"Lumpy" Tires

The one time I had a similar situation was when I drove my father in-law's car after it sat unused for several years. Literally the tires had a slight flat spot set in the steel belts. It took about a month of driving for them to not have a bump after starting. Since the vehicle was a gift, I didn't complain.

I have had a number of sets of new tires from major name brands over the years with factory defects.

The most common one is being manufactured off center from the center axis of rotation. That is they are physically round and balance out perfectly on the balancing machine but if you watch them while they are spinning on the balancing machine you can clearly see the center axis of the tire does not match the center axis of the shaft they are spinning on.

That creates an odd wobbling and shaking feeling at different speeds that the high school level tire monkeys cant seem to figure out. It balances perfect but shakes on the vehicle which is apparently way beyond their and most of their managers mental capacities to comprehend requiring multiple trips to the shop to get it properly corrected with a new set of tires.

You can always set them up in a lathe and turn them true to the wheel and then rebalance.

They may be defective or out of round. Go back and have them checked.

If they are defective they can be a safety hazard, so be safe!

I suspect that:

A: They are new and the tread pattern is still "squared off" (not broken in).

B: Once you have put 500 or so miles on them the "bumping sensation" should dissipate.

Based on your description, my gut says tread pattern is still "squared off".

By all means do be safe and have the dealer check them out for you.

Thanks Guys,

First, I dont have a lathe with enought throat to accomodate these tires.

The tires have close to a thousand miles on them. All commuting on city streets at less than 45 MPH. I've had them on the freeway at 70MPH with no apparent problems.

The frequency of the thumping cannot be correlated, by me, to the tread pattern. The pattern would produce a higher frequency vibration, I think. My gut feel is that the vibrations are about 1/4 of the tread patterns features. They're 255/70/16 with street tread.

I don't think it's out of round cause it disappears at about 5 MPH.

I'm going to call today to make an appointmment at the dealer next week.

Please do let us know what you find.

I just got off the phone with the tire dealer. I'm going in next week to have them inspected. The person on the phone wasn't any help. Not that I expected any.

Lyn,

I feel with you.

Here, I am ruining all the (pep boys - and not the cheapest) tires after 5-6.000 miles. The car becomes a cakewalk inside. With me, the carcass collapses and you feel it when it is articulated enough by striking your hand over the surface when lifted off the ground. I guess more than 20 pieces on 4 cars.

In 2 cases they even messed up the bodywork of the cars.

Wish a good answer could help you, but I doubt it.

Thanks,

I wish I could understand what you and JonathanG said.

Here, I thought it was just me

I'm not sure how much effort you want to put into this little diversion. If you need something to do, I have a few thoughts:

1) Indicator of some type: Chalk, perhaps... Mark the tires, slowly drive on something that will reveal the witness indicator. This would be a fair amount of dinkin' around, but would might tell you if the tires have a depression that is not hitting the pavement, if there is non-linear tracking (wobble)...

2) Have someone else drive the vehicle... you follow and observe, drive alongside and observe... this may reveal an out-of-round situation that is being absorbed by the shocks at some speeds.

3) I had another, and now I have lost it. Two thoughts per post is my limit anyway.

[edit] While I was composing you put up #8. I remember my last thought:

3) Call the dealer, make an appointment.

I kinda looked at them yesterday. Didn't see anything. Even if I discovered something it wouldn't keep me from driving it and my appointment isn't till next week.

One thing that no one has mentioned yet is the lug nuts. If one or two of them are less torqued than the others on a given wheel, you might get exactly what you describe.

In 2001 I purchased a brand new Toyota 4Runner. I had a similar, but slightly different, tire problem. I would get a bump at low speeds and vibration at highway speeds. After having the dealer check alignment, balance and such, they determined the tires had a flat spot on them. They claim that it's from when the vehicles were shipped over from Japan and strapped down tight on the ship (puts a very high load on the tire for a continuously long time).

Toyota changed them out for a new set and all was fine.

I'm not a car expert... but is it possible you have unidirectional tires? All or some of which are rotating the wrong direction? When you drive the car in reverse to you get the same lumpy sound?

Just a thought mind you, but as we all know, radial tires develop a sort of memory, hence the rule of thumb that dictates rotating them front to rear instead of side to side to maintain the the general rotational direction. My thought was that maybe this "memory" is being developed in your new tires and will eventually subside. In any case, best of luck! New rubber is getting to be an expensive proposition these days.

I had the same tires on this pickup for about 7 years. Talk about sticker shock!

