Vibration at 55-70mph

[DOCMORGY]

Hello all

Quick question that may have been answered before, but I still need to know. I just purchased a set of new 17x9 Cobra R replicas & had them mounted with 275-60-17 Eagle GT II tires (also brand new). Now, at 55-75mph, there is a pretty pronounced shake in the steering wheel. I've only put about 300mi on the tires thus far, so don't see any evidence of uneven wear. As far as I know my front-end alignment is okay because I never felt this with my stock 15 in wheels with 35K mi tires on them. Any suggestions? I had them mounted at a reputable Costco with whom I've never had any probs before. Thanks in advance for any advice.

 

[EXRob]

Very common. Have your ball joints inspected, make sure you get a proper alignment and proper wheel balancing. That should correct the problem.

 

[DOCMORGY]

I appreciate the prompt feedback. Why would this problem surface only after installing the new wheels/tires? Due to the increased mass, perhaps? I had never experienced anything like it with my stock wheels/tires. Also, if the ball joints were going, wouldn't I have felt that previously...I doubt that the new tires/wheels have caused them to go faulty since I experienced this shimmy immediately after having them installed. But, I'll check out all of those options with my next service & see what pans out. I wonder if perhaps one of the wheels is out of round from the factory?

 

[kkreit01]

This is very common while plus-sizing on Explorers. My brother had the same with 16" wheels and 55 series rubber. I had the same on a '98 2wd with 17" 55 series rubber. I then put the same set of wheels and tires on a '00 4x4, and didn't have any problems. I've since replaced the tires with some used Michilin 235/65/17, and they are horrible. I don't think anyone can really explain or always fix these shakes. I've also experimented with tire pressure. 28 psi in the front seemed to work best for my crappy tires. I hope to get new ones soon. It is very annoying and frustrating.

 

[X~FACTOR]

Try putting your stocker back on. If the problem disappear then its more than likely that your new set is out of balance.