Why do my rear stock 16inch allum. rims for a formula hum. MY buddy which I bought the car from told me it had stock 15inchers on it before, he put the formula rims on. ANd now the rims hum, why is that. It has firestone 245mmR16 on it too.

 

Thats not the Rims you hear humming, its the Rearend gears that are humming. Maybe the rear has been rebuilt, not to specs, which by the way is not that hard to do. OR its the stock rearend thats on its last leg. Get some more info from the dude.

I bet it hums really bad on Deacceleration right?

 

Humming can also be the tires. If they are aggressive tires or the tires are 'chopping'. Feel the tires and see if they have any up and down areas on them. Bearings will also make a hum when they are worn out, but since it started when you put the tires on I would guess the tires are the problem. Are the 245/50R16's new?

 

find a freind with 15inch wheels, put them on and compare the sounds.

 

The way that the tread pattern wears, if you put the tires on the wrong side, they might hum. When a Radial tire wears, it wears the edges of the front of the tread differently than the rear, if you switch sides it could hum... Try reversing the rear wheels from right to left and see if it makes a difference.

Just a thought...

As for a rear end whine is a little different. I have one of those, but get this it only occurs at 75mph, and goes away on acceration or deceleration. Its getting better after 6000 miles I barely hear it anymore. I called Richmond and they said it sounds like I got them pretty good if thats all I hear.


John

 

i would probably go with the rear bearings on this. i just recently replaced mine and the humming has gone away. actually it was more of a throbing sound that matched the speed my car was moving.

the faster, the louder and faster the throbing was...my $.02

 

Maybe it forgot the words to the song? LOL Are the tires specific as to rotation? See if they were mounted correctly. Also adjust the air pressure and see if it changes. Otherwise I agree it could be any of the causes already mentioned. Lon

 

well, its my buddy that sold me the car, and he jsut put the 16inch rims on like less than a year ago, he told me after he replaced teh 15 inchers to 16incher it kicked in the humming, right than. He got the tires new when he got the new rims, and the tires (firestones) have alot of life left in them, I personally think its the tires. If it is the rear end going, what other symtoms would it have. I got 15 inch rims actually sitting in my garage, put only one with the a tire on it. I think I'm going to ask my buddy who has a monte carlo ss, with 15"alluminum rims to try them on my firebird. ANd see how it goes. You guys also think it could be something to do with the rear brakes.

 

not sure about those firestones, but Goodyear has some "directional" tires, they should only go one way...

 

I'm going to check the tires tonight, see what they are.

 

The tires I had on my 95 had arrows to indicate which way they should rotate

John