding a vintage 26″ wheeled steel chariot through compromising terrain: the almighty underbiking ride keeps you honest, allows for honing your skillset, and can be damn fun.

Yet, on the flip side, I am attracted to high-tech, modern carbon bikes in small doses. Hence the allure of this Yeti SB135.

Before testing out the SB135, it had been a while since I’d ridden a carbon full suspension as, in the intervening years, I’ve been enjoying sampling the steel offerings out there from smaller, bespoke builders. Yet, the appeal of the high-tech is palpable—lighter, faster, smoother-shifting sounds fun, right? Mix in Yeti’s 27.5″ platform for the SB135, and my curiosity was piqued. The last 27.5″ wheeled bike I reviewed was the Santa Cruz 5010 and the previous 27.5″ wheeled bike I’d ridden was the Transition Scout that was loaned to me for a Moab trip. It was on that very trip I realized that while I admired the 27.5″ wheel platform, it wasn’t necessarily for me nor for the terrain I enjoy riding.

Yet, the SB135 was just strange enough, foreign enough, new-and-techy enough to have me put my steel sled with cable-actuated shifting aside for a few weeks and spend some time riding Yeti Turq and SRAM T-Type shifting…

I reviewed the T4 Turq level 150/135mm build kit with SRAM XX Transmission that comes in at $10,300 and weighed 30 pounds on the nose. 

From SB140 27.5″ to SB135

While I’m not in the dark when it comes to Yeti’s full suspension offerings, I am not an esteemed encyclopedia regarding the bifurcated nomenclature between travel and wheel size. Looking at the family lineage of the SB line, the new SB135 bike (named so for the 135mm in rear suspension travel) is perhaps the closest to the late 27.5” SB140, which has now been replaced by this SB135.

Initially, I was confused, as I recalled Yeti had just released a new SB140 last fall, but it was a 29er. After some emailing with Ryan Palmer (Yeti’s marketing manager) he explained that the SB140 from 2022 didn’t replace the old SB140, it replaced another 29er, the SB130. Confused yet? I don’t blame ya!

For the sake of clarity, I’ll only look at the 27.5″ Yeti SB140 in terms of what changed geometrically with the new 27.5″ SB135.

Geometrically Speaking

The above chart reflects the geometry of the SB135, which you can compare to the older 27.5″ SB140 geo chart if you’re interested in the minor geometry tweaks between the two models. In short, the new SB135 has a slightly steeper seat angle (by not even half a degree) and most of the other numbers remain the same. I primarily look at reach, stack height, and effective angles to give me a good idea of how this bike will ride and what size I should be riding.

It’s easy to look at a geometry chart and form an understanding, but the real reason why I wanted to review the SB135 was to challenge my bull-headed allegiance to the 29er wheel platform.

Changes in rider fit across the SB135 size spectrum is perhaps a little difficult to decipher from a standard geometry chart. Looking at the profile shot above, you can see that the XL SB135 has an ultra-low-slung top tube.  To make the best fitting bike for smaller riders, the team at Yeti designed an entirely different frame for the S and XS sizes, illustrated by the below graphic.

Small SB135 overlaid on a Large SB135

Yeti worked on drastically reducing stand-over height in the XS and S sizes while allowing for maximum seatpost insertion and accommodating more dropper post models, all while still fitting a water bottle. How? Well, for starters, they moved the forward shock mount to the downtube instead of the underside of the top tube on the larger sizes, shrunk the shock linkage, and completely redesigned the swing arm. Neat.

27.5 vs 29

There was a time when I thought wheel sizes should reflect frame sizes. Hear me out. My logic was, by the time you massage the geometry numbers to have a size XS or S fit a 29er wheel, the geometry will be very different from the XL version of the same model. Whereas if the XS and S had a 27.5″ wheel, and the M, L, and XL were on 29er wheels, you could get a very similar riding bike under two very different riders.

I say this as a 6’2″, 190-pound, “athletic build” (i.e., sometimes chonky), male with a 36″ inseam and long arms. 29ers feel more appropriate for my gangly limbs and weight. For me, there is a sensation of being “in” the bike, with a lower center of gravity, than riding “atop” it. With a 29er, the bottom bracket can be a bit lower (in relation to the frame geometry) because the wheels are larger. The lower center of gravity makes maneuvering these large wheels easier for me. Mostly.

