LONG TERM REVIEW: TRANSITION REPEATER POWERTRAIN CARBON E-MOUNTAIN BIKE

Transition Bikes is joining the SRAM Eagle Powertrain rodeo with their all-new Repeater Powertrain. The travel has been bumped up to 170mm front and rear on this second-generation machine, as well as longer and slacker geometry numbers and revised suspension kinematics to make it even more capable. It’s a big bike, but it’s designed to provide a balanced and settled feel on the trail.

DRIVE SYSTEM

SRAM’s Eagle Powertrain provides 90 N/m of torque, is paired with SRAM’s 720Wh battery, and features their Auto and Coast Shift features. Building on the momentum of its Eagle Transmission debut earlier this year, SRAM has introduced its first foray into the world of eMTB motor and drive units with the Eagle Powertrain, which fully integrates with the Eagle Transmission drivetrain systems and enables multiple points of personalization through the AXS app.

The tune on the Powertrain was developed with SRAM’s BlackBox athletes, and claimed to provide a natural-feeling and traction-generating application of power that is “profiled to work in concert with how real riders actually pedal.” The SRAM Drive Unit is powered by Brose and offers a claimed 90 N/m of maximum torque and 680 watts of peak power, with a 720Wh battery that is removed with a single Allen key.

The control unit of the system is the AXS Bridge display, which shows relevant system information on a compact and full-color screen and is controlled via the AXS Pod controllers, making for a clean and wire-free ebike cockpit. The AXS app allows you to customize the functions of each Pod button, utilizing both short and long holds to control all aspects of the bike with up to eight different functions.

New to SRAM’s mountain bike lineup, the Eagle Powertrain system introduces Auto Shift and Coast Shift features to the Transmission groupset. As the name implies, Auto Shift uses an algorithm to automatically shift to the optimal gear according to the rider’s power and cadence while still having the ability to manually drop into a higher or lower cog with the Pod controller. Coast Shift allows the rider to shift gears without having to pedal, made possible by the chainring moving freely from the cranks and essentially spinning whenever the rear wheel is spinning.

SRAM keeps things simple when it comes to the ride modes for the Eagle Powertrain—Range and Rally. Range mode (as the name implies) is used when maximum battery range is desired, on more mellow and flowy trails, or when you’re running low on power and need to make it back to the truck before you run out of juice. Rally mode, on the other hand, is when maximum power is wanted and for steep and punchy climbs. Both modes are fully tuneable and customizable in the AXS app, letting you dial in the 90 N/m of power to how you see fit.

FRAME

The new Repeater PT comes with a full-carbon frame spec’d with dual 29-inch wheels, but a flip chip on the lower shock mount allows the rider to run a mixed-wheel setup if they wish without affecting frame geometry.

Chainstays sit at 455mm across the four frame sizes (SM, MD, LG and XL) with a 63.5-degree head tube angle and an effective seat tube angle between 77.5 degrees and 79.2 degrees, with the smaller sizes having the steeper seat tube angle. A size-medium frame has a 455mm reach and a 1262mm wheelbase, with a stack height of 635mm, all fairly standard-issue numbers for enduro bikes these days.

Low durometer chainstay protectors are located in key areas to silence chain slap, and there is a pair of bosses on the downtube for a water bottle cage and another pair under the top tube for other accessories.

SUSPENSION

Compared to the previous 160mm-travel Repeater version, rear travel has been bumped up to 170mm, but the new bike still uses an eMTB-specific version of Transition’s four-bar Horst-link-style GiddyUp suspension system.

Our build comes spec’d with a RockShox Vivid Select+ shock, but it’s also fully compatible with coil shocks. It has 26.6-percent progression and the suggested sag range is 28–34 percent. The rear end is paired with a 170mm-travel RockShox ZEB Select fork.

COMPONENTS

There are two build kits for the carbon-framed Repeater PT, both receiving the full wireless treatment and available in Graphite Grey or Bonfire Red colors. Retailing at $11,499, the XO build, as the name implies, gets XO Transmission shifting and RockShox Ultimate suspension paired with Code Silver brakes.

