2017 YT Jeffsy CF 27 Pro
(discontinued)

Vital Rating:
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Free shipping on orders over $50 (continental U.S. only).
International shipping available. Some exclusions apply.
Tested: 2017 YT Jeffsy CF Pro 27
This ultra-fun, high-value bike encourages the kind of exploration and hootin' and hollerin' in the woods that defines the mountain bike experience.
Rating:
Vital Review
s1600 YT Jeffsy 27 Review 763732

The wheel size debate is a dead horse beaten into mushy glue by this point. The hatred forged by some toward 29ers is likely rooted in experiences from a time when the only options were Gary Fisher hardtails. The market has matured, and frame, wheel, suspension, and tire selection have come a long way. 27.5 and 29-inch bikes are different tools that excel in different ways. That being said, this tester has a hard time wrangling many 29ers. Remember how Danny Hart had a skid mark up his ass for the first half of the 2017 season? That skid mark is how some of us feel on big wheels.

This past February, YT introduced the Jeffsy 27. It looks a lot like its brother the Jeffsy 29, a bike we've reviewed in detail before, and from a quick glance you might find the two difficult to tell apart. So why did they make a 27.5 version? Was it just because some people are so resistant to accept a wheel size? We set out to find what the new ride had to offer aside from smaller hoops and the appeal of high-value, direct-to-consumer sales that the brand made popular in the mountain bike world.

Strengths

  • Incredible value
  • Ultra-progressive suspension design gives it a playful, bottomless feel with good off the top traction
  • Ability to increase rear travel with a shock swap
  • Externally routed rear brake
  • High-end build kit that won't leave you wanting
  • Ships to your door

Weaknesses

  • Limited to miniature water bottle size
  • Occasional harshness over medium size bumps at speed
  • Not a standout in the climbing category
  • Outdated front fork and hub axle standard
  • Seat tube lengths may be a bit too tall for some
  • Requires minimal assembly

YT Jeffsy CF Pro 27 Highlights

  • Carbon fiber frame
  • 27.5-inch wheels
  • 150mm (5.9-inches) of front and rear wheel travel
  • Virtual 4-Link (Horst) suspension design
  • Tapered headtube
  • Internal cable routing for shifter (partial) and dropper (full) // External for brake
  • Dropout chain suck guard
  • Integrated frame protection
  • 180mm rear brake post mount
  • Coral red and jet black paint/graphics look fast as shit
  • 92mm GXP press fit bottom bracket with ISCG05 mounts
  • Boost 148mm rear spacing with 12mm through axle, non-Boost 15mm front
  • Measured weight (size Medium, no pedals): 27.8-pounds (12.6kg)
  • MSRP $4,799 USD

Just like the Jeffsy 29, the finer details are pretty dialed on this ride. With exception to the cute little sippy cup of a water bottle and a non-Boost front axle, the bike checks all of the key specification boxes that many of today's riders are after.

The Boost-spaced rear end moves through a familiar Horst style linkage that YT refers to as their Virtual 4-Link suspension design. Suspension characteristics that were generally well received were transplanted over to the new model. Like all YT bikes, the layout is progressive enough that running a coil shock is perfectly doable:

The model we tested comes paired with a Metric-sized 230x60mm FOX Float DPS Performance Elite air shock, providing 150mm of travel. Those looking for a little extra party can move to a longer stroke 230x65mm shock – which YT does on the highest end CF Pro Race build – to get an additional 10mm of bump-eating capability.

YT is well regarded for offering component specs that are great values and sensible choices. It’s clear that they do their homework on choosing what an educated rider would want for a given budget.

As we've come to take for granted, the Maxxis High Roller II EXO casing tires provided a good balance of weight, traction, and rolling speed. YT specs the bike with a firmer 60a rubber compound on the rear tire for better durability.

e*thirteen's TRS+ wheels delivered on being reliable and cost appropriate. The loud rear hub comes with the association of a much more expensive wheelset, but it’s not all talk. The fast engagement was great to have when ratcheting our way through tricky climbs or getting on the gas after blowing a corner. They came setup tubeless on our bike, and we suffered no flats or burps during the test (knock on wood). By the end of the test they weren't perfectly round but could still be trued to a very good tolerance.




SRAM’s super adjustable Guide RSC brakes didn’t suffer from any of the previously known issues associated with these brakes and performed well throughout. The wise choice of a 200mm rotor up front meant plenty of power was on tap when paired with the still capable 180mm rear rotor. We only dealt with minor fade on the longest of descents and even that was quite manageable.

The 12-speed SRAM X01 Eagle drivetrain never dropped a chain, skipped a shift, or left us wanting. This drivetrain performs better and lasts longer than the previous 11-speed options from SRAM.

The bike is quiet down the trail with the exception of the buzzing rear hub. The only part that was changed for the test was the SDG Fly Mountain saddle which was swapped out purely for subjective preferences.

Long Term Durability

Some of the rubber frame guard material has started to lift on the chainstays due to heel rub, but this is nothing that some tape or glue touchups couldn’t fix. The downtube has sounded off a few dreaded rock strikes with no observable damage, and the finish has held up quite well with only minor blemishes. There are a few chips in the finish near cable entry/exit ports, however.




We performed two bolt checks more out of curiosity than anything else and found nothing loose in the pivots. We never had any suspension squeaking or odd frame noises. Though press fit bottom brackets have a poor track record, this one never creaked. A season of wet riding might have produced a different outcome, but we had no issues.