Now, with a 27.5 wheel, the smaller wheel diameter has many benefits – at least on paper. If you care about rotational weight, 27.5″ wheels are marginally lighter. As are the tires. Again, we’re talking about sub-100g differences here, which means less rotational mass.

They’re also smaller in diameter (duh), so, again, when paired with the less rotational mass, they will “spin up” to speed faster, accelerate out of turns quicker, and in general, be more “flickable.” Yet, their smaller diameter means those rock-crawling and rooty-tooty lines you’re used to on your 29er will take more finesse. Even climbing up ledges takes a lot of adjustment.

For me, where the 27.5 wheel dominates is fast and flowy, middle-tier techy singletrack which we do have a fair amount of in Santa Fe, usually at the bottom of the rocky and steep trails.

To Switch Infinity and Beyond

The last time I rode a full-suspension Yeti was around 2017 or 2018, so I needed to catch up on what had changed with Switch Infinity. Honestly, this is my least favorite part of bike reviews and probably why I am still in love with my single pivot. Complex systems don’t do it for me. I like replacing pivot bearings in 10 minutes, not hours. Yet, I enjoy noting various suspension designs’ different ride qualities and characteristics. For instance, Horst Link feels too “planted” for my riding style. Single Pivot designs can be very springy and lively. When engineered correctly, anti-rise won’t be a concern either. The Murmur engineering nailed this point perfectly.

Switch Infinity is a whole different nut, however. The lynch pin of the design is a four-bar system that relies on a linear path of the main pivot. It’s also incredibly versatile, allowing engineers to adapt their bike’s riding characteristics depending on its usage. It’s also a primary reason why Yeti doesn’t use flip chips; they are kinematic nuts who want to perfect the ride quality and flip chips simply add another layer of potential quirks. Keep it simple-ish, stupid.

Yeti redesigned this system with a new bushing interface, less bearing wear, which overall, should keep things moving smoother, for longer. I’ve only had this bike for a few months, so I can’t speak to these claims or the system’s longevity, but Yeti does a great job at breaking down the current model of Switch Infinity if you like neat graphics.

Stripping away the engineering charts and graphics, my takeaway with Switch Infinity is that is delivers a jibby, yet smooth, and incredibly well-balanced ride quality. I prefer to have my weight a little more back on a 27.5″ wheel bike, to avoid getting jammed into rocks or roots and the Switch Infinity system seemed to prefer that: either a fore or aft riding position.

There were very few times when I experienced “extremes” regarding the suspension’s limitations. Setting sag at 30% delivered the best riding feel on my fast trails, but bumping it back to 25% for the big mountain days kept the bike balanced in various terrain. The SB135 is the most advanced riding suspension system I’ve reviewed in recent years, and the frame details and build kit just added to the experience.

SB135 Details and Build Kit

Modern carbon bikes have all sorts of wonderful moments. For someone who rarely rides one, documenting their modern lines is always a fun time. The SB135 has no shortage of beautifully-engineered and designed curves – from an asymmetric swingarm, frame protection, and many ports for internal routing. Even though the model I reviewed came with AXS Transmission, the ports for derailleur cables are still there.

Not to mention it has a threaded bottom bracket and the bike’s cable management would please even the most OCD of riders!

What I did find amusing was the lack of AXS dropper, which would really tie the whole T-Type Transmission build together, but the consistent Kashima coating of the Fox components is easy on the eyes.

As for peripherals, you get a branded Yeti Ergon saddle, Yeti bars, Burgtec stem, DT SWISS XM1700 wheels, 2.6″ Maxxis tires, and the new SRAM G2 brakes, which I quite enjoyed. Overall, it’s a suitable kit for a T4 Turq-level Yeti build. This is like going for the “luxury” upgrade in a car…

T-Type: The SRAM Empire Strikes Back

I think I should point out that I am perfectly fine with my cable-actuated drivetrains, yet I have three bikes with AXS shifting. I’ve never had a bad experience with the AXS bikes, but—on the other hand—I have never had to think about the cable bikes either. Hell, I even love riding friction, so I’m not trying to sell you on anything. I’m merely attempting to be as objective as possible here…

Man. I cannot think of a more divisive, controversial release than SRAM’s T-Type “Transmission” groupset. The whole notion that your bike needs a SRAM-dedicated derailleur hanger, replacing a cheap, prolific piece of aluminum that can save your frame in the event of a crash, for a proprietary piece of tech seemed arrogant to say the least. What happens when Shimano does something similar? Why would they rule out an entire existing population of bikes that are incompatible? Is the bike industry capable of consistent quality control that the T-Type hanger demands? I’m far from a retro grouch but man, my 3x, 5-speed, friction-shifting bikes got a lot of ride time when Transmission was launched (they still do get a lot of play, FWIW.)

