AudiQ5sleeper

Question: is your cross bar installed? if so, you may hear a hum or whistling sound at high speed. try taking off the cross bar if you do have it mounted.

TonySCV

I'm with you Dennis... that's why I've tried 3 different tire sets on this car (Michelin Latitude, Pilot Super Sport and Bridgestone Dueler) - unfortunately the sound happens on any road type, but the sound "resonates" over imperfections, so although I hear the sound less on asphalt roads as they are generally smoother, particularly in CA, I still hear it whenever I'm on a bumpy asphalt road just as much as I do on concrete.

The only thing I haven't tried is all-seasons with a tread pattern that is more "blocks" vs. some of the deep-grooved treads that exist on the 3 sets of tires I've tried so far, but I'm 99% sure at this point given my previous tire tests that it's not the tires. I hear the noise regardless.

My dealer appointment is Thursday and the shop foreman is going to ride along with me on a test drive. I'll let folks know what I hear.


Thanks... this is exactly why I want to at least bring the car in under the suspicion that it's a wheel bearing issue, even though the car is so new, because otherwise it's too easy for the service department to be dismissive and just say it's a tire issue. That's why I've gone to the trouble of troubleshooting the tires myself beforehand. Most of the time it IS the tires, but this hollow-sound I have is very pronounced. Road surface makes no difference and thankfully there is a freeway right near the dealer that has a mixture of concrete and asphalt surfaces so I can do a test drive to demonstrate the issue occurs on all of them.

I have heard a similar hollow sound on other Audis but it is FAR less noticeable. This is much more prevalent.

soonerfan

Roof rack cross bars. Never had mine up there on either Q5, but I'd imagine they would make some noise merely from the wind turbulence and the noise would increase with speed. I listened to the video and I've never heard anything like that hollow droning from any of my Audi's. It's almost like a harmonic....there's a four pronged strut that bridges the top of the wheel arches under the hood that is secured by bolts. Far-fetched, but that could be ever-so-slightly loose?

AudiQ5sleeper

its hard to figure out where the humming is coming. I had a defective wheel bearing. the tech showed me how to tell if its a bad wheel bearing. He did two ways. One is doing aggressive steering side to side. second is popping the gear into neutral. Once the car was in neutral you can hear the hum loud and clear lol. but I don't know about the OP. He may have to test out the cross bar as well. some say its the side mirrors etc.

TonySCV

No.

AudiQ5sleeper

your better off going to the dealers.

TonySCV

Back from the dealer service department after 2 days of troubleshooting. The service department was terrific. Great folks who really took the time to get to the bottom of this.

Service tech did a ride along with me, heard the same noise, and they went to work. Inspected the suspension, differential, drive shaft and wheel bearings - all OK.

They decided to swap out the wheels on my SQ5 with 20" wheels off of a Q5 S-Line they had on hand, thinking it may be something related to the SQ5 rims. Same tire size - 255-45/20, same OEM tire (Michelin Latitude). Different rims. They test drove the car and noise was drastically reduced - almost imperceptible. One of the techs realized something during this experiment that ultimately turned out to be the root cause.

To my surprise (and their surprise), there is a 10PSI difference between what Audi recommends for a Q5 3.0 with 255-45/20's vs. an SQ5 with 255-45/20's. The owner's manual validates this:



So they put my SQ5 wheels and tires back on my car and dropped the pressure from the recommended 40PSI to 31PSI to test it out - sure enough, the hollow humming sound was dramatically lower. They then installed 2 other sets of tires (Michelin Super Sports and Continental DWS) same issue. At 40PSI - humming like crazy. Drop the PSI = vastly less noise.

The humming noise wound up not being a specific brand of tire after all, it is a combination of the high tire pressure and the vehicle or rim design that's generating the noise. Although there was some resonance/loudness variation of the humming between the 3 different brands of tires (the PSS's were a bit louder overall vs. the Latitudes and the Conti DWS's), they all exhibited the same behavior. More noise at 40PSI. Vastly less noise at 31PSI.

While they couldn't recommend that I keep the tires at the lower pressure per the guidelines from Audi, that was clearly the root cause of the issue.

Although I'm relieved to now know the cause and what can be done to address it, why the heck is there such a big difference in recommended tire pressures given identically-sized tires and nearly identical curb weights between the SQ5 and the Q5 3.0? 31PSI average vs. 40PSI average in the manual is a huge difference.

Should I have any concern about running the tires a few PSI lower on the SQ5 than what the manual suggests?

- T

MP4.2+6.0

Half joking, but half not. We know the ride height change was gutted to conform it as a light truck for US stds. We also know from the parts listings there is no roll bar or similar tweak. From some recent posts the air pressure difference came up, but not for any obvious good reason on an SQ like weight/load. If you want to challenge the weight issue as any rationale BTW, realize either the TDI or the Hybrid are heavier. But those Q5 versions don't have the tires pumped up when fit w/ 20's of the identical size. Seems like they spec'ed the air pressure either as a mistake or some goofy way to try to stiffen up ride and maybe steering feel.

As it were, seems like the air has been kind of let out of the sport tuned suspension hawked by Audi USA marketing, and now literally so given it seems to generate excessive noise.

koobah

Does the OP have Q5 like mentioned in the first post or an SQ5 with 20" wheels?

TonySCV

Apologies - SQ5