Blocking gears
I'm attempting to set up my son (15) for his first race at the end of the month, an individual time trial. I'm trying to block out his gears rather than buy junior specific equipment. He's got a 50-34 on the front, and a 28-11 on the back. The problem is that the 50-14 is the biggest combination that will pass the roll out which means I need to block out the 11, 12, and 13t cogs. However, the high-range adjustment screw will only allow me to block out the 11 and 12.
Question: Is there an equipment adjustment that will allow me to block out the 13T (such as a cable adjustment or something) or am I stuck with having to get a different cassette or a junior specific crankset?