vibes at 80+ mph, are my expectations off? Tire balance question

[mapper]

ISSUE HAD BEEN SOLVED. IT WAS A BAD TIRE. Not a problem with the truck.

Yes, I'm mostly a car guy. But I've been in plenty of trucks running well at 80 so I'm assuming a Gen 2.5 Montero is capable of such feats. Am I wrong?

Story:
Took a trip to San Rafael Swell last weekend and the shaking at 70+mph on the interstate was nearly unbearable. Made me angry. Speed limit is 75 here. Did the return trip on the interstate with cruise at 65...which also makes me angry (but did allow me to get 20 MPGs!!)

So when I got back to town I had Discount rebalance my tires. The guy said they were definitely out of balance and it appeared some weights has fallen off. Interesting because the same shop mounted and balanced the tires only 2 weeks prior. Anyway, this time he used different style weights.

Definitely improved the driving at 65-75 mph. However now I find a fair bit of shaking at 80 mph. Is it wrong of me to expect a smooth ride with 31" A/T tires at 80 mph? Tires are Hankook Dynapro At/m. I also now have a low speed wobble in the steering wheel at about 40-45 mph that definitely was not present before. Looking at the wheel/tire combo I see one front tire has 3 consecutive weights on it to the tune of 70 grams (2.5 ounces)!! I used to balance car tires and this would be VERY BAD form in the car tire world. Rotating the tire on the rim would usually eliminate the need for such blunt force weighting on car tires.

Should I accept this on a truck tire? As it stands I'm planning to take the tires back to be rebalanced again. It's annoying and making me feel kind of like an ************ for going in a 3rd time. So, as stated in the title, are my expectations off? Should the Gen 2.5 with 31" ATs be running smooth at 80?

I also had my alignment shop and mechanic check out the suspension. Both shops said there were no problems with suspension. Despite that I feel some play in the steering wheel and slight knocking over bumps. I'm getting ready to replace brake discs and put new sway bar links. I'm and wondering if re-adjusting/tightening the wheel bearings will help the steering wheel play situation and maybe improve my high speed vibes?

A penny for your thoughts.

 

[FordGuy1]

You should be able to balance tires that small no problem, I have 35" Toyos that my guys balanced and they are perfect at 80+. Sometime you just need to find a guy who really know how to balance. The quality of the balancer and it being properly calibrated also make a difference.

 

[ZMagic97]

what year vehicle and how many miles. Could be suspension components instead of the tires. I can comfortable do 85 in my lifted JK with 35s. It's an 08 with only 38,000 miles: all the suspension is tight.

 

[mapper]

Truck is a 98 with 178k. Not new...but nothing ancient either.

 

[PirateMcGee]

Could be the wheel bearings. Jack up the front and sit facing the wheel/tire; grab the tire top and bottom and push/pull to feel for movement.

 

[mapper]

Could be the wheel bearings. Jack up the front and sit facing the wheel/tire; grab the tire top and bottom and push/pull to feel for movement.

There is some movement which is why I was curious about the bearing question. I'm under the impression that can be adjusted. Is that correct? Or should I be adding bearings to my RockAuto shopping cart?

 

[ZMagic97]

I'd just do new wheel bearings. Worth the investment IMO.

 

[off-roader]

I'd just do new wheel bearings. Worth the investment IMO.

Use OE bearings & races if at all possible. Also check your idler/pitman arms for wear. At 178k it's possibly due for new bushings and other items.

 

[mapper]

Made another appointment with Discount to try balancing tires again. I do think, first and foremost, I have an issue of lousy tire balancing, but I wanted to make sure I wan't having too high of an expectation for truck tires OR the montero chassis. Some cars are just inherently susceptible to vibration due to the design. I used to work at a BMW shop and the pre E30 3-series car (I forget the model designation) was notorious terrible chassis resonance.

In any case I went ahead and adjusted the bearings before making dinner tonight. Actually a very simple, but marginally messy, job. Mine had some play and are a bit tighter now. Took me about a half hour start to finish, reading post number 10 from this thread as I went:

http://www2.pajeroclub.com.au/forum/showthread.php?t=21573

Will see on the way to work tomorrow if it helped at all. It my be a good investment to just put new ones in but I really dislike changing parts just for the sake of changing parts.

As far as I can tell my steering and suspension joints are good. I checked them personally and now have had two separate mechanics confirm as much. Certainly wouldn't hurt to have new ones, especially the bushings, as Offroader notes. But again, not into changing stuff out without trying to dig down to the real culprits first.

My swaybar links, on the other hand are definitely toast.

 

[nwoods]

I'd just do new wheel bearings. Worth the investment IMO.

Yup, happening to me right now too. Low speed wobble, not high speed.

