Child Seat on a Road Bike

I have experience of child seats on a Pinnacle CX-commuter and an MTB.

Personally I wouldn't put one of those clamp-around-the-seat-tube seats on any of my bikes. They could well do more damage than just paintwork given the weight of the child, the leverage the seat exerts on them, and the impact of bumps in the road, especially if the seat post isn't inside the tube at the point that it clamps.

I have used Topeak Babysitter II and CoPilot Limo rack-mounted child seats and if you have the necessary mounts on the frame, I'd say these are a decent bet. I prefer the Topeak in several respects, but both are fine. Both need a specific rack, but this can also be used with panniers etc when not using the seat.

For me, the main issue with these on road bikes is that getting up hills is tricky with the extra weight unless you have very low gearing. It's much more manageable on an MTB.

Also, depending on the weight of the child, the frame flex can be very alarming if you try to stand up out of the saddle, so I'd advise against this. With my very tall 3 year old who's now not that far off the weight limit of the Topeak seat, this is particularly problematic. With my average size one-year-old it's still an issue but less severe. Again, this is less of a problem on the MTB. I can't see this being any better with the seat-tube mounted seats. A road bike is likely to be worse than a CX bike in this respect.

Do also consider the trailer option. I think this is your best bet if you can afford it.

Another possibility is the Weeride top-tube mounted seats, but they push your knees out so not much good for any more than a very short and gentle ride.

Lots of useful and important advice here: http://www.bikeradar.com/gear/article/beginners-guide-to-cycling-with-ki...

Don't take them on a decent length ride until you've got a feel for how happy they are in there and how long they will tolerate it. My kids love the child seats but the younger one won't be happy if the ride is more than about an hour.