So currently we have 2 cars, although one of them is borrowed from family, and they want it back. Usually on Thursdays my wife drops our son off at pre-school, and then I leave my job, pick him up, switch to the bike and ride it back. I looked at the mileage, and while it adds 17 miles in the middle of the day, it's all relatively flat and I can't think of a reason why I couldn't ride to work, ride to pre-school where my wife would have left the trailer, and then ride home. My question is I have both a road bike and a mt. bike, and I have towed the trailer plenty of times with the mt bike, but I have never towed it with the roadie. Its a Raliegh Grand Sport, aluminum frame and while its not exactly the top of the line, I do like it and don't want to jack it up. Can I tow with it? The ride from school to home is about 6 miles all flat except the final mile which is up a pretty good hill. Or should I suffer with the mt bike, making the commute seem longer if it isn't really.

I don't see why not. I've towed a pretty heavily loaded Burley Flatbed Trailer with my Specialized Allez Elite many times.

This is a pretty light load, but the pack probably weighs more than most pre-schoolers and the cooler was at least 1/3 full of ice, often full of ice and fish for the return trip.

The "secret" is that "it's all in the hitch".
Good safe hitch will equal a good ride no
matter what bike you have as long the bike
has the gearing.

It's a Burley D'Lite so I assume it's a good hitch. We shall see next week.

I have towed two out of three of my boys in our Burley D'Lite (the toddler will be ready for it this summer). I always towed it with a road bike until last summer when I bought a mountain bike. Although, the mountain bike felt steadier, the road bike was fine to begin with. So, the mountain bike was an improvement, but not one that made the road bike worse, just different.

As a related aside, when my oldest got too big to fit in the trailer with the middle son, I switched him to a trail-along that connected to my seat post, then attached the trailer to the trail-along. The "bike train" (as the boys call it) DEFINITELY tracked steadier with the mountain bike than with the road bike. But, that configuration is far different from a single trailer no matter how heavily loaded it may be.

The Burley D'Lite has the exact same hitch as the trailer above from CommuterRun's post. (Burley flatbad) Burley uses the same hitch on everything, or at least they used to before running the company into the ground.