Gearbox and Rohloff Titanium GMX+ Options Now Available

Gearbox and Rohloff Titanium GMX+ Options Now Available

Looking for a bike with a low-maintenance drivetrain that will survive the apocalypse, or are you simply sick of derailleurs and dirty chains?

Curve now offers custom build options for the titanium GMX+ model to support Rohloff internally geared hubs as well as Pinion and Effigear gearboxes for either chain or belt drive. It's a super-versatile option for bikepacking and extended cycle touring at the more rugged end of the spectrum.

Curve Titanium GMX+ Effigear Gearbox Bikepacking Bike

The ever-popular GMX+ has proven itself a trustworthy companion for loaded, off-road adventures where you could face any terrain - from sandy desert tracks to rocky single track. With clearance for up to three-inch tyres, the GMX+ is a go-anywhere bikepacking machine. It's a super versatile bike, working equally well in drop bar and flat bar modes. With a low, non-suspension-corrected, front end, the GMX+ can even be set up with a moto-style riser bar for a relaxed basket-packing rig. With gearbox and Rohloff options now available, the titanium GMX+ is even more versatile.

Titanium Rohloff GMX+ Bikepacking Bike - Curve Cycling

We have been testing a gearbox version of the GMX+ for many years now. You might have seen various incarnations at the Handmade Bike Show Australia in recent years, where it gained a lot of attention. After substantial testing we are now proud to release this model into the wild.

Curve Cycling Titanium GMX+ Gearbox Bikepacking Bike - 3D printed yoke

To achieve the rear-end stiffness required, the gearbox GMX+ features a 3D printed titanium yoke which is attached behind the gearbox case. While this increases the cost a little, it is necessary to achieve the ride quality we demand while maintaining clearance for up to three-inch tyres. Earlier prototypes just didn't have the rear-end stiffness we wanted.

Gearbox Titanium GMX+ Bikepacking Bike - Curve Cycling

The Rohloff-compatible GMX+ is a little simpler. It has the same bottom-bracket, yoke and chainstay assembly as the regular production version. Things get changed up at the dropouts. The Rohloff-compatible GMX+ comes with sliding dropout inserts that work seamlessly with a standard Rohloff Speedhub in QR-configuration. We can offer inserts for use with either Post Mount or Flat Mount brake calipers.⁠

Curve Cycling Titanium Sliding Dropout Rohloff GMX+
In our opinion, sliding dropouts are the best way to tension the chain or belt in order to effectively use a Rohloff or gearbox. Or, if you want the ultimate simplicity, this system will also allow you to run your GMX+ in singlespeed mode. There are a few other ways to achieve belt and chain tension, but a sliding dropout is in our experience the most reliable and straight-forward method. We have therefore developed our own sliding dropout system, with a range of inserts, that can accept various wheel, axle and brake types. Feel free to contact us if you're curious about the available options.

Titanium GMX+ Belt Drive Chainstay Split - Curve Cycling
The gearbox and Rohloff compatible GMX+ models can be run with low-maintenance belt drive set ups. Different to a conventional chain, a belt cannot be broken for installation. For belt drive compatibility we also add an almost invisible split in the drive-side seat stay.⁠ You have to look carefully to spot it.

Gates Belt Drive Titanium GMX+  - Curve Cycling

In the past it has been difficult to get drop bar shifting to work well with gearbox and Rohloff systems. That is a thing of the past. We have some tricks up our sleeves to get drop bar shifting to work with Effigear, Pinion and Rohloff systems. If you want a flat bar set up, that's easy to manage straight out of the box.

Pinion Dropbar Titanium GMX+ Curve Cycling

Frames supporting internal gear systems are made to order, with a lead time between six and nine months. There is a surcharge for these custom options which will vary depending on the particular model and dropout options you are after.

Get in touch to learn more about pricing and current lead times by sending us a message here.⁠ You might also be able to twist our arm on similar customisations to other models.

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