Hmm. I think DH calls it a "50?" My older son is on the next size up. Both sizes come with a "restricter screw" which depending on how tight you have it screwed in, governs how far the kids can pull the throttle back. You can give it less power than a "power wheels" if you want too. Right now we have the little bike set to do between 5 and 7 mph. I wouldn't mind a little less, (since I am incredibly paranoid) but with any less juice it can't even get started over our rocky terrain. We started the little one at 2 and a half. When he began, he couldn't reach the hand break because his hands were too small. So we would to attach a short strap to the bike frame and run behind him so we could pull his bike to a stop to keep him from running into trees until he figured it out. One day, we forgot the short strap and I thought it would be fine to use the dogs 30ft lead.....which ultimately got tangled around my ankle and he got so much momentum that my leg was pulled out from under me. This year, he can finally reach the brake and he has really excellent throttle control for slowing down so now we just chase him on the 4 wheeler! lol.....
I think the biggest "issue" for starting is finding a safe, flat area for them to learn. Around here, all the state trails are in the mountains with plenty of hills and ledges to fall off of.
Anyways, I have a friend who's little boy was 4 last summer and we let him ride it. He crashed it more times in an hour than my kids ever have. I am not sure how well he was doing on a bike at the time, but I would definitely use their bike safety skills as an indicator of when they are ready to hop on one! In all honesty, its a little nerve wrecking for me to watch the kids on them. However, one of the only times my DH REALLY smiles, is when he's on wheels- or watching the kids on theirs, and my kids really, really LOVE them as well. Riding is main motivator at the moment for my older one to do well with his schoolwork and general attitude (and oh does he have ATTITUDE TO SPARE) Three strikes in a day looses dirt biking on the next trip, and if he's already lost the trip and he gets another three strikes the bike gets sold. Lets just say, we still have the bikes ;-) He also has a sticker chart for good "grades" and when he earns an obscene amount of stickers, he gets to try a motocross track for the first time. He is very excited about that!
he is very dedicated and just taught himself how to ride a bike with no training wheels today! (proud mom moment). His favorite thing to do is watch little boys ride dirtbikes on youtube....maybe he's seen yours
