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So I have noticed lately that from 30-60 mph I can hear a light thumping from my right rear. Could this be a seam going bad in the tire or an allignment issue?? It still has the balance weight on the wheel so I am thinking it is balanced correctly. Or could it be that I dented a rim? If I did dent it, wouldnt I be able to really feel the wheel dent?

Thanks guys...

 
Rep Power: 347

If a tread belt was starting to separate, you would not only hear a thumping but FEEL a thumping. And just because a wheel has weight, doesn't mean it's balanced. If the wheel wasn't balanced, again you would feel before you heard. My two cents is that it might be a bearing going out

 
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You mean an axle bearing?

 
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Hub bearings...How loud is the noise that it makes? Is it like metal on metal thump or like when you hit a pothole thump?

 
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its constant up to about 60mph......I know its the back right tire.In order for a rim to be bent enough to make the noise wouldn't I be able to see the bend? Maybe there is a flat spot on the tire. I do have to fill the tire up every week with air. Maybe this is causing damage to the tire. They are 205 40 17's....

 
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OH YEAH i just went through that and helped others with that. it IS your wheel bearing. to make sure, lift you car and then try to move the wheel in towards the struts and then out towards ....out (i'm NOT talking about spinning the wheel). if it wiggles, it's for sure your wheel bearing. it cost me 120 for a brand new one installed. but idunno about other places

 
Rep Power: 347

Props to the person who backed up my theory
And no...I work at a tire shop. I've seen rims bent so bad that you think "No WAY will this balance!", and they take almost no weight. If it's bad enough to see a bend, they might be...might not. Best would be to take it to a shop, have them reballance them, and ask the guy doing it to make a note of which ones are bent. I balanced some Motegi rims a couple months ago...No bends, but they took about 5 times more weight then any normal wheel should have ever taken. My front two are bent quite a bit, but I only feel them shake if I go above 90. And they took about 1/3rd of the weight to balance then those Motegi's did. It's mostly a function of how well balanced the wheel/tire assembly is. Most tires these days come with the light part of the tire marked...A good installation tech will match the light part up to the heavy part of the rim.

 
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Alright guys thanks..I will take it to get balanced. I will ask him if he sees a bend and I will have him check the bearing...Anything else I should do? Also are you all sure this is the problem? What would cause the bearing to go bad?

 
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miles cause bearings to go bad. They just wear out. Not much you can do.

 
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Perhaps this would be an excellent time to do the Rear disc conversion

 
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Yeah well I am in college soI don't think that will be happening.....I just need to be sure of what it is.....

 
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Doesn't matter man...You can still dream, Can't you? My only problem is finding a wrecked Si. I've seen ONE 02-05 Si in my area...ever.

 
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Well, I went to get them balanced and it looks like the rear right rim has a slight wobble to it. The bearing is fine. Sadly, I don't think I can buy just one of these rims. So my new question is, should I save up for a whole new set of 4 rims, or should I just get thicker tires and hopefully the sound of the rim being dented will go away? The sound is from around 40-60mph with thin 205-40-17's. What do you all think?

 
Rep Power: 424

the sound isn't going to go away with thicker tires. If the rim is dented, its dented, you need to replace it. You should be able to get 1 of any rim thats still in production. If its discontinued, but not some ultra rare JDM rim, then check ebay etc.....
Otherwise, buy 4 new rims.

 
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Well that sucks. Is it possible to take it to a wheel repair shop and have them undent it. Like I said, you can barely notice it until about 40 mph. And I called Aerospeed (the manufacturer of my rims) and they wont sell an individual rim. So now I have to decide what to do. See if the rim can be fixed or buy 4 new rims...The latter option sounds difficult considering i am a college student with a limited income...

 
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How bad is it bent? Two of my rims were curbed...pretty hard. They're bent to the point that you could see the tire moving up and down when it was on the balancer. I have both of these on the front, and I only feel a very slight vibration above 100. Make sure they're statically balancing the tire with peel and stick weights. I balanced my own tires using this method, and like I said, with both of them being on the front it's barely noticeable.

And on another note, it's possible to unbend a rim...Not perfect, but just enough so it's not so bad. I've done this a couple times at work. I'm going to do it with mine. What I'm going to do is stick it backwards on the balancer and then take a big ol' hammer to it

 
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it's your struts.. One of them has been blown. But that's just a guess. Just take a look at the struts and see if they're leaking oil. If they're leaking oil, you need to just get new struts. Trust me I know more than Boilermaker in these areas...

 
Rep Power: 327

.... gets out crystal ball to figure out whats wrong on this car

boiler is one of the most knowledgeable people on this board when it comes to suspension, and stuff....... Even if the struts are leaking YOU have no way of knowing if thats what is causing his problem. As for whats causing the problem .. WHO knows i would suggest taking it to someone and see if they can give a free estimate. My GUESS from whats been desrcibed would be a bad tire, bearing, or even possibly a strut but unlikely from the description. Quick easy diagnostic would be to rotate the tires and see if the noise moves to the front of the car