A kiddie trailer is the absolute worst of all trailer configurations to commute with. Around here a small army of semi-homeless use them to cart around salvage and/or their belongings. They don't know or care about drag coefficients but anyone together enough to be reading this forum should. I bought a single wheel trailer because in NYC and nearby Hoboken, NJ a single wheel is the only kind of trailer configuration that will make it through the gaps that a cyclist has to slither through on a daily basis. Now that I am on the West Coast and with much more road room, the single wheel layout still feels right. Two wheels are fine for big loads as was mentioned but a purpose built cargo trailer will carry that load with a minimal amount of frontal area and this is has a huge effect on the amount of effort it will take to haul your load.

Little story about wheels. My most expensive bike of my seven is the tandem we use for club rides and nice weather recreation. It is cheap as tandems go, but at $2K it was more money than I had ever spent on a bike. The cheapest bike has got to be the tandem we got from Wal-Mart as a grocery getter/commute taxi/knock-around town, car surrogate. At $250 it represents the $99 price point of dept. store bikes in stores like Wal-Mart, Fred Meyer, Target and Costco. That is the bike that is set up to pull the Bob Yak. A Bob Yak is rated for 70lbs but we routinely load it with !20lbs on grocery day. A single wheel trailer puts a lot of weight on the rear wheel of a bike and a tandem puts more weight on a wheel than a single. In six years there has not even been a millimeter of wobble in the wheels on the Wal-Mart tandem. Meanwhile the rear wheel of the Raleigh tandem would constantly break spokes and go out of true. Thank goodness it has disc brakes because some outings the wobble was so bad that a rim brake would have been useless! After the fourth round of spoke replacements @ $25 only because I have a good relationship with the LBS mechanic... finally I just had him rebuild both wheels same rims, same hubs but all new spokes - $80 each wheel. Ouch. Wheel building is the only area of bike repair that I cannot handle. I have bought a truing stand but haven't gotten the nerve up to take on even a minor truing assignment. Anyway... go figure. The cheapest wheels I own are hands down the strongest.

H