We tested the GX build that costs $10,499. It receives the ultra-smooth-shifting GX Transmission drivetrain that is powered by the bike’s main battery so that’s one less thing to recharge and think about. It shifts as seamlessly as its higher-end XO and XX big brothers.

Test riders rolled their eyes when they saw its Code Bronze brakes, but guess what? They worked well. Yes, these are the same Codes we complain about in just about every review with one key difference: the rotors. Transition wisely chose large 220mm HS2 rotors front and rear. Between the larger diameter and extra thickness, they manage heat far better than the Centerline and smaller-diameter versions, allowing them to stay consistent and fade-free.

DT Swiss H 1900 spline aluminum wheels continue to impress us with their durability and overall ride feel. A spec we don’t see too often but love to ride is Schwalbe’s Magic Mary and Big Betty tire combo with Supergravity casings. The front comes in the super-soft compound and the rear in soft. They perform exceptionally well over a wide range of conditions and soil types, only giving up performance in true hardpack over some others.

The ANVL cockpit is comfortable overall, but riders were not blown away by the SDG saddle. It’s far from the worst we’ve used, though. One super-nice touch is the inclusion of OneUp’s EDC tool that tucks away cleanly in the fork’s steerer tube.

CLIMBING

This may be a big bike on paper, but climbing on the Repeater is a joy. However, it has strong points and a few weaknesses. It scoots along under power with efficiency and tractability that defies its long-legged suspension. Unlike some four-bar bikes that can feel a bit eager to sink into its travel, this one tends to stay high in its stroke—a plus when smashing your way up ledges and over obstacles.

Even with the power response cranked all the way up and in Rally mode, SRAM’s Powertrain provided solid assist power, but it doesn’t knock the test rider’s socks off like Bosch’s or Rocky Mountain’s systems do, or even the Brose-powered Specialized bikes we’ve ridden. SRAM’s version has good torque initially, but tends to flatten off slightly where others pull harder. Test riders sometimes wish for a real Boost or Turbo mode to give them a shot of power when they really need it. The power is smooth and predictable but not class-leading in total output.

Test riders had fun experimenting with the Auto Shift system, and some felt it was the highlight of the bike. With a long press of the shift button, you can swap between manual and Auto Shift modes. You can also tune the shift response for a faster or lower pedaling cadence. We tend to prefer the lower cadence settings. Most of the time it shifted exactly when we wanted to, especially on fire-road climbs or in mildly undulating terrain.

The problem is that the system can’t tell that you’re approaching a tight switchback or steep ledge, so you have to manually override the shift by simply pressing the button. It will stay in that gear for about four to five seconds before going into Auto mode again. Although we could typically time things right for most obstacles, there were times where it would shift when we didn’t expect or want it to. We also put a novice rider on the bike—so much of a newbie that they had to ask what brake was front and rear. They loved the Auto Shift system everywhere.

DESCENDING

Going downhill is what this bike is really made for, and it does it as well or better than anything in its class. It’s truly impressive how hard you can push this bicycle and come out straight with the rubber down on the other side. It handles incredibly well for such a big bike flicking easily though tight corners and feeling solid at speed.

Its suspension is really well tuned, soaking up small trail chatter and big G-outs equally well. This build may sport RockShock’s second-tier suspension, but we couldn’t tell on the trail. Part of the magic came from the tires (pun intended). Schwalbe’s tread designs, compounds and casing worked really well for our test riders on everything from dry to wet and sloppy.

SRAM’s Powertrain really took center stage for some riders on the descents but not for the power. Its Auto Shift system does a really good job of putting the bike in the right gear when you descend. Without thinking about a thing, you just pedal out of each corner in the right gear, even after hard braking . It senses your speed and automatically shifts as speeds change.

