I have a 2005 Honda CRV (RD7), with 190k km on the clock. Over the last 10000km or so, there's been a slight hum coming (I'm pretty sure) from the rear, and sloooowly getting worse.
The specifics of the noise:
- It starts getting noticeable around 60km/h
- It peaks in volume around 70km/h
- It seems to get slightly attenuated from around 80km/h onwards
- It is worse when I have load in the rear (1-2 passengers)
- It's a really loud hum, filling the cabin, but with no specific rhythm to it
- I can't say for sure that it gets worse or better in turns
- About 20k km ago, I put a new set of Pirelli P7s on the rear. At the time, I wasn't aware that my rear suspension was in need of some work, and the tires accordingly feathered.
- I replaced the rear shocks about 7000km ago, but the damage to the tires had already been done.
- I have checked all the other recommended sources of noise, including flushing both the transmission and rear diff - this does not seem to have materially improved the noise.
- I've had the car for almost 3 years, and do an equal mix of city and highway driving.
- I'm in Brisbane, so salty air could be a concern. To the best of my knowledge though, the car has never done any beach driving.
- Also to the best of my knowledge, the car has never done any serious towing (or carried big loads), or gone proper offroading.
In summary, I can't for sure pinpoint the noise source to bearings (usual tests like spinning, tugging, cornering have inconclusive results). I also can't get any consistent idea of how long a set of bearings on the CRV should last. The tires are definitely feathered (probably about 1-2mm ridges), but I have no idea how much noise they would contribute with all else being equal.
Based on a LOT of other posts on the net, service center and mechanic opinions on this particular issue isn't always accurate, and unfortunately I don't have the money ($500/bearing installed, $150-200/tire) to throw at the problem and hope for the best.
Any advice would be greatly appreciated!
PS - I am probably skilled enough to install the bearings myself, but they're still $150 a side, and apparently on this particular model there's an issue with getting ABS sensors out of the hub without breaking them, which will add another $50-100 per side potentially.
Ok, I've rotated the tires front to back, and also tested with the spare in the place of the heavily feathered tires in the back. I found:
- There is a slight reduction in overall noise, but it is not completely gone. Whether this is because there might still be a different problem, or whether it is because the feathered tires are now generating noise at the front, but resonating through the cabin, I don't know.
- With the slightly reduced noise, I tried the swerving slowly at about 60km/h trick. The noise seems to dissipate slightly when I veer right, and stays about the same when I veer left. For reference, this is a right-hand drive vehicle.
- The pitch changes slightly between about 60 and 80km/h, after which it drops in volume to about 100km/h, making it difficult to detect.
- At 100km/h, it becomes 'rhythmic' - basically coming and going at probably 1Hz or so.
Just did some more reading on tire wear patterns. It seems that the guys at the shop describing the issue to me, had their terminology wrong. What I have, is heel/toe wear, NOT feathering. It is also not related to my (previously) worn suspension, since that would likely cause diagonal wear.
Would this cause road noise as well?