Im thinking about adding bike pegs to the back wheels.
Anyone know are the size of bolts on back wheel?
Thanks for any help :)
If you mean you want to bolt up passenger pegs to the rear axle shaft, I wouldn't advise it. I often read where people have stripped the axle shaft in one form or another. If that happens, you are forced to replace the rear wheel assembly. Which of course holds the motor. A very costly mistake.
Besides that, I would be worried that the Mission frame isn't engineered to hold that additional weight in the rear. Even a small child's weight could eventually lead to frame cracks over time.
Maybe you should consider buying a Rad Runner or a Rad Wagon. Both of those bikes are built to carry passengers.