Problem with tires/rims/balancing
 

Basically, I just bought some new 17" rims from Dayle about 3 weeks ago and new Pirelli tires. From the beginning, they did not seeem to be balanced properly. The car would start to vibrate around 55-60mph, subside slightly between 65-70mph, then start vibrating again. I can feel it mainly in the steering wheel but the whole car seems to be vibrating as well. Took them off and had them rebalanced - same problem. So what are the possible problems and solutions here? Tires? Rims? Alignment? I am more than a little irritated at this point so any ideas would be welcome. Thanks!!

Is the shop doing a full dynamic balance (weights on outside and inside of wheel)? If not, take it to a shop that will do that. If the rim won't take weights on the outer lip of the rim, have the shop put sticky weights just behind the spokes (and install clamp weights or sticky weights at the inner lip of the rim too).

If that shop did do a full dynamic balance, then you need to take the wheels back there and check the wheels for out-of-round and runout. Out of round and runout can be due to rims and/or tires. The best way to tell if its the rim is to remove the tire and put the rim on a balancing machine that has runout gauges on it. The newer Hunter balancing systems seem to be the only machines that have the gauges to measure runout.

Also, make sure that you are using good quality lugnuts. Crappy lugnuts will allow the wheel to wander which can cause vibration.

First, alignment does not cause vibration.

Sometimes the person(s) balancing the tires needs to be shot. I've seen so many balance problems occur due to operator error in just mounting the tire to the balancer. A lot of wheels require that the wheel be 'back-coned' when mounted on the balancer. But, for some reason, most guys will slap the wheel on the balancer then place the cone on from the front side of the wheel. This many times does not properly center the wheel on the balance arbor and will cause the wheel to spin off center.

Beyond that, you should seek out this balancer: http://www.gsp9700.com/pub/search/FindGSP9700.cfm
It applies 1000 lb. against the tread of the tire and spins it slowly, measuring deflection against the drive roller. If the tire/wheel combination has excessive 'road force' issues it will direct the operator to measure the wheel run-out. After that is done it will provide tow positions, one for the tire and one for the wheel. The operator then deflates the tire, breaks the bead loose and aligns the two marks. This will place the tire/wheel in its best position for road force run-out. After this is done the tire/wheel is placed back on the balancer for final balancing.

Note: normally the balancer considers 30 lbs. or less to be acceptable. Don't let them get away with that. Shoot for 15 lbs or less, under ten is great!

This type of balancing costs more (probably figure around $75 for 4 tires) but the results are fantastic. I do this stuff for a living, and have for more years than I care to admit. The process is a bit labor intensive but you get more for your money than you would with a 20 second per tire balance.

Hey ... thanks for the info - I used the link to find a place here locally and made an appointment for tomorrow morning. Didn't ask how much they are going to charge but I really don't care at this point, I just want to get the car right. Thanks again!!

Great! Just pay attention to what they do and don't accept over 15 lbs. road force without them trying to reposition the tire on the wheel. When the tire first spins the screen result will have a figure near the top left that will read "xx lbs.", that's what you need to watch. Not all tires will make the grade but if they're brand new I would contact the manufacturer/seller for a replacement for a tire that won't go below 20 lbs.

Okay, just got back and one tire was at 35lbs. They repositioned the tire on the rim and now it as 15lbs. I can still feel the vibration at higher speeds so I called TireRack and they are sending a new tire to be installed. All the rims checked out. Can one tire cause that much vibration if they got it to 15lbs? Thanks again Beav!

Sometimes. Even though the tire has less road force since repositioning there is an obvious heavy spot in the tire. This heavy spot will slap the road with each revolution and sometimes is bad enough that repositioning can't quite compensate. You see, you can balance an egg-shaped tire but it you can't make it spin against the road smoothly. Repositioning cures the offset and balance cures the centrifugal forces but the slapping can only be cured by replacement.

Have you always had a vibration problem or just since installing these tires/wheels?

Other times the wheels can be the culprit. If the wheel isn't 'hub-centric' it centers itself un the hub purely by the location of the bolt holes rather than the center hole. The balancer normally uses the center hole (although there are adapters available to mount by the lug holes) and if the bolt holes are a bit off a vibration results.