Planet 9

**emccombs** · #1 03-22-2009, 04:07 AM

I have a loud wheel hum. I say loud hum, because I dont know what it is. It is noticable at 40mph but gets unbearable at 70mph. Above 70, I dont care

Has anyone else experienced this?

I attached the pics of my wheels. They are 19" wheels and the tires are Michellen Pilot PS2

All 4 tires have great wear left and all look to be wearing evenly. It is so loud that I cant talk on the phone. I have to pull over.

Any ideas? I could do an alignment, but there is absolutely no pull whatsoever, there is no uneven tire wear, and it's been going on for as long as I've owned my car. I bought it used a year ago.

Thanks!

lspain · #2 03-22-2009, 11:56 AM

What you are describing does not sound normal (no pun intended). The Cayman does not have a lot of sound isolation coming from the wheel wells, so you get a fair amount of road noise coming into the cabin. In my experience road noise is not a hum but does increase with speed. Does the car have any mods...like an aftermarket exhaust? Manual or tiptronic? Does the sound rattle things in the cabin like a resonance?

**K-Man S** · #3 03-22-2009, 01:07 PM

A hum is not normal, but you should first compare against another Cayman to make sure yours is indeed different (I'm assuming so from the description), then I would have your wheel balance checked as a starter along with wheel roundness.

sidtc · #4 03-22-2009, 03:37 PM

Wheel bearing?

cheerIO · #5 03-22-2009, 07:04 PM

Originally Posted by sidtc

Wheel bearing?

+1 on the bearing guess.

**emccombs** · #6 03-25-2009, 06:41 PM

Sorry guys.. I should have responded sooner...

More info:

I sort of "resigned" to the noise until I drove the 09 CS. The 09 CS had 19" wheels (different ones) and I could tell instantly that there was about 1/2 the road noise. So after an hour of launch controls

I took it back

I then asked my salesman to ride with me and he said that the noise is WAY TOO loud. My salesman (@ Roger Beasley Porsche in Austin) has been selling Cayman's for awhile and said there is no way it should be that loud. That generated this post.

There are no mods to the engine of any kind. It is stock. I find the noise so unbearable, that sometimes I wont drive it because of it. If I can just get this figured out, I'll be alot happier so that I can hear our not-so-great-but-works BOSE speakers

So far, what I'm hearing is that it's not normal from you all and the salesman. I really think it's the tires, because the engine/drivetrain sounds fine.

I'm going to see if I can record it with my crackberry and post it.

CSDriver · #7 03-25-2009, 06:59 PM

Originally Posted by K-Man S

A hum is not normal, but you should first compare against another Cayman to make sure yours is indeed different (I'm assuming so from the description), then I would have your wheel balance checked as a starter along with wheel roundness.

+1. I would have the wheels balanced. One of the weights might have come off. Mine appear that they are glued on the inner part of the rim. It would make sense that the vibration/hum would get worse as you go faster.

beez · #8 03-26-2009, 01:28 AM

Originally Posted by emccombs

Sorry guys.. I should have responded sooner...

More info:

I sort of "resigned" to the noise until I drove the 09 CS. The 09 CS had 19" wheels (different ones) and I could tell instantly that there was about 1/2 the road noise. So after an hour of launch controls

I took it back

I then asked my salesman to ride with me and he said that the noise is WAY TOO loud. My salesman (@ Roger Beasley Porsche in Austin) has been selling Cayman's for awhile and said there is no way it should be that loud. That generated this post.

There are no mods to the engine of any kind. It is stock. I find the noise so unbearable, that sometimes I wont drive it because of it. If I can just get this figured out, I'll be alot happier so that I can hear our not-so-great-but-works BOSE speakers

So far, what I'm hearing is that it's not normal from you all and the salesman. I really think it's the tires, because the engine/drivetrain sounds fine.

I'm going to see if I can record it with my crackberry and post it.

Couple of questions... you have 19" wheels - are these factory wheels? If not, who makes them? What pressure is in the tires? How many miles are on the tires? Do you think they're the original tires that came on the car when the previous owner bought it? Is there a vibration with the noise, or just the noise? Does it make this nice on all surfaces (concrete or asphalt) equally?

brad

**emccombs** · #9 03-27-2009, 05:28 PM

I bought the car used from the same dealership that I drove the 09 CS from. The sticker matches the wheel type. I assume they are original. 2/4 tires are a little low an air pressure. I'll inflate, but it's been this way for a year (ever since owned it). 22,000 miles on the tires. I haven't noticed if it gets louder on a specific surface. There are no vibrations and the steering wheel doesn't vibrate,move, or wobble. It is rock solid.

It has been raining, storming, and hailing here in Texas for the last week, so I haven't driven it. I'm going to try some of these suggestions to see if I can see a difference.

Tomasz · #10 03-27-2009, 11:17 PM

I have the same wheels with PS2s. They are MUCH louder than 17s with winter tires that I just took off. Especially on roads where smooth asphalt is now pitted and feels lke concrete. Tires also get MUCH louder with age, 22,000 miles - you should need new tires. Consider something different than PS2s. They are not a good touring (i.e. highway) tire.

But if this bothers you, find another used Cayman with similiar mileage, same tires and test drive on the same road.

Tomasz

**bwass24** · #11 03-27-2009, 11:29 PM

What strikes me is 22,000 miles on your tires. Based on everything I've read here that is quite a lot more miles than PS2's get on a Cayman and worn tires will definately make a lot more noise than newer tires.

blue_eyes · #12 03-27-2009, 11:33 PM

Originally Posted by emccombs

I have a loud wheel hum. I say loud hum, because I dont know what it is. It is noticable at 40mph but gets unbearable at 70mph. Above 70, I dont care

Has anyone else experienced this?

