More on the longtail minivelo idea

I want a longtail, something like the Surly Big Dummy or the Kona Ute, because of its practicality. You can haul a lot of stuff on those bikes, but I'm not sure I'd like to own a bike of that size. I think one way of reducing the length of the bike would be to use 20 inch tires, and make the rear chainstays not too long. Xtracycles extend the wheelbase about 15 inches - and this makes it possible to haul up to six panniers on the extended rear platform.

I'd be happy with a pair of large panniers - so an extra 8 to 10 inches of extended wheelbase should be OK. If an xtracycle bike would have 30+ inches of chainstay length, my plan would be to go 22 to 25 inches - this brings the BB to the center of the wheelbase.

I also want front suspension, and plan to use standard (26") MTB suspension forks with 20" wheels, and use disk brakes.


My initial plan is to use the Be-Bike Haze frame as a template, at least for the front of the bike:


Keep the geometry for the front of the bike intact, build an extended rear with an integrated rack, and find a way to break apart the front triangle for easy transport.

Here's an illustrated guide to what I want to do:

The "ghost" of the be-bike is there so that you can see where the changes were made. The red frame is the front of the bike with be-bike geometry, while the blue rear part shows the extended longtail with the integrated rack.

This shows the bike broken apart. The fork rests on top of the looong seatstays, while the rest of the front triangle falls to one side of the stays. The rear rack can be built wide to accomodate the front triangle. The front wheel is strapped to the side of the rear triangle. Skate wheels are shown attached to the rear rack like a brompton.This shows the bike top side down, so that it can be rolled around.  A soft cover can be made, open at the bottom. Paded with cardboard or newpapers, it should be a large alternative to a suitcase, since the rear rack protects most of the components anyway. 

There are a couple of concerns.  A bashguard should be sufficient to protect the chainwheel during travel.  disk brakes will give good stopping power, but the rotors might get bent during transport. 

The budget is also a concern.  Since there's a definite small budget to the custom frame, I don't think I can go with S&S couplers. I'm thinking the ritchey/dahon system might be easier to replicate, or maybe copy some other coupler that uses bolts instead.

The simplest front rack

 

Image from Dennis Bean Larson

Fixed Gear Gallery had a grocery-getter competition. One of the entries that caught my eye was this bike from Dennis Bean-Larson.  The main detail that struck me was the use of an old front fork as support for a front rack.  The platform is made from wood, and the rear supporting plank of wood is simply connected to the handlebars using a velcro strap.  More details here.