Sunday, January 17, 2010

Yuba boxes technical

The boxes for the Yuba aren't complicated in construction, but there are a few things that might interest other enterprising V2 owners.

First, I made a few modifications to the rack to simplify the project. The V2 is unique in the way its rack bolts to the main frame where the front two of the four vertical stays bolt both to the top rack and the frame. On the V1 the stays are all welded to the top rack and bolt to the frame, and on the V3 everything is welded together. The bolt-on stays on the V2 stick out past the plane formed by the edge of the top rack and the welded rear stays, so if you strap a flat thing to the vertical rack (like a sheet of plywood, for instance) the front stays will mar and gouge the surface. I did a little more work with files to get them back to a position safe for cargo. I neglected to take before photos, but the notes on the Flickr pages should be clear enough to anyone who's spent time with a V2. I painted the filed surfaces with clear nail polish as a quick-and-dirty rust preventative.


This let me make simple boxes without any weird contortions to make up for the funny shape of the bike.

The boxes themselves are made from almost a whole 4'x8' sheet of 12mm marine plywood using glue-and-screw assembly with 3/4" quarter-round oak trim on the inside edges. The width of the vertical rack is 10" at it's base and 7" at the top rack. Each box is 13" wide at the base and 16" wide at the top, with the same 1.5" bottom-to-top slope on each side to match the rack on the inside and look nice and symmetric on the outside. The slopes on the front and back were chosen to be reminiscent of a Bakfiets and maintain heel clearance for the pilot. The finish is a water-based stain under a UV-absorbing spar varnish, both low-VOC.

The baby seat is a second-hand infant car seat with the carry handle cut off. It's strapped in with a high-strength NRS cargo strap with a layer of closed-cell foam (pipe insulation) between the seat and the box for suspension. The rain cover shown is the same UPPAbaby Bubble that Totcycle used for his Madsen infant seat. I'm less than impressed with the cover, as it doesn't actually act as a rain cover because the ventilation mesh on the sides isn't covered by the rain shield. Also, the rain cover is also the sun cover and therefore opaque. This bike needs to be all-conditions for Portland weather, which means great rain protection while letting Jasper look out and us look in. It'll do for now, but Katie and I are scheming a sweet ventilated rain cover for the whole box.

Also in the works is a matching top deck and dyno-powered lighting system.


Julian said...

Yeah, that cover is drizzle-worthy but not rain-proof. But it was great shade, especially with the top layer tucked back under itself, and the mesh zipped down or tucked away depending on how aggro big sister was with the babe.

A see-through ventilated box cover sounds great, especially if easily removed and stowed, which is the other thing I like about the UPPAbaby thing.

How's the bollard clearance on trails down your way? I'd be a bit nervous with that rig on our Burke-Gilman trail (my commute) because of some not-so-generous-clearance posts.

Kimberly Hubble said...

I've enjoyed reading your blog. We're planning on transporting our infant in a cargo bike, but aren't sure how we will secure the infant car seat in the box. How is the cargo strap secured to the box on your bike? Thanks!

inkandpen said...

Kimberly, we use NRS straps. We built strap-width holes into the bottom of the box and pass the straps through the slightly-carved up car seat and through the holes in the box. There's some foam padding in between to soften the baby's ride. In other words-- it's a bit improvised. But it works. :)

Kimberly Hubble said...

Thanks for explaining... and congrats on your new arrival. We ended up doing something similar with first a thick blanket and then, this morning, a chunk of old crib mattress between the box and car seat base. Has worked for the three days we've been riding...