Ritterview

I perused Flickr uploads of pics from NAHBS, and saved interesting tandem pics to a Gallery.



Wyganowski


Scott Quiring and Ti Tandem


Quiring


Engin


Reugamer


I'm not sure what booth this is. The sign says "Custom Tandem".


Bilenky winning Best Road Bike Frame with a tandem


Bilenky


Co-Motion


Co-Motion disc brake detail

TandemGeek

More importantly, a Rohloff-specific rear drop-out from Co-Motion with Avid disc brake + Rohloff hub.

Ritterview

Thanks TG, I knew that something was going on here, but I wasn't sure what. Its a Rohloff SPEEDHUB 500/14
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The tandem with the Rohloff is the red one on top. It has only one chainring.



Another Co-Motion Rohloff:

zonatandem

Nice stuff!
Have ridden a custom single LaSuprema with Rohloff gearing. Impressive, but bit pricey for that hub.

Chris_W

Anyone know whether they've done special spacing on those frames to accomodate the 135mm Rohloff hubs, or if they have modified the hub itself?

TandemGeek

No hub mods: it's 135mm rear spacing and 32h spoking, and that's what builders work with. There are a lot of off-road tandems running the 135mm rear-spaced Rohloff and there have been very few issues with them. Where there have been issues, Rohloff has been covering most of them under warranty. Heck, Ventana has used 135mm rear wheel spacing as its spec. since day one. Admittedly, off-road tandems use 26" wheels and, frankly, if I was to build a road-going version of a Rohloff-equipped tandem I'd probably do the same for a variety of reasons. But, that's just me.

Pricey, compared to what? A Rohloff replaces the rear hub, cassette, rear derailleur, front derailleur both shifters and allows you use use a drive crank with a single chain ring. With the price of cassettes these days, never mind Di2, the price premium isn't all that bad and can be amortized in 10k - 15k miles assuming normal drive train component wear.

Moreover, as can be seen in the videos I hosted out on my Rohloff Blog, it's a first class piece of hardware with 125 precision parts: https://tandemgeek.wordpress.com/2010...eedhub-chains/

WebsterBikeMan

It's just a wee tiny step from there to a Gates Carbon drive belt, to go with the Gates Carbon timing belt.

"Look ma, no chains".

Ritterview

Co-Mo has already done this, here on a half-bike.

etasch

Indeed quite interesting! Do you think an aluminum or carbon tandem frame can be designed to accommodate a “breakaway” rear triangle? I have only seen this done on single cromoly frames.

Ritterview

Wyganowski definitely cannot be criticized on this frame for for making the stoker compartment overly tight.

zonatandem

While the Rohloff is a brilliant piece of German engineering, the price for the hub is still a bit of sticker shock for most folks.
Yes, you can avoid derailleurs and $TI shifters but it tends to limit you (as is) to 14 gear selections. You also need a modfied rear triangle to adapt the Rohloff and there likelly is an upcharge for that. There is/was an issue of fitting the shifter on drop bars.
Most folks now are drooling over Gates belts, 10 and 11 speed ca$$ettes and darn few are even dreaming of Di2.
Rohloff has it followers/adherents but this is a low number production hub. You'll not fnd (m)any at your local bike shop.
Pedal on!
Rudy/zonatandem

Chris_W

Another problem with the Rohloff hub is the gear spacing. It closely matches that of a MTB cassette, with 13.5% increments between gears to achieve it's >500% overall range with 14 gears. I find those kinds of jumps a bit much on a road bike, where I prefer more tightly spaced gears. The Rohloff hubs are quite popular with MTBers and tourers in Germany and many other parts of northern Europe. However, I think Rohloff needs to make a second model with around 11% increments and a 400% gear range if they want to get into the road bike market.

There are options available to mount the shifter on drop bars, which include this and this, but they are far from ideal.

TandemGeek

I think they've pretty well figured out there's just no market for that...

Roadies ride what racers ride and the Rohloff will always be too heavy compared to derailleur-driven, external cogsets... never mind eliminating a quick rear wheel change with the added step of disconnecting and reconnecting the shifting cables or other complications on the drive-side if a chain tensioner wasn't used (more added weight).

It's simply best suited for trekking, commuting, touring and MTB'g. Again, a great idea for a grand touring tandem where weight and close-ratio drives aren't a major consideration.

TandemGeek

There's not need to modify the rear drop-out. You simply use a bolt-on reaction arm, similar to what you'd use with an Arai drum brake on a tandem that didn't have a Pac-Man fitting brazed on to the frame.

Ritterview

The reduced efficiency would literally be a drag on a tour, would it not? If it is as best 96-97% efficient, and is 1-2% less efficient than a conventional set-up, those watts lost to heat which were no big deal on a commute or jaunt to the coffee shop, might reduce the joy of a 75 mile ride.

TandemGeek

Dirty or worn chains will give you a bigger efficiency hit than the Rohloff... which is to say, most folks would never know the difference once you factor in all of the other things that tax your efficiency.

PMK

I would agree a Rohloff may not be for many based on price and weight. As for it's applications, there are many positive attributes.

I notice many tandems are built with a moderately wide ratio rear gearset. Very similar to the Rohloff. So in this respect it's not all bad.

Those wanting or needing a closer spacing, should with little effort be able to run a front der setup and with careful chanring selection build an even spaced 28 speed that should have no problem finding the right gear.

Another benefit of the Rohloff is how it can be shifted. While at the STR last year, a large group of riders came to a "T" in the road during Sundays ride. As luck would see it, the stop sign was ours. The stopping location was on a short slight climb. This left a few teams not in a proper gear to pull away. Some even just fell over as they attempted to get moving. A Rohloff in this situation can be pedaled backwards to the gear of choice which could limit these gear choice mistakes.

I have ridden a Rohloff equipped MTB, not mine but a friends. With the weight being low and virtually at the hubs center this wasn't even noticed.

The most notable feature was the shifting, much simpler and less time from gear to gear. especially on a downshift. A slight overrunning of the wheel will accomplish the shift.

Outside of how it performs, these hubs are able to let a bike be built with non tandem specific cranks, a right side drive is no problem thereby saving a bit of weight on the stoker cranks. In theory, it could be possible to run a right side Gates timing setup with a Rohloff rear hub.

Most riders admit that when new there is more drag, but typically once bedded in, the units run very smooth and efficient, requiring a fluid change each year.

As I said these aren't for everyone, especially if you are on the minimum weight program. But they are neat.

PK