Semi-circular marks on thru/through axles?

[LittleWheelsandBig]

Something is making at least some SON thru axle hubs rotate in the fork during use, as described and depicted in https://yacf.co.uk/forum/index.php?topic=116103.0


shows a typical mark (wrapping nearly half the circumference) from the end of the hub axle.

Does this same movement occur in normal hubs? I am asking if your axles show a similar mark. Just pull out your through/ thru axle and see if it has semi-circular mark/s.

This poll is an attempt to see if the same thing happens in all thru/through axle hubs but is only noticeable when using dynohubs.

[JulesP]

SON thru-axle hub that has been slipping.

[LittleWheelsandBig]

Edited to add no visible marks option.

Negative results is useful data regarding whether disc brake hub axles rotate in use.

[mrcharly-YHT]

'Slipping' or 'rocking'. It is possible that there is fractional movement under braking.

[LittleWheelsandBig]

True but the rocking seems to lead to precession of some sort. The dynohub axles rotate enough to damage cables and connections.

I have no idea if the same behaviour is seen in non-dyno wheels. Marks on the through/ thru axle would suggest that the same behaviour occurs but is not critical. If lots of through axles have these marks, regardless of whether dyno or not, then it is endemic.

[Brucey]

I suspect it of being endemic, and shall be interested to see if that is borne out or not.

cheers

[LittleWheelsandBig]

If this hub axle rotation is endemic, then the hub axle-to-fork interface may need some additional consideration but that is something for highbrow bike design types to worry about.

[JonB]

Nothing on mine yet but it's quite new (~1000km) and only taken the wheel off a couple of times. Will keep an eye on it and report back if I see anything.

[Jack_P]

I was undecided so put no visible marks. The anodizing has lightened slightly but I would expect that where there is metal on metal interface over time.
This axle has done over 25000 miles, approx 18K of that with a SON dyno hub.

Disc brake rotational forces can be large on a hub, guessing this is causing some rotation. The Son hubs have no serrations on their inner surface which most other hubs have to provide some grip interface.
Looking at my forks (On a Tripster ATR) the fork surfaces have their own indented serrated marks probably left from originally using a serrated hub interface.

Perhaps this has happened more for you if you have used the SON hub from new. 



I was considering some lightweight Allan key screw in axles as replacements for security, then a friends axle in his newish Cannondale snapped (rear hub) which put me off.