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Discussion Starter #1
So I'm driving through town today with the windows down and sunroof open (first 60+ day in a loooong time) and a guy in a cadilac comes up next to me.

He Says, "Your pass. rear axel is bent!"

I say,"Is the wheel wobbling?"

He goes,"Yeah, really bad."

I reply,"Thanks, I'll check it out"

So, first, I'm not really sure how to check it out, since this just happened a couple mins ago and I think I'll either have to have someone I trust drive behind me, or jck it up and see if I can see any peceptable movement.

There is zero vibration in the car at any speed, and I don't remember hitting anything that would bend the axel, I think I would remebr an impact like that.

I just did my brakes and am still running winter tires/wheels (I know, stupid) but could there be anything else that this might be?

Not really worried at this point, but still something I thought I would throw out there.

Thanks for any insight.

Bob
 

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Run the tires on a wheel balancer to check for bent or defects...
 

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im thinking its a belt shift in one of your rear tires... have somebody toss the rear wheels on a balancer and watch it... ull be able to tell if it's a wheel or tire... good luck
 

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My first reaction would be "I don't have an axle - it is 4 wheel independent suspension" and then asked a few more questions about what he saw...

He didn't tell you your hubcap was loose too, did he? :)

Ok, with no vibration noticeable, I would expect you'll find a dent in your rim OR that the Caddy guy was just messing with you!

d-
 

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So your saying the M5 doesnt have an axle?

Regardless of the type of suspension, the car still has a drive axle. It just has two and you can bend an axle on an independent suspension car just as you can in a standard straight axle, just ask the IRS mustang guys.

Ryan


My first reaction would be "I don't have an axle - it is 4 wheel independent suspension" and then asked a few more questions about what he saw...

He didn't tell you your hubcap was loose too, did he? :)

Ok, with no vibration noticeable, I would expect you'll find a dent in your rim OR that the Caddy guy was just messing with you!

d-
 

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if the axle was bent on the m5, you would not see it unless you were under the car. you would definately feel it as sensitive as we are to these cars.
these cars have more negative camber than most other cars while the suspension travels right? maybe there were a few choice bumps on this road and the suspension traveled up and down- but not straight up and down. kinda like ) instead of ] get it?
 

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So your saying the M5 doesnt have an axle?

Regardless of the type of suspension, the car still has a drive axle. It just has two and you can bend an axle on an independent suspension car just as you can in a standard straight axle, just ask the IRS mustang guys.

Ryan

i think he was referring to a straight/solid axle and if this were the case, you would have to feel something!
 

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So your saying the M5 doesnt have an axle?
That's right - the BMW M5 does not have an axle, nor does it have a pair of axles. If you are referring to the 2 shafts connecting the differential to the wheels then you are looking for the term "half-shaft".

An axle, to the extent that it can be applied to our cars at all, is an imaginary line that extends through the center of both wheel hubs. Obviously an imaginary line cannot be bent. It can also be a term used to refer to the entire set of components, but again, and entire set cannot be bent.

Regardless of the type of suspension, the car still has a drive axle. It just has two and you can bend an axle on an independent suspension car just as you can in a standard straight axle, just ask the IRS mustang guys.

Ryan
No, they don't. They have a drive shaft. And since I worked with the Mustang guys when they were developing the IRS (which, incidentally, has a pair of half-shafts attached to the rear differential) I really don't feel like I need to call any of them.

Just to complete the picture for you, the drive shaft connects the tranny to the differntial. The half shafts, including a pair of CV joints on each end, allow the differential to turn the wheels.

Any other questions? :)

d-
 

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Ok buddy whatever.

Are you saying an "axle half shaft" cannot be bent? I was lost in your text book lnowledge...


Ryan


That's right - the BMW M5 does not have an axle, nor does it have a pair of axles. If you are referring to the 2 shafts connecting the differential to the wheels then you are looking for the term "half-shaft".

An axle, to the extent that it can be applied to our cars at all, is an imaginary line that extends through the center of both wheel hubs. Obviously an imaginary line cannot be bent. It can also be a term used to refer to the entire set of components, but again, and entire set cannot be bent.

No, they don't. They have a drive shaft. And since I worked with the Mustang guys when they were developing the IRS (which, incidentally, has a pair of half-shafts attached to the rear differential) I really don't feel like I need to call any of them.

Just to complete the picture for you, the drive shaft connects the tranny to the differntial. The half shafts, including a pair of CV joints on each end, allow the differential to turn the wheels.

Any other questions? :)

d-
 

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Discussion Starter #14
Geeze guys. Settle.

You sound like my wife and I bickering over her calling a sweatshirt and a sweater both sweaters, somehow I'm supposed to tell the difference.

Anyways, I still haven't noticed any vibration. I jacked the rear end up and spun the wheel and didn't see anything.

Either the tire is bad and will show up on a balancer or the cadi guy saw some wierd suspension bounce and misinterpreted it.

Thanks for all the feedback. You guys are great.

The axle sidebar was good too!

Bob
 

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these cars have more negative camber than most other cars
+1. You would feel a bent axle (OK, half shaft;)) . The car would have trouble driving straight. If the OP has no driving issues (and the wheel bolts are all tight), I wouldn't be too concerned.
Regards,
Jerry
 

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So I'm driving through town today with the windows down and sunroof open (first 60+ day in a loooong time) and a guy in a cadilac comes up next to me.
Sounds like your car was sitting all winter. Maybe it's something as easy as your tires being warped out of shape from sitting around so long?

You can check if your output shaft is bent by simply setting something straight-edged on it. I doubt it's a perfect measurement, short of taking out the shaft and rolling it to see if it wobbles, but it's better than nothing.
http://www.realoem.com/bmw/partgrp.do?model=DE93&mospid=47592&hg=33&fg=25
 

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Side question: Does one recommend BMW for alignments or will any alignment shop be able to align to BMW specs? Thanks, guys.
 

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Side question: Does one recommend BMW for alignments or will any alignment shop be able to align to BMW specs? Thanks, guys.
Any good alignment shop. There is no magic. And they usually charge a lot less.cherrsagai
Regards,
Jerry
 

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Discussion Starter #20
Sounds like your car was sitting all winter. Maybe it's something as easy as your tires being warped out of shape from sitting around so long?

You can check if your output shaft is bent by simply setting something straight-edged on it. I doubt it's a perfect measurement, short of taking out the shaft and rolling it to see if it wobbles, but it's better than nothing.
http://www.realoem.com/bmw/partgrp.do?model=DE93&mospid=47592&hg=33&fg=25
Drove car all winter, however the slipped belt thing is looking to be more true. I was recently talking to one of my emplyees who was following me the other day (car enthusiast as well). He said he noticed the tire, but then observed that the rest of the car was ver still and the tire appeared to be at the same angle and orientation to the body as the other rear tire. So he actually forgot about it until I asked him this morning.

The winter Blizzaks are slowly self destructing in this 60+ weather. I'm assuming that is what it is.

Bob
 
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