Tires not round


#1

Trying to track down shaking esp. at highway speeds, all tires having been recently balanced, I checked all 4 for roundness. Two are uneven by 1/8" or more in spots. I wonder if removing the wheels, deflating the tires, breaking the beads free of the rims (is this doable at home?), steel wooling any rust (these are steel rims), using some soapy water on the bead-rim contact area, and reinflating the tires to or beyond their recommended maximum would seat the tires better and eliminate the problem.

I have done this kind of thing many times to get bicycle tires to seat evenly on the rims. Is it feasible to do with car tires?


#2

It’s unusual for tires to be this off. How old are they?

Check your lug nuts and the wheels where the nuts seat. You could have rust there, or the wrong type of nuts which don’t match the wheel. This could cause the wheel to be slightly off.


#3

Tires are about 4 years old. Have never been as smooth riding as I expected from Goodyear.

Lug nuts all original, wheels mounted by me using torque wrench. The out-of-roundness is at the tire tread, not the wheels.

Is it even possible to, at home, break the tire free from the wheel? Not remove the tire, just see some space between tire and mounting surface of the wheel?


#4

I have broken tire beads from the rim with an old bumper jack years ago. If you have 45 series tires or shorter you may not be able to break the bead.

Check with your tire shop on the price of “road force balancing”. If the tires have run-out, the high or low spot can be marked so that it can be remounted to mach the run-out in the wheel. The tire is then taken to the tire machine and re-indexed as per the markings, then recheck and balanced. This can reduce the run-out to acceptable limits.


#5

If you have another car available it’s possible to break the beads with a length of 2 X 8 lumber. Place it across the tire after deflation with the edge of the lumber near the wheel rim and slowly drive another car up onto the board while carefully watching out of an open drivers window.

This is much easier to do with steel rims. Alloys can be tougher and may lead to profanity.
Kind of been there and done that a few times while in a jam.


#6

Thanks for your responses. I’ll give it a try at home.

Any advice on what to use to lubricate the tire-wheel interface?


#7

Right or wrong I use dawn dishwashing liquid .


#8

Agree w @Sloepoke, soap based lube. The tire guys use a slimy soap lube called RuGlyde (sp??) but liquid dish soap works great, washes off and dries so its no longer slippery. Don’t use WD-40 or any oil based lubes.


#9

Reseating the tires to the rims will not alter an out of round condition. And radials are rarely out of round. Are your tires bias ply? How did you determine that the tires were1/8" out of round?


#10

Have the tires checked for a belt separation.


#11

I expect a tire 1/8 " out of round would definitely cause noticeable problems. It sounds like you’ve got to the bottom of the cause of the vibration. Good for you. If this happened to me, probably the first thing I’d do is just remove, then remount the wheel, paying att’n to the recommended lug nut tightening sequence for those wheels. Usually it is to tighten in a star pattern or criss cross pattern to 1/3 the final torque. Then to 2/3, then to the final torque. Do this by hand. Then re-measure it for out of roundness.


#12

A 1/8" difference in tread is quite large. Can you tell us what model of Goodyear tire you have and what car they’re on?


#13

@shanonia

Please post a picture of your tires

If they’re 1/8" out of round, we should be able to see it

Are the tires choppy?

Is the tread bulging . . . ?!


#14

When mounting economy type tires I sometimes see 1/8" of tread movement on the balancer, it looks like defective tires and the customer will be back the next day dissatisfied but the tires balance OK and there are no complaints.

After the OP re-positions these tires they will need to be balanced. This is a lot of work considering that this can be accomplished in less than an hour with modern equipment.


#15

I don’t get what reseating the tires in a different relative position on the rims would accomplish, other than ruining the balance.


#16

I agree unless it can be visibly seen that there are areas that the tire isn’t properly seated on the rim . If that is the case , breaking the bead on one side at a time & cleaning the bead & rim & re-inflating & then doing the other side shouldn’t ruin the balance . I have seen a few tires that didn’t appear properly seated all the way around the rim but not many & don’t know if that would cause the tire to be out of round at the tread .


#17

I searched in vain for any in formation on tire concentricity standards. Does anybody here have any info on this? Capriracer?
1/8" sounds high, but never having checked a tire for concentricity and never having had to chase down a standard, I’m guessing in the dark. :confused:


#18

NYBo said: "I don’t get what reseating the tires in a different relative position on the rims would accomplish, other than ruining the balance. "

Wheels are not round. They have high spots and low spots - and if you can match the high spot of the tire with the low spot of the wheel, the assembly is more round. This process is called “match mounting”.

The same mountain bike said: "I searched in vain for any in formation on tire concentricity standards. Does anybody here have any info on this? Capriracer? … "

There are no specs in this area. Tire uniformity, wheel uniformity, roundness, balance, etc. are not regulated in any way. Nor should there be. The levels that cause problems not only vary from vehicle to vehicle, and driver to driver, but have changed dramatically from the past and will likely continue into the future.

And to add some more fuel to the fire: The OP didn’t tell us what he measured as an 1/8". It is pretty common for folks to measure the sidewall area in the lateral direction - and that is exactly the wrong area and wrong direction. Not only does the sidewall hardly contribute at all to “Out of Roundness” of the tread, it is the radial direction (Up and Down) that is the important direction.

Personally, I think the OP is going about this all wrong. If he is serious about getting rid of the vibration that he claims was there 4 years ago when the tires were new, he ought to have done it then, and he ought to have a Hunter GSP9700 RoadForce balancer tell him which tire(s?) are bad and by how much and what he can expect as an outcome (Yes, the GSP9700 can do that!)

Frankly, this sounds more like someone who is looking for a project to work on where he doesn’t have to spend money - rather than an annoying problem that needs to be fixed.


#19

I’ve always been a stickler for smoothness, so I would also be aggravated and seeking a solution.

But I really like the suggestion of a road force balancer. They really can detect tire problems that regular spin balancers cannot. I’ve always been a strong advocate of these machines for diagnosing problems with smooth operation.


#20

I just recently had our tires balanced and rotated and noticed a distinct improvement. I did not have to drive the other vehicle up on a board and remove and replace tires one at a time and still have to go have them balanced.
Just go to a tire shop and have it done correctly and safe.

I also have this mental image of the board breaking or the wheel and tire flipping up and damaging the vehicle.