Look, I love SRAM. My bikes are all kitted with SRAM, from cable GX to AXS GX, and cable XX1 to AXS XXO. I’ve run the gamut on my riding experience with the brand. My Moots is an AXS-only bike, with no cable stops or ports for a dropper line and I’ve had zero issues with it. In fact, my AXS Reverb is the only dropper from SRAM that hasn’t needed service or replacement. I’ve put thousands of miles on that bike, and while AXS pedals “okay” in my mind, I was fine with its performance, not wanting anything more out of it. Push button. Derailleur shifts. Bike moves forward. There’s nothing romantic about SRAM’s shifting performance. It gets the job done.

In the history of off-road drivetrains, nothing rides as smoothly, quietly, efficiently, and shifts under load as precisely as Transmission. I’m admitting it. It’s the best drivetrain experience I’ve had on a bike. Part of that is the SB135’s smooth pedaling performance that feels like butter on a hot skillet, but a lot of that is all that marketing mumbo jumbo that SRAM proclaimed from Mount Olympus down to us peons.

The bike pedaled in unison; with each stroke, it felt “locked in,” symbiotic to the frame. When you needed to have instant engagement, it was there. Shifting under load up some shit trail? Right there, ready to go. High-speed, out-of-saddle sprinting while shifting, it was there. It didn’t skip a beat. Not once. The ergonomics of the controls are drastically improved over AXS. It even looks really good. Damn. What am I saying?

There’s a tendency for us bike reviewers to push back on marketing claims. To dismantle and dismiss it as hype. Or maybe it’s cynicism and a love for non-normative bike tastes? Or maybe new technology is just really great. Shit. Is it late-capitalism? Maybe in five years we’ll look back at naysayers, the T-Type haters, and laugh. But I still can’t get behind a non-reverse-compatible kit… That, for me, is what will keep me from putting Transmission on my bikes. Not because I wouldn’t want to, it’s because my conscience won’t let me.

That’s the fun of reviewing bikes like the SB135. The chassis is new, so it’s compatible with T-Type. It’s carbon. Engineered. Lightweight. Modern. All the things “newness” demands. And the ride quality ain’t that bad, either.

Riding the SB135

The biggest adjustment I had to make when riding the SB135, coming from my Starling Murmur 29er, is where my body weight was in relation to descending and climbing. Now, I can’t compare the two bikes because they couldn’t be farther apart in terms of ride quality, but I can compare where my body rests while each. With a long wheelbase, 160/140 29er, I like to be even-keeled in terms of riding position. With the pedals level, my hips relaxed, and my elbows bent, resting a majority of my weight in the bike’s lower center of gravity.

On the SB135 however, I find that shifting my weight slightly more forward when riding fast and swoopy trails enables me to snap out of corners, carrying my speed. And when the terrain got steep, I had to fight the tendency to want to be over the front of the bike. Before we talk too much about descending, let’s talk about climbing.

Climbing the SB135 was a real treat, especially noting it’s almost four pounds lighter than my Murmur!

Life at 7000′ in the Southern Rockies ain’t easy. Every ride is a hard ride when you’re going into the mountains. At least for me. I’m not a fast climber but can hold my own in a group ride setting, usually mid or back of the pack. My personal bikes are geared 28:52 as I like to spin, and 29ers going up don’t spin quite as well as 27.5″ wheeled bikes do, for the aforementioned reasons (lower rotational mass, smaller diameter, etc.)

With the SB135, I felt more over the front on steep climbs–the 76.9º effective seat angle is designed to do just this–making tight switchbacks much easier to navigate. This has a lot to do with the seat angle, the front center, and wheelbase. By comparison, my Murmur’s wheelbase is just over 51″, almost 2″ longer than the SB135. Most of our trails are either switchbacks or straight up, vertical slogs over decomposed granite. Being able to “sit in” on the front of the saddle and spin the wheels up to a comfortable cadence is paramount here.

