Vibration problem

[juiceman]

Ok, I am at my whits end.

Had a front bearing start going. I replaced the tires and this is how I discovered. Replaced bearing and now I am getting vibration from 30 smooths out alittle at 50 then gets to be a hum like vibration at 60.

I only have 1k miles on the tire. Cooper lifeliner SLE. YEah I know cheap (you get what you pay for) but now I cannot even enjoy the car. My good mechanic had the car for two days and checked everything out and said there was nothing mechanical wrong and that it must be the tires.

Please help with any input.

[Mayhem_J30]

struts?

[aaacomp]

I had a similar problem after changing tires (not wheels). The problem ended up being the lugs had been over-torqued. I replaced all on the front lugs and everything is great.......................:thumbup

[juiceman]

I am going back today, I noticed they do not use a torque bar

If I remember the torque on the j30 lugs is ~75 in-lbs.

I called my mechanic and spoke to the tech and he said it is definately the tires because he ran the car up to speed on the rack and they were so bad the whole car vibrated. He even dialindicated the rims to dsee if they were ok and thye wer

He said that eve though a tire looks ok at hand spin that at speed it can distort.

will update later

[Mayhem_J30]

so they never balanced them? bummer.

[Q45tech]

Remember Nissan has a spec of no more than 20 grams per side for both wheel and tire to balance. Plus any imbalance getter than 5 grams can be felt.The critical measurement is radial force imbalance must be below 15 pounds at 70 mph.

Tire: testing, mounting correctly, and maintenance always costs more than the tires themselves if maintained to spec.

[DrewQ45]

One way to check if it's a tire or rim issue is to move the front wheels to the back and vice versa. If the characteristics changed then you would have narrowed down your problem.

Could also be bent rims.. Try to be on site during wheel balance. Take a good look at the lip of the rims while they spin on the balancing machine. Any oscillation indicates a warped rim. Look at outer edge of tire too... Any oscillation there (while the rim remains steady) indicates warped tire. There are more exact methods to do this but I've always found this to be a quick/cheap method. The establishment should inform you of this if they notice it, but sometimes they don't give a care or are too busy to mention it.

The worst vibrations I've ever felt in a car were caused by driveshaft U-joint bolts being loose.

..Drew (back again).....

[Mayhem_J30]

The worst vibrations I've ever felt in a car were caused by driveshaft U-joint bolts being loose.

ditto

[juiceman]

Just got back. Took off the Cooper and put on BF Goodrich and has somewhat improved but not too much.

The J does not have servicable ujoints does it? I always heard that you had to replace the drive shaft

I don't know what else to do

[juiceman]

Put a good jack under rear diff lift point and got car to idle in gear

The rims look very true

The tires on the other hand do not. Side to side and slight up and down

I do not get this. Should the tires be true from the maker. This is the third set of tires on this car in the last 2K miles. I should have kept with the firstone sh30 but they took too much of a set for my driving habits ( I know all tires do but some much more than others) plus were alittle stiff for my liking

What is going on? Am I just jinxed?

I am bringing it back tomorrow and see what goes. I can't believe I have to make another trip. This time I am standing over the guy.

How much up and down and lateral motion is considered acceptable? In my eyes zero.

Right now the meaning of infiniti is the amount of trips I will waste on tires.

[maxnix]

Quote »Right now the meaning of infiniti is the amount of trips I will waste on tires.[/quote]All the Infiniti is doing is turning the wheels & tires you selected to mount.

Look at Q45tech post on tires to see where your manufacturer ranks in terms of quality.

[juiceman]

I do understand but these bf goodrich are the exact tire that was on the car when I bought it and they were fine but worn

I was just trying to go to base one

It is back in the shop and now they are going to do something else.

BTW Q45tech stated that every manufacturer has some good and bad tires depending on size and model. That is why I went back to the original but to no avail

The infiniti crack is just letting steam off, I love this car but have had a string of thing go wrong lately that can't get resolved. ie After I returned home last night my computer would not start. Seems my week old hard drive crashed. That was number three. I hope its over

[Q45tech]

You must check you wheels without tires to make sure that the wheel alone requires no more than 10 grams per side to zero balance. This is the FACTORY oem spec! If they exceed this they must be repaired or replaced.......I wouldn't change them till they exceed 15 grams on the outside if the inside is less than 10 grams or 24 grams total!

Measuring the lateral or radial out of round will accomplish the same thing just easier and faster to spin up the wheel as how do you measure an error of 0.002".

Nine times out of 10 it is the tires unless you can see the wheels move slightly.

The J30 never came with BFG! If all else fails even the dealers try Michelin MXV4 in a V rating.

Go to an Infinti dealer and let them solve your problems.

