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anyone ever break a 12mm thru axle?

Jan. 3, 2018, 8:02 p.m.
taprider
taprider
Posts: 294
Joined: April 26, 2004

I did break the pivot axle (bottom bracket to chain stay region) of my frame. The original axle was hollow aluminum (~9 mm dia by 70 mm long), the warranty replacement is solid aluminum.

Now I look at my 12x148 thru axle and see it is hollow, and see some hubs do not have an inner axle/cylinder from one side completely to the other side, and just have pressed on end caps held in place with O rings. This observation indicates to me that the thru axle is not just doing the work of an old fashioned skewer (squeezing the hub between the chain stays) but also doing the work of a wheel axle and supporting you and your bike mass while cranking out the watts or landing jumps.

On google I see some Maxle's broke at the threads or lever/cam, but don't see any axles broken in the middle (like some of my old QR type steel axles)

Wouldn't a solid thru axle be safer? (only ~12 grams heavier in aluminum)

Jan. 4, 2018, 8:53 p.m.
trumpstinyhands
trumpstinyhands
Posts: 199
Joined: March 1, 2017

I've never seen one break and in my line of work I see a lot of broken bikes /parts! I've seen the inner sleeve on hubs snap in two, but maybe surprisingly not the thru-axle itself. Seen plenty of old school 9/10mm QR type axles snap, once even on both sides at the same time which was pretty impressive.

Jan. 5, 2018, 2 p.m.
nouseforaname
Posts: 3518
Joined: Dec. 17, 2003

Posted by: taprider

I did break the pivot axle (bottom bracket to chain stay region) of my frame. The original axle was hollow aluminum (~9 mm dia by 70 mm long), the warranty replacement is solid aluminum.

Now I look at my 12x148 thru axle and see it is hollow, and see some hubs do not have an inner axle/cylinder from one side completely to the other side, and just have pressed on end caps held in place with O rings. This observation indicates to me that the thru axle is not just doing the work of an old fashioned skewer (squeezing the hub between the chain stays) but also doing the work of a wheel axle and supporting you and your bike mass while cranking out the watts or landing jumps.

On google I see some Maxle's broke at the threads or lever/cam, but don't see any axles broken in the middle (like some of my old QR type steel axles)

Wouldn't a solid thru axle be safer? (only ~12 grams heavier in aluminum)

The stress is probably low in the middle, high where the threads end. QRs are/were being stretched, more so than a Maxxle, so maybe a different failure mode as a result.

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