Lyn

I used a less aggressive 'rib' tread for street driving and swore off discount brands after going through 7 tires to find 4 without defects. I was saving maybe $20 bucks and having to cycle through the tire store repeatedly. Side lumps, out of rounds, things you could only see inflated - too much bother.

Then found out there are only about 3 companies that make 70% of the 'brands' and the same defect culling I was doing was what I was paying for.

But long and short - check the lug nuts too.

It sounds almost like you have ply separation in one or more of your tires.

It sounds almost like you have ply separation in one or more of your tires.

Oooops, sorry about that! I guess I was still laughing about the title of the tread, I mean thread Sorry Lyn, I do understand your frustrations with Lumpy Tire problems. I had a tire that suffered ply separation, out of warranty of course, that had the same symptoms that you described.

255/70/16 with street tread?

Crikies, that tire is almost as wide as it is high. You might be hitting something under the car, such as a suspension member or inner fender. I'd check the tires for rub marks. Look on the inside of the tire--rubbing on the outside is too obvious and easy to spot. Look for shiny spots on the fender or suspension.

Did you have such monster tires on it before, or did you just upgrade to a new size?

These are standard for my vehicle. Last set was this size,too.

I had a macho-4wheel drive with big tires, these are street tires.

Dodge 2500 1999 SLT 4wd came stock w/245-75-16's.

Dodge 2500 2007 SLT 4wd came w/265-70-17's.

And many two wheel drives are running 19" wheels to allow use of truck tires

I had one set of tires with side wall separation problems. Same symptoms. What broke the camel's back, when the second one acted up brutally shaking at highway speeds within a few seconds. The dealer found the 3.rd developing defect, confessed to a bad batch, replaced all four. I easily could have a nasty accident.

Not before, never since, knock on wood!

Sounds like a shopping cart, many of which are built with square wheels....

When you go into the dealership that sold you these tires, have the Service Manager and the Technician check the Static Balance as well as Harmonic Balance throughout all speeds for zero up to the speed rating of the tires.

I've found out the hard way after buying a full set of tires that not all harmonic balancing machines are created equal, and that you may have to run them on two or more machines to find out the balance problem.

You may also have to check for out-of-round in both axis with a dial indicator when it's on the balancing machine and hand rotated. The tires may have been stored too long or improperly, or are out of specification...

If you don't get any satisfaction from the dealer, then by all means go up the chain of command and demand a meeting with the tire manufacturer's Regional Director.

Good luck with those tires.

Did the garage balanced them when new? Idea:

Chalk an even "clock" on the side wall and call out to a watcher when the "bump"
occurs, and have them note the clock number on the floor each time.

This will give you a pretty close area for you or the garage to check.

Hope this helps. jt.

My wife asked me what I was doing? I said, "Nothing."
She said, "You did that yesterday!" I said, "I didn't finish."

Yes, they balanced them. Balance is not an issue. This occurs when the vehicle is moving at 2-4 MPH.

And finally, it's bumps, as in plural, and definitely not a flat spot.

Back from a test spin. More information:

When the bumping occurs I am going about 2-3 MPH. The vibration seems to be somewhere around 25-35Hz with an amplitude about equal to running over a line of pencils, maybe. If I try, I can keep the vibrations going for what seems like more than a complete rotation of the tire.

It does not happen when I back up, which puzzles me.

Do not run at 2-4 mph, eh?!?

Many devices have a "do not dwell here" speed range.

Your car may be the unique one, displaying it at such a

low rpm. Other than that?

STOP playing with it. It will go away. (Or I think so)

Second guess: There is something (weighty) inside the tyre.

At slow speeds it "falls" within the tyre creating a tapping or ribbon beat.

At greater speeds it is thrown to the circumferance and travels such it does
not have time to fall and cause the beating. (centrifugal)

I would consider:

i. someone at the garage is having a joke, or

ii. garage wants to get more money off you for further servicing, or

iii. someone maybe disposed of "rubbish" inside the tyre, instead of the rubbish bin.

Just guessing here naturally. Hope this helps. jt.

I thought my new girlfriend was great. But after nosing through her wardrobe
and finding a nurse's uniform. a French maid's outfit and, a police woman's uniform,
I dumped her..... It's obvious, she can't hold down a job!

Nope. this is a contact problem, not a fish.

