Bent front axle

Kaptain Kanji

Kaptain Kanji

Registered
In the process of taking the Big Girl's front wheel off to replace the tire, I once again noticed that the axle unscrewed with uneven pressure. I had given it a precursory check last time I had it out and didn't see anything wrong with it. I've noticed she pulls to the right and I've been wondering why the tracking was off. Since I have a little time before the dude changes out the tire, I figured I'd check the axle carefully. I put a precision straight edge on the pipe section of it and rotated it. Sure enough, there's a noticeable bend in the tubular section, as in VERY noticeable..!! I guess this would be enough to cause the tracking problem and it definitely needs to be replaced. I got one off FleaBay last night that looks to be in good shape, so when it arrives, I'll check it and if good, install it and make the Big Girl a little happier.!! :-)
Anyway, I guess the moral of the story is, if you unscrew your axle and it doesn't feel like it's turning smoothly, check it for straightness.
If you look at the attached pic, you'll notice the right side of the axle has daylight between it and the scale.!! The left side of the axle is sitting flush with the scale.

Axle.jpg
 
Ok.. the front end is uncharted land for me..

How does something like this happen?

Sent from my HERO200 using Tapatalk
 
First question is how do you know that 99 cent ruler is perfectly straight?

Secondly, I don't think that's the reason your bike pulls to the right!

Your axle fits tightly into two bearing races that is PERFECTLY in alignment. If the axle is truely bent enough to make a difference it's not going through the wheel without the use of a hammer. Then, once it's in you probably won't get it out without driving it out with a dowl.

Where that axle shows daylight is right at the point the bearing sits. If the axle is bent and your straight edge is actually straight you should be able to rotate the axle 180 degrees and there should be daylight back towards the middle of the axle.

Personally, I don't think you have axle issues! :dunno:
 
Personally I wouldn't trust that HIGH GRADE leveling device your using. Unless you use a precise leveler, I would NEVER trust anything wooden when dealing with metal objects. Especially a really cheap one that I can guarantee does not take into account warping in their manufacturing process:beerchug:

You can also check the tire alignment when it's mounted, that should tell you if the tire/wheel is straight while spinning. If so, I doubt you have a problem :thumbsup:
 
well although its possible that axle could be bent just a little, i dont think that once its through the races like tufbusa has said its goona make a difference... something else is possibly causing the bike to veer i would think, probably the tire you had on..???
 
Ha Ha, you guys are funny. NO, the measuring device, T-square, is not made of wood. It's an expensive piece of steel equipment with a perfectly straight edge. YES, if I spin the axle 180 degrees, there is a nice hollow spot under it that you can see daylight thru. YES, the axle IS bent. The axle was bent by the nice young chap that owned the bike previous to me. Apparently he delighted in laying the bike down, until he wore the frame sliders down to NUBS..!! :-)
As far as whether it would affect the tracking, I can't say for sure because I'm not an engineer, but I know for sure it needs to be replaced.
 
Tufbusa said:
First question is how do you know that 99 cent ruler is perfectly straight?

Secondly, I don't think that's the reason your bike pulls to the right!

Your axle fits tightly into two bearing races that is PERFECTLY in alignment. If the axle is truely bent enough to make a difference it's not going through the wheel without the use of a hammer. Then, once it's in you probably won't get it out without driving it out with a dowl.

Where that axle shows daylight is right at the point the bearing sits. If the axle is bent and your straight edge is actually straight you should be able to rotate the axle 180 degrees and there should be daylight back towards the middle of the axle.

Personally, I don't think you have axle issues! :dunno:
Click to expand...

:laugh: +1
 
It would be interesting to compare axles when your new one arrives...

Also, how does the tread wear look on your front tire?

:beerchug:
 
Just a thought, wouldn't a bent axle cause the front wheel to vibrate or shake? As the wheel spins I would imagine it would move on the vertical axis as if it were spinning with an oval at its center.???
Just thinking out loud. Not an engineer so I could be, and probably am, wrong.
 
Well, the front tire had strange wear on it, along with being slightly cupped.
I just miked out the axle and it's NOT tapered.
I checked with the straight edge again, and at one point it's arched and the other point 180 degrees across from that, it's concave and at the two points in between it sits level and flush on the straight edge. This would indicate to me that the axle is bent.!!
Nevertheless, I'll compare it with the replacement and see how that one looks.
Interesting.....
 
Kaptain Kanji said:
Ha Ha, you guys are funny. NO, the measuring device, T-square, is not made of wood. It's an expensive piece of steel equipment with a perfectly straight edge. YES, if I spin the axle 180 degrees, there is a nice hollow spot under it that you can see daylight thru. YES, the axle IS bent. The axle was bent by the nice young chap that owned the bike previous to me. Apparently he delighted in laying the bike down, until he wore the frame sliders down to NUBS..!! :-)
As far as whether it would affect the tracking, I can't say for sure because I'm not an engineer, but I know for sure it needs to be replaced.
Click to expand...



