Vibration above 60km/h

[msommers]

I've just developed a vibration in my vehicle recently but it's really bizarre. I had Duratracs put on about 8,000kms ago or so and only in the last few days have I noticed this vibration, which is more like a studder above 60km/h, maybe like very mild washboard. It kind of feels like the road is very slightly bumpy and it's trasmitting through the vehicle. The place I feel it most is my seat, not my steering wheel which is actually very subtle.

I up'd the PSI from 33->45 in my Duratrac load E which should be fine but that was over 1,000km ago easily. I also rotated my tires with my oil about 6,000kms ago. Any sort of "offroading" at site with a lot of mud etc was at minimum 900kms ago (likely 1,100km or so) and I've cleaned the suspension and underneath thoroughly a few times now.

Does this sound like textbook unbalanced tire(s) issue? To me it does but given how much I've driven on the tires I'm not entirely sure what to think.

[VaN_HaMMeRSTeiN]

Weight prolly fell off your wheels, get them balanced.

[FraserB]

45 psi seems pretty high. I'd lower them down to where a chalk test has then wearing evenly.

If re-balancing doesn't help, check all the driveshaft joints.

[msommers]

Unbelievably, Gary from Urban South was able to get me in tomorrow morning to check out the balance - those guys are amazing.

I was reading a lot that the higher load tires should have more PSI put in them than the C loads. That was on the 4runner forum where someone was talking about the duratracs. Maybe I'll have to check that out more.

I know I have to lube up the driveshaft on this next oil change in ~2,000km so maybe I'll do that a bit earlier as well. I think at some point very soon I'm going to change the transfer case and F/R diffs oils.

[FraserB]

Tire inflation should be set so that a band of chalk across the tire will wear off evenly.

How many km on it now?

[msommers]

You're right I should grab some chalk and check it that way. Overall they probably have ~8,000 km on them.

[Supa Dexta]

Originally posted by FraserB
45 psi seems pretty high. I'd lower them down to where a chalk test has then wearing evenly.

If re-balancing doesn't help, check all the driveshaft joints.

Its an E tire, 10 ply - they need air.. Mine are at 55/65.. But besides running dirt roads a lot, why are you running E's on a 4 runner? You can run them lower on air, but they are designed for loads and psi..

Hit any pot holes lately? Might have broke a belt.

Mud stuck on the inner rim at all?

[msommers]

All the lugs look in good shape and if there was mud on the inside of the rim, I should have noticed it on the drive home!

Running an E tire was for a few reasons. It's a more sturdy, puncture resistant tire and was only marginally more expensive. Secondly, this summer I plan to do a bunch of camping in some hard to reach spots and again the puncture resistance against rocks is preferred since I don't want to be changing tires out in the bush! Lower psi will help with that and they're able to handle it as you've mentioned. Some guys on the 4runner forum were complaining about the C load and no one was complaining about the E load so that was another attributing factor.

Are you towing a lot? 65 seems pretty high depending on what tire you're running.

[Kloubek]

It does indeed sound like a balancing issue. The suggestion a weight fell off seems pretty sound.

I had this exact same issue before myself; a wheel was not properly balanced, but it would not show itself until 70-80k.

After 60k, does the vibration get worse as you increase speed? Ie: What is it like at 120k on the highway? If it is a misbalance, I would expect at 120 for it to be shaking your vehicle like a mad bull....

[msommers]

So turns out it was just a minor imbalance on a couple of the tires and I also didn't clean the rims as well as I thought. All fixed up though. Thanks again, Gary!

[spikerS]

I was also going to suggest checking for worn ball joints. If they get a little too much play in them, those can rattle around too.

glad to hear it all worked out.

[msommers]

The 4runner only has ~39,000km on it but worth checking out, thanks Spikers!