I've been trying to track down a slight vibration that begins at 45mph and would like to get your advice or opinion. A couple months ago my beloved Toyo P4's hydroplaned and threw me sideways at 35 mph over a curbed median. I did a 180 and ended up on the other side of the road with a dead engine, a severe misalignment, and a pretty bad shimmy/vibration when driving. So a few days later I hobbled over to the dealer for an alignment and to check for damage. They said the car was fine but the right front wheel was bent. Fine. I ordered and installed a brand new wheel... and that removed most, almost all, of the vibration but I still feel and hear something at 45mph. I'm thinking maybe another wheel is bent. After a few more days my brand new Yokohama Parada SpecX's came so I went and got them installed and got a road force balance at Kauffman Tire, with the understanding that the RFB would certainly tell me which wheel is off. The manager said they're all within spec but needed a little weight repositioned/added. Okkkk, so it's not the wheels. Braking is smooth as butter so I did'nt think it could be the rotors or hubs but at 66k miles I could stand for new rotors anyway. Well I installed the new fronts today and took the opportunity to measure rotor, and then hub, runout with a dial indicator. On the right front, the "damaged" side, I see 5mils of hub runout. On the left front, the "undamaged" side, I see about 2 mils of hub runout. SRT8 spec is 1.2 mils of rotor runout... which shoiuld mean hub runout needs to be some value less than this. Would I feel/hear a slight vibration from this tiny amount of runout?
Lol interesting point. Guess that's why spec'd hub runout is essentially zero. Funny thing is after installing new front rotors, I re-measured runout only to get the same readings. But when I went for a test drive the vibration seems to have gone down a bit! Wth? Hoping when I do the rears that it goes down even more...
Check your end links and A-arms for slight damage... If they are out of whack the slightest, it could cause vibrations...
I'm actually fairly concerned about suspension damage. Even though the vibe is small, it's not 100% like it use to be, maybe 95%. I'm somewhat of a dummy in suspension talk. By end links do you mean pretty much where all the parts bolt together in the pictures? Which would be the A-arms?
End Link = 4 A-Arm = 2 The rear, the end link is not numbered. It is the thin bar running vertical just to the left of 3 and 4..
Excellent, thanks for pointing that out. Any tips on what to look for... torn bushings... anything thats bent? I've been trying to figure that out but it's just not clear to me. The steering wheel is smooth. I feel a little something on the shifter knob... I think... and on the floor under my feet. That says its in the rear right? Sound wise I can't tell where it's coming from, front-rear or side to side.
Look at the bolts. Look for any gaps between to parts that are bolted together. Anything that looks abnormal is likely bad...
Likely but not necessarily. If you could feel it mostly in the steering wheel then you could say it's from the front. Then again, about the only way you won't feel it in the steering wheel is if it's straight up and down and with road force balanced wheels that's going to be unlikely. More likely a runout thing or even more likely like Ron says. If you could drive it somewhere where you don't have traction that would give you some clues.... come to think of it. Try a couple of different tire pressures. Like all the way up at 45lbs or 50lbs (max pressure on the tires) and see what it's like. If it's something like a wobble I'd kind of expect it to be worse at lower pressures than with the tires hard as a rock and riding on a little strip in the center of the tread. Then again, with rock hard tires you might not have a chance to feel the vibration. Might tell you if it's vibrating vertically or horizontally.
Traditional diagnosing seems to have defied logic on this. The problem was indeed the 5 mil runout on my right front hub, yet the steering wheel was smooth as butter. After installing my new hub today I rechecked runout, and it was pretty much unmeasureable on my cheapie Harbor Freight dial indicator. Runout was less than 1 mil!! Spec is 1.2mils. After I get it put back together... the test drive was glass smooth and dead quiet. Lesson learned... hitting a curb hard enough to bend a wheel can bend your hub too. If you have something thats 5 mils wide and set it down, most people wouldn't even be able to see it... yet that much hub runout is enough to cause a slight vibration and noise.
