Jack the front of your car up and try to move the wheel, that is grab the top and bottom of the wheel and wriggle it the grab each side and do it again. If it moves you have a stuffed wheel bearing.

Judging from the way you have described it and your apparent general knowledge of cars, I suggest you take it to a trusted mechanic.

 

ttt

 

CV joint?

 

If the car is raising and lowering in conjunction with the noise I would venture to say you have a seperated belt in your tire. THis should also cause a vibration though and you dont relaly mention a vibration. Next guess would be wheel bearing. Like punter said jack the wheel up and grab the top and bottom of the wheel and see what kind of movement you get. You should have very little if any movement. Obviously the tire is going to flex some but the actuall wheel and hub should not move. while you ahve it jacked up you can rotate the tire and see if you notice any humps on the tire while it is rotating. IF you see any humps then you most likely have a seperated tire.

 

ttt. Thanks for all the suggestions so far: tire, wheel bearings, CV joints! Please keep them coming!

 

wouldnt think it would be CV joint, normally the noise they produce is only heard when turning hard to the left or right. It will usually be worse going one way or the other depending on which one is bad. I think your best bets are either the tire or the wheel bearing.

 

Cyorke,

There is some vibration (noticeable in the seat and the steering wheel) at highway speeds. In my original post, I described the vibration as "thumping once per wheel revolution", which I estimate at at least 5 thumps/bumps per second at highway speeds; so essentially a vibration Is this what you mean by vibration?

Cooncidentally I have a spare tire. Perhaps I should have them mount and balance that and see if that fixes it?

-Steve

 

can you tell for sure what side the vibration seems to be coming from? If so jack that side of the car up and rotate the tire. Look for any kind of bump in the tire as it is rotating. You can also run your hand around the tire to see if you notice any high spots with your hand. If you find one that seems to have high spots in you could mount your spare and see if that takes care of the problem. What you are explaining sounds so much like a bad tire. The belts seperate from the insidde of the tire and there is no supposrt then you end up witha buble in the tire. This is the high spot I am talking about. It is simialr to when you hit a curb and you get that knot on the sidewall except it is in the tread of the tire.

 

Cyorke, thanks for the followup. I know what you are talking about with the bumps/knots/protrusions in the sidewall from hitting a curb, because I got one once on another car. Out of curiousity, what usually causes the kind of the tread that you suspect here? Thanks!

 

most likely it would be caused by hitting potholes or something of that nature. But tires like cars are made by humans so there are defects in tires.

 

Have you tried switching the front right and front left tires to see if it truely is tire related? It's something cheap to check that anyone can do and you wouldn't have to pay to mount your spare.

Good luck.

 

So have you actually looked at any of the suggentions given??

 

If the car is raising and lowering in conjunction with the noise I would venture to say you have a seperated belt in your tire. THis should also cause a vibration though and you dont relaly mention a vibration. Next guess would be wheel bearing. Like punter said jack the wheel up and grab the top and bottom of the wheel and see what kind of movement you get. You should have very little if any movement. Obviously the tire is going to flex some but the actuall wheel and hub should not move. while you ahve it jacked up you can rotate the tire and see if you notice any humps on the tire while it is rotating. IF you see any humps then you most likely have a seperated tire.

as Cyorke said check the tires, you can carefully run your hand along the tread a feel if there is any changes in the surface.

KEEP IT SIMPLE FIRST!

All other problems listed have other signs (noise and driveabilty issues),
you could have somebody drive beside you if the tire is so badly out of balance it will start to hop.

 

Tonight I jacked up the front-right wheel and check all around the inner sidewall, tread, and outer sidewall, running my hand along, for any bumps: none. I also visually inspected the outer sidwall and tread: nothing out of the ordinary. Same for the front-left.

Likewise for both front wheels using the jacked-tire/wheel-bearing test: both front wheels are very firmly attached.

Also in a big parking lot I drove in fully-locked left and right circles under mild constant gas pedal pressure and hearding no clicking; so nothing to indicate a CV joint degredation in the noise department.

I also did a cursory visual inspection of the inner and outer front CV joint boots on both sides and saw nothing egregious, though admittedly it wasn't a thorough examination, so I will have to follow up on that.

I've heard that in general it's a bad idea to rotate tires (even in this case where none of the 4 tires are uni-directional tread and the same size), but this Saturday morning I'll try moving the front left to the rear right and likewise for the other two to see if the bumping stays at the front-right (meaning it's an axle, CV joint, wheel bearing, or tranny issue) or moves (meaning it's a wheel/tire/issue).

A local car shop I've used before says for $20 they'll do a test drive and visual (meaning non-electrical) inspection. I might take them up on it some morning this week.

Thanks for all the interest.

 

Have you had a look at your rear tires? you may think it's coming from up front but it may actually be in the rear.
Also are you running with wheel covers? if so remove them and then try a drive.

Sounds like you've covered everything in the front that would give you the noise that you describe.

Also try a different road ( route ) and see if the same thing happens,

Hope you find the problem