 

[seanpistol]

I have Dynapro AT Ms and I have had them balanced three times trying to get rid of their high speed shake. I've wondered if it's a characteristic of the tire along with people that don't know how to balance...

They have worn so nicely and have 50k on them with plenty of life left. But they are so noisy for such a not aggressive tread, and the balance issue is frustrating... new tires soon.

 

[mapper]

Yup, happening to me right now too. Low speed wobble, not high speed.

I primarily have a high speed thing going on. I tightened the bearings a bit last night. I no longer have the intermediate (40-45mph) "wobble". The truck drives better down the highway now, actually tracks/responds very nicely...unfortunately the tighter bearings transmit MORE of the higher speed vibrations. Hopefully the Discount boys can get these figured out.

I think the slower speed wobble was from the way they weighted the left front tire. There was almost 3 ounces on the outside AND inside of the rim in the exact same spot, 6 ounces total in one spot on the tire. Like I said, I don't know truck tires, but that seems totally wrong/lazily done to me. Spoke with the manager yesterday and hopefully he'll put someone on it who has some more skill.

This is actually reminding me that last spring when I switched out snow tires on my Volvo I had the same problem at a different Discount Tire. They kept telling me the tire was bad but I knew it drove smooth the previous fall. Took 3 trips but they finally got it. I generally like Discount but at this point I'm getting ready to move on.

 

[FordGuy1]

I primarily have a high speed thing going on. I tightened the bearings a bit last night. I no longer have the intermediate (40-45mph) "wobble". The truck drives better down the highway now, actually tracks/responds very nicely...unfortunately the tighter bearings transmit MORE of the higher speed vibrations. Hopefully the Discount boys can get these figured out.

I think the slower speed wobble was from the way they weighted the left front tire. There was almost 3 ounces on the outside AND inside of the rim in the exact same spot, 6 ounces total in one spot on the tire. Like I said, I don't know truck tires, but that seems totally wrong/lazily done to me. Spoke with the manager yesterday and hopefully he'll put someone on it who has some more skill.

This is actually reminding me that last spring when I switched out snow tires on my Volvo I had the same problem at a different Discount Tire. They kept telling me the tire was bad but I knew it drove smooth the previous fall. Took 3 trips but they finally got it. I generally like Discount but at this point I'm getting ready to move on.

Did you have any vibs or shaking before the tires were replaced? If it was fine then I think it could only be your tires. Your bearings can be pretty loose and not cause vibs but it will really amplify other issues.

 

[mapper]

Did you have any vibs or shaking before the tires were replaced? If it was fine then I think it could only be your tires. Your bearings can be pretty loose and not cause vibs but it will really amplify other issues.

I recently purchased the truck and the tires on it were garbage; cupped and unevenly worn. Drove pretty smooth straight ahead, tough to recall but better than these, I believe. They were hell around curves though. Those tires were also the wrong size, P-rated and too small by a fair bit, so I have no clue if they were garbage as a result of being on this truck or another prior to this one. I assumed the whole front end needed reworking based on those tires. This is why I checked over the front end and asked each of the mechanics who worked on it to check the front end as well. I was surprised when I checked it and nothing seemed obviously loose and again when the first told me it all looked good. I never drove a longer trip on the previous tires.

Fast forward to installing proper tires (31x10.5 C-rated). The truck feels much more like it should in every aspect...aside from the high speed vibes we are now discussing.

I had been especially concerned about the shocks because of the tire cupping and some body roll the truck previously had. Proper tires completely cured the body roll and every other "standard" type shock test indicates they are working as they should.

When I had it aligned I asked them to check the front end. They gave it a clean bill of health. The same shop recently condemned a lower ball joint on my Volvo and I can tell you that ball joint, though not new, still has a lot of life. The alignment definitely helped some of the initial vibrations I was feeling.

My commute is only about 4 mins of freeway time through an interchange. You really have a to work a truck like the montero to get up to 80 on that stretch (easier with the too small tires). So I can't definitively comment one way or another about the old tires. It wasn't until I tried to leave town on the interstate in Friday afternoon traffic, with the 31s, that I noticed how much it all vibrated. After just over an hour dealing with traffic and the vibration my nerves were totally fried. I needed a margarita :sombrero: but had too many miles left to go.

 

[mapper]

Well, third time balancing was not a charm. Basically exact same vibrations. They fixed the obscene amount of weight on the one wheel by spinning the tire on the rim. Unfortunately while driving back from the shop on the highway I heard what sounded like a wheel weight flying off and hitting the wheel well.

I'm going to do my brakes before I worry about it any more. Then I'll probably take the tires elsewhere.

Seems implausible to me that brakes could be implicated but maybe the warped rotors are somewhat to blame. If the vibrations were just coming through the steering I'd be more inclined to blame the steering but the whole truck is shaking, can feel it in my calves. Getting frustrated with this truck. May be a much shorter ownership experience than I thought.