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Yeti Cycles SB4.5 Carbon Mountain Bike Frame - 2016

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Item # YTI003A

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  • Green, L ($2,210.00)
  • Green, XL ($2,210.00)
  • Turquoise, S ($2,210.00)
  • Turquoise, M ($2,210.00)
  • Turquoise, L ($2,210.00)
  • Turquoise, XL ($2,210.00)
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Yeti has produced a lot of big, scary, enduro sleds that gobble terrain with the abominable aggression of the company's namesake, but the latest monstrosity to mate the Switch Infinity suspension design with a slack head tube may be the most frightening of all. The all-new SB4.5 Carbon Mountain Bike Frame is driven by 29in wheels, led by a 67.4-degree head tube, and enabled by 4.5in of Yeti's signature suspension design. Just a few months ago, we would have told you this combination was unlikely, if not impossible; yet here it is, in all its abominable glory.

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 Boost-ed 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. This is one of the slackest head tubes we've ever seen on a 29er, and it makes for a boost of confidence while picking lines across terrain that would make a more typical 70-71 degree head tube 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. It also erases the momentary harshness that its predecessor, the Switch Link design, would display when pushed to the absolute limit.

Of course, most riders will never experience that dead spot on the Switch Link, but the SB4.5 isn't for most riders. It's for the all-mountain racer who demands that their machine flattens big hits with the same tenacity that it cleans long climbs — a rare breed in the enduro scene as a whole, but common enough in Yeti's Tribe of enduro, bikepacking, XC rocket ship pilots. Please note that the frame is built for one-by drivetrains only. In our experience, the SB4.5's Switch Infinity suspension isn't quite as soft off the top as the 5.5 and it finds the bottom when we overshoot a landing. That said, the steeper head tube produces sharper handling and rewards technique while picking lines, making the SB4.5 more fun if you're not into just bombing terrain with your eyes closed.

  • A trail machine that pushes the boundaries of wagon wheels
  • Switch Infinity suspension is the industry's most advanced design
  • Geometry straddles the boundary of slack and moderate
  • Steep angles (for Yeti) reward a surgical approach to terrain
  • Carbon construction saves weight and adds stiffness
  • Boost axles track on descents and transfer power on climbs

Tech Specs

Frame Material:
carbon fiber
Switch Infinity
Rear Shock:
FOX Float Factory DPS
Rear Travel:
114 mm
44 / 56 mm tapered inset
ISCG Tabs:
one-by only
Bottom Bracket:
Brake Type:
30.9 mm, stealth dropper routing
Seat Collar:
35 mm
Rear Axle:
Boost 12 x 148mm
Tire Size:
up to 2.3 in
Claimed Weight:
5.4 lb
Recommended Use:
Manufacturer Warranty:
5 years limited

sizing chart

SB4.5 size by rider height


Geometry chart

Yeti Cycles

Geometry Chart


SB4.5 Carbon
140mm Travel Fork

Seat Tube


Effective Top Tube






Stand Over

Head Tube


Head Tube Angle


Seat Tube Angle


Bottom Bracket Height




S 16.5in 22.8in 23.9in 15.6in 29.6in 3.5in 67.4o 73.3o 13.1in 17.2in 44.4in
M 17.5in 23.8in 24.1in 16.6in 29.6in 3.7in 67.4o 73.3o 13.1in 17.2in 45.4in
L 19in 24.8in 24.5in 17.5in 29.6in 4.1in 67.4o 73.3o 13.1in 17.2in 46.4in
XL 20.5in 25.8in 25in 18.3in 29.6in 4.7in 67.4o 73.3o 13.1in 17.2in 47.5in

Reviews & Community


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Bought this as a whole bike build

  • Familiarity: I've used it several times

This is my firs non-hardtail mountain bike and I'm a road cyclist who never developed the technical skills to be a super mountain biker. You're not going to get some minute detailed review because I'm not a die hard mountain biker. I got a great deal on this bike at the end of this year. I use the mountain bike just to mix up my training and ride with friends on the trails some times. I can't get over how the bike performs on the trails though. I'm able to hang/more or less with a lot more skilled riders with this machine. So far, I'm loving it.