NO that T-square is not an expensive piece of steel equipment! And it's used mostly in the wood industry!
 
put a indicator on it...run the length see what you get...and yes...get a new axle
 
Temeraire said:
Just a thought, wouldn't a bent axle cause the front wheel to vibrate or shake? As the wheel spins I would imagine it would move on the vertical axis as if it were spinning with an oval at its center.???
Just thinking out loud. Not an engineer so I could be, and probably am, wrong.
Click to expand...

Good thought but incorrect. The wheel has a bearing race that the axle sits on. Nothing spins on the axle. What would happen if the axle is truely bent would be the wheel would not be in perfect alignment with the forks. This would actually make the bars off center as it's the trail within the steering geometry that centers the wheel itself with the rear.

So even if the axle was tweaked, it would have little if any effect on steering.

If the steering pulls the bike to the right, my guess is one of the forks or the triple tree is tweaked? Sometimes after a crash the forks get a little twisted as a result of the impact. I have on numerous occasions loosened all the fork clamps allowing the forks to relax then re-torque the clamps and most of the time the bike steers just fine afterwards.

Will be interesting to see how this works out!
 
Tufbusa said:
NO that T-square is not an expensive piece of steel equipment! And it's used mostly in the wood industry!
Click to expand...

Sorry to disagree here Tuf but that is a precision square used in the tool and die industry and is made of a high grade metal, It is more accurate for measuring than for being square but the scale is surface ground to be within .0005 (on most some may be a little more), but to give an idea of how perfect that is a human hair is .003. As far as the price depending on what brand you get I have seen the as much as $250.00 and as low as $45.00. Snap-on is $73.00
SQUAREB12, Set, Measuring, Machinist’s, 2 pcs.

To me it looks tapered but the way he described it it sounds bent, if he measured it with micrometers then its not taperd. Micrometers are also another measuring device that are perfect within .0005 some more expensive ones are even closer than that.

Another thought, since his front axle is the one thats bent wouldn't you be able to put the axle in with little effort since each fork moves on it own??? That would be the cause for it getting tight then loose as its rotated the axle moves the fork up and down but when it tries to move it front and back it tightens up. And no it would not affect the driving or even cause a vibration because the axle doesn't move just the bearings so once the axle is in the bearings rotate on the same spot of the axle. If the axle did move like it does in a car you would then have a vibration.
 
Last edited:
KvHotDog4 said:
Sorry to disagree here Tuf but that is a precision sguare used in the tool and die industry and is made of a high grade metal, It is more accurate for measuring than for being sguare but the scale is surface ground to be within .0005 (on most some may be a little more), but to give an idea of how perfect that is a human hair is .003. As far as the price depending on what brand you get I have seen the as much as $250.00 and as low as $45.00. Snap-on is $73.00
SQUAREB12, Set, Measuring, Machinist’s, 2 pcs.

My apologies for calling his $250 T-square inexpensive! Personally, I couldn't tell by the photo.

By the way, how could you tell that is an expensive T-square? :dunno:
Click to expand...
 
If the previous owner was prone to laying the bike down then there might be something more than just an axle thats tweaked. ???
 
Kaptain Kanji said:
In the process of taking the Big Girl's front wheel off to replace the tire, I once again noticed that the axle unscrewed with uneven pressure. I had given it a precursory check last time I had it out and didn't see anything wrong with it. I've noticed she pulls to the right and I've been wondering why the tracking was off. Since I have a little time before the dude changes out the tire, I figured I'd check the axle carefully. I put a precision straight edge on the pipe section of it and rotated it. Sure enough, there's a noticeable bend in the tubular section, as in VERY noticeable..!! I guess this would be enough to cause the tracking problem and it definitely needs to be replaced. I got one off FleaBay last night that looks to be in good shape, so when it arrives, I'll check it and if good, install it and make the Big Girl a little happier.!! :-)
Anyway, I guess the moral of the story is, if you unscrew your axle and it doesn't feel like it's turning smoothly, check it for straightness.
If you look at the attached pic, you'll notice the right side of the axle has daylight between it and the scale.!! The left side of the axle is sitting flush with the scale.
Click to expand...

Take a pic with the other side of the axle flat like you did in the pic.
 
The axle does not rotate...sounds like your forks are out of alignment. If you can get the axle in and out of the forks and wheel...and the wheel spins freely once everything is tightened properly, then buying a new axle is a waste of $$$.
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