Sunday, October 08, 2006

Surly big dummy







Here's what the websites are saying.....

Earlier this morning, at the Interbike trade show in Las Vegas, Surly took the wraps off a new bike, the Big Dummy. Not sure if that’s a final name (from Sanford & Son, starring Redd Foxx). Big Dummy is the first production longtail bike built around Xtracycle’s modular rack system. To use Xtracycle’s racks presently, you need to bolt Xtracycle’s FreeRadical product to your regular bike. This works really well, but soon you can buy a purpose-built frame for the job:Scot Dion, maker of sweet custom longtails, sent more detailed photos.

Introduced to great acclaim at Interbike five years ago, Xtracycles have earned their renown as the only passenger and cargo hauling rigs that ride nearly as nimbly as ordinary bikes, and that you can still hoist up stairs, fit into elevators or onto a bus rack. Xtracycles are inch for inch, pound for pound, hands-down the most practical way to carry lots of stuff on a bike. They certainly changed our lives. Still, the radicalism of the idea—bolting a wheelbase extension onto your bike—has somewhat limited its acceptance. With its credibility and distribution in virtually every bike shop in America, Surly introducing this bike delivers a huge load of validation that should nudge the longtail bike concept truly into the mainstream.

Yes, it will be Stokemonkey-compatible. I haven’t ridden Big Dummy, nor seen more than these pictures at the moment, but I sent Surly a Stokemonkey a ways back in a blind bid to learn what I needed to do. There are lots of unanswered questions (like when will it be available and for how much? [rumor: next spring, $820 frame/fork]), but something tells me I’ll be equipping a whole lot of these things with assist over the next years.

Surly’s bike should offer a better strength-to-weight ratio and more torsional stiffness than the bolt-together approach. It should also offer more deliberately tuned handling than comes about with the retrofit path. While retrofit Xtracycles perform a whole lot better than people suppose before they try, both of these considerations, along with aesthetics, are what inspired my Xtravois project in 2003, and similar independent efforts now tagged “longtails” on this here blog.

One of the handling fine points is steering geometry. As I’ve at least begun to explain elsewhere (1, 2, 3), I’ve found that bikes with poofy tires and a weighted front wheel (the rider’s weight in the longtail case) benefit from uncommonly low geometric trail. Surly’s Big Dummy has a steeper head angle than the 71 degrees more typical of bikes with 26″ wheels. They’re also testing unusually high fork rakes, the highest of which brings trail down into the 50’s (mm) with even the fattest of tires. A lot of these ideas about steering geometry are presented lucidly by Jan Heine in his study of old French tandem and porteur bikes, both of which I think bear on longtail designs, too. The Kogswell Porteur is an explicit embodiment of Heine’s work.

The Bike Hugger people posted a glimpse before 6 am today, scooping me! Check their ongoing Interbike coverage for more detail; I know I’ll be!

Initial reactions are positive (DUH!):

NEWS AT ELEVEN............

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