Front axle snap, design flaw?

[bergerhag]

A fellow swedish rider had his '09 front axle snap.


I went out to shed and measured up my '10 axle. My bike is not rolling one more meter with that axle.

The bigger inner diameter where the fork yoke mounts passes by a tiny amount the larger outer diameter of same area. This makes the material thickness at the edge of spacer less than 0.6 mm [edit measured 1.3 mm] (0.0236 inches).





Fortunately my '05 450 has got anoter style of axle. Swap imminent.

[gasgasman]

More than likely, his wheel bearings froze and the spacer was rotating on the axle. Which made a weak spot.

[Fredde N]

Originally Posted by gasgasman

More than likely, his wheel bearings froze and the spacer was rotating on the axle. Which made a weak spot.

Hello...
It was my axle that snapped. I don?t think that there is a problem with the bearing, i have 2 sets of wheels (front and back) which i switch between, and i just switched all bearings front and back (about 20h ago) on both.

After i read your post i went out and checked the bearings and it rolled just fine, but still i could maybe be broke. I also took a video with my iphone that i could put up.

Here is two close up, but what i can see it?s a little rust there so maybe there has been a crack or something earlier.

[gasgasman]

OK.
Doesn't look like the bushing could have caused that.

Thanks for the warning to check ours along with the other safety checks.

[lankydoug]

Originally Posted by Fredde N

Hello...
It was my axle that snapped. I don?t think that there is a problem with the bearing, i have 2 sets of wheels (front and back) which i switch between, and i just switched all bearings front and back (about 20h ago) on both.

After i read your post i went out and checked the bearings and it rolled just fine, but still i could maybe be broke. I also took a video with my iphone that i could put up.

Here is two close up, but what i can see it?s a little rust there so maybe there has been a crack or something earlier.

I looks like it's been cracked for a while but still should have never cracked. If you had the wheel off 20 hrs ago you should have been able to see the crack.

[bergerhag]

It would be interesting if you who own 2007 and newer bikes could measure the depth of the first part of the axle, the one dimension that is 47.9 mm in my little drawing. Please post year too. Is this a bad batch of axles, or are they all like this? If all are like this, then it might not be as alarming as I first thought. We havent had that many reports of broken front axle. At least not yet.

[GMP]

I have an '07. I'll do that next time I have the front wheel off. I pull the wheels often to clean and grease the seals, and have never seen anything odd. This has got to be a first, so logically if it is a major design flaw I would think you would not be the first. Perhaps a machining issue with that particular part, stress riser set up on that step? Good point though. How was the bike ridden, both before and during the failure?

[Jakobi]

I saw this happen in real time earlier this year. It was however on a 2010 Yamaha WR450F. Everyone was in awe and luckily didn't happen at speed. Cracked and snapped in the exact same place too!

[swazi_matt]

are there any aftermarket options available for a swap?

[bergerhag]

Ok, after more careful inspection, i have found it not so alarming. The inner diameter changes the last 3 mm, and the critical point thickness appears to be at least 1.3 mm. Still thin, but better than 0.6 mm.

The 2004 -2006 axles are much thicker at that point.