So long as you keep up with regular maintenance, we have no qualms saying this bike should provide you with years of reliable riding. YT provides a handy exploded diagram to make pivot service easier. The bike is backed by a three year warranty (five in the US) and crash replacement program.

What's The Bottom Line?

The main word we kept coming back to through the course of the test to describe the Jeffsy 27 was FUN. It encourages the kind of exploration and hootin' and hollerin' in the woods that still defines the mountain bike experience for us after all these years.

It’s not plush, but it’s not harsh. If you’re a passive passenger there are better bikes for you. The Jeffsy 27 requires you to push it a little to really show off its potential.

Regardless of what you feel about wheel size, the geometry adjustments made to the 27 version of the Jeffsy are good tweaks over the 29 version, making this a great option for anyone looking for a 27.5 trail bike. While it might not be the best enduro race machine for those purely concerned with hunting speed, you would be hard pressed to find a better everyday trail ripper, especially for the money.

Visit www.yt-industries.com for more details.

Vital MTB Rating


  • Climbing: 3.5 stars - Very Good

  • Descending: 4.5 stars - Outstanding

  • Fun Factor: 5 stars - Spectacular

  • Value: 5 stars - Spectacular

  • Overall Impression: 4.5 stars - Outstanding


About The Reviewer

Kevin Shiramizu - Age: 32 // Years Riding MTB: 20 // Height: 5'7" (1.70m) // Weight: 170-pounds (77.1kg)

During the two decades Kevin has been riding mountain bikes he accumulated multiple state championships in Colorado for XC and trials riding, a Junior National Championship title in trials, and went to Worlds to get his ass kicked by Euros in 2003. His riding favors flat corners and sneaky lines. After a doozy of a head injury, he hung up the downhill bike for good in early 2010 and now foolishly rides a very capable trail bike with less protection and crashes just as hard as ever. He likes rough, technical trails at high elevation, but usually settles for dry, dusty, and blown out. He spent five good years of his youth working in bike shops and pitched in efforts over the years with Decline, LitterMag, Dirt, and Vital MTB. He also helped develop frames and tires during his time as a guy who occasionally gets paid to ride his bike in a fancy way in front of big crowds of people.

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Specifications

Product
YT Jeffsy CF 27 Pro
Model Year
2017
Riding Type
Enduro / All-Mountain
Rider
Unisex
Sizes and Geometry
S (Low, High)
M (Low, High)
L (Low, High)
XL (Low, High)
Wheel Size
27.5" (650b)
Frame Material
Carbon Fiber
Frame Material Details
High modular carbon fiber, downtube/seatstay/chainstay protection
Rear Travel
150mm
Rear Shock
FOX Float DPS Performance Elite Air, EVOL extra volume air sleeve, 3-way compression (open, medium, firm), external rebound, 230mm x 60mm, black coating
Fork
FOX 34 Performance Elite Air, FIT4 damper cartridge, external 3-way compression (open, medium, firm), low-speed compression (open mode), external rebound, tapered steerer, 100x15mm QR thru-axle, 44mm rake, black coating
Fork Travel
150mm
Head Tube Diameter
Tapered
Headset
Acros AiX-326, IS42/28.6 / IS52/40
Handlebar
Race Face SixC, 35mm clamp, 780mm width, 35mm rise, 8° backsweep, 5° upsweep
Stem
Race Face Turbine, 35mm clamp, 50mm length (S/M), 60mm length (L/XL)
Grips
The Sensus Lite
Brakes
SRAM Guide RSC, 4-piston caliper, Centerline rotors, 200mm front, 180mm rear
Brake Levers
SRAM Guide RSC, tool-free reach adjust, tool-free contact point adjust, SwingLink lever
Drivetrain
1x
Shifters
SRAM X01 Eagle, 12-speed
Front Derailleur
N/A
Rear Derailleur
SRAM X01 Eagle, 12-speed, Type 3, carbon, cage lock
ISCG Tabs
ISCG05
Chainguide
N/A
Cranks
SRAM X01 Eagle carbon, 175mm length
Chainrings
SRAM X01 Eagle, 34 tooth direct mount
Bottom Bracket
SRAM BB92
Pedals
N/A
Chain
SRAM PC X01, 12-speed, with PowerLock
Cassette
SRAM XG1295 Eagle, 12-speed, 10-50 tooth
Rims
e*thirteen TRS+
Hubs
e*thirteen TRS+, 100x15mm thru-axle front, 148x12mm thru-axle rear with XD driver
Spokes
 
Tires
Front: Maxxis High Roller II, EXO MaxxPro, 27.5" x 2.4"
Rear: Maxxis High Roller II, EXO MaxxPro 60a, 27.5" x 2.4"
Saddle
SDG Fly MTN, custom YT Logo
Seatpost
Race Face Turbine, internal routing
S: 375mm length, 125mm travel; M,L,XL: 440mm length, 150mm travel
Seatpost Diameter
31.6mm
Seatpost Clamp
Standard single bolt
Rear Dropout / Hub Dimensions
148x12mm Boost
Max. Tire Size
 
Bottle Cage Mounts
Yes (single small bottle)
Colors
Coral Red/Rawr, Rawr/Jet Black
Warranty
5 years main frame, 2 years swingarm and other YT components
Weight
27 lb 12 oz (12,587 g)
Miscellaneous
Virtual 4 Link suspension technology
Price
$4,799.00
More Info
What do you think?
Where To Buy
Free shipping on orders over $50 (continental U.S. only).
International shipping available. Some exclusions apply.
Free shipping on orders over $50 (continental U.S. only).
International shipping available. Some exclusions apply.
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