I'm still not convinced anyone has identified the weight difference between "department store" bikes and more upscale ones (Trek, Specialized, Giant) or even customized ones. People throw out references to "2-5 lbs" or "5-8 lbs," but what's the real difference in weight .... and at what price? I don't think you'll see any weight info. published on Trek, Specialized or Giant web sites for kids bikes and I've never seen a comparison published anywhere else.
Has anyone in a LBS weighed their different brands of kids bikes (16, 20, 24 inch)?
After we identify the lbs difference, someone with a physics background should figure out the increased force that's necessary to move a bike that is XX lbs heavier.
Here's a helpful link:
http://www.coe.uncc.edu/~rkeanini/hu...pulsionweb.htm
I'm still not convinced a few pounds makes a significant difference until you're in high level races for really long distances or where every second matters.