Straightening Rims: ?
Thread Starter
Junior Member
Joined: Oct 2020
Posts: 41
Likes: 2
From: Princeton, NJ
2020 C300
Straightening Rims: ?
Some mild and very occasional vibration at certain speeds led me to bring my car into the dealer. Apparently, my 19" rims are little out of shape. He did some balancing and told me see if this solved the problem, but that I might have to have them straightened at some point.
Balancing helped, but didn't solve the problem. My question is how this would affect the strength and integrity of the wheel. Whatever damage there may now be for now is mild, but is this something that you can do every now and then as a form of maintenance? Or is this a repair that should be done as sparingly as possible?
Thanks for sharing your experience.
Balancing helped, but didn't solve the problem. My question is how this would affect the strength and integrity of the wheel. Whatever damage there may now be for now is mild, but is this something that you can do every now and then as a form of maintenance? Or is this a repair that should be done as sparingly as possible?
Thanks for sharing your experience.
MBWorld Fanatic!
Joined: Sep 2018
Posts: 3,243
Likes: 933
From: New Orleans Area
2015 E400 Sedan
Wheels are some AL alloy.
When it deforms and the material is overstressed and changes shape you have exceeded the material's Yield Stress (not a good thing)
So to force it backy ou could MACHINE this material that has moved so it is out of the way so to speak but then you make structure thinner in those areas and more prone to yielding.
Another method is to overstress it again but opposite direction by a press or something.
But when you do this you are starting to really FATIGUE the material; Think paper clip and bend it back and forth - Eventually it breaks and is for sure weakened with every bend.
Also with reshape back to spec you may make material cross sections thinner then original since well it was bent OUT OF SHAPE.
So to answer your questions:
How bad is it? I mean a few thousand of inch out of whack o something we can measure with tape measure (1/6, 1/8, ...)?
Is it just out of round with sort of a flat spot?
OR is the hub and tire bead centers are not concentric anymore?
IS hub flange still parallel to tire bead?
Heck are inner and outer tire bead concentric, parallel, round etc?
yeah geeky engineer who has designed things that spin
The less you repair the better off you are.
PS this is why MB now sells wheel& tire insurance as they know their wheel are like made from GLASS and easily bent.
PSS are you sure it is not a tire issue? out of round, flat spotted, belt issue, etc?
When it deforms and the material is overstressed and changes shape you have exceeded the material's Yield Stress (not a good thing)
So to force it backy ou could MACHINE this material that has moved so it is out of the way so to speak but then you make structure thinner in those areas and more prone to yielding.
Another method is to overstress it again but opposite direction by a press or something.
But when you do this you are starting to really FATIGUE the material; Think paper clip and bend it back and forth - Eventually it breaks and is for sure weakened with every bend.
Also with reshape back to spec you may make material cross sections thinner then original since well it was bent OUT OF SHAPE.
So to answer your questions:
How bad is it? I mean a few thousand of inch out of whack o something we can measure with tape measure (1/6, 1/8, ...)?
Is it just out of round with sort of a flat spot?
OR is the hub and tire bead centers are not concentric anymore?
IS hub flange still parallel to tire bead?
Heck are inner and outer tire bead concentric, parallel, round etc?
yeah geeky engineer who has designed things that spin
The less you repair the better off you are.
PS this is why MB now sells wheel& tire insurance as they know their wheel are like made from GLASS and easily bent.
PSS are you sure it is not a tire issue? out of round, flat spotted, belt issue, etc?
Thread Starter
Junior Member
Joined: Oct 2020
Posts: 41
Likes: 2
From: Princeton, NJ
2020 C300
A geeky engineer is just who I'd like to get input from!
The bent paperclip idea is basically how I've been thinking of it--that there's only so much rearranging that can go on before metal is over-fatigued. I realize I don't have that much hard data from the dealership and can't answer any of your questions. Are there precise measurements somewhere in the service departments records? I'll check. How to know if it's a tire issue?
My takeaway is if it's not real broke... don't fix it.
I suppose I was wondering if it's ok to fix it "a little".
Thanks and welcome any other experience here.
The bent paperclip idea is basically how I've been thinking of it--that there's only so much rearranging that can go on before metal is over-fatigued. I realize I don't have that much hard data from the dealership and can't answer any of your questions. Are there precise measurements somewhere in the service departments records? I'll check. How to know if it's a tire issue?
My takeaway is if it's not real broke... don't fix it.
I suppose I was wondering if it's ok to fix it "a little".
Thanks and welcome any other experience here.
MBWorld Fanatic!
Joined: Sep 2018
Posts: 3,243
Likes: 933
From: New Orleans Area
2015 E400 Sedan
Have tire removed at good tire shop... see if they can balance.
Maybe swap tire from one wheel to another and see where problem goes - with tire or wheel.
Also ask them to check wheel for:
Bead is out of round
Bead is concentric with hub bore
Bead circle is perpendicular to hub bore
Nothing is perfect so expect it to be a little off for each.
Question is how much. in my world of gears, bearings, rotating shafts, pins etc.
Tolerance depends on speeds, sizes etc.
And since we have RUBBER FLEXIBLE tires to help absorb and errors tolerance for these 3 things might be larger than you think.
I bet SAE or some euro law has specs on what this tolerance is acceptable.