[juiceman]

I know BFG was not orginal but it was what was on the car when I bought it and they were smooth as glass otherwise I would not have bought the car. This is the base one I talked about.

I am giving the tire place today to figure it out and if not I will take to an infiniti dealer. This tire place actually felt the problem wher the last one did not. I am also going to upgrade to a pilot if they cannot get it fixed today

My mechanic checked the runout and said they were very true and to spec, what spec I do not know but I did look at the rims spinning and could not see any visible runout. I have a good eye for this type of thing and did not see anything to give me reason to worry

I never could determine the tire that came on the car but all on-line places say they recommend an H rated tire.

What ever tire resolves this issue will be the one to stay on the car as long as they are made.

I love my infiniti, just a bit frustrated. Even the tire manager said the car was so smootha nd quiet that it made the problem more noticeable.

[maxnix]

How many miles has elapsed since the car was dead smooth on the BFGs? Probably significant degradation of the carcass has occurred since then. Checking the wheels to ensure trueness is a compulsory first step.

The H rated XGT will suffice, but you will experience greater performance from the V rated. The 3rd generation XGT were so hard and suffered so much in the rain I quit using them, even though they are a well made tire.

Sorry to hear about your hard drive, but it seems to me that tech failures occur in triples in a short period of time. Wonder what's next?

[Q45tech]

Have your rotors been trued and then mounted [remounted in the 4 possible positions] and indexed to the factory spec of 0.003" in the last 3,000 miles [dealers don't do this nor does anyone without getting paid EXTRA as it takes 20-30 minutes per wheel].

Many times the tire/wheel imbalance couples with the rotor miniwarp to make a varying vibration that comes and goes in intensity and frequency at 50-75 mph.

Thus is the problem with precision vehicles: let them go to pot after 6 years and they need serious attention.

Atlanta has 4 or 5 stores that specilize on tires and balancing problems for high end cars Rolls Royce, Ferrari, MB, BMW etc. We always send our discriminating clients there to hear [or get a second opinion or third opinion] from German guys in Lab Coats......they end up with new wheels [$600 -$1,000 each] and Michelin or Bridgestone $200-$300 tires and a prescription to come back every 90 days for a $100 rebalance. Any curb hits demand a call to 911 and the car immediately air lifted to the doctor [wheel doctor that is].

You need to find a precision tire shop that is used to dealing with serious but subtle problems and people that spend $200,000 on their cars!

[juiceman]

Went up to a michelin and solved 90+% of problems. Tires balanced out with very little weight. I am sold that getting the best pays off in the long run.

The only other thing I am looking into is the rear rotors. Feel they may be slightly warped giving my the vib at certain speeds (60+) I want ot get an indicator and check them out and then resurface as required. I may even replace lugs as someone suggested

Thanks for all the input.

Next job is an induction cleaning. Is $100 ok for the BG version?

[maxnix]

Good going. Now you are on the road to ultimate seat sensitvity, of which Dennis is the guru.

[aaacomp]

I had tires and wheels changed on my Q and when I got it back the vibrations were just to much, so I put the orginals back ,, helped , but it still had vibs at 50 Had tires changed and still had the vibrations..When all around the car with clicker,, couldn't get the all the lugs to click without continuing to tighten.. Changed all lugs and vibrations gone.. The lugs had been over torqued..............................:thumbup

[Q45tech]

The problem with rotor trueing is you may be able to true the rotor but you may be installing it on a warped hub.The spec is 0.0028" max and you will feel a vibration if it is 0.003" which is a tiny infintesimal amount and 1/20 what you can see with you eyes [expert eyes].97% of the time the car comes from the factory well within all specs.

But slam bam tire/brake work may make it worse than when you came in.

Warped rear rotors are felt in the seat and as a fore/aft skip in braking as you slow down. Infiniti used a slightly higher percentage of rear braking force than was common in US cars as the rear drive could handle it [weight balance].

Luckily the J30 suspension is less robust [less camber control] than the Q so you don't have to worry about additional vibration transmitted to a upper link and then to the body plus the isolated front sub frame helps even more.

Check your shocks as they wear pretty fast and 5-6 years and they are worn out [the nitrogen gas leaks out and they don't rebound] floaty upward movement after the bump.

It amazes me that vibration conscious owners resist Michelin wasting time, their body and mind trying to believe a cheaply made tire will do the best job in this area.

But you have to be careful since Michelin makes some really hard HIGHWAY tires like the X and MX4 and the lower quality stuff they make for Sears: Rainforce, etc. These tires are not compatable with Infiniti as you lose too much performance in stopping, handling, and aceleration due to the hard compounds.

