Product news: How do you actually start designing a tandem? And who even comes up with the idea of riding a tandem? Two on one bike, giving up control, no brakes, no gears, just pedaling? André Joffroy built his dream tandem and tells us in a guest article what is behind it.
Portus Twinduro Tandem: A custom bike?
Riding a tandem has its own special appeal, I first got to know it more than 10 years ago on a Gitane tandem, and it has been appealing to me ever since. A good two years ago I finally wanted to take the next step, an all-round tandem for all-road and MTB. I had already fallen in love with a bike but it was hard to get in Europe so it became a custom bike, hand welded and brazed in Germany at Portus Cycles.
The special feature, the frame got the rear triangle of my favorite bike, a Salsa Fargo rear triangle with alternator dropouts. The bike itself is based somewhat on the geometry of the Salsa Powderkeg, with elements of the Fargo, optimized for 100mm spring travel or a correspondingly corrected rigid fork, with an erected stem also suitable for dropbar handlebars such as the Woodchipper. And as it should be for bikepacking all-rounders, a bike with neat eyelets so that something goes on well.
All thrown into the pot, stirred well once, and out comes the Portus Twinduro. A mountain bike tandem with all-road genes.
Portus Twinduro Tandem: Hydraulic wheel hub
It has been fitted with parts that I appreciate and love, Formula fork and 4 piston brakes. On request, the Italians can come with a long cable and plenty of braking power. Two Hope cranks provide the drive, the output is realized via a Kinderay hub.
The hub is the real revelation in this project, hydraulic shifters deliver reliable shifting even over a long line. The clacking of the hub goes under in the wind, but is responsible for the high torques that the hub can endure. Speaking of propulsion, a tandem, assuming a strong person heating it, feels like an e-bike, power when you need it. You notice that on the frame, it flexes a little under load, but it's always going forward, or sharply around corners.
Portus Twinduro Tandem: A custom bike?
The tandem has a large turning circle, and to keep it on track it could not be less than the beating under the handlebars, a surly cheater bar, stable, incredibly nice feeling when riding with a subtle flex that is easy on the hands, surrounded by SQLab grips that are flattering on the hands.
After a long ride, however, you notice your arms, keeping a tandem on track takes a lot of strength. In order to absorb these forces well, a Thudbuster had to be mounted at the rear and a Hellbender headset at the front, both from Cane Creek and well-proven. The Thudbuster swallows the blows that would hit the stoker in the back, and the Hellbender headset withstands the forces that occur longer thanks to its bearing construction. Only a viscoset would be more dampening here.
A tandem needs trust in each other and the willingness to give up or take on responsibility. We trade from time to time, so responsibility and strength rest on both shoulders. Everyone heats up or brakes.
The Portus Twinduro is a special wheel, in the right hands a weapon of unity, in the wrong hands it brings discord. It is not for nothing that tandems are also called divorcycles in English.
