The company in the UK that I bought my 9yr olds racing bike from sells multiple sizes of single chainrings for the kids bikes starting at 30T and going up 32T, 34T etc etc
https://kidsracing.co.uk/collections...12671464603711
My son competes in road races, normally 6-8 miles long and in triathlons, mostly 3-4 miles in length. Most of the races are on pretty flat courses with a few small hills. When he comes out with me on rides we will tackle bigger and longer hills
He has been riding on a 32T single chain ring and I'm wondering would there be any benefit or harm to moving up to a 34 or 36T ring
thanks