Sonder Transmitter GX Eagle Revelation review£1,899.00

Outstanding playful updated aggro hardtail

BikeRadar score4.5/5

The original Transmitter subverted expectations of how nuts you could go on a sub-£1k bike. And, now it’s been stretched out for more balanced handling, without losing the bargain price tag.

Sonder Transmitter GX Eagle Revelation frame

If you think you’re going to be getting a basic frame from this bargain-priced brand, think again. The Transmitter was designed by one of the best in the business, and oversize multi-section, tapered, split and ridged main tubes and plate chainstay sections make for a pedigree ride that’s efficiently purposeful without being punishing.

Bolted clips hold the gear, brake and semi-internal dropper post lines, and there’s an ISCG mount on the threaded bottom-bracket shell. Boost dropouts complete the short back end (425mm), which means clearance is tight with a 2.8in tyre.

The aluminium frame tubing gives the Transmitter a lively but responsive ride character
The aluminium frame tubing gives the Transmitter a lively but responsive ride character

Sonder Transmitter GX Eagle Revelation kit

This mid-range model costs £2,199, if you buy it through one of Alpkit’s three shops, but choosing to have it shipped to you (for free) from their UK workshop saves you £300.

For your cash, you get SRAM’s GX Eagle 12-speed transmission with massive 10-50t cassette and X-SYNC 2 chainring. Whether the smooth-feeling, 125mm-stroke RockShox Reverb hydraulic dropper post is a reliability win compared to  cheaper cable-operated posts found on the other bikes is debatable.

The fork is a 130mm Revelation RC, and the kit from in-house brand Love Mud includes super-wide (45mm internal) but heavy (2.5kg) wheels. A lightweight (but massive) 3.0in WTB Ranger front tyre keeps the whole package relatively competitive on mass, while the Tough carcass of the 2.8in rear tyre stops premature puncturing and sidewall damage.

The Transmitter is a smooth and efficient terrain skimmer
The Transmitter is a smooth and efficient terrain skimmer

Sonder Transmitter GX Eagle Revelation ride impressions

Even with an obvious armoured stiffness from the rear tyre and a bar that feels harsh when slammed hard, the massive, minimal-tread rubber means the Transmitter is still a smooth and efficient terrain skimmer. It flows across roots, rocks and other ripples as though you have a micro motor assist.

Meanwhile, the heavy rims and rear tyre mean acceleration isn’t quite as clean and crisp on smoother surfaces, but it’s no slouch when it comes to gaining speed. The way the tyres crawl over and mould around irregularities gives good traction considering how little physical tread they have. Meanwhile, plenty of room under the bottom bracket makes pedalling over rough ground easier.

The wide 780mm bar in a 35mm stem gives a responsive yet power-assisted steering feel through the stable 65-degree front end. Add a short rear triangle, and the result is a well-weighted feel to the handling, considering the radical angles.

Plenty of room under the bottom bracket makes pedalling over rough ground easier
Plenty of room under the bottom bracket makes pedalling over rough ground easier

As soon as things get wet or sloppy you will need more bite up front, but you can negotiate your own tyre choice when you order rather than pay for full-price replacements.

Sonder’s decision to fit a Tough version on the rear is a massive confidence and survival bonus when you’re battering through rocks or sprinting as hard as the Transmitter insists you do to get the most from its insolent character.

All that tube manipulation means the frame still feels lithe and lively. Swap the wheels and it’ll even take 29er rubber for cross-country speed without feeling overly harsh, although clearance will max out at around 2.25in on the bigger rims and they jack up the bottom bracket, giving a more precarious feel in dicey situations.

Keep the Sonder on the right sort of plus-tyres for your riding and it’s a brilliant partner for late braking and chance taking.

Guy Kesteven

Freelance Writer, UK
Guy started filling his brain with cycle stats and steaming up bike shop windows back in 1980. He worked the other side of those windows from '89 while getting a degree in “describing broken things covered in mud" (archaeology). Dug historical holes in the ground through the early '90s, then became a pro bike tester in '97. Guy has ridden thousands of bikes and even more components the world over since then and can remember them all in vivid, haunting detail. Can't remember where the car keys are, though.
  • Age: 45
  • Height: 180cm / 5' 11"
  • Weight: 68kg / 150lb
  • Waist: 76cm / 30in
  • Chest: 91cm / 36in
  • Discipline: Strict sadomasochist
  • Preferred Terrain: Technical off-piste singletrack and twisted back roads. Up, down, along — so long as it's faster than the last time he did it he's happy.
  • Current Bikes: An ever changing herd of test machines from Tri bikes to fat bikes and everything in between.
  • Dream Bike: His Nicolai Helius AM custom tandem
  • Beer of Choice: Theakston's Old Peculier (not Peculiar)
  • Location: Yorkshire, UK

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