All three of our kids grew up on lightweights, from the smallest 16" wheel drop bar Peugeot we carried on the back of a tandem from Luxembourg, through the 18" wheel 6-speed Motobecane, through a 24" Zinn, Denti, Guerciotti, and Denti. We then discovered that many of the 26" wheeled bikes (we prefered the 559 size wheels tothe '650' triathlon size whenever possible.)could be made about as tiny as the 24", and tires are easier to get, more stable, and much quicker and smoother. We started with a Tom Teesdale but discovered that turnkey ubnits from Cannondale and Fuji are affordable and EZ to get
I still race 559's on my tandem that sees the Nats yearly.
We have avoided the Terry design, ever since it was invented by classic frameman Bill Boston. (many still mis-associate the invention of the design with Georgena Terry!!)
The dual 26 has a more classic asnd functional look, rides better, and makes rim, wheel, tire, and tube availability easier
We have 24" wheeled bikes with frames down to 34cm and 26" wheeled bikes with frames down to 39cm.
Of course this is moot for most 13 year olds
There are many chapters on bb height and crank length for these kids that are available too.
There are many white elephants out there - 24" wheelked bikes with frames as high as 50cm. Many of these came from the time when intermediate (age 12-14) had to race 24" bikes
There were other jokes in the ABLA too, like the no tubular rule, but nthat, too, is another rant
Larry "never liked 'shopping cart style small front wheeled bikes" Black