Maybe a little google searching AUTO WHEEL TOLERANCE DIMENSIONS etc.
ll I know is if you can see it by eye - That is too much runout.
I would fix one time if not too far from where it needs to be.
I would not fix if it had to be move a bunch .
Remember another method of straightening is heat/cold but this ruins finish.
Maybe swap tire from one wheel to another and see where problem goes - with tire or wheel.
Also ask them to check wheel for:
Bead is out of round
Bead is concentric with hub bore
Bead circle is perpendicular to hub bore
Nothing is perfect so expect it to be a little off for each.
Question is how much. in my world of gears, bearings, rotating shafts, pins etc.
Tolerance depends on speeds, sizes etc.
And since we have RUBBER FLEXIBLE tires to help absorb and errors tolerance for these 3 things might be larger than you think.
I bet SAE or some euro law has specs on what this tolerance is acceptable.
Maybe a little google searching AUTO WHEEL TOLERANCE DIMENSIONS etc.
ll I know is if you can see it by eye - That is too much runout.
I would fix one time if not too far from where it needs to be.
I would not fix if it had to be move a bunch .
Remember another method of straightening is heat/cold but this ruins finish.
MBWorld God!
Joined: Dec 2019
Posts: 32,331
Likes: 6,312
Wheels are some AL alloy.
When it deforms and the material is overstressed and changes shape you have exceeded the material's Yield Stress (not a good thing)
So to force it backy ou could MACHINE this material that has moved so it is out of the way so to speak but then you make structure thinner in those areas and more prone to yielding.
Another method is to overstress it again but opposite direction by a press or something.
But when you do this you are starting to really FATIGUE the material; Think paper clip and bend it back and forth - Eventually it breaks and is for sure weakened with every bend.
Also with reshape back to spec you may make material cross sections thinner then original since well it was bent OUT OF SHAPE.
So to answer your questions:
How bad is it? I mean a few thousand of inch out of whack o something we can measure with tape measure (1/6, 1/8, ...)?
Is it just out of round with sort of a flat spot?
OR is the hub and tire bead centers are not concentric anymore?
IS hub flange still parallel to tire bead?
Heck are inner and outer tire bead concentric, parallel, round etc?
yeah geeky engineer who has designed things that spin
The less you repair the better off you are.
PS this is why MB now sells wheel& tire insurance as they know their wheel are like made from GLASS and easily bent.
PSS are you sure it is not a tire issue? out of round, flat spotted, belt issue, etc?
When it deforms and the material is overstressed and changes shape you have exceeded the material's Yield Stress (not a good thing)
So to force it backy ou could MACHINE this material that has moved so it is out of the way so to speak but then you make structure thinner in those areas and more prone to yielding.
Another method is to overstress it again but opposite direction by a press or something.
But when you do this you are starting to really FATIGUE the material; Think paper clip and bend it back and forth - Eventually it breaks and is for sure weakened with every bend.
Also with reshape back to spec you may make material cross sections thinner then original since well it was bent OUT OF SHAPE.
So to answer your questions:
How bad is it? I mean a few thousand of inch out of whack o something we can measure with tape measure (1/6, 1/8, ...)?
Is it just out of round with sort of a flat spot?
OR is the hub and tire bead centers are not concentric anymore?
IS hub flange still parallel to tire bead?
Heck are inner and outer tire bead concentric, parallel, round etc?
yeah geeky engineer who has designed things that spin
The less you repair the better off you are.
PS this is why MB now sells wheel& tire insurance as they know their wheel are like made from GLASS and easily bent.
PSS are you sure it is not a tire issue? out of round, flat spotted, belt issue, etc?
Have tire removed at good tire shop... see if they can balance.
Maybe swap tire from one wheel to another and see where problem goes - with tire or wheel.
Also ask them to check wheel for:
Bead is out of round
Bead is concentric with hub bore
Bead circle is perpendicular to hub bore
Nothing is perfect so expect it to be a little off for each.
Question is how much. in my world of gears, bearings, rotating shafts, pins etc.
Tolerance depends on speeds, sizes etc.
And since we have RUBBER FLEXIBLE tires to help absorb and errors tolerance for these 3 things might be larger than you think.
I bet SAE or some euro law has specs on what this tolerance is acceptable.
Maybe a little google searching AUTO WHEEL TOLERANCE DIMENSIONS etc.
ll I know is if you can see it by eye - That is too much runout.
I would fix one time if not too far from where it needs to be.
I would not fix if it had to be move a bunch .
Remember another method of straightening is heat/cold but this ruins finish.
Maybe swap tire from one wheel to another and see where problem goes - with tire or wheel.
Also ask them to check wheel for:
Bead is out of round
Bead is concentric with hub bore
Bead circle is perpendicular to hub bore
Nothing is perfect so expect it to be a little off for each.
Question is how much. in my world of gears, bearings, rotating shafts, pins etc.
Tolerance depends on speeds, sizes etc.
And since we have RUBBER FLEXIBLE tires to help absorb and errors tolerance for these 3 things might be larger than you think.
I bet SAE or some euro law has specs on what this tolerance is acceptable.
Maybe a little google searching AUTO WHEEL TOLERANCE DIMENSIONS etc.
ll I know is if you can see it by eye - That is too much runout.
I would fix one time if not too far from where it needs to be.
I would not fix if it had to be move a bunch .
Remember another method of straightening is heat/cold but this ruins finish.
