Talk:Tire balance

Untitled
The following comment is made on the Tire Balance page:

"Strictly speaking, it is mathematically impossible to exactly align the principal axis of the inertia tensor with the axle by adding a finite number of small masses. But in practice, this is exactly how an automotive technician reduces the wobble to an acceptable level when balancing the wheel. The reader may refer to the linked articles on basic engineering mechanics for more details."

I find this surprising. I looked at the two references at the bottom of the page, but did not see anything supporting this claim. Can anyone point me to a reference that supports this please?

Thanks,

Kimaaron (talk) 14:52, 11 May 2009 (UTC)

I know of no such theorem and agree with Kimaaron. The reference by Vance, Rotordynamics of Turbomachinery, page 179, (1988) states "If only two correction planes are used, a flexible rotor can be balanced for only one speed" Halpaugh (talk) 14:25, 13 May 2009 (UTC)

I have deleted the incorrect statement. If someone can produce evidence that it is correct, then they may put it back. But we must see the evidence. The references cited do not discuss this. Or if they do, I was not able to find it. If the original contributor can cite specific pages in the references, I'm willing to look again.

I also added a little more material leading up to that point talking about reaction forces in bearings due to the imbalance.

Kimaaron (talk) 20:56, 12 May 2010 (UTC)

I just reviewed a video (http://www.weightsaver.com/VIDEO/index.htm) explaining the SmartWeight system mentioned towards the end of the main article. After watching that, I suspect that the contributor talking about the impossibility of balancing using a finite number of weights really meant using a finite number of quantized weights. It seems the weights come in increments of 0.25 oz. I suspect, although I'm not 100% sure, that it may not be possible to achieve perfect dynamic balance of a rigid rotor using masses that are multiples of a fixed value (such as the 0.25 oz unit). By the way, the video is quite long - maybe 10 minutes, although I did not time it and it does not display a timer - but it does include a pretty good description of some aspects about balancing tires and it does not hype their product excessively. Kimaaron (talk) 21:21, 12 May 2010 (UTC)

experience
I bought tires at a very small shop that used a bubble balance, and they were not able to get the wobble out after 3 tries. A large chain shop did it with a machine and fixed it first try. The steering wheel actually wobbled at speed. Bachcell (talk) 23:42, 16 June 2010 (UTC)

Bubble balances are Static only they cannot see couple imbalance.

Couple in a tire and wheel assemble on a vehicle is felt in the steering wheel as a pull right and left or a shimmy side to side when driving.

That said the "Tire" can be the point of imbalance. This can be if is side wall strength varies form side to side about the circumference of a tire. Tire Uniformity is like the black magic of imbalance. — Preceding unsigned comment added by 97.78.88.146 (talk) 15:06, 29 September 2014 (UTC)

Bead balancing
Bead balancing seems to be the best of both static and dynamic balancing worlds. It opens up a solution to the fact that previously mentioned there is not way to perfectly balance a wheel and tire being that this would be an infinitely iterative process and you only can adjust 0.25 oz. or so at a time (not quite infinitesimally small). Additionally, once the road is sloped/slanted or the car enters a turn, I would imagine that this would throw off the balance, due to the change in the physics as now the suspension system and its ability to absorb the imbalances/imperfections in the road come into play and become a greater force than the original imbalance in the tire and wheel. Perhaps the dynamic balancer only test to a certain camber degree? 5 or 10? Albeit, these balancing beads are super expensive and I imagine there are quite a few factors: material, size, weight, durability that would come into play when picking the optimal combination. Just thinking these should be addressed as another alternative to balancing. — Preceding unsigned comment added by Mredit15 (talk • contribs) 04:32, 11 August 2014 (UTC)