It got cold here for the first time over the last few days, and I've been getting a sort of whop-whop-whop noise out of the rear end. It's happened during acceleration, coasting, and left turns for sure. It seems to go away when I'm on the brakes.

Any ideas?

 

Did you change over to winters recently before the noise started?
Any new work done (brakes) otherwise?

 

Sounds like a brake or bearing issue....
Does the change match your speed change?
Notice if the hub area seems hotter on the noisy side than the quiet one?

 

Nope, same tires as before. It does sound a lot like wheel/tire noise, though, except in that it goes away sometimes.

It might be brakes. I know from my last chat with my mechanic that the rear rotors especially are on borrowed time.

I'm hoping it isn't a wheel bearing. >.> Next time I have to go somewhere I'll give the hubs a feel check.

 

I'm with Zippy....bearing was my first thought as soon as I read the title. I have ridden a couple of motorcycles that had a similar noise and it ended up being bearings both times. Keep is posted.

 

Almost certainly not a bearing or brake issue—no temperature difference between the hubs, and it's also dependent on engine speed instead of road speed.

I was driving home tonight, and I heard the noise more clearly than usual, in 3rd gear at about 2100 rpm. I went to neutral and kept the revs between about 2000 and 2200, and I could hear it in that range. When I got home, I tried it in the driveway and didn't have the noise anymore. I think the noise is coming more from generically down as opposed to down and behind me, which, along with neutral/in-gear making no difference, seems to suggest clutch to me. It has been 83,000 miles or so without being replaced, and I have no idea how hard it was used before I bought it at 67,000.

 

At 83k, it wouldn't hurt to replace the clutch anyways. I guess a bearing would have been too easy.

 

My First thought was cupped tires, no noise at slower speeds, then with increased road speed the noise would get a little louder, until it was at harmonic balance.

Cheap and easy check, double check tire pressure and swap fronts for rears, and take for a quick spin at the speeds you were running when you heard it.

Rears are most likely to start sounding up over time... one really great reason to stick to a regiment of tire rotation, I do mine about every 5K miles.

Motor on!

 

Turns out it wasn't a bad thing at all: although the clutch will need a replacement soon, this noise is an exhaust system noise. The bumpy roads of Dallas knocked something near the back of the car loose. If I kick the exhaust, I get a 'whop' that sounds a lot like the one I sometimes get in the cabin. I figure some clip came loose, and occasionally a bump jostles the exhaust so that it's sitting crooked enough to resonate at certain engine speeds. Another bump will jostle it back to a position where it's dampened.

 

Now that is fortunate. Glad you were able to sort it all out.