On my red S4 I have Bridgestone RE730s. Over the past few weeks I have noticed a progressively louder growling/whining noise on the car. Today I took the car to a local Porsche mechanic and had him test-drive the car. He then put the car on a lift and listened to various points on the car and was unable to hear or replicate the noise. For now we have concluded it is tire noise. There is plenty of tread left on the tires. I have two questions:
1. Has anybody had experience with RE730s being louder than other tires?
2. Other than absence of tire contact, are there any circumstances where a rear end noise from a car in drive on the road cannot be duplicated with the car in drive on a lift?
1987 Porsche 928S-4 Guards Red (Weekend Car)
I think this is commonly reported with 730s as they wear, but I wouldn't want to say it is much more common than with many other performance tires made for our cars.
In general you can distinguish wheel bearing from tire noise when driving in
- tire noise changes as you go over different surfaces (concrete versus asphalt)
- bearing noise is usually more pronounced when turning and often won't be heard (early on) unless you are turning, but I have had tire noise get louder when turning
Had a similar noise on my 88S4. I attempted to test the noise by running
in gear while the car was on a lift. Although there was a definite noise
from the right rear while driving, there was none with the weight off the
wheels. The tires were new so I replaced the right rear main bearing...
noise gone. The bearing replacement is not too difficult. If you need the tools (e.g. 3/4 drive wrench), let me know, I'm just up the road in Stafford.
Larry Gunter asked: "1. Has anybody had experience with RE730s being louder than other tires?"
My answer is YES (wish I could make the print larger!!!).
I put a set of these tires on my '88 S4 shortly after they were introduced. I really liked them for about the first 3-4 K miles. Quiet, sticky, responsive. By about 6-7K miles (<40% worn), they were so noisy I couldn't stand them. Worked a deal with 928 Specialists and Tire Rack for Tire Rack/Bridgestone to give me credit (in my opinion, Tire Rack did an unsatisfactory procedure for the amount of credit). I've had Bridgestone SO-3's, Michelin Pilot SX and Michelin Pilot Sports on the car since. In my opinion, the Pilot Sports are the least noisy.
I made the mistake of putting the RE-730's on my MB 560SEC after I'd had
them on the S4 for about 2K miles (while I was still pleased with them).
Same result on the Benz. After about 6K miles they were SO noisy I couldn't tolerate them any longer there (the Benz is MUCH quieter than the S4). Sold
the 730's and replaced them with Yoko ES-100's. I can now hold a conversation with my wife at normal decible levels in that car again!!!
I believe it IS tire noise Larry. I even tried reversing the rotation (swap tires left to right and vice versa), which had helped with some other tires - NO SIGNIFICANT noise reduction from the 730's.
When we run M & S rated tires (mud and snow) for that aggressive tread
.......guess what ? they SOUND like snow tires ! Reading through the
customer comments on Tireracks Site may help determine which ones are less noisy But if you want QUIET try the low performance lower speed rated less
expensive lower traction harder compound longer wearing tires with smaller gaps between the treads . They just do not LOOK fast . If you never drive
over 100 MPH maybe you do not need 180 MPH tires (or a 928) . O K so it is not about need just what you want ............compromises , compromises .
I've been there last year, and really really suspected the bearings. It went away instantaneously when I put the winter tires on. Car was never quiet but the grinding sound went away. Its especially loud when you are almost at a stop or at certain speed/street combinations. Sounds as if the bearing is gone. You put it on the lift and turn the wheel: all seems ok. You turn fast turns, and that does not change the sound a lot. It definitely does not control the amount or pitch of the sound.
I put the summer tires on again early this year, and have started to complain again. I still doubt the bearings from time to time, and suspected the tranny and the final drive also. Its all come back to me ;-)
Soon its so cold that I will put the winter tires on again and will probably notice that the silence has more or less returned.
The winter tires are loud tires, but my Marshall summer tires are way beyond. The compound of the tire has become harder in time, and the wear is not completely flat either. A hollow center (worn) seems to increase the noise substantially. Good is that the tires have a very good wear resistance. Bad is that the are hard, loud, and do not perform miracles in wet and rainy days. Horrible is the performance in the cold winter days.
What I still don't know is how much of the noise is coming from the bearings. Its been rumored that worn bearings are only easy to spot when you take the axle loose from the tranny and gently turn the wheel. A stethoscope would be required to carefully examine the sound. Haven't done that yet. It might still be different from turning under load.
so.... get some good tires on and give it a try. Have a look at
Does that help?
'88 928s4 cherry red