Mojo Geometron GPI Belt Drive Prototype

November 2nd, 2016

By Andrew Dodd in Bikes,Tech

Could the Mojo Geometron GPI be the future?

The team at Mojo Suspension are renowned for their constant tweaking and refinement of existing bikes – which led to them producing their own Geometron bikes with German specialist frame builder Nicolai bikes.

Even though the bikes feature very progressive geometry, the Mojo guys don’t sit back.

On a recent visit to Mojo Suspension, we caught up with Tim Williams on the Mojo Geometron GPI prototype bike he raced at round 7 of the Enduro World Series in France…

Mojo Geometron GPI

Everything about the Mojo Geometron GPI just looks right! Low, long and we love the look of the bike with no rear mech. We could be sold on this system!

Mojo Geometron GPI – Pinion Gearbox and Gates Belt Drive.

The Mojo Geometron GPI is based around the same platform as the Geometron series of bike – and fetaures the same 155mm rear wheel travel and 63degree head angle.  But instead of running a regular drive train, there is a 12 speed Pinion gearbox hanging off the main frame. That means no rear mech or cassette – and even the chain is gone on this bike.

Mojo Geometron GPI

Although Gates say there is no additional friction compared to a chain drive – the system does look like it will have some friction.

Instead it features the Gates Carbon Drive belt system.

The Pinion gearbox version of the Geometron bike is around 2.2kg heavier, though the weight is in a very manageable part of the bike – the sprung mass. This has a significant effect on the handling of the bike too…

Mojo Geometron GPI

“Descending trails with gravity on your side (steep stuff) the Mojo Geometron GPI is amazing. The suspension is sublime – with a freewheel in the box and on the hub there is no input to the suspension from the drivetrain.

Also, all that extra weight down low helps the sprung/unsprung ratio. The same Fox FLOAT X2 from my standard Geometron was used on the GPI.  Although it was already working great on the standard bike, the exact same shock felt even better on the GPI!”

Tim Williams, Mojo Suspension


“Something I’ve really liked about the Mojo Geometron GPI is how smooth the drivetrain stays when covered in mud. There’s none of that grinding and crunching you associate with wet weather MTB riding – just a constantly smooth action.

Oh, and you’ll never snap another rear mech on this bike, I’ve snapped two XTR mechs in the last few years – which is painful to the wallet!”

Tim Williams, Mojo Suspension

Mojo Geometron GPI

“I’m not sure if there are any specific limitations of the belt drive, but the overall drive system (Pinion box and belt) has a few that I found.

The grip shift style shifter that the box uses wasn’t an issue – although I had thought it would be beforehand.  In use I found the fact you can’t upshift under power a bit frustrating. I know with a standard drive train we all ease off a little to upshift for a smoother gearshift, but with the Pinion the amount you have to back the power off to upshift is significant. For instance, coming into a steep climb or even a short rise in the trail in the wrong gear means it’s almost impossible to upshift. On a standard drive train you can still keep some power on and crunch your way up the cassette to keep moving!”

Tim Williams, Mojo Suspension

Mojo Geometron GPI

A lot of people will complain about the shifter, though Tim found it works fine and wasn’t an issue.

“Then there’s the extra weight, 2.2kg simply won’t go uphill as fast as a bike that’s 2,2kg lighter!

On trails that require more pedalling. the Mojo Geometron GPI is not quite as good as the regular Geometron, as you can feel that extra weight on even the smallest inclines. That’s of course talking from a racers perspective. Just out riding for fun then it’s probably not an issue”

Tim Williams, Mojo Suspension

“I would really have liked to use a Power Meter on the Mojo Geometron GPI, but as the BB axle is Pinions own size I couldn’t bolt on my Stages crank.

Pinion say that the box is as efficient as a standard chain drive train – with some variation depending on gear choice.

But I’m not convinced. Testing with a power meter would give me some definitive answers”

Tim Williams, Mojo Suspension

Mojo Geometron GPI

We love that the team at Mojo Suspension go to such lengths to find out what really works. They will never sit on the fence and throw out judgement – they’ll put it to the test. Every single time.

And right now, we hear that Mojo main man Chris Porter is riding a bike with a 27.5in rear wheel, and a 29in front wheel  – we look forward to hearing about that!

What do you think of the Mojo Geometron GPI that Tim Williams from Mojo has been testing?

Do you like the idea of a gear box?

What about the Gates Carbon Belt?

We’d love to hear your thoughts – please comment below and start the chat! 




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