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Hope Hubbub

April 18, 2023 2 Comments

I got lucky recently when a tandem wheel appeared for a rebuild wearing a hub worth checking—ingenious design, suited to heavy use—a Big 'Un, made by Hope from 1997–1999.

The hub's flanges are hemispheres facing outward. Spokes exit flange back sides lying across the shell on their way to the rim. On the left rear, the flange does double duty—anchoring spokes and mounting a brake rotor. What a cool idea and appearance.

The Hope Big 'Un was designed for DH but its strength was well matched to tandems. The basic shape has been seen on and off on motorcycles—here's a patent drawing for motorcycle use.

Why did Hope discontinue it? In spite of excellent function there must have been issues with builders, lacing is a bit nonintuitive. In a world of fast fashion and where standard hubs work so well, this bit of design cleverness is simply not needed. At heart, we're a pretty bottom line industry.

Backstory
The wheel was spec'd on a custom Erickson tandem built for Robbins Peak in 2000. Once ridden in a rain deluged Paris-Brest-Paris (2007), it recently become a generous loan to Jacquie Phelan and Charlie Cunningham. Charlie suffered a stroke in 2015, some weeks after a hard crash. Today stoker is his riding option.

How did a tandem of this vintage come equipped with a disk brake? Forward thinking by Glenn Erickson! It was intended as a drag brake—the bike primarily uses cantilevers. A drag brake on a tandem applies a steady, heat dissipating force on long descents so the rims don't overheat.

The original rim, a Mavic T217 in 40H, did a great job but the sidewalls began to wear through and a pothole dented one bead. I went with a Velocity Dyad replacement.

Pro's

The flange does double duty—spoke anchor and rotor mount. This makes a more efficient structure and keeps brake heat away from the bearings.
Spoke elbows make generous contact with the spherical flanges, which surely enhances fatigue life.
All spokes pass through each flange from the concave side in so the left-right complexity of lacing is reduced.
The hub has a very cool appearance, functional novelties bring character and interest to bicycle mechanisms.

Con's

The shape is more difficult to make. Hard to beat two flat flanges on a horizontal tube.
Lacing must be done in the right order or spokes become tangled. Experience with conventional hubs does not translate.
The rotor mount is integral, so it's more difficult to change diameter or style (Shimano center lock...)—more a limitation to the maker than the user.

Takeaway
Laced up easily, tensioning and truing were completely normal, and the finished wheel felt solid and strong as expected.

Anecdote
The old wheel was true except for its dent. Tensions were high and it appeared to be in fine shape. I output the measured tensions and, wow, what a different picture.

This spoke structure hid major issues. Pardon the low resolution! Hastily built new wheels may feel OK despite tension imbalance and old wheels can seem fine despite damage and corrections.

Check spokes 10–11, notice both left and right tensions are low. Must be a flat spot where spokes were loosened so the rim would not thump. To either side are twin extremes—spokes 6–7 and 11–13. Both groups show very high right and very low left tension. The rim is hiding a wide "W" lateral shape.

Spokes 36–37 are hugely imbalanced, showing a big side bend that could only be corrected by over tightening right and hugely loosening left spokes. Elsewhere, each imbalance tells a revealing story for a wheel that basically looked great (besides a dent).

For a deeper understanding of a wheel's condition it is sometimes useful to loosen spokes so the rim can display its true nature. You might be surprised and choose to rebuild rather than true.

Let's end with a couple images of Big 'Uns. If any of you get the chance to commercialize such a cool idea, savor the moment, I'll be your biggest fan. While the design may not endure, I hope you have fun!