I'd asked some questions a month or so ago. The bike I mentioned modifying is finished. It's a Raleigh rx24, the wheels were off AliExpress as at 100.00 to my door I couldn't build them cheaper already having hubs and the knowledge. They're pretty amazing for weight and stiffness being designed for a folding 20" bike.
The cranks started at 155mm and with the new wheels they would touch the ground. There was plenty of material to take off 35mm and still not have the hole go through the milled out area in the back, she can (and has) still scrape the pedals on the pavement but they could go no shorter. One hole did come out .5mm off to the side but both are the exact same length which is more important. With the post set forward it puts her over the bb closer to what a road bike would be. At this point she's scary fast to watch as a parent and my wife was getting ansy watching her but she had a blast. We've also found a tri group that does swimming and will be joining them soon.
The cranks started at 155mm and with the new wheels they would touch the ground. There was plenty of material to take off 35mm and still not have the hole go through the milled out area in the back, she can (and has) still scrape the pedals on the pavement but they could go no shorter. One hole did come out .5mm off to the side but both are the exact same length which is more important. With the post set forward it puts her over the bb closer to what a road bike would be. At this point she's scary fast to watch as a parent and my wife was getting ansy watching her but she had a blast. We've also found a tri group that does swimming and will be joining them soon.