Clever idea, Turbo231, to ride your customer's bike back and carry your chopper in the trailer. But I can see how it would be annoying if the bike didn't fit you well. Must have been especially difficult on small kid's bikes--but I guess you carried those in your trailer instead.

As Reynolds and Tim199 suggested, one of the simplest ways is to mount a fork-mount rack on the back of a pannier rack and fit the fork of the bike to be carried in the mount. The main limitation is you need some way to carry the front wheel (e.g. a wideloader or side rack on a longtail) or else you have to carry it in your hand.

If you have a trailer, the best way to carry a bike depends partly on how valuable it is to you. We've built trailers for several community groups that collect old bikes and fix them up to sell/lend/give away. They usually just stack the donated bikes in a pile on the trailer . More valuable bikes are often carried using a fork-mount rack like Kookaburra1701 said. We also make a side-mount rack that allows people to carry one or two bikes vertically on the trailer without removing the front wheel:

http://www.bikesatwork.com/store/pro...t-bicycle-rack

You need to be a little cautious carrying just one bike this way, however, since the load is so unbalanced. Some compensating ballast (a toolbox, for example) on the other side of the trailer is probably warranted.

-Jim G.
Bikes At Work