FYI: what all those letters mean

sneakygroundbuzzard wrote:

CapriRacer wrote:
Wow, there was a lot wrong with that article.

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The dots on the sidewall? Those are supposed to be for uniformity (think runout and you'll be close!), not for balance. The high point of the tire is supposed to be matched up with the low point of the wheel, so the assembly is rounder. Every car manufacturer does that, but the valve hole is only sometimes used to mark the low point of the wheel. - AND - In the replacement market, tires aren't always marked - and red is the more common color.

There's no harm done matching up the dots on the tire with the valve hole on the wheel, but most of the time, it doesn't do anything of value.

And let me state this again. This is about out-of-round, not balance!

I'm going to agree and disagree with you on that

I worked as an auto tech for 25 years and have installed literally tens of thousands of tires.

The dot is there to help with out of round, but out of round will cause an imbalance issue

When mounting tires on modern vehicle wheels a good tire tech will always line up the yellow(most common color ive seen) with the valve stem hole on the wheel.then check the balance of the assembly,if is excessive a good tire tech will then break down the bead and rotate the tire on the wheel assy one quarter of turn and recheck the balance,and keep doing this until he finds the best position of the tire on the wheel assy that gives the best balance while needing the least amount of weights to be added.

Most dealerships and tire specialty shops these days will also use a road force balancer and not just a spin balancer. a road force balancer applies force to the tire/wheel assy while spinning it.this force replicates the tire rolling down the road on a vehicle. this is the best way to get a true balance of the tire wheel assy. and usually when done properly can make for the least amount of weight to be added to the wheel,these machines are so high tech,they will actually tell you if your better off breaking down the tire from the wheel and tell you how far to rotate it in which direction for best possible balance(only way i have tires balanced on my vehicles). they will also tell you if you have an excesive hard spot in a tire and that the tire should be replaced,they will also let you know if your wheel assy is bad and needs to be replaced.

Sorry, but I worked for a major tire manufacturer and we marked the tires at the high point, not the heavy spot. Where to mark was determined by a machine - Tire Uniformity Grader (TUG) - and it was a separate machine from the one that measured imbalance.

Proof? That Road Force machine you mentioned? That's a Hunter Engineering machine and if you watch carefully, the first part of the procedure uses a load wheel that measures the loaded runout (in pounds or Newtons). When that part is done - and before it spins the tire to determine the imbalance - it displays the amount of Road Force - THEN, the spin determines the amount of balance weights (in ounces or grams) and where they are needed. Those are 2 separate operations.