Before buying this wheely I spent a LOT of time reading through all the reviews as to whether to get the small or large wheely for my 1.5 year old boy/girl twins. And I made the WRONG decision - so I am hoping I can help others.
I have big kids (95% on height) so I figured I should buy the big one so they can grow into it. When I first bought it for them they pushed it around with their hands, but quickly got bored because their legs were too short to ride on it. Now that they are 2.4 years old and their legs are long enough, they are more excited to ride a tricycle or a scooter, and this is too 'sedate' for them.
So this is what I would recommend. Measure the inseam of your kid's legs. If they are 14" or longer, then buy the large size. But if their legs are shorter and you want them to ride on it now, then buy the small size.
Now, something to think about - I keep the wheelys outside - so my kids have a lot of options of things to ride on. So they hardly ever choose the wheelys. If this was an 'inside toy' with no other exciting options to ride on, then they would probably use it more.
So, to summarize:
- legs (inseam) shorter than 13" - buy the small.
- legs (inseam) longer than 14" - buy the large
- if your kids are already on tricycles, scooters or anything that goes a bit faster, they will be bored with this outside - and I would plan on it being an 'inside toy' where it will be used more.
- if you are going to use it inside, then I would buy the smaller one because it will take up less space and will be more maneuverable.
- Basically I should have bought the small so they could have used it when they were younger and not yet ready for faster toys.
I hope this is helpful to you!