Loud noise from Honda Accord 99 when driving above 40mph

If, while recreating the noise at speed, a slight turn of the steering wheel either way makes the noise significantly louder or quieter, then it is likely a front wheel bearing. If the noise doesn't change much at all I would suspect tires.

Feel across the tread of all tires and look for one with a misshapen tread area. If they all feel OK, rotate them front to rear and see if the noise changes.

If the noise is stil present, lift the car safely on jack stands with the rear wheels chocked for safety. Have someone in the car with parking brake on, put it in drive (second gear if manual transaxle), and spin the front tires at aproximately 10 - 30 mph while you listen one at a time. It would help to have someone else hold the opposite side tire still with a car ramp or whatever so that your side will spin alone. Compare both sides. It's really not safe on the ground, but on a lift I would do this with a stethoscope to the inner knuckle area for a better listen.

There are several products on the market like ChassisEar that are clip on mics with long wires that you test drive and listen through with headphones. This is a great way to locate difficult suspension/ steering noises if you have the money for a kit.

Don't rule out the rear wheel bearings if you have no luck locating a problem in the front. Sometimes front to rear noises can be difficult to nail down with just a simple road test.

Toyota MDT in MO

thanks alot for the advise, very informative.

rouhel