I attached the pics of my wheels. They are 19" wheels and the tires are Michellen Pilot PS2

All 4 tires have great wear left and all look to be wearing evenly. It is so loud that I cant talk on the phone. I have to pull over.

Any ideas? I could do an alignment, but there is absolutely no pull whatsoever, there is no uneven tire wear, and it's been going on for as long as I've owned my car. I bought it used a year ago.

Thanks!

Potential power steering pump noise.

beez · #13 03-28-2009, 12:25 AM

Thanks for the answers to the questions... as a couple of others have said, 22k miles on a set of PS2s is a lot... I'm thinking this has a lot to do with both the mileage and the age of the tires. The car's an '06 so the tires are almost 3 years old, couple that with the loss of tread, and who knows how many heat cycles, and you have some very hard tires with not much tread to isolate the rest of the car from the road. PS2s are pretty loud anyway.

A new set of tires will help this, obviously.

brad

**Santa Fe** · #14 03-28-2009, 01:37 AM

My guess is also that your tires are telling you their life is up. From the Owner's Manual.
"Tire life
The original equipment tires on your Porsche have
built-in tire wear indicators. They are molded into
the bottom of the tread grooves and will appear as
approximately 1/2 in. (12 mm) bands when the
tire tread depth is down to 1/16 of an in.
(1.6mm). When the indicators appear in two or more adja-
cent grooves, it is time to replace the tires. We
recommend, however, that you do not let the tires
wear down to this extent."

intubator · #15 03-28-2009, 01:48 AM

Hey Emccombs, I think your hum problem may be a slightly loose front spindle nut causing uneven bearing loading when the wheel turns. This will give the same hum sound as a bad bearing and over time will destroy the bearing if there is enough play. It may also affect the handling if its really loose but may not if its only slightly loose. To check the play remove the front wheels, remove the dust caps off of the spindle nut, pull the cotter pins and tighten the nut until snug and turn the hub. The hub should turn smoothly but tight, if it feels notchy or bumpy then the bearing or race may be shot. If it turns OK then back the nut off a 1/4 turn from snug and reassemble. Doubt that its your tires unless you hit a pothole or something that would cause the steel belts to separate which would cause an out of round situation that would get progressively worse as your speed increases. I actually had a separated belt on a brand new tire last year, turns out the tire was damaged by an inexperienced tech during installation.

**Santa Fe** · #16 03-28-2009, 01:58 AM

Originally Posted by intubator

Hey Emccombs, I think your hum problem may be a slightly loose front spindle nut causing uneven bearing loading when the wheel turns. This will give the same hum sound as a bad bearing and over time will destroy the bearing if there is enough play. It may also affect the handling if its really loose but may not if its only slightly loose. To check the play remove the front wheels, remove the dust caps off of the spindle nut, pull the cotter pins and tighten the nut until snug and turn the hub. The hub should turn smoothly but tight, if it feels notchy or bumpy then the bearing or race may be shot. If it turns OK then back the nut off a 1/4 turn from snug and reassemble. Doubt that its your tires unless you hit a pothole or something that would cause the steel belts to separate which would cause an out of round situation that would get progressively worse as your speed increases. I actually had a separated belt on a brand new tire last year, turns out the tire was damaged by an inexperienced tech during installation.

Possible I suppose but if so and not tires the car is under warranty and that is something your warranty would cover rather than a DIY.

**K-Man S** · #17 03-28-2009, 04:27 AM

I concur, if you think it might be the wheel bearing/hub then you need to take it to your dealer and let them work on it under warranty, your hub/bearing isn't something you want to just mess around with if you don't know what you are doing. I seriously doubt it is the spindle, more likely a bent wheel / tire problem, but your dealership should be able to check both and report back.

**emccombs** · #18 03-28-2009, 05:22 PM

I think I may have found the problem.

I measured tread depth Outside Middle Inside on all four tires. Left is driver
out, mid, in
Front Left: 5m, 5m, 5m
Front Right: 6m, 5m, 5m,
Rear Left: 4m, 3m, 2m
Rear Right: 4m, 3m, 1.5m

The rear tire tires are wearing very badly from outside to in. I originally just measured the outside tire and I thought they were close enough. By measuring all 3 locations it is clear that the rear tires are wearing uneven. I suspect it's been that way since I bought it.

I also checked the bearings by lifting the car on my used-to-be-nice-but-no-leaks-a-little garage car jack, and the wheels feel "tight"

I suspect the unaligned rear tires is fighting against the rest of the car which is causing the hum. I also dont really like the tires anyway, so I'll pick up some new ones.

I am taking my car in for the annual service in about 2 weeks. I'll have them check the wheels, bearings, and alignment. I'll then get some new dawgs (with apologies to Randy Jackson) and I bet that fixes it.

Thanks to all!!

**emccombs** · #19 03-28-2009, 05:25 PM

which brings up a good question. Which tires shoud I buy? I'd rather have a little more comfort than road handling. I also would like good wear. I really dont need it that "soft." I have other cars and wont drive it in the rain or bad weather. Thoughts? I haven't researched this on this website, and I'm sure people have plenty of good ideas already.

intubator · #20 03-28-2009, 05:49 PM

I have had a great experience so far with my Bridgestone Potenza RE050-A's, they are lasting longer than the PS2's I had and offer very similar dry traction, excellent wet traction and are quiet. They are about $100 less per tire than the PS2's as well!