I got a spare wheel off of CL and got a new tire from a store where it was stretched to the wheel and then balanced. When I mount this spare , it make pulsating noise and it increases beyond 50 mph and significantly louder beyond 60. That means my foot off the gas pedal and I can hear that cupping noise, wondering how to fix this ?
Are you sure the rim is true?
The wheel is a used one bought off of Craigslist. so it's not new, but no visible damages or dents.
If the wheel isn't true, it could be causing the vibration/noise you're talking about. If the wheel is true, it would have to be either the balance job or a bad tire.
I'm sorry. does the wheel being true implies it's a good wheel and bad other wise ? The wheel doesn't have any visible damage when it was bought, can it still be a bad wheel. ?
My apologies. If the wheel isn't true, that means the wheel is not completely straight. It can be that way due to a dent (as you mention) or the center of it (where you bolt the rim to the car) might not be right.
At any rate, you can check this a couple of different ways.
- Drive the car and have someone watch the suspect wheel while you drive. It should be fairly obvious if it's out of true.
- Jack the car up and spin the tire by hand. It should be readily apparent if the wheel is true that way as well.
If neither of these pans out (wheel looks good under observation), take it back to where you had the tire mounted at and tell them you believe the job they did sucks ... well, ask them nicely if they could recheck the balance to ensure it's right. If the balance is good, it can only be a bad tire after that (as long as a known good tire in the same location isn't having any issues).
just adding to @paulster2's answer, when it's jacked up if you spin the wheel and look at the rim on the inside(inner side) you might notice a flatspot(a flat deviation to the wheels circular shape), that could cause the noise/vibration, usually happens when you hit a pothole or mount a kerb at speed.
if the wheel is flatspotted it can be heated up and bent back into shape but there is a chance of your wheel cracking, if it's buckled from the center then you would have to either find a new wheel or make do with it