Front end vibration - Diesel Forum

dleffman · 05-23-2006, 12:26 AM

have front end vibtation at 45-65 mph. Replaced tires w/30000 with new steeltex replacements from recall - still vibtating with balanced tires on factory rims - IDEAS? (Note that 93 m'tang serviced at same forestone store has similar issues from 45-60 mph).

Thanks.

gregrob · 05-23-2006, 04:34 AM

Are you an attorney, just curious ?

Hoowasat · 05-23-2006, 04:15 PM

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Note that 93 m'tang serviced at same forestone store has similar issues from 45-60 mph.

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Doesn't that ring a bell in your head? I would be suspect of the balancing machine calibration at that store ... assuming, of course, that the same machine was used for both vehicles. Do other customers of that store report the same problem?

MotionMan · 05-23-2006, 04:23 PM

I would go to wheel balance next, heck it could be a wheel bearing but if you can't see the problem you can only eliminate the source. It could be one of a dozen things but at 30k you should be rotating them and balancing them anyway, maybe they threw a weight. I bet this is it, unless you hit something things don't change that fast, well not usually.

dleffman · 05-25-2006, 12:26 AM

Thanks for the responses. As for the replies, the answers are as follows:

1. Yes

2. I had previously considered that the Store's machinery was off - but there are multiple machines and to conclude that a M'tang with over 100K and a uerathane suspension - lowered - new tie rods and upper and lower control arms rear) would react the same as a bone stock vehicle a MFG's specs is far too much of a logical leap to make. I did notice some tread "blocking wear" - uneven blocks on edge of tires (a symptom that showed up on the M'tang during its factory original first set of tires - but just recently showed on the EX) and was hoping to gain insight as to the potential cause of the "blocking" from esperiences of others who have linked vibrtations and the cause of blocking (maybe improper alignment adjustments - as the M'tang lost that characteristic begore the suspension cchange through the addition of fully adjustable camber and caster plates ( which does not apply to a leaf spring set up tp my knoweldge).

3. I taking the EX in for its last ESP service (as almost out of warranty) and will graciously pay the dealership to try to fix it after inquiring as to tire wear analysis explanations - assumes someone reallly understands the leaf spring - tire wear correlation.

Thanks again.

David

DOC4444 · 05-26-2006, 08:24 PM

The wear pattern you describe is typically under-inflation unless you don't have "E" load range tires. If you have stock size "D"s, you don't have enough tire. If you have not replaced the OEM shocks, you will eventually see "cupping" across the face of the whole tread.

Fix what's tearing up your tires, first (if you have "E"s already). If they are not mostly round, the truck will shake even if they are perfectly balanced.

DOC

dleffman · 05-30-2006, 11:36 PM

Thanks Doc.

All sets are Load Range E replacements for the D recalls.

I have not replaced stock shocks - but will do so. Any ideas? Bilstiens? Rancho? OEM?

dleffman · 09-05-2006, 11:31 PM

Well after several balances which did not work, replacement of rear U joints eliminated vibration

**Beast** · 09-06-2006, 07:47 AM

Glad it took care of your problem. Vibrations can be annoying.

barlowcw · 09-09-2006, 09:43 PM

I had a similar situation. Bought new tires and noticed on the trip home a vibration beginning at 55 and increasing as I went faster. Took the Excursion back to get the tires re-balanced. Same result.

The problem for me was a bad drivers side ball joint. I replaced the ball joint myself and the vibration went away.

We need to make a list of possible causes of vibration after a new set of tires are installed and balance is proven good.

1. Bad ball joints
2. Bad rear U joints
3. Shocks are in need of replacing.

In my case I had the new shocks already. I was suspecting the U joints but the ball joint was found easily and fixing that proved good.

DOC4444 · 09-10-2006, 10:33 AM

But what about the "other" problem, the uneven tire wear? I'm glad you found the vibration source, driveshaft u-joints, but if your tires are showing "cupping" on both shoulders, fixing the joints won't solve the tire problem. It sounds like they are running underinflated. If you had some other problem, alignment, joints, etc., it probably would not be so consistent.

I have found, using a tire pyrometer that, depending on brand, close to stock size "E" load tires have a wide optimal pressure range when run on an empty 4WD 7.3 PSD Ex.

16" Pirelli Scorpians ATs: Anything over 58 PSI F/R cold results in center temps much higher than the shoulders. (Even temps mean even wear.)

17" BFG Rugged Trails: 72 PSI cold F/R is needed to simply get even temps over the face of the tread.

You would think it would be the other way around (lower profile, stiffer tire usually would need less air), but I have the data to prove it.

DOC4444

barlowcw · 09-10-2006, 10:33 PM

Doc4444,

Thanks for the info on the tire infalation and tread heat measurments. I wore out a set of 16" Pirelli Scorpians ATs in less than 30,000 miles. I ran them at 60-65 psi. The center wore out before I could adjust the pressure low enough to compensate. I do not reccomend these tires. The tires were loud and did not wear very good.

Having a tire pyrometer would be nice. Right now I'm running 16 inch BF long trails a D rated tire inflated to 55 psi. I am hoping for better results than the E rated Pirelli's.

I have read other posts negative about the long trails, not wear related though. The complaint was trouble getting the tires balanced.

I'm planing on having the tires rotated every 6,000 miles hoping that will extend the life a bit.

How expensive is a tire pyrometer and where could I get one?

Mudraga · 09-11-2006, 10:19 AM

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How expensive is a tire pyrometer and where could I get one?

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You have one already! Use your hand. Sure it isn't perfect, but it WILL tell you if the outside is hotter than the middle when you lay it across the tire. We don't need no stinking gauges! [img]/ubbthreads/images/graemlins/biggrin.gif[/img] That's how we did it on the Legend cars I used to pit crew for. Worked great.

dleffman · 09-13-2006, 10:57 PM

As I replaced the tires I really did not pay any more attention to it. I may put old ones back on and see. Perhaps the cupping was in my mind as an excuse to blane the tombstones. The second set are running fines - as though the Ex was "new" What a relief.