Abs helps some but you can find yourself taking 10-15% longer to stop with even a 400 treadwear index [except the Pilot H4 which really is a 300 index during the first half of its life then becomes a 500 after 20,000 miles].

Infiniti came with 170 treadwear and the tires lasted less than 20k [worn to the cords] so any tire that lasts longer is probably worse and will degrade the performance of the car sometimes signifcantly!!!!!!!

It scares me that owners would trade braking distance for tread wear - since they never follow too close.5-10 feet surely matters.

[juiceman]

I guess if we all listened (especially to our parents) the world would be a safer and better place. But as with anyone, experience is the best school.

I will not ever put another tire on any of my cars other than Michelin. I will not skimp on brake pads etc. I do and have always believed in proper maint though and will continue to do so contrary to my wifes thinking

The cooper dealer took the tires back for a full refund.

I got some of the vibe back again today. It is not when braking at all and when the car is running 30+mph I think the tires help tremendously but I still need to do some investigative work.

I do not know if it is the shocks as the car had the system fully extended numerous times yesterday and now today when the system rested overnight, some vibe returned. I did the old method of shock testing by pushing down and watching for the return. Very smooth but as you say this is a high end car so maybe alittle can make a difference.

Also, when the transmission was flushed, they did not replace the filter. Can a transmission provide vibration when the filter is clogged. I am assuming that the vibration is drive line related.

Just exploring all options. Looking for good performance shop who has worked on Z cars and if not one local will go to dealer. Just want to try myself as it is a very good learing experience for the future up keep of the car.

Thanks or all the input!

[Q451990]

I would assume that the transmission mount setup is similar on the J as the Q? Someone help me here.

At least on the Q's the back of the transmission has a rubber mount isolating it from the crossmember that supports it. They tend to sag over time allowing the vibrations to reach the chassis where the crossmember bolts on. It's attached right below the driver's seat, so you have a very direct path to the driver!

You'll tend to notice this vibration a lot when starting out in first with the car facing uphill - at least that's where I felt the improvment when I replaced mine.

Other potential culprits have been mentioned here... driveshaft, rotors (but usually those are a braking only type vibration in my experience).

As far as the transmission - I've heard of torque convertor hunting, where it can't "decide" if it's time to lock up or not and will hunt between the two, but that's usually a bucking feeling in the drivetrain. The T/C can also be unbalanced and cause vibrations, but I don't hear of that very often. If you've already had the flush done I'd have a pan drop and filter replacement. You'll only loose a few quarts of fluid, so they can just top it off.

Glad to see you're making progress!

Heath

[Q45tech]

When you push down on shocks you are feeling 1/3 shock and 2/3rds of the spring. The shock rebound is twice as stiff as the spring so unlike that you and two linebackers can lift the car off the ground on one corner in ONE SECOND.

30 years ago shocks failed on compression not so with modern designs they fail in extension. So the push down test is essentially worthless!

Every car on which we have changed shocks [100's of Qand J] even those with 40k came back saying wow they couldn't believe the difference, some were not as happy since the car no longer floated and weaved.

The other point is you seem to think that a warped rotor only shows up in braking........the pads are always just off the rotor so when ever a high spot comes along a vibration occurs at any speed......if warped in ONLY one tiny spot it occurs at 60-65 mph if half the rotor is displaced it occurs at 30 mph.

You should find a specialists with a Vibration Anaylser which measures the exact frequency and strengths of what assuredly is a series of complex and changing vibrations. Once the parameters are known EXACTLY quite easy to determine the faults as every rotating device has a specific frequency at each speed.

Do you feel the vibration more in the steering wheel, seat or floor board or as a differential betweeen the gas pedal and the floor?

http://www.rion.co.jp/products-e/NA/sou ... bro6-5.htm

[juiceman]

More of a middle of the car seat some and floor board. Only very slight in steering wheel. but now that you mention it when I had the rear of the car lifted and ran in gear both rear rotors rubbed some then not etc. Maybe 50/50

I also remember that not all vibrations are what they seem. When I first bought the car it had a resonant hum that seemed to come from the rear of the car. I changed the belts and noticed that the ac tensioner pulley was going. Replaced and the hum/vib disappeared. So I must take this in consideration. The vib definately changes frequency with speed proportionately.

That said, I will resurface the rear rotors asap. Do you recommend replacing the pads too? They only have about 15K mi on them. OEM by the paperwork was installed.

After that I will look into changing the rear shocks. I think based on the manual that this is a DIY.

I hope to improve this car as much as financially possible in the quickest time possible.

I live 1hr north of tampa and need to find someone good local. I hope that the above solves it. Will inform you when done.

Again thanks to all. As always I feel like you all treat me with respect even though I do not have the experience you do.