Greg says “thraxle,” which sounds like some sort of insect anatomy term, but it’s (just barely) short for thru-axle. Never mind that a conventional 9mm skewer is also a thru-axle, the term refers to the new bolt-in 12mm and 15mm axles that have been standard on mountain bikes for several seasons now but may only recently be reaching critical mass on mixed-terrain and even road bikes. Watch new fork offerings to find out for sure whether we’ve reached tipping point, but I suspect we have.
Why is this happening? Well, as disc brakes proliferate, thraxles provide the advantage of greater lateral stability, i.e. less wheel flex, so that rotors remain centered in their calipers. Disc wheels set up with the older QR system do seem to have more brake rub than wheels with the new axles. If discs are the first domino, then thru-axles are the second.
All of this is converging on mixed-terrain and road bikes now, because riders have come to see how much more confidently they can descend big mountains with disc brakes. The idea that discs are the ideal braking system for carbon rims is a bit of a red herring, I think, since carbon rims haven’t entirely trickled down to the average roadie yet. But even on alloy rims, the advantage on those big drops has convinced more and more riders to go disc.
Thraxles also serve those who fetishize stiffness. I’m not one of them, but I don’t argue with them about it either. Thraxles are stiffer. Do you want that? Maybe. Maybe not.
There is an element here, too, of product liability reduction, as manufacturers work their way through the massive quick release skewer recall.
Of course, part of the challenge of moving to a new axle platform, and the main source of my frustration, is that it synchronizes with so many other standard changes (e.g. tapered forks/headsets, electronic shifting, press fit BBs, etc.), so that our parts bins and spare wheels become vestigial to the whole process of upgrade and afterlife (one of my favorite hobby horses). Another challenge is settling on a standard, 12mm or 15mm, until some a-hole decides 13.5mm is best. You know that’s coming.
This week’s Group Ride asks, do you thraxle? Do you own a disc brake bike that isn’t a mountain bike? Or, are you disc-skeptical, and thus thraxle-opposed? Is this just the industry selling us something new? Or slowly solving a real problem, answering a real need?