Tire noise, bearing or diff ??

[amancuso]

OK, I just bought my 325Ci this Saturday. One thing I hadn't noticed before was just how much road noise I hear when I'm driving the car. There is a constant noise whenever the car is rolling. There are no vibrations or anything like that. The noise only changes over different types of pavement and gets a lower pitch as I slow the car down. There is no difference when taking corners or anything, which leads me against it being a wheel bearing.

I know its hard to diagnose on a forum, but any thoughts are welcome

Al.

UPDATE... noise is gone via new tires, see post #28 in this thread

[Critter7r]

Dunlops or Bridgestones?

Once either of those tires in the sizes that are on the pic in your sig get a few thousand miles on them, they get LOUD. I'm pretty sure it's the fault of the car as much as how the car wears on the tires and the tires' compound. Whatever it is, the two don't agree on how a tire should wear. We've have much better luck with Goodyears and Pirellis as far as the noise issue goes.

[amancuso]

OK , I've got Continental Contisports on them though. According to the manufacture date, they were made in early 2004, and have an ok amount of tread left on them, but the sides are well worn.

[Critter7r]

Oh, I forgot about the Continentals. But ALL the sizes of those tires are loud on BMW's (and a lot of other makes as well) after a few thousand miles (10k or so). If they're more than about 30-40% worn (so about 5mm tread remaining), they're likely the culprit.

Two options: Swap the tires around so that the outside edge becomes the inside edge so that the wear pattern changes (not recommended if the tire reads "this side out" on it). Or get new tires.

Ok, so 3 options, you could just live with it. But the tires are nororiously noisey in the 17 inch variety shown in your sig. I doubt you have any other problems. if the tires are the same size front and rear, you may try just simply rotating them to see if it helps the noise at all. And if you're really worried about it, you could try a set of 16 inchers off someone else's ride if that's available to you to rule out the other problems you mentioned and see if it's quieter.

[amancuso]

Thanks for the advice! I'm thinking about new tires, any recommendations that won't break the bank?

[matthewo]

i have 19s with cheapo tires in the back(federal) and falkens up front, they make a lot of noise on the highway.

[nathancarter]

My 2001 325i had real bad road noise due to the worn OEM Continental tires. They were worn in a very strange pattern, every 2nd or 3rd tread block was worn down noticeably more than the ones next to it. I don't know if that's referred to as "cupping" or not, I don't think it's quite the same as cupping.

They sounded like a pickup truck with mud tires, especially on a very smooth road.

Replaced the tires, and it was very quiet and smooth.

[pphil09]

sounds like tires...

I run pirelli's

[amancuso]

will 235/45 17's fit on my car? I have a set that I bought for my 5 series, but I don't really to put them on right now... the noise in the 3 is driving me nuts!

[Aren G]

Depends, it usually goes like More Grip = louder, Less grip = quieter

[Critter7r]

will 235/45 17's fit on my car? I have a set that I bought for my 5 series, but I don't really to put them on right now... the noise in the 3 is driving me nuts!

Technically, no. You need to stay with the 225/45 front and 245/40 rears (if they're staggered, otherwise they're 225/45 all the way around). But the 235/45's will only be about a half inch taller, so they'll fit, but you'll notice the difference in how they look. Performance and speedo accuracy will be affected a little also.

Depends, it usually goes like More Grip = louder, Less grip = quieter

That's a very generalized statement. Lots of soft compound tires have tons of grip and are very quiet and lots of hard compund tires don't have a lot of grip and are noisey. Some soft, quiet tires get louder as they age, some don't. And then, just to make things fun, some tires that work great on some cars, on other cars... not so much.

[Aren G]

I said Usually, not definitely.

Soft compound mmm

[Critter7r]

I said Usually, not definitely.

Soft compound mmm

oh, I know. I just was trying to explaing the scope of the general-ness of your post.

[Spidey12]

I had mad road noise on my 328i. I just got back from the mechanic who replaced my wheel bearing (he originally thought it was the rear diff but luckily it wasn't) and it only cost me 80$.

My tires are worn the way yours are too..the sides are worn more than the other parts of the tire...BUT my car after having the wheel bearing changed has no noise at all...so my guess is its your rear diff...ive heard it creates a low and high pitch that changes...as you described. Have the rear diff checked out before you shell out on tires.

[Critter7r]

Wait a minute.... you had noise and worn tires just like the OP and replacing the wheel bearing fixed your noise, so you're telling to have his diff checked??