Avg. ride time: 3h 19m per week
  • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

Do you have Raw/Black Frame size S?

Hi, we have sold out of the size S raw/black unfortunately. Contact me directly if you are interested in the turquoise or any questions on build options.

Hi. Does this frameset come with the XC or Trail tuned shock?


Hey there!

Great question! So for this particular model, it does look like a xc tuned shock but is in fact a trail tuned shock.

Please contact me directly the next time you have any questions!

Karissa Lamb

Expert Gearhead



Yeti removed the spacer, adjusted the damping and these shocks have the same shim stack and air volume as the trail. The shocks on these bikes are the physical XC shock, but have been re-valved to match the trail tune shock. Contact me directly with further explanation!

Like finding an old friend.

  • Familiarity: I've used it several times

This bike is so much fun to ride. That's the review in a sentence. But in more detail: You don't know your on 29" wheels. It's nimble and tossable. It pedals like a hard tail. The custom tune shock works so well with the frame and switch infinity tech. Fork is fantastic as well. I went with the full bike, X01 build. The bike being built and then shipped in CC custom bike box was a huge plus. I kept all the packing materials because it's perfect for shipping your bike to an epic local for memorable riding.

Like finding an old friend.

29er with a Vengeance

  • Familiarity: I've used it once or twice and have initial impressions

This bike has become one of Yeti's most popular selling bikes!

As a 29er fanatic myself (on a Santa Cruz Hightower as of right now) this bike was a blast to ride at some local trails here in Park City. The switch infinity suspension is definitely the real deal. Coming out of berms, pedaling up-hill and pinning the fast/flowy portions of the trail - this is where their proprietary suspension technology truly excels. The 4.5 owns the bigger wheels to handle technical and rowdy sections and the perfect amount of travel to handle 90% of all single track out there.

I just recently finished a spec'ing out a custom build for a customer and I CANNOT wait to hear how excited he is once it arrives. Full XX1 Eagle, ENVE M60 HV wheelset and one hell of a badass looking bike - this bike truly came out to be a work of art.... Picasso and DaVinci would have been impressed. Props to our guys in the shop who build out bikes like this on a regular basis:)

If you are thinking about your next bike and leaning toward a new 29er, this could be the perfect bike for you.

Feel free to give me a call at 801.204.4555 to chat about spec'ing out an awesome custom build.

29er with a Vengeance


    I own this bike and have spent ample time on it this year. Ive always had more XC type 29rs so was a little hesitant on switching over to more travel and slackness. My fears soon vanished after the first ride. This trail 29r is extremely well rounded. It climbs as well as any XC bike out there and absolutely rips on the downhill. The new boost spacing makes the bike very laterally stiff as well which also allows for a shorter wheelbase making the bike very agile and responsive.The bike has a very balanced geometry as well. I'm 5'10 and sized up to a large which felt as though it was custom made for me. This bike is highly recommended for any die hard 29r fan out there. Performance is the key and Yeti nailed it.

    If you have specific questions with the bike Im always happy to help. Feel free to reach out to me direct! We can do some minor modifications to the build so let me know if you need anything.

    *** these will have the trail tune rear shock***

    The pic below is me rockin the SB4.5 on the Whole Enchilada trail in Moab. That bike was made for this trail! It performed very well with the 8000 ft of technical descending the trail brings.

    Wes Branham- Account Manager




    What More To Say? Top Notch Trail Bike

    • Familiarity: I've used it once or twice and have initial impressions

    Before anything else, wow. Very impressed with this rig. Oh boy, I haven't been this stoked riding a new bike in a while. I'm 5'11" and often am split between a large and medium, though am finding myself more with large frame and a shorter stem. I rode a large in this and LOVED IT. The trails ridden were in Park City, which are mostly smooth and flowy with a dash of chunk thrown in there.

