Turner Bicycles spent the better part of three years developing its second carbon-framed mountain bike – the 2016 RFX v4.0 Enduro. The back story is that RFX was first introduced in aluminum in 1999 as an all-mountain/freerider and had earned a loyal following. Founder and designer David Turner was nearing the production phase with a carbon fiber version when the industry abruptly switched to 27.5-inch wheels. Turner considered the options and decided to scrap the substantial investment he had in molds and prototyping costs for the 26-inch RFX, and forge ahead with an all-new 27.5-inch wheel machine.
Looking back, Turner said that starting once more from scratch gave he, and suspension designer Dave Weagle, the opportunity to incorporate knowledge learned from the rapid evolution of enduro-specific bicycles which took place at the time he was working on the original 26er. As a result, the new RFX is longer, a bit slacker up front, and its suspension is better suited for high-speed runs down trails that were once the realm of big bikes. But, unlike many contemporary enduro bikes that prioritize downhill performance well above pedaling efficiency, the RFX V4.0 balances its edgy frame numbers with a crisp-pedaling dw-link rear suspension. That, and Turner's switch to carbon construction, has produced a wonderfully versatile, 27.7-pound enduro racing machine that that should become a favorite among all-mountain trail riders as well.
Details: RFX v4.0 Enduro
• Purpose: Enduro competition, all-mountain/trail
• Frame: High modulus carbon construction, 160mm-travel dw-link rear suspension, external hose and cable routing, 142/12mm axle, threaded bottom bracket, ISCG 05 chainguide tabs.
• Wheel size: 27.5, clearance for 2.4-inch tires.
• Shock: RockShox Monarch Plus with Debonair sleeve.
• Fork: 160mm stroke recommended (RockShox Pike furnished with builds).
• Adjustable head angle: Tapered head tube designed to use FSA +/-1 degree headset cups.
• Front derailleur compatible: Direct mount and cable guides for Shimano side-swing mechs.
• Screw-in cable guides: Adel-type clamps secure hoses and housings to the frame.
• Suspension pivots on Enduro Max sealed ball bearings.
• Sizes: Small, medium, large, and X-large.
• Weight as tested: 27.7 pounds (12.6 kg). (Frame weight: 6.5 pounds/2.96kg with shock and hardware)
• MSRP: Five complete builds from $4573 for the GX, to $6533 for Shimano XTR (Frame and shock - $2995).
• Contact: Turner Bicycles
Turner designs its frames at its headquarters in Murrieta, California, and then outsources the aluminum manufacturing to a US frame maker in Portland, Oregon, while the carbon manufacturing of the Czar and the new RFX v4.0 is delegated to a high-end frame maker in Asia. Neither should be cause for concern, as Dave Turner has been in the game since 1994 and has relied upon outside manufacturing since day one. To ensure that all the bits are up to snuff, Turner does all of the final checks, machine work, and assembly in Murrieta. Complete builds are also assembled there, ride-checked, and then partly disassembled for shipment.
Toray is a Japanese carbon fiber supplier that is considered by bicycle makers to be the number one source for high-performance composite materials. Reportedly, the RFX chassis is laid up exclusively with a blend of Toray's high-modulus uni-directional carbon products, which results in a lighter, stiffer and extremely strong frame. Turner did not stray from the proven profile of its aluminum frames when he penned the carbon RFX, including a nod to their traditional rectangular seat stays and steeply sloped top tubes. The suspension is also similar, with a Dave Weagle-configured dual-link system driving the shock parallel with the seat tube. Call it antiquated, but there can be no argument that the bottom bracket area is the strongest part of the frame to mount a shock - and doing so leaves room for a single bottle mount on the down tube.
Taking full advantage of a high-strength molded material, the RFX's swingarm is widened to provide ample clearance for 2.4-inch tires near the bottom bracket and up top, the traditional seat stay bridge has been eliminated to provide room for the tire and also to clear the seat tube at full compression. Dave Turner has been a shorter-is-better proponent when it comes to chain stay length, so it should come as no surprise that the RFX's rear end is designed around 17.25-inch (438mm) stays - pretty good for a 160-millimeter-travel bike with a 27.5-inch wheel and DH-width rubber. The performance of the Turner's RockShox Pike fork needs no introduction. The big surprise was how well the Monarch Plus Debonair damper played with the RFX's dw-link suspension.
Details abound on the newest Turner, beginning with the use of ball bearings in the pivot locations. Turner, who had been a staunch supporter of composite bushings, switched to Enduro Max ball bearings for the RFX because they allegedly enhance the suspension's response to small bumps, and because their full-compliment ball configuration is specifically designed for a bicycle suspension's high loads at low rotational speeds. The post-mount rear brake caliper features threaded aluminum dowels that eliminate the possibility of stripping a threaded insert bonded inside the carbon swingarm. The one place you will find a threaded insert is the bottom bracket, which is also endowed with ISCG 05 chainguide tabs.
