BTW - this balancer starts at around $9000. I'll bet a dollar to a donut that every tire store owner/manager knows about it.The stores that don't have one are too dang stupid/cheap (funny how stupid and cheap so often go together) to realize the benefit of having one available and are only concerned with grabbing your $7.50 -$15 per wheel for balancing on a machine that costs around $2000-$3000 and will be done in 15 seconds. If you complain about a vibration they'll balance them one or two more times before they begin the song and dance that preludes your frustrated departure. Seen it too many times.
Ya, this machine is expensive and it takes quite a bit more time to balance four tires properly - sometimes the tires and wheels need to be marked, dismounted and re-mounted. So be prepared to pay more - and get more.
Normally I don't recommend customers in the shop but this is one time that I do, unless you are absolutely comfortable with the guys doing the work. Here's why: when the tire/wheel ass'y is mounted to the machine a roller is placed against the tire tread with 1400 lbs. force. The ass'y is then rotated and deflection is measured. Then the ass'y is spun at high speed. At this time a screen appears showing the amount of deflection, in pounds or kilos. A lazy person will let higher numbers flow past. Even Hunter (the manufacturer) has some 'loose' figures. I work on Lincoln-Mercs and while Hunter will tell you 30# on a Navigator tire/wheel is acceptable, I'm here to tell ya that anything over 15# will be coming back to haunt me. Then again, many established Lincoln owners are the epitome of the 'Princess and the Pea'.
So, if 15 lbs. is discernable on a Navigator tire/wheel at, say...70 mph, how many lbs. will it take for your tookus to feel 'shaken and not stirred' on tires half that size? Personally, I'd shoot for under 10 lbs. with 15 lbs. max.