I now have a tag-along for the 3yr old. I've sorted bars she can reach but she can't really reach the pedals.
I want to put some pegs or blocks where the bottom bracket is which she can reach no problem, and remove the cranks until she can reach them. Its got a standard bb.
Does any company make something already? (I doubt it)
Anyone got advice as to how to knock something up?
Stunt pegs? Blocks of wood?

Remove BB, slot a cylindrical piece of wood in. How to keep it from sliding out.. Nail small squares of wood on both sides. It might still rotate though, not sure how you could stop that, unless you made it fit really tight. Doubt a 3 year old could apply enough force to rotate it.

Dazzy, I just Ziptied one crank to the seatstay to keep the pedals level when Ethan started, I recommend getting a seatpost mounted backrest (with chest strap) as well, as Ethan fell asleep on our first few rides.

Hows things in Derby? must phone soon.