First Look: Sonder Transmitter Carbon

Although Sonder Bikes is just barely two years old, the Alpkit-owned brand has been making quite a splash since we first saw its new bikes at the London Bike Show in 2015. Starting out with the entry-level Transmitter alloy hardtail, Sonder has been earning itself rave reviews, including one from us in Issue #100 of Singletrack Magazine. The alloy Transmitter has been a popular one with Singletrack readers too, having been nominated for Best Bike Under £1000 during the 2016 annual Singletrack Reader Awards.

With that in mind, you can appreciate that we were pretty darn excited to see the brand new Transmitter Carbon during the London Bike Show this year. Promising lower weight, improved geometry and a smoother ride quality, the shapely carbon frame is designed to take the Transmitter’s on-trail performance to the next level. And all at a very handsome price.

The Transmitter Carbon is the newest mountain bike from Sonder.

“The Transmitter Carbon is long, low, slack and fun. We’ve taken what we’ve learned from the original alloy Transmitter and evolved the geometry, we’ve extended the reach and the long and low wheelbase gives stability and control at high speed. The Transmitters are bikes that just fit in with hard riding. But mostly, they are to be ridden and enjoyed. Easy to ride and maintain, fast and lots of fun” – From Sonder Bikes.

The Transmitter Carbon frame can be had for £699, and complete bikes start at £1499.

Sonder Transmitter Carbon Features

Carbon fibre frame
Built for 27.5+ wheels
Accepts up to a 2.8in rear tyre
Recommended fork travel: 120-130mm
65° head angle
73° seat angle
425mm chainstay length
Boost 148x12mm rear spacing
Threaded 73 mm threaded bottom bracket
Chainstay mounted disc brake for clean lines and damage protection
Internal cable routing with stealth dropper option
Available sizes: Small, Medium, Large
Painted or raw carbon finish
Frame RRP: £699
Bike RRP: £1499 – £3199

This ain’t your average carbon hardtail…

Like the alloy Transmitter, the carbon model is built as a versatile, capable UK trail bike. In the case of this blue beauty, it’s built around 27.5+ tyres, with a 3.0in wide WTB Ranger on the front, and a 2.8in wide Ranger on the back. Combined with modern geometry, a stealth dropper post and a RockShox Revelation fork, this isn’t your average carbon hardtail.

Using a full carbon fibre frame, there are loads of lovely shapely tubes and junctions that flow nicely into one another. You can get the frame on its own for £699, or in a complete bike package starting at £1499. In the grand scheme of carbon fibre hardtails, that is very impressive value for sure.

The 2018 RockShox Revelation fork aims to bring Pike performance to a more modest price point.

Geometry is optimised around a 130mm fork, which in the case of the GX Eagle build, is a 2018 RockShox Revelation. Using the same chassis as the venerable Pike fork, the new Revelation is a beefy number with 35mm stanchions and dedicated Boost 110x15mm lowers. Inside is the DebonAir spring and a Motion Control RC damper.

Sonder has chosen to spec the 29in version of the Revelation fork, meaning it has clearance for the 27.5×3.0in front tyre. In theory, that means you could also fit a 29in wheel up front if you wanted to. Technically a 29in wheel will fit in the rear of the frame too, but Sonder’s head designer, Neil Sutton, doesn’t recommend it due to the limited tyre clearance and extra height that gets added to the BB.

Sonder Transmitter Carbon frame geometry.

Up front is a 3.0in wide WTB Ranger tyre, complete with the TCS Light casing and Fast Rolling rubber compound.

The WTB Ranger tread is more ‘Californian Roost’ than ‘Calderdale Slop’.

The micro-knobbly tread pattern on the WTB Ranger tyres is much more suited to riding around hardpack trail centres than through gloopy mud in the backcountry. But with more ‘proper’ plus treads becoming available, there’s scope to swap these out for something with more meat for riding gloopy surfaces. In fact, we’ll be doing just that, with several sets of test tyres in the wings ready to be tried on the Transmitter Carbon.

New carbon fibre hoops from Love Mud. 35mm internal width and tubeless ready.

For £2249, the Sonder Transmitter Carbon SRAM GX Eagle Revelation would normally come with a set of Alpkit’s own alloy wheels under the Love Mud label. On our test bike however, Alpkit has hooked us up with a set of carbon fibre Hullabaloo wheels, which are brand spankin’ new. Apparently the carbon rims are some 230g lighter than the equivalent Rumpus alloy rims, with a claimed weight of 2.04kg for the complete wheelset.

The tubeless ready carbon rims feature a 35mm internal rim width, and roll on sealed cartridge bearing hubs with a 4-pawl freehub mechanism out back. A complete set will set you back £799 on its own, though if you’re buying a Transmitter Carbon like this, the carbon wheel upgrade is available for £570.

2018 RockShox Revelation RC forks doing the sliding, and SRAM Guide callipers doing the stopping.

148x12mm thru-axle dropouts and post-mount 160mm brake tabs.

The rear brake calliper tucks neatly into the rear triangle out of harms way.

With the brake mounting to the inside of the chainstay, the seatstay tubes can be engineered to be lighter and thinner for more compliance.

Sonder is a big fan of threaded bottom brackets, and you’ll find one on the Transmitter Carbon frame.

Several build kits are available with the Transmitter Carbon – ours has the latest GX Eagle groupset from SRAM.

34t Eagle chainring on the front.

To match the yuuuuge 10-50t cassette on the rear. 500% gear range for those doing the maths.

The frame is 1x only, allowing Sonder to build the Transmitter Carbon with short 425mm chainstays and clearance for 2.8in wide tyres.

There’s something about that seat tube junction. Smooooove!

Plenty of room for mud and other sediments caught by the rear wheel.

With slender seat stays and a flattened top tube, Sonder has aimed to increase compliance with the Transmitter Carbon frame.

That might just be the thinnest top tube of any test bike we’ve had through the office.

Cockpit is kept clean and contemporary, with loads of components coming from the Alpkit stable.

The 6061 alloy riser bars measure at 780mm wide and feature a 15mm rise.

Dainty little stem from Love Mud.

Love Mud lock-on grips to top ‘n’ tail the cockpit.

SRAM Guide R brake levers offer tool-free reach adjustment, and the MMX clamp system that…

…integrates with the RockShox Reverb 1x lever. Nice!

Simple internal cable routing holes just behind the head tube.

The stealth dropper post line passes through the main triangle just above the bottom bracket shell to avoid a tight bend around the BB.

RockShox Reverb Stealth dropper post as standard, with an Alpkit saddle on top. 125mm or 150mm travel options are available for the Reverb.

We’ll have you a full review of the Transmitter Carbon coming soon to singletrackworld.com. If you’re curious about the bike, or you want to know more about the alloy Transmitter and any other bikes in the range, check out the Sonder Bikes website for more information.