Sorry if this is one of those 50+ posts. But I hadn't balanced my tires in about 12,000 miles. I had a rotation at 6k, and this time at 12k, had them BALANCED and rotated. What I want to know is why the old weights were left on the wheels, and then new weights added, for what the machine asked for? Ive balanced tires many times before, and I would always remove ALL old weights, then mount and measure the wheel and spin. So all wheels/tires got a fresh balance. Is this wrong, a bad idea, not necessary? The tire tech that balanced mine said that if they removed the old weights, the machine would ask for the same amount that was removed + whatever the machine asked for. But how so?

My theory:
1. If a tire/wheel weights "x", and the installed weights weigh "y" the total weight is "xy." Then the machine asks for "z" weights, or no weights at all.

2. If the weights are removed first, then the tire/wheel still weights "x." Then the machine asks for "y" So the total weight is "xy."

SO how would the machine know the amount of weight (y, from 1.) that was removed before you mounted it to the machine? Also, tires wear, thus removing material. Hypothetically, if a tire is 31" new, then wears to 30", why would the weights that originally balanced the 31" stay on for a tire that is now 30"?

Everyone will have their opinions Im sure, so lets hear them!!

 

I work at a tire shop...so here's my theory...they either left the old ones on and added like you said....or they reused the old ones. I reuse weights on my tires when I Balance the at work only because they are still good and I feel like I'm taking money from the company even if I pay(weights aren't too expensive)...I woukdnt do reuse on a customer's though.

to your other question. As long as you have proper alignment and suspension is up to date, a tire that was balanced new should be balanced when worn. Hypothetically of course. Most of the time it's off a quarter of an ounce or so

 

The tire store you take your jeep to has lazy employees. If they are going to rebalance they should take the weights off and start from zero applying weights where the machine specifies.

If/when you take them in next time request they remove the old weights before the balance. If you're paying for the balance and rotation then it shouldn't be an odd request.

 

Use balance beads. Problem solved.

 

I agree with all three. Yes, seems it's a "lazy" shop that doesn't want to hassle removing the old weights before balancing. Like you point out, makes no sense. There is really no harm there I suppose, just ounces on a heavy thing anyway. 2 Yes without something odd going on, (the kid locking the breaks and seeing how far he can skid), or maybe a shock issue that reportedly can cause odd wear. Should be OK for a long time. I'm sure I've gone well over 12K without an issue, and I do notice and care. 3 Yea, thought of balance beads myself. The stock alloy wheels that came on one of mine (89-90) they seem to never balance right. I changed rims.

I think your tire guy is full of "IT". The rim is the only constant one might leave weight on for, and it's the tire that may, (or may not) need some correction.