If you're looking for a whip-fast bike that can handle some bigger terrain on occasion, look no further than the 2017 Yeti Cycles SB4.5 Turq X01 Eagle Complete Mountain Bike. It blends XC speed with geometry to handle the bigger stuff, and now carries Yeti's new Turq designation for an even lighter footprint than its predecessor. Turq manifests as a more precise carbon layup that's carefully molded to reinforce key stress points without adding bulk, resulting in strength where you need it and light weight where you don't. In the end, Yeti claims that Turq construction nets a savings of 300g compared to the regular SB4.5 Carbon—a stat that lends the SB4.5 Turq more climbing pedigree and complements the bike's surprisingly climb-happy X01 Eagle drivetrain.
Yeti also says 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 boosted 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. Its 67.4-degree head tube is one of the slackest we've seen on an XC-leaning 29er, and it makes for a boost of confidence while picking lines across terrain that would make a more typical 70-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 didn't 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. 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 value finesse over just bombing terrain.
- A mid-travel 29er with expanded capability
- 4.5in of smooth Switch Infinity suspension
- Geometry balances slack and moderate for confident handling
- Turq carbon construction drops weight and bolsters stiffness
- Boost axles track on descents and transfers power on climbs
- SRAM's X01 Eagle drivetrain provides the ultimate bailout gear
View more All-Mountain & Trail
SB4.5 size by rider height
|140mm Travel Fork|
Effective Top Tube
Head Tube Angle
Seat Tube Angle
Bottom Bracket Height
Reviews & Community
- Familiarity: I've put it through the wringer
I typically tend towards long travel sleds. I love flying down trails at breakneck speeds, and sending big jumps and drops. I've always had smaller wheels because the bikes built for the riding I do tend to have 27.5 inch wheels. With that being said, the 4.5 is one of the funnest bikes I have ever ridden. even with a garage with Bronsons, Hightowers and the like, I usually grab that one to go play around on, and whenever I am at a dirt jump park without my hardtail I grab the 4.5.
The switch infinity pedals like a dream. This is the best pedaling bike I have ever ridden, with minimal bob even in the open settings, which usually isn't the case since I tend towards mashing the pedals as opposed to a more refined pedaling technique. It zips up climbs, and the best part is I don't feel at a loss on the way back down on all but the most rowdiest of trails. It definitely does not feel as forgiving or as fast as a longer and slacker enduro /all mountain bike on the downhills, especially when it comes to the most technical of rides, but it is plenty capable of riding them if you aren't trying to get the KOMs on the way down too.
I tend not to mention component spec when I talk about a frame because it can change, and so its not really a review of the bike, but Srams eagle definitely merits a mention. It has the smoothest shifting performance of any group I have ever ridden, and that alone would make me choose it over any competitor, but the gear range really puts it head and shoulders above the competition.
To sum it up, if you are looking for a bike that can smash any climb, and still feel like a ton of fun while on the way back down, look no further.
If you have any questions about this or any other mountain bike, shoot me an email at email@example.com, or give me a call at 1.800.409.4502, EXT 4589.
Still The One
- Familiarity: I've put it through the wringer
I’ve been at Competitive for 5 years, and in that time, I’ve changed bikes after each year. The SB45 is the bike hat has bucked that trend. From XC/Endurance racing, to trips to Moab, this bike’s versatility is boundless. Anchored by Yeti’s Switch Infinity suspension platform, which provides excellent small bump compliance and a progressive mid stroke, I have yet to feel a harsh bottom out on this bike. Add to that the unparalleled pedaling performance, and you have in my opinion the best suspension platform in the industry. Personally, I’m the one holding this bike back when things get really rowdy. Are there other bike that have more of a “hold on and stay off the brakes” mentality, sure, it’s the 4.5’s big brother the 5.5, but I’ve ridden that also, and felt that it was overkill for the majority of trails I ride day in day out. Yeti wraps all that into a frame with progressive geometry, clean internal routing, and great visual lines.
My bike with carbon wheels, X01 drivetrain, and a Fox dropper tips the scales at 26.5 pounds with pedals. If you’re looking for a bike that can rip the local descent, and hold its own at the town XC race, the SB45 fits the bill.
XC with an All Mountain Mentaility
- Familiarity: I've used it once or twice and have initial impressions
Let me just start by saying... the 4.5 blew my expectations out of the water/(dirt)!
I've heard from many of my clients and colleagues how capable this ride is, but after demoing it at the Moab Thaw the other weekend (1st trip down to southern UT this year! whoop whoop) I truly felt how capable and versatile it really is.
With 140 mm of travel up front and 114 mm in the rear, the 4.5 is built to be an efficient XC machine with the ability to handle aggressive and burly terrain. I have to woefully admit, before hopping on to test it out I thought to myself, "I'm going to bottom this thing out within minutes." To my surprise, I couldn't have been more wrong. Where this bike shines is on the technical climbs, steep ascents and bumpy/rocky flowy trails. I wanted to test how the bike handled some drops and rowdier lines so went and did just that. The bike continued to shine even on those technical and rowdy descents. What Yeti has done with their Switch Infinity technology is truly impressive... The "translating main pivot" is especially advantageous on steep and rocky climbs and burly descents. The 4.5 handles just about everything you can throw at it.
I have ridden a 29er since I got my first full suspension bike back in 2012 and have never looked back. With the advent of BOOST technology 29ers have now taken over (in my opinion) the xc/all-mountain/enduro scene.
My only complaints with this build was the narrow feel of the handlebars and the lack of engagement of the DT swiss hubs. After a couple component swaps this build would be perfect!
If you have any questions on this bike, a custom build variation of the 4.5 or anything else feel free to reach out to me directly and I'll get you all squared away.