Coast shift works well, too, automatically rotating the chainring for a shift while coasting. The problem is, you have to think about the shift itself and when to do it. It’s easy to toggle between modes with a simple long press of the shift button, but we tend to prefer turning off that part of our brain, focusing on the trail ahead and just cranking the pedals.

WHAT DID WE LOVE?

Even seasoned test riders are surprised by how much they like the Auto Shift system. It’s not perfect, but even experienced riders liked how it worked once they got used to it. Many choose to ride in Auto Shift mode and simply input a manual shift as needed. In another perhaps even bigger shocker, we really like the SRAM Code brakes on this bike. Above all, we love riding the Repeater. It feels like a big bike when you need it to, an agile machine when you want to dance with the trail, and SRAM’s Powertrain with Auto Shift made us smile.

WHAT DID WE HATE?

There is not much to hate about the Repeater. However, we experienced a motor failure six weeks into testing. The motor let out a shriek and quit providing assist in the middle of a mellow fire-road climb. Although SRAM has not confirmed this, past experience leads us to speculate that this was a belt failure, which is far from unheard of in Brose motor systems. We went through the same warranty process a customer would through a shop and were back on the bike in less than a week. We didn’t have any problems with the replacement motor on this bike or any of the SRAM Powertrain equipped bikes we have tested since.

BOTTOM LINE

In spite of the motor failure, we are thoroughly impressed by both the Repeater and its SRAM Powertrain drive unit. They come together in a cohesive package that rips. While we like SRAM’s Powertrain with its wireless drivetrain integration, it’s likely just the beginning of holistic drivetrain systems that fully integrate the drivetrain with the drive unit.

A lot of focus was put on SRAM’s drive unit because it’s so new, but the bike itself is more impressive. From a performance standpoint, it’s right up there with the best electric-assist enduro bikes we’ve tested like the Rocky Mountain Altitude Powerplay, Yeti160 E and Pivot Shuttle LT.

As its name suggests, it’s exactly the kind of bike you want to session your favorite descent over and over again, and SRAM’s system helps deliver the experience in a truly unique way.

TRANSITION REPEATER POWERTRAIN CARBON GX AXS

www.transitionbikes.com

CATEGORY: eMTB Enduro

WHEEL SIZE: 29″

SUSPENSION: 170mm (front and rear)

Price: $10,499
Weight: 53.25 pounds (without pedals)
Sizes: S, M (tested), L, XL
Frame tested: Carbon, 170mm travel
Motor: SRAM Eagle Powertrain
Controller: SRAM POD Bridge MMX
Battery: SRAM Eagle Powertrain full-size (720Wh)
Shock: RockShox Vivid Select+ (205x65mm)
Fork: RockShox ZEB Select, 170mm travel
Wheelset: DT Swiss H 1900 Spline 29″
Tires: Schwalbe Magic Mary, Super Gravity, Ultra Soft 29×2.4″ front, Schwalbe Big Betty, Super Gravity, Soft 29×2.4″ rear

Seatpost: RockShox Reverb AXS (170mm travel)
Saddle: SDG Bel Air 3
Handlebar: ANVL Mandrel alloy
Stem: ANVL Swage (40mm)
Grips: ODI Elite Flow Lock-On
Headset: FSA NO.55R/44
Brakes: SRAM Code Bronze Stealth
Rotors: SRAM HS2 220mm (f)/220mm (r)
Rear derailleur: SRAM GX AXS Eagle Transmission
Shifters: SRAM POD Bridge MMX
Crankset: SRAM GX Eagle eMTB (160mm)
Cassette: SRAM XS 1275 T-type 12-speed, 10-52t
Chain: SRAM GX Eagle Transmission
Chainrings: SRAM XX T-type direct-mount 34-tooth

GEOMETRY SIZE LARGE

Head tube angle: 63.5°
Effective seat tube angle: 78.5°
Reach: 455mm (17.9″)
Stack: 635mm (25″)
Bottom bracket height: 345mm (13.6″)
Chainstay length: 455mm (17.9″)
Wheelbase: 1262mm (49.7″)