I’ve been using a Thule thruride for the past 7 months for a carbon Jeffsy 29er. As OP has stated YT specifically state no frame clamps so no real option but to source a frame clamp alternative for me. Researched the thruride and picked up on the possible axle damage from metal clamp concerns….I wasn’t concerned about any cosmetic surface damage to the thru axle because (as far as I’ve read) it’s job is to hold the hub against the innners….no spinning roll itself as that’s down to hub bearings and so axle surface state (within reason) is irrelevant. I hadn’t clocked the perhaps more relavent concerns about fork lowers flex and movement of threaded inserts on axle without a hub to lock against and stabilise until now.
One posible Jeffsy solution for this thruride shortcoming is a 20mm to 15mm sleeve adapter that both protects the axle from direct clamp force and gives the fork lowers a hub substitute to clamp onto. USA based MTB tools do a boost and non boost version available directly from website or via eBay…this is the non boost:
https://m.ebay.co.uk/itm/MTB-Tools-Mountain-Bike-20mm-Thru-Axle-to-15mm-Thru-Axle-Adapter-for-100mm-Fork/252265312182?hash=item3abc2f2fb6:g:vVoAAOSw9mFWNiTy
this was recommended in a lengthy thread on this topic here:
http://forums.mtbr.com/cars-bike-racks/thule-thruride-535-new-model-anyone-using-969924.html
The downside is that you compromise security…..the 15mm thru axle is no longer locked in via the clamp mechanism and could be simply slid out to remove the bike. I’m currently sourcing one as never leave the bike unattended on roof anyway
I’ve found the thruride great to use and rock solid on motorways. Specs state cleared for up to 140km/h…..and no more peering up nervously at a wobbly front wheel 591 mounting ….much easier to load on and off the vehicle and a lower profile that’s made a small difference to fuel consumption versus my old bike on a Thule 591. Just remember you need room in the car for the front wheel…may not suit everyone. Hope that’s helpful.