    What I like about it:

    -Fast! I've ridden the SB5 before and while I was impressed with the pedaling performance of the Switch Infinity suspension design, this excelled with the bigger wheels. I left the suspension open the entire time (as recommended by Yeti) and never felt it sagged or wallowed. In fact, it did the exact opposite and was active and lively while pedaling. Just could hammer away and you feel like you get the full power transfer of each pedal stroke.

    -Going to give another point for the suspension for descending on it, really just fun. While its definitely not bottomless, unless you're getting really rowdy, the 29" wheels and suspension design felt more than 4.5" and could eat up the chunk.

    -While it may not be as nimble as some smaller wheel counterparts, I was impressed how nimble the SB4.5 was. The 67.4 degree headtube angle is slack, but I could corner well and bite into berms.

    What I didn't like:

    -Maxxis Ikons are the bane of my existence. I rode a SB4.5 with an Ardent on the rear, which is great! Still roll well and relatively lightweight but Yeti, why must you insist on this having an Ikon on the rear? First change to this set up (and my only real "mandatory" one if I were to personally get this bike) would be throwing the Ardent on the rear and getting a beefy front tire on it.

    -No easy waterbottle cage access. One underneath is better than nothing, but not by much.

    -740mm bars are just a touch too narrow for my liking. I don't need 800mm, but would be nice to have at least 760mm.

    I often opt for 27.5" bikes, but this was seriously a blast. If you were looking for a trail bike that pedals fantastic and is an all around kick ass bike, look no further. The saying of "you get what you pay for" is so true with this bike - $6899.00 gives a bit of sticker shock, but holy 29" wheels this rig has all that is right.

    Give me a call at 801.204.4547 or email at cojohnson@backcountry.com if you have any questions on the bike or would like any help getting the best bike for you!

    What More To Say? Top Notch Trail Bike

    Fast out of the gate!

    • Familiarity: I've used it once or twice and have initial impressions

    I got to ride the SB4.5c at a dealer event this summer, and this bike flat out impresses. The 4.5 was one of the few bikes that felt effortlessly faster on the first ride than my current bike (the much loved SB66, and the Pivot Mach 6 being the others). I previously owned and loved the SB95c, and couldn't wait for Yeti to slap the Switch Infinity suspension into that frame. With the geometry carrying over similarly from the SB95, only the chainstays and rear travel have shortened. The 10mm drop in travel had me initially scratching my head, but the bottomless feel of the Switch Infinity link, and increased stiffness of the Boost fork and rear end left no lack of confidence in pointing the bike down and hanging on for the ride. At 5’7” - 140 lb, frame stiffness is rarely something I notice, much less stress, but the SB4.5c is the stiffest frame Yeti has ever made, and it noticeably holds its line through rough and off camber terrain. The chain stays are also the shortest of any bike in Yeti’s lineup (even the 27.5 SB5), and gives the 4.5c a wheelbase-defying playfulness on the trail. After riding, I was sure the wheelbase was half an inch shorter than the SB95, not a quarter inch longer. After comfortably riding a medium SB5 and ASR with short stems, I opted for the small SB4.5 frame as the smaller 29er frame gives me a more “balanced” feeling, and that again held true. Overall the SB4.5c is the well-rounded trail bike Yeti set out to make, light enough to hold its own on an XC startline, but stiff and slack enough to be able to throw line choice to the wind and put a grin on the faces of those who can hold on and stay off the brakes. Give me a call or email if I can answer any other questions about the SB4.5c: JJakupcak@backcountry.com / 801-736-6396 x4378

    I'm thinking of an XC racing bike, but hesitating on the SB4.5c because it's advertised as a trail bike. What shock tune did you use? I'm leaning towards the Yeti or Trek Top Fuel 9.8 SL. Thoughts???