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wobbling like unbalanced tires, but it's not

Hello, I'm hoping someone out there might have some insight to my mysterious problem. It's been going on for a while now so I've accumulated some good details to help with the diagnosis.

So, a little over a year ago I bought new tires for my 2005 Tacoma 4x4 and went up from 265's to 275's with some really nice Pirelli Scorpion ATR's, problem was, I started noticing some serious wobbling in both the steering wheel and the front end in general, it seemed to be at certain speeds. I had done some research online to find that some people had trouble with the balancing on those Scorpions so I naturally thought they needed to be rebalanced. But balance after balance, nothing seemed to improve. In total I went in for balancing 6 times! Even went to different places to make sure I didn't get a machine that was somehow calibrated wrong. I also took it in to the dealer and had them look at everything to make sure all was well with the truck, they said everything looked fine. So my frustration finally came to a head last month when after another balancing the wobble was still there, and I decided to change out the tires thinking I just got a bad set. I test drove the truck right after changing the tires and could feel a little wobble so I took it back and they re-did the balance. Sadly that was rush hour and I couldn't get up to the speeds that I normally felt the wobble. (usually between 55-65mph) The day after switching the tires, (new tires are back to 265's Falken Ziex all season) I took off on a nice road trip up California from San Diego to Lake Tahoe.... wobble was still there. But because the trip was a nice 9 hour drive I had PLENTY of time to notice some of the intricacies of the wobbling. At first I thought the wobbling was speed dependent; BUT after setting the cruise control on the open road at 72mph I started to notice that the wobble would come and go seemingly at random. I started thinking that it may be the road surface but put that theory to rest when I felt the wobble on brand new paving (yes, believe it! California does have some freshly paved roads out there) and on older paving as well. The wobble just seems to come and go even at the same speed and on seemingly similar surfaces. It's driving me crazy! I have to believe it's not the tires that are causing this, but since the dealer can't seem to reproduce the problem when they test drive I'm looking for any help that can point out the right place to look.

So to summarize; the problem seemed to start when I got new tires a year ago, rebalancing 6 times did not solve the problem, put new tires on and still getting the wobble. It doesn't seem to be as dependent on speed or surface, although the worst of it happens in the 55-65mph range. (If I go faster it seems to smooth out, but we're talking 75+) The wobbling is felt and seen in the steering wheel and the front end of the truck. (my gut tells me it's coming from the front right of the vehicle). I even had them do an alignment so it's not that either.

Please can anyone help? I look forward to your sleuthing abilities to help me figure out this conundrum.
Thanks in advance,
Didjeridug
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Comments

  • Sounds like you may have a bent rim. The tire changing machines can bend a rim if the tire technician is not careful. It will usually occur when unmounting the old tires. The amount of deflection can be undetectable to the human eye. A dial indicator will need to be mounted with the detector running along the bead edge of the rim. Then rotate the wheel and measure the amount of deflection. Check inner and outer beads.
  • Thanks Keith, please excuse my ignorance but is the rim on the wheel itself or on the vehicle. I've had the tires rotated and the problem persists so if it feels like it's coming from the front right side would I have them look there first? Is this something the tire shop (Evans Tires) could fix or something I need to take into the dealer?
  • edited February 2012


    Didjeridug--Many folks still seem to use the term "rims" in place of "wheels".
    This dates back to the days (70+ years ago) when the tire's rim and its wheel were separate entities.
    Back in those days, the wooden wheel would usually stay attached to the hub while the tire and its rim were removed for repair or replacement.

    However, the correct term nowadays is "wheel", if we are talking about the metal component to which the tires are attached. A wheel has a rim (the part of the wheel to which the tire is attached), and the rim of the wheel can indeed be bent, but when you hear someone talk about your "rims", they are usually referring to the car's wheels, rather than to the edge (rim) of the wheel.
  • The inertia of a heavy wheel/tire combination can overcome a vehicles chassis. The "death wobble" that can occur from oversized tires is very similar to the wobble caused by weak A frame bushings and radius rods. I cannot calculate the limits and won't guess that your problem is the result of exceeding the limits of the vehicles suspension system but it sounds very familiar. Several 4x4 vehicles have been brought in with serious handling problems at highway speeds when the suspension was in perfect condition but massive tires were installed. When OE wheels and tires were installed handling was like new.
  • "Rim" and "wheel" are interchangable except for split truck (or heavy equipment) wheels.

    Anyway, there is a technique called "roda force balancing" that balances the wheel & tire by psinning them with simulated road force applied. It presses a spinning drum against the tread while it runs. These can detect internal defects, poor concentricity, and other problems that regular balancing machines cannot. I'd be inclined to try spinning the wheels on one of these machines first. The store where you bought the tires may even have one.
  • Thanks for everyone's input. I'm hoping for a little more if possible. I called the tire shop and asked about "road force balancing" as "the same mountain bike" suggested... they do have that machine available, but while discussing the problem with them... the guy said it's pretty much impossible to bend the rim while changing the tires out. Since a few of you have stated otherwise, I'm hoping to get some more input on this possibility. This whole problem started after they changed the tires so I'm inclined to believe that yes, they did do something when swapping tires, but the more info I have, the more confident I can be in challenging the tire shop.
  • If you can, help yourself by jacking up one wheel at a time and then spin it with something such as a small grinding stone or a wire brush wheel in the chuck of a drill motor applied to the tire tread. A helper could run the drill motor for you. Then compare the passing tire tread with the ground or pavement underneath. This might help you to lead the experts to the source of the problem. At the least, it would tell you what is not the cause of the problem.
  • I know you have had the tires balanced 100 times, has any of them been on a "ROAD FORCE" balancer?? This is a special tire balancer that actually puts a roller against the tire to simulate the road. These are much better and finding bent rims, and poor tires then the older spin units. Also if you have a steering stabilizer on this truck (if you look under the front end it looks like a sideways mounted shock absorber). I would replace it with a new unit, maybe a higher performance unit. Dealing with Jeeps I have seen this cure a lot of issues.
  • This doesn't sound like a tire issue. It's a little unclear, but it sounded like the OP rotated tires from to rear and the problem stayed in the front end.

    I'm thinking CV joints.
  • Hopefully my link will work. This OP's problem seems significant enough that a "cure" is on the market.

    http://www.automedia.com/Balance_Tires/ccr20001001rt/1

    Didn't Mercedes Benz have a similar solution 70 years ago.
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