It gets tricky when it comes to descending, and it took a while for me to adjust my riding. As mentioned above, 29ers and 27.5″ bikes demand different riding positions, ATMO anyway. With a 27.5″ wheel, I have to adjust where I’m riding in relation to the bike, not to put as much weight over the front end because the smaller wheels tend to get stuck in rocks or roots and aren’t able to roll down ledges like a bigger 29er wheel. Shifting more of my weight to the back of the bike and trying to get lower in steep, techy terrain was paramount. Whereas on a 29er, I can be more neutral, or even-keeled. Yet even on very familiar terrain, with adjusting my weight back more, my body still wanted to be catapulted forward on the Yeti. It is a finicky line to find!

However, on the fast and flowy parts of the trail, I was able to be more over the front of the bike and feel more efficient and fast. The first time I sent a favorite jump of mine, I overshot the landing and almost ate shit, having whipped the bike too far out, overcompensating for my normal big wheels. After a few more rides, I finally had in-air maneuvers more controlled and dialed.

I really don’t like saying a bike is “perfect for” a specific terrain or rider, but here we go… For me, a 27.5″ wheeled bike excels in fast, steep, flowy, and jumpy terrain better than a 29er. Yet, a 29er excels in steep, rocky, chunky terrain. As consumers, it’s hard to navigate the waters when it seems like the bike industry is over-selling long-travel 29ers to everyone, regardless of home turf.

Keep in mind, you should buy a bike that is suited to your local riding, and the routes you do most often. Say you live in the Midwest and have spent a good amount of time on your bike, which is best suited for your local terrain. Then you travel on a MTB trip to more formidable, higher-consequence terrain–say, Colorado, for instance. For me, I’d rather know my bike better, how it moves, what it’s capable of, and be more comfortable on it, than riding too much bike at home for the sake of it because I might go ride terrain that merits a long travel 29er.

If I was averse to our upper mountain rides and was content with faster, flowy, jump-line trails, I’d go with a 27.5″ wheeled bike all day, but I live for those steep, rocky descents where every inch of wheel diameter helps. While 150mm of front travel was enough for me during this review period, I am intrigued by how a 160mm fork would change the ride quality but in the end, I do wish it had a longer front-center to help in those steep and rocky descents.

Overall, I enjoyed this bike because it challenged my opinion about 29ers, and honed my skills by riding an entirely different platform than I’m used to. I think the industry is very fast to move on to the next trend far too often. A few years ago, 27.5″ wheels dominated, but now long-travel 29ers are the new hot thing. Kudos to Yeti for sticking to their guns and making a bike that addresses what might be a niche crowd at this point but is still very relevant for the modern rider and, honestly, makes a lot of sense on a lot of terrain.

Yeti has a number of build kits, with a Lunch Ride option, allowing for over-forking the SB135 to 160mm. The Sb135 I reviewed here is 150/135mm travel.


Wheel diameter is preferential, as is frame material, but riding a carbon rocketship like the SB135 is a real treat. It climbs with a relaxed yet precise demeanor and demands an adapted riding position when coming from a 29er sled. The lightweight chassis, Switch Infinity suspension system, and SRAM T-Type drivetrain Transmission add to the blissful experience. While I wish the front-center was a little longer to compensate for the smaller diameter wheels, I really appreciate bikes with a snappier feel.


  • Yeti found the sweet spot in terms of modern geometry with a 27.5″ wheel
  • Lightweight, at only 30lbs for a size XL
  • Detailing is some of the finest in the industry
  • Switch Infinity creates a balanced, planted ride, that almost prefers being further back or forward on the bike, perfect for the smaller wheels.
  • Lifetime Warranty
  • A high-tech, engaging, and light-footed trail riding experience
  • Five unique frame-sizing designs
  • Turquoise is a great color for bikes (in the Southwest) ;-)


  • Expensive. $10,300 as reviewed here. Yetis are not cheap bikes. Even the lowest-priced C1 kit is $6400
  • Switch Infinity system will eventually require more time servicing than other external systems
  • 27.5″ wheels aren’t for everyone and require adjustment of body positioning more frequently
  • It could use a tad bit longer front center for more technical terrain.


This was a lot to review, so if you’re still reading this, thank you. If you have any questions about my riding experience with the Sb135, drop them in the comments, and if you’d like to see more information about the Sb135, roll on over to Yeti.

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