Making a new top box.

[D.O.G.]

I’m planning to make a new top box for my Honda V-Twin Magna, (VT250C).



I’m not looking for a perfect aero shape, there are too many other bits and pieces sticking out in the breeze (including me) to hope for clean flow, I just want an improvement on the storage box I have now.
Craig Vetter’s website has given me ideas, but I’m not keen on enclosing most of the bike, it’s already a lot wider than his Helix.

I sit upright, so my first thoughts are –
The box to be shoulder width (500mm) and height (550mm) at the front, with the sides tapering to the 300mm and the top tapered down to 450mm. A length of 600mm is about flush with the back of the bike. The front and top edges would be radiused.

My questions are:
What do you think of the sizes? The box will be larger than I really need for carrying stuff.
Do you think it’s worthwhile adding the extra complexity of trying to follow the curves of the template for the sides?

[freebeard]

What do you plan to use for material?

Curving the sides would stiffen them so it can be lighter. Extending the front radiused edge down to at least the seat could keep your sides warmer by reducing the wind buffeting [?]

How do you expect it to open? Could you get two fiberglass saddlebags and bolt them together?

[D.O.G.]

Originally Posted by freebeard

What do you plan to use for material?

I've got the option of thin aluminium sheet or heavier aluminium/plastic composite sheet.

Curving the sides would stiffen them so it can be lighter. Extending the front radiused edge down to at least the seat could keep your sides warmer by reducing the wind buffeting [?]

I can't make compound curves easily, I could do a plan curve though.
I was always going to add skirts from the bottom of the box to the level of the passenger foot pegs once the box is complete.

How do you expect it to open? Could you get two fiberglass saddlebags and bolt them together?

I was thinking of hinging the top at the front.
That's a great idea with the saddlebags! I have a pair I could use, but they're a bit short.

Am I right in assuming it's better to have the box as tall as my shoulders, rather than at my shoulder blades?

[D.O.G.]

I’ve just come across a you tube channel by Kraig Schultz that has interviews with Vetter Challenge competitors.

I’ve seen still photos of many of these bikes before but seeing them in in the round via these videos really brings home their size and shape so much better.

[freebeard]

I've got the option of thin aluminium sheet or heavier aluminium/plastic composite sheet.

3mm Polymetal (or equivalent) would be my choice. Prefinished on both sides and no internal framing required.

The height might be personal preference.

[Frank Lee]

If your current box is the size, strength, and weight you like I'd consider simply adding lightweight coro fairings on it. Easy to experiment with different configurations that way too.

[D.O.G.]

Originally Posted by Frank Lee

If your current box is the size, strength, and weight you like I'd consider simply adding lightweight coro fairings on it. Easy to experiment with different configurations that way too.

I must be carrying more now than I used to (the bike's been off the road for a few years), the current box's usable internal space is a bit too tight.

One comment from Sendler's interview has stayed with me, talking about his tail unit "If I did it again, I'd make it bigger".
Even if my new box is half empty, it's filling the space behind me and a shoulder height back rest might help to stop me slouching in the saddle.