Originally Posted By: LT4 Vette
Quote:
i never needed more than 1 oz per wheel of weight and the car never had any balance issues whatsoever.
Is the very small weight (1 0z. ) needed to balance that tire any indication of tire quality ?
I've seen some no-name tires with multiple wheel weights needed to balance the tire.
There are three elements to "Quality":
1) Design Quality: That is, how "robust" (I really hate that word!) is the design. In another thread there's a discussion about the number of plies in a tire - and that would be an example of "Design Quality".
2) Manufacturing Quality: That is, how good the manufacturing process is in preventing things that should not happen. This is what we usually think of as "defect prevention". So unless you analyze lots of tires - X ray, visual inspection, shearography, etc. - you won't be able to assess this.
3) Manufacturing Consistency: That is, how much different is one sample from another - and this is the area this question is addressing. Of course, balance is one of those properties that is easily measured and might be an indicator of consistency.
But there are a couple of things that affect the balance:
1) The balance of the rim itself. Many people don't think about the rim when they discuss tire balance, but it's always there. One of the interesting things is that a rim's imbalance could both make the tire and rim assembly require more weight to balance - or less weight - depending on the relative position of the imbalance of the 2 components. So if you see a lot of balance weights, you can't really be sure if you are seeing the rim or the tire or the combination (Although it is generally the tire requires more weight.)
2) Consistency: The only way to assess that is to measure a large number of sample and then construct statistical comparisons. Very tedious.
3) Sorting: Most tire manufacturers have machinery in their factories that measure various properties of tires. Balance, uniformity, and bulges are common things that are measured.
If you can measure it, you can sort it (that is remove items with high values) Reports from several former Michelin employees seem to point to a lot of scrap tires at Michelin's plants - this seems to point to sorting as one way Michelin maintains its "Quality".
From my perspective, this is all a matter of cost. If you can get someone to pay 30% more for your product, you can affort to throw away worst 10% of your production - and anyone could make their quality look good if they could throw away the worst ones. But if you can't afford it, then you can always sort at the dealership level - which has an unfortunate side effect.