rims offset

[jamcllw]

I'm sure that this has been talked about before but I can't find it anywhere.
I have aftermarket wheels on my car with a lug pattern of 114.3mm if I'm not mistaking Alero's wheel patern is 115mm. My car shakes like crazy when going down the road around 70mph. Is this the reason or are they out of balance, maybe an alignment, maybe the lowering springs? The offset on the wheels are e+ 38/45 and are 17x7. I dunno any help would be appreciated.

thanks

Check out this thread http://invision.aleromod.com/index.php?showtopic=20 and pay particular attention to areas that discuss hubcentric rings.