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?

[Fredde N]

Originally Posted by lankydoug

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.

Well, i guess i have had to wheels off 5-6 times during this time, because i switch between racing and practice wheels/tires, but i haven?t notice this. I ordered a new axle yesterday and i think i will put a small innertube/pipe that goes beyond this point on the new axle.

I don?t want to crash like this again because of this. When we picked up the bike the day after, i have had 4th gear in...

[mrkartoom]

This is something you certainly don't see everyday and I'm not sure you'd ever notice it unless you were looking very closely. It does look like it had a crack previously (possible very small) and finally broke. Whether that crack was from fatigue, a flaw in design or machining, or something else I guess remains to be determined. Regardless I will certainly inspect mine as well and do some measurements when I have it off. If that section is as thin as your measurements indicate then I'd be a bit concerned as well. I'd think a piece of stock the exact thickness tacked across that area as you mention would be one good way to beef it up. I had a local welder do the same for the kickstand on my husky after a section was added in the middle to lengthen it.

[bukwheat]

Originally Posted by Fredde N

Well, i guess i have had to wheels off 5-6 times during this time, because i switch between racing and practice wheels/tires, but i haven?t notice this. I ordered a new axle yesterday and i think i will put a small innertube/pipe that goes beyond this point on the new axle.

I don?t want to crash like this again because of this. When we picked up the bike the day after, i have had 4th gear in...

4th gear! Yeow! Hope you didn't get hurt....

Even having the wheel off as many times as you have, I'm not surprised you didn't notice it, I mean, how many times do you hear of an axle failing.