Is there a Don here? Did you build a rack adapter for a tandem?

I believe you're asking about Don Vogel who is a registered user of this site. You can go to someones profile and email them if you have an account on this site and they haven't turned off the contact form. Try going to :

http://bikekentucky.com/user/21/contact

That should allow you to email him directly.

Sounds like a cool project (I have some older cars I've restored, and have a heightened interest in restoration projects).

Since my tandem (a 700C drop handlebar road style) is used only occasionally, I decided to fabricate a low-cost bike holder that could have multiple uses.

I have a 2" receiver hitch on the back of my SUV, so first I purchased an "excess cargo carrier" (typically used to carry coolers/luggage) that's rated to carry a few hundred pounds. The cargo carrier simply slides into my receiver hitch, and has metal l-angle around the perimeter, and open wire mesh in the body.

I then purchased a piece of treated 2" x 6" x 8' and fastened short pieces of treated 4" x 4" at both ends (held in place with screws up from the bottom along with l-angle supports). I drilled holes thru the 4 x 4's and put in all-thread rod, approx. 1/2 in dia., to hold the front and rear of the bike (I carry two 9/16" wrenches to tighten/loosen the nuts that hold the bike down). The 2 x 6 was then fastened to the cargo carrier with u-bolts. Note- if you decide to go this route, the distance between the all-thread rod (your "axles" to hold the bike) have to be the exact same measurement as your bike, as there's no adjustment once the 4 x 4's are mounted.

I quickly tired of removing the back tire for transport, so I simply removed the 4 x 4 at one end of the rack. The rear tire now sits between two narrow pieces of treated lumber. I also use a nylon ratchet style tie-down, hooked to the cargo carrier and draped over the rear handlebars, to hold the back of the bike down.

The drawback to leaving the rear tire on is that the bike is almost 8' from the rear tire to the handlebars. Meaning that on a narrow road, I have to keep an eye out for mailboxes and opposing traffic getting too close.

In conclusion, the above rack is cheap, but heavy and does take a few hours to put together. If you're good working with your hands, and have some type of roof rack on your vehicle, you may also consider (if you have a trailer hitch) running a piece of square tubing straight out the back of your vehicle to support the rear tire, and project something back from the roof rack to fasten the fork to. That way you don't have to worry about a bike hanging over each side of your vehicle.

Best of luck, let me know how your project turns out!

Note- if you need some help with cutting/fitting/fabricating just give me a shout and I should be able to help out.