Yeti SB4.5 trail bike review
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 Kashima | Chain: SRAM 1130 | |
| Shock: Fox Float Factory DPS EVOL | Bars: Easton Haven Carbon 740 | |
| Wheels: DT Swiss XM401 | Stem: Easton Haven 55mm | |
| Hubs: DT Swiss 350 | Seatpost: RockShox Reverb | |
| Tires: Maxxis Ardent 2.4/Ikon 2.2 | Saddle: WTB Volt | |
| Brakes: SRAM Guide RSC | Headtube angle: 67.4 degrees | |
| Rotors: SRAM Centerline 180mm/160mm | Chainstay length: 437mm | |
| Shifters: SRAM X01 | Seat tube angle: 73.3 degrees | |
| Front derailleur: None | Weight: 26.5 pounds (w/XTR pedals) | |
| Rear derailleur: SRAM X01 | Price: $6900 | |
| Cable routing: internal |
Rating:  5 out of 5 |
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| Crankset: Race Face Atlas |
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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.
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.
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.
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.
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 »
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