[Spidey12]

Wait a minute.... you had noise and worn tires just like the OP and replacing the wheel bearing fixed your noise, so you're telling to have his diff checked??

Yes but when I turned corners the noise changed and i didn't have a pitch sound it was more of a whine. OP himself ruled out wheel bearings because the sound doesnt change when turning around corners....

I mentioned the tires so he can have hope that just because its worn in a certain way it doesn't mean its necessarily the tires making the noise....

so if wheel bearings are out, tires are a maybe...whats left...REAR DIFF. I'd check it first before paying shitloads of money on tires which are a MAYBE not 100% the culprit.

get it now?

[f1fan99]

Yes but when I turned corners the noise changed and i didn't have a pitch sound it was more of a whine. OP himself ruled out wheel bearings because the sound doesnt change when turning around corners....

I mentioned the tires so he can have hope that just because its worn in a certain way it doesn't mean its necessarily the tires making the noise....

so if wheel bearings are out, tires are a maybe...whats left...REAR DIFF. I'd check it first before paying shitloads of money on tires which are a MAYBE not 100% the culprit.

get it now?

Somebodys got some extra sensitive ears if they can hear the wheel bearing pitch change that slightly from turning. I would not rule out wheel bearings based on that. Tire noise sounds very different from bearings, at least it always has to me. Have someone sit in the back (or you) while someone drives it, and try to differentiate whether it's coming from the left/right/center or what of the back.

How many miles on this car???

[nathancarter]

Somebodys got some extra sensitive ears if they can hear the wheel bearing pitch change that slightly from turning.

Actually, that's a common and accepted way to check wheel bearings... do some low-speed slalom-style driving and see if the noise changes significantly. The weight and load on the bearings will change as the car turns, thereby changing the pitch or volume of noise created by failing bearings. Good bearings are uniformly quiet, but bad bearings aren't uniformly loud.

[amancuso]

Well as far as where it's coming from, I notice it sounds worse in the drivers seat then when I was in the passenger seat.... The pitch of the sound does not change when rolling and putting the car in Neutral either.

[GWEEDOspeedo]

Reading through I don't believe I noticed if you stated your tires are properly inflated and wearing well. Also, is your camber a nice 90 degrees? Do your wheels 'toe' at all?

Reference

[amancuso]

Reading through I don't believe I noticed if you stated your tires are properly inflated and wearing well. Also, is your camber a nice 90 degrees? Do your wheels 'toe' at all?

Reference

The tires are properly inflated as per the sticker in the door jamb... As far as camber, I've no idea how to judge that.

[GWEEDOspeedo]

If you have a level in the house, take it and hold it against the wheel so that it's flat against it. You can also stand something, that you know is perfectly straight, on its end and butt it up against where the tire hits the ground and it's perfectly perpendicular with the ground.

Using your eyes while looking at the wheels/tires from behind works too

[the andrew]

OK, I just bought my 325Ci this Saturday. One thing I hadn't noticed before was just how much road noise I hear when I'm driving the car. There is a constant noise whenever the car is rolling. There are no vibrations or anything like that. The noise only changes over different types of pavement and gets a lower pitch as I slow the car down. There is no difference when taking corners or anything, which leads me against it being a wheel bearing.

I know its hard to diagnose on a forum, but any thoughts are welcome

Al.

The bearing will oscilate a hum when it's beginning to fail, usually above 40mph and the hum usually won't change due to road surface changes , ex: smooth or coarse.

[the andrew]

Reading through I don't believe I noticed if you stated your tires are properly inflated and wearing well. Also, is your camber a nice 90 degrees? Do your wheels 'toe' at all?

Reference

The sport susp has a bit a neg. camber naturally due to the factory specs and suspension geometry, like /----\ , of course not that much, ya know.

[Critter7r]

If you have a level in the house, take it and hold it against the wheel so that it's flat against it. You can also stand something, that you know is perfectly straight, on its end and butt it up against where the tire hits the ground and it's perfectly perpendicular with the ground.

Using your eyes while looking at the wheels/tires from behind works too

Except that all BMW's and notably the sport suspensioned vehicle have negative camber, more so in the rear. No wheels on the OP's car are going to be perfectly vertical.

The sport susp has a bit a neg. camber naturally due to the factory specs and suspension geometry, like /----\ , of course not that much, ya know.

Like that ^.