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Sonder Transmitter review, semi fat = full fun!

I’ve had a bit of a project in mind for a while now; a hardtail that takes advantage of the new 3″ size ‘half fat’ tyres we’re seeing. A semi fat 29’er is perhaps a step too far though, I still want the darned thing to go around corners! So how about a 27.5″ plus bike? Now that could be interesting…

As a number of you have found, if you’re going for a whole new type of bike the easiest way to come up with a design is to copy or adapt something you’re already riding. Which means… I needed a test mule!

The short list?

If you’re drawing up a shortlist of affordable, long, low and slack plus sized hardtails you won’t need a very big bit of paper. I liked the look of the Stif Morf but it’s not a plus frame. The Dartmoor Primal Plus isn’t that slack. The Nicolai Argon GLF is a serious piece of kit but costs £1250! But, if you trace the DNA of the Brant Richards designed Morf you also find the very similar Sonder Transmitter.

Sonder Transmitter with added pimpage…

Sonder is the new direct selling bike brand from outdoor specialists Alpkit. The Transmitter is a bit of a departure for them as it’s not just aimed at the backpacking crowd, it’s a hardcore hardtail designed for ragging around UK trails.

The Transmitter fitted my purposes nicely; 3″ tyre up front, 2.8″ at the rear, plus sized 40mm internal width rims with a 65 degree head angle. And it’s available with a decent kit build for not much coin. I went for the Pike/Reverb/SRAM GX edition for £1899 – nice!

How does it ride? Blooming awesome!

Considering I didn’t have much choice in the matter it’s probably lucky that the Transmitter turned out to be an excellent choice. I’ve been riding bikes a lot, for a long time – and I’m impressed! There’s definitely something to this plus sized tyre business, especially on a hardtail.

After a quick Stans tubeless conversion with 39mm tape I’ve settled on 12psi front/14psi rear. Cornering and climbing traction is excellent, I’ve not found the limit yet! Downhill you can rag it as hard as a short/medium travel full sus, the wider bars and slack head angle give it huge confidence. I recently went to Cwmcarn and beat all my uphill and downhill Strava PR’s that I’d previously set on my Nukeproof Mega TR! I’m looking forward to converting my riding buddies to the joys of the chubby hardcore hardtail…

Big thumbs up to the SRAM gears, brakes, fork, dropper etc. everything works as it should. The saddle is comfy and the seat angle is bang on for steeper climbs.

Geometry based on the 120mm fork, mine’s a little slacker now!

Stuff I’ve changed?

  • I’ve opened the Pikes out to 150mm travel from the original 120mm by replacing the air shaft, the 27.5 Boost fork uses a 29’er length air shaft as I’ve found out. (Although the usable travel is around 140mm as the fork does ‘settle’ into the negative spring slightly). This doesn’t seem to have upset it much and has kicked the head angle out to a very impressive 63.5 degrees! Downhill prowess is now assured, just don’t forget that you’re relying on that spongy back tyre for rear suspension 😉
  • Grips! Didn’t even make it out of the garage, the diameter is too large and they don’t feel right. Swapped for some standard Renthal lock ons.
  • Bars – I didn’t like the shape for some reason and found them a little narrow, swapped for some 780mm Renthal carbons to save a bit more weight. The extra width makes the bike feel unstoppable downhill.
  • The original WTB Trailblazer rear tyre seems a strange choice as it’s got a centre line tread which makes it look a little ‘canal towpath’. It grips well though until you pinch flat it and think ‘why didn’t they fit the Tough version rather than the Light version’? Lesson learned, it’s now been swapped for a similar sized ‘tough’ WTB Ranger running at 14psi which seems to match the rest of the bike better.
  • Re-routed the cables around the headtube so they don’t rub so much.
  • Swapped the front pads out for some Uberbikes Race Matrix, these seem nice and grabby just how I like them. We’ll see how they cope with heat and wear…
  • Bled the Guide brakes as the rear was feeling a little spongy, they feel more consistent now. Also the first time I’ve seen brakes that use the ‘Bleeding Edge’ connector, it’s always annoying having to buy more tools but this does seem to make things more straightforward. They’re certainly easier to work on than the old Avid Jucy’s I used to run!

Minor things I’d change?

GX Gears – they come with a black finish to the cassette and chainring that starts to wear off as soon as you ride it, why not cast fashion aside and make them silver to start with? 😉

Forks have a larger axle cutout for the bigger, Boost standard, Torque Cap hub flanges but the wheels have standard sized hubs. Locating the front wheel in the fork can be a bit of a fiddle to say the least.

Free tyre levers and allen key – nice touch but I would have preferred a chainstay protector as I had to go and buy one straight away.

Project SYD frame tweaks…

I’ve put my thinking cap on and come up with a list of tweaks that I’d like to see in my own frame design, project ‘SYD’.

  • Seat tube – could be a lot lower to allow for a longer dropper. It would also make the frame smaller and lighter. Given that droppers are often buried deep in the frame it seems sensible to try and make better use of them structurally.
  • The cable guides could perhaps be a little tidier too, I like to run my rear gears on the left hand side of the frame for example so they don’t rub the headtube as much. They could do bolt on cable guides to the side of the headtube like Nicolai do.
  • ISCG chain guide tabs on the bottom bracket? With a modern thick/thin chainring I think we can knock these off too, I’ve never had a problem with chain drop even on the most teeth rattling descents.
  • And finally? That join between the chainstay and the dropout casting? It’s not the prettiest 😉

Weight after the tubeless conversion and bar swap is around 29lbs. Although I’ve added a bit more back on again with the tougher rear tyre. Huge weight savings coming soon thanks to some lighter wheels courtesy of Olivier and his trick wheel builds

And then it’s time for something very special indeed for the frame, project code-named ‘SYD’. Watch this space as they say…