It’s easy to think that we’ve hit the limits of many cycling innovations, but our findings in new patents continue to show otherwise. While folding bikes are often shunned as unfashionable, or perhaps only for utilitarian purists, we found a promising patent that could potentially make any style of bike into a compact folder – helping to reduce air transportation cost and hassle when space is at a premium.

The 62-page document is exhaustive in its details of the various applications for this concept, with the following excerpt explaining the key components:

The down tube is connected to the rear frame structure at a pivot proximate the bottom bracket shell, the pivot facilitating pivoting of the front frame structure with respect to the rear frame structure in a common vertical plane, about the pivot.

The bicycle frame also includes a frame lock, which when engaged substantially immobilizes the pivot to place the frame in a riding condition, the frame lock, when disengaged, facilitating relative movement of the down tube and the seat tube towards each other about the pivot in the common vertical plane, to place the frame in a collapsed condition wherein the down tube lies alongside the seat tube.

A detachable top tube (and split top tube design) allows the rear triangle to swivel out of place. Note that the seat post must be removed, so the seat tube can clear the point where the split top tube joins together (see image above).

The beauty of the system is that it could apply to virtually any tube shape – such as deep aero tubes. All you need is the integrated pivot system, and you can get as fancy as you want with the rest. What about e-bikes, internal gears, etc? No problem:

The frame may be configured to generally correspond to a frame geometry and a wheel size associated with one of a conventional bicycle, an electric bicycle having an integrated electric motor for propulsion, a road bicycle, an urban commuter bicycle, a touring bicycle, a hybrid bicycle, a cyclocross bicycle, a single speed cross country mountain bicycle with rear suspension, an internally geared rear hub cross country mountain bicycle with rear suspension, and a fat bicycle.

Above: The fully-folded aero road bike concept.

A second iteration (above) uses a detachable seat tube, with a pivot located just above the bottom bracket shell on the down tube.

This iteration doesn’t need the split top tube, instead tucking the seat tube in the rear triangle. Note the bottom-mounted brake caliper, since a traditional top-mount brake would likely get in the way.

Finally, a very swoopy-looking flat bar iteration looks like a simple and effective way to reduce the size of a full-size bike.

It’s yet to be seen how much weight would be added by these folding designs – or the added cost to implement it. Even with some weight, the prospect is exciting, giving us options beyond the popular Ritchey Breakaway or S&S couplers.

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2 years ago

> The beauty of the system is that it could apply to virtually any tube shape – such as deep aero tubes.

the limitation is rear tire width. The twin TT booms will need to go around the tires in the folded position, which leads to weird pedaling if you don’t want rub at the knees.

> This iteration doesn’t need the split top tube, instead tucking the seat tube in the rear triangle.

and also loses the compactness of the rear wheel staying on.

2 years ago

It’s a bottom mounted caliper in figs 8 B&C so that the brake cable doesn’t need to be run up the seat tube. Any cable run along the top tube would prevent the bike from folding.

2 years ago

English cycle uses this system since years.

2 years ago

As far as I see, unmonting fork and wheels gives you pretty much the same packed shape, works with any bike, just might not be as fast. Train conductors though still make you buy extra tickets for the bike luggage and yell at you from what I’ve experienced with what I descrobed above, so I doubt these “folding” gikes will do the trick for them.