My son has outgrown the 24" wheel Felt F24 I built up for him. While the dimensions are still suitable, his abilities exceed the performance of the little wheels. After much searching I decided on the Kinesis Racelight KR-210L frame in a 40cm size.http://www.kinesisbikes.co.uk/products/junior-female-fit/racelight-kr-210l
It's not the lightest frame out there. But, honestly, I can't afford to spend the kind of money necessary for a lighter frame that he will outgrow in a year or two. I seriously considered a 44cm Specialized Dolce or Ruby, but the frameset can't be had and I didn't want to buy a complete bike knowing I would strip the parts and never use them.
Planned build is as follows:
Kinesis Racelight KR-210L Frame 40cm
Enve 2.0 Fork
Shimano Ultegra di2 Drivetrain
Converted BMX crankset with ti bottom bracket
Homebuilt ~1200g carbon clinchers (separate thread to follow)
Cockpit and other bits TBD based on what we have available
I'm doing this on a budget. The di2 group was given to us by a friend in the industry. (My son has fans.) The fork is dependent on my luck with ebay. Other parts except wheels I already have. Wheels are shaping up to be a fun project of Archtek 20mm carbon clincher rims with Bikehubstore hubs and cx-ray spokes. If things go to plan I can build the wheels in the 1200g range for around US$500.00.
My goal will be to get the build under 6kg. The frame is portly though and I'll likely use alloy bars, stem, and seatpost. So that is an ambitious goal. I think frame, fork, wheels, and the di2 parts alone are around 5kg so I'll see what I can do creatively. My son is going to be racing so there are rules to be followed... clinchers, minimum spoke count, junior gearing, etc. But this should be a fun project... frame was just ordered, other parts to follow. I'll post updates as I have them