Junior gear restriction with SRAM AXS — does an XDR junior cassette exist? (+ bike choice for my 15yo)
I’m in Belgium, buying a first proper road bike for my son (15, 1m79 / 5'10", 89cm / 35" inseam). He’s joining a club, riding socially now, racing U17 next season. Road is the priority.
Main question is gearing. Belgian U17 uses a maximum development of 7.68m — that’s metres travelled per crank revolution, roughly equivalent to a 7.9m/26ft rollout limit in the US system, so similar idea, slightly different measurement.
One of the two bikes has SRAM Rival AXS 2x12. With a 48T ring he’d need a 14T smallest cog; with 46T, a 13T. AXS cassettes start at 10T on an XDR freehub.
- Does an off-the-shelf junior cassette exist for XDR?
- Or is it custom (Miche) / a swap to an HG freehub body?
- Anyone here run AXS with legal junior gearing? How did you solve it?
The two bikes:
Cube Attain C:62 Race — new, €1,699 (~$1,850) — carbon frame, Shimano 105 12sp mechanical, 50/34, 11-34, Newmen C.38 carbon wheels tubeless-ready, 8.9kg, full warranty.
Specialized Allez Sprint — used, €1,999 (~$2,175) — alloy, ~1,000km, Rival AXS 2x12, Quarq power meter, DT Swiss wheels, S-Works cockpit. Shop mechanic’s own bike, invoice included.
Leaning Cube: cheaper, carbon, new, better wheels. The Quarq is tempting but electronic shifting on a teenager’s first race bike seems expensive to break, and alloy wasn’t what I set out to buy.
Happy to be told I’m wrong on either. Thanks.