Up front, the RFX's tapered headset interface is designed around FSA's angle-adjust headset cups. Stock frames are shipped with zero-degree cups, but customers can order the adjustable, plus or minus one-degree, cups directly from Turner Bicycles. The stock head angle is 66 degrees, so RFX owners can opt for either a 65 or a 67-degree angle depending upon their skillsets or theaters of operation
RFX frames buck the internal cable and hose routing trend, and perhaps that is a good thing. Turner uses threaded bosses and a combination of Cannondale-style T-stops on the downtube and Adel-type clamps elsewhere on the frame to secure full-length housing and hydraulic hoses. A port on the seat tube facilitates internally actuated dropper posts. Most RFX builds will leave Turner with one-by drivetrains, but the seat tube is offset to the left and a pair of threaded bosses are included to mount a front derailleur for customers who desire a side-swing Shimano front changer and a multi-ring crankset.Five Build Kits
Turner Bicycles offers five build kits
that include three with SRAM drivetrains (GX, X01 and XX1) and two based upon Shimano's XT and mechanical XTR ensembles. The SRAM GX and both Shimano builds can be configured as one-by or two-by drivetrains, while the X01 and XX1 are obviously one-by only builds. Base prices for the Shimano XT and XTR builds are $5610 and $6533 respectively, and the SRAM GX, X01 and XX1 builds start at $4573, $5737, and $6207.
Our test bike was assembled with a mix of components that Turner admittedly had laying around because their MY-2016 component shipments had yet to arrive. The mix of parts was eclectic to say the least: SRAM's entry-level GX one-by transmission, Enve M70 wheels with 2.35-inch Schwalbe Nobby Nic tires, a Thomson DH handlebar and 50mm stem, and a KS LEV dropper post. Suspension was RockShox's best: a 160mm Pike RCT3 Solo Air fork paired with a Monarch Plus Debonair shock. While our test bike did not match up with any of Tuner's official build kits, it is safe to say that its overall performance would be close enough to provide a fair evaluation of any of the five available options.
|The Turner responds naturally to body English, so lofting the RFX over short drops or rock gardens becomes intuitive in one or two rides.|
Take the time to get the RFX's suspension tuned and you will be rewarded with a bike that holds a tight line in the bends and jumps like an alley cat. The Turner seems to work best with the fork's spring pressure slightly higher than the shock's, which is typical of bikes that use dw-link rear suspension. For reasons unknown to us, the dw-link system is sensitive to spring pressure and compression damping. Overdo either by a small margin and the bike's tail end will ride high and overdrive the fork. Get it right and the bike will hold its pre-set ride height almost everywhere, which turns out to be a massive confidence builder.Cornering:
We expect long-wheelbase bikes with head angles in the neighborhood of 66 degrees to oversteer
when pushed hard into a corner, and as cute as that may look on every Pinkbike video posted in the past three years, a bike that holds a tighter line and bleeds off speed with both tires when its rider overcooks a bend will always be the faster and more maneuverable. The Turner's geometry blends those two traits with a light feel at the handlebar and the ability to hold a precise line on just about any surface. When it is pushed beyond its cornering speed, both wheels will break traction at about the same moment, but the rear tire will initiate a slight oversteer. As a result, the RFX feels easy to control and when drifting, its line can still be adjusted midway through a turn to steer around a rock or rut, instead of forcing its rider to wait out a stylish rear-wheel slide. Climbing/acceleration:
The RFX does not waste energy while climbing, and its mush-free feel at the pedals encourages short bursts of acceleration. The cockpit feels long and roomy and its 73.5-degree seat tube angle has a just-right feel. That said, there is no denying that the RFX is a 160-millimeter-travel bike, shod with aggressive rubber, so it doesn’t exactly leap forward with each press on the pedals. When the time comes to grind up a long ascent in the saddle or to stand up and power over a roller, the Turner gets the job done as well or better than any enduro superbike that has come through PB for a review.
Interesting to note is that the RFX handles best with the shock sprung quite softly, and yet the dw-link rear suspension maintains ride height while climbing some fairly steep grades. The rear suspension feels stiffer under power, which usually translates to a loss of grip in wet or gravelly conditions, but there was adequate traction available to scratch our way up most technical trails. On the subject of ride height, we are happy to report that the RFX, with a 13.4-inch bottom bracket height, does not bang its pedals on every protruding rock and root that stands in the vicinity of its crankarms.
Those who spend significant time pedaling out of the saddle will want to switch the shock’s low-speed compression lever to the middle or the semi-locked position to keep the Turner’s tail end hardtail stiff, but there is enough anti-squat in the suspension so that most riders will opt to leave the shock open or at most, in the middle position, for just about any kind of climbing.
Descending/technical: Skilled or not, most trail riders will find the RFX hard to fault on the downs. While not exceedingly stiff, its chassis is rigid enough to hold a precise line across ragged off-camber terrain that would have most lightweight trailbikes bending and twitching like the front row at a rave concert. In a straight line, the Turner's 66-degree head angle and generous front center measurement make easy work of rock drops and chunky chutes. When a difficult section of trail rears its ugly head, the RFX is just as happy to wiggle its way down the safest option, or take the "we shall see" straight-line approach. More often than not, we exited steep or technical sections with a sense that we could have pushed harder or carried more speed.