They've gotten all the money they are going to get from me. The tires have a lifetime guaranty, and they stand behind it. That's why I buy my tires there.

i had a similar problem , traced it to water inside the tyre from a gas station air compressor ,obviously someone didnt drain water out of the air compressor tank.

my symptom was vibration , despite it being a near new tyre

first tyre shop charged me $ 25 " to balance it " , it was still the same

second tyre shop tried to balance it , after half an hour he pulled the tyre off the rim and splash ! , there was the problem.

thats what i would be looking for , as the post above me pointed out , it could be a lug nut or a lead wheel weight inside the tyre , or water.

Thanks.

I had a tire that needed airing up every so often. I took it to my Chevy dealer. They said they couldn't find a leak. Eventually I was told that it was a bad tire that needed to be replaced because it had a separated band in it. It was not under warranty and they did not even have a tire available quickly for it although they were trying to promote themselves as tire dealers. The car was purchased new from them. My suspicion is that the tire was defective and was bleeding air somehow. I wouldn't know how to prove it. The car is an Aveo with Korean tires. The other three tires have been fine. I only had about 12,000 miles on the car at the time.

I would have your tires inspected by independent dealers, and see if they are OK. A set of tires can be expensive, and you really don't want mismatched tires. I would consider small claims court, if you are not satisfied.

Cold weather can cause temporary bumps because the tire is initially out of round. As soon as the tire warms up it stops.

OK, I am going to break down, reach ion my pocket and pull out two pennies: as mentioned previously (post 16 I believe, among others) it sounds suspiciously like the belt are having a separation issue (maybe they didn't get enough attention when they were younger). I had a Plymouth wagon in a previous life and was dirt poor (with tinkering I squeezed 17 mpg out of it), so I would pick up tires from a wrecking yard and have them mounted. After I had put on a couple of tires, I noticed at very low speeds that the car felt lumpy. After close scrutiny I determined that it was coming from the rear and had a slight side shift, almost a wobble. I looked at all the tires and closely at the back ones and could never see any issue. Well long story somewhat shorter, I was driving down the freeway one night and heard a high frequency zipping sound followed by a shotgun blast: a steel belt had separated and finally failed catastrophically. I think a belt separation would give you the symptoms you describe and still be able to be balanced. As someone mentioned earlier, they need to mount each tire on a spin balancer and slowly rotate by hand to check for any inconsistencies.

Most tread separations do not produce the frequency of vibration that I'm getting. The vibes also go away completely over 4MPH.

See post #28.

I just checked the lug nuts and they are all fine. These guys do a post install check with a torque wrench. That tells you if they are too loose, but not too tight.

Most tread separations I've seen are more pronounced and visible.

I've been trying to correlate this to the tread features themselves which are 1" x 2" wide with a 3/16" separation on each side. The interior rows are smaller.

It doesn't seem to happen in reverse.

jack up each wheel off the ground and spin the tyre by hand to see if you can hear anything tumbling inside the tyre

cheaper than pulling each tyre off the rim right ?

Some tires are made with segmented molds and the tread pattern can "wander" from side to side as the tires rotate. From 2-4mph the side to side scrubbing could be giving you the lumps, especially if the pressure is set low. I had a vibration problem at very specific speeds with a new set of SUV tires with that condition, which eventually scrubbed off as I racked up some miles. Have the dealer rotate the tire with a fixed reference aligned to a rib of the tread to see if the tread pattern moves side to side.

I'll just take a wild guess on the brand (which hasn't been disclosed yet):

Les Schwab--now there's a man with a spare tire!

Les doesn't do Arizona.

I don't know anything about this sort of thing, so my apologies if this is stupid, but, is there any chance that the tracking is slightly out; the treads are moving out (or in) for a bit until they overcome the stiction, then, jump back to central; before starting again.

I think, at this point, you know as much about this as the rest of us.

Hello, Anybody here?

Well, I finally had the tires looked at and rotated.

I'll swear, after rotation, I can't make the tires do the cobblestone vibration any more.

Go figure.

Cheers.

NO! WAIT! It's still there. Sorry.

Just like a cobblestone street.

Just throwing this idea out there... (anyone feel free to add or destroy this at will as I'm not a car guru).

With as much focus and attention the tires have received (balancing, rotation, etc) with no solution... it seems rather likely to me the problem lies elsewhere... a bad u-joint or the like.

First remember, I'm an old man. These kids at the shop automatically discount anything I say as rubbish. If they can't see the tire hopping around on the balancer, it's ok to them and the cobblestone effect is my imagination.

This condition was apparent as soon as I drove away from the tire shop. Nothing else has changed.

I have contacted the manufacturer and he says take it back to the shop and have them call the factory when they have the tires off.

Well no tread separation is evident and I haven't had time to spend two hours waiting for them to tell me everything is fine.

Thanks for the input.