Like all good trailbikes, the RFX allows its pilot to do most of the work from a centered position over the bike. That, and the Turner's tendency to remain at ride height keep the rider positioned to handle just about any surprise that may pop up on an unfamiliar trail - which is an attribute that will come in handy for enduro racers. Another positive in the RFX's technical handling quiver is that the rear wheel tends to follow the front under braking. The rear suspension remains supple enough when the rear brake lever is squeezed to keep the tire on the ground and rolling, so the chassis remains quite calm in situations where some of its well-reviewed competitors would be bouncing around on the chatter.
With its suspension biased to be slightly softer in the rear, the RFX becomes an excellent jumper. The chassis remains level with very little pull-back required to keep the rear end from lifting over peaky ramps. In fact, the bike has a tendency to jump front wheel high, so an over-zealous pull back can result in a "Hail Mary" moment. The Turner responds naturally to body English, so lofting the RFX over short drops or rock gardens becomes intuitive after one or two rides. The RFX is one of the easiest handling bikes we have ridden since the Intense Tracer 275 Carbon or the Santa Cruz Nomad.
|In a straight line, the Turner's 66-degree head angle and generous front center measurement make easy work of rock drops and chunky chutes.|
Few customers are going to order a Turner RFX outfitted with a mix-and-match component spec like PB's test sled, so it makes little sense to dwell upon the merits of every part on the bike. There are a few components, however, that warrant a shout out. If we were asked to recommend a particular build from Turner, it would be either the SRAM XX1 or the X01 (ours used a SRAM GX one-by drivetrain). We are not squeezing on Shimano here, just underscoring that a SRAM one-by eleven offers the whole package for all-mountain and enduro riders: Just-right gearing, no fuss shifting, chain-drop security and best-in-class feedback at the shift lever. Shimano brakes would be our first choice, but SRAM's Guide stoppers are up to task, and would not be a deal breaker by any stretch of the imagination.
Schwalbe Nobby Nic tires:
FSA angle-adjust headset: Long-travel trailbike development is nearing the stabilization point, but vocal factions remain that are pushing for steering geometry which only makes sense for dedicated gravity racers. Turner's solution, the FSA Orbit Extreme Pro headset allows non-believers from both DH and XC/trail camps to adjust the RFX v4.0's head angle one degree in either direction - which should be enough to tune its steering to suit without ruining its handling altogether.
Enve M70 carbon wheels: We know that most riders will not be willing or able to shell out Enve wheels, but the precise feel that they give to the Turner when pounding over erratic rock piles and rooted sections should be a reminder to anyone who is moving up to a long-travel enduro racing machine to spend the money on a high-quality, stiff wheelset that has wide enough rims to stabilize tires in the neighborhood of 2.3 to 2.4 inches. It makes a difference.
Schwalbe's 2.35-inch Nobby Nic excels as a rear tire, but it falls short on hard-pack surfaces as a front tire. Up front, it grips well until it doesn't grip - and then all hell breaks loose. Pair the Nobby Nic in the back with Schwalbe's Magic Mary up front and the RFX would feel invincible in the turns. Pinkbike's Take:
|Turner's RFX v4.0 Enduro is the real deal. Considering that it is only their second carbon offering, we expected it to have at least one glaring shortcoming, but truth be told, it checks all the boxes. Dave Turner didn't overreach when he penned his first carbon fiber long-travel chassis. He incorporated trail-proven numbers and suspension metrics into a conservative frame design that was optimized for carbon construction methods - and that is a good thing.|
Turner has been punching out winners in aluminum for over two decades, and has collected a substantial fan base along the way. The RFX v4.0 offers loyal customers a chance to make the jump to carbon and follow Turner into the future. And, for those new to the brand, test-riding an RFX will be an unexpected pleasure. David Turner is one of the more talented riders to occupy the top seat of a bike-making business, and his vision of the perfect mountain bike - versatile, balanced, and confidence inspiring - reflects a lot of saddle time. As an AM/enduro racer, the RFX v4.0 is all of those things - with a big serving of attitude. - RC
View larger-format and additional images in the review gallery.
About the RiderStats: Age: 38 • Height: 5'9” • Weight: 170lb • Industry affiliations: Owner, iMountainbikeHarold Preston hails from Johannesburg, South Africa, a skate boarder who discovered mountain bikes when he made his home in San Diego, California, in 2015. Preston is an all-mountain crusher, a well-respected rider among the area's gravity community, a mentor to a number of youths who have done well in national and international competition, and often a guide to pro riders who show up each winter. Harold was first rider to show RC around San Diego's secret trails and has since become a PB test rider and one of his most trusted friends. Most will recognize Harold as the rider who often appears in RC's photo shoots.