A more detailed response dave.. et al.
"Deep6, I believe we went over this in great detail some time ago.
Some people just won't listen."
Ok so I'm stubborn... sue me!!!
"Several things to consider which I think were covered before.
1. Wheels can be out of round. Not likely, but possible. Firstly, are the "hub centric"? ie. do they self center snugly on the hubs or do you have to center them with the lug nuts? If they are hub centric, then you can put them on a balance machine and check the runout of the wheels (both lateral and radial). If they are less than .040" then it is within factory tolerances (ie. as good as a factory wheel). Some better wheels are manufactured to .020" tolerance."
yes, this is where I'm starting to think. I took my car to a specialty auto clinic that specializes in tire/rim installations especially "high performance" applications. The owner of the shop has a Mitsu 3000GT VR4 with over 600hp. He seems to know what he is talking about. But back to the rims. I have "hub- centric rings that allow my wheels to be centered before tightening the lugs down. I was using a set of wheel spacers and the vibes were worse. I tossed the wheel spacers and had the guy grind down about 1/4" off of the bottom of the upper ball joint up front. This solved my up front rubbing problem. When he mounted up a second tire for me due to excessive road force, he noted that that particular rim didn't have the best runout.
"2. Obviously you can also check the tires this way also. If the rims are decent (they usually are), then it's time to look at the tires. Have they been match mounted? Do they require large amounts of weight? Like it or not tires are the usual culprits."
His thinking behind the rims that I am running is that they are of inferior quality being manufactured in the Phillipeans (sp?)
He said that he had a set of my rims too and bent them in a couple of days of driving on NY streets. 3 of the 4 wheels do not require large amounts of weights but the last wheel in question did. However it was the second new tire tried....
"3. You have chosen to mismatch the tires with narrow rims. This is bad juju. With a properly matched rim and tire combination the bead of the tire carries it's load directly on the bead surface of the rim. When the tire is too wide, then the lip of the rim starts to influence things by putting pressure on the actual sidewall of the tire. The sidewall of the tires is not made as precisely as the bead and so it can prevent the tire from running true like it is designed."
Hey don't talk about my juju like that!
However, what you are talking about here is making some sense and that is why I might be running into some problems. Even though the rims/tires read as "balanced" when actually running them in a real load situation, in effect things are "out of round". Hence, I would like to keep the 255 series tire but run the larger rim to rule out his scenaro.
"4. Not to mention that you put a heavy tire on your light weight rims. Why did you do that again? I think we recommended a 235/55 to you in the beginning. Lower weight, lower rolling resistance, and a correct match tread width to rim width. Hmmm, imagine that? I'll say it again, the tread should be no more than 1/2" wider than the rim. The lower the aspect ratio, the more crucial this becomes. "
Yes yes, I know now. I see everyone running big tread on their cars and I wanted a peice of that cake too!!! I confess, I wanted to try and figure out some "other" way of accomplishing it... but it didn't work out perfectly. In my mind.... a 235mm tire is only 10mm wider than stock.... what's the point? Why invest the money? Lower Rolling resistance? Is this why I'm having even more trouble getting good mileage out of my car since switching tires?
"You already had these "road force balanced" right? Unless you have runout problems with either the wheels, I vote that you need to get different tires. 17X9's are going to be either super heavy or super expensive. DT will take the tires back if you tell them that they suck and you want new ones."
Yes, I've had the assemblies "Hunter 9700 Road Force balanced" 3 times now. I took them to the dealership where a buddy (who owns 2 SC's himself and definatly knows what he's talking about) balanced them. However the best that his machine would do was about just under 20Lbs for 3 wheels and no less than 48lbs for the offending wheel.
When I took my car to the auto clinic, he told me that he makes sure to calibrate his Hunter 9700 on a weekly basis and he assured me that he could get my wheels under 10lbs per wheel of road force. That is what he recommended for a smooth ride. He was able to accomplish this again on the other 3 wheels but the best he could do with the offending wheel with a brand new tire was 25lbs. He mounted that one in the back so I wouldn't feel it as much.
So far HIS balancing act has been the "best". I'm able to drive the car smoothly... for the most part between 45mph and 55mph. However, just today i did extended highway driving on them and most of my driving was 70-75mph and I could visibly see the wristwatch on my right wrist shimmying with the steering wheel. When I let go of the wheel, I could see it slightly shaking back and forth. I would think this is more than just the "increased road feel" of a lower aspect ratio. I've also noticed that the first 2-3 miles of driving, even on smooth pavement gives me a little more vibe too. This was all observed on freshly paved asphalt.
My alingment is "dead on" and the auto clinic guy did a good job of it. My problem though is vibe through the steering wheel that just cannot be quelled. Perhaps then, is another portion of my front suspension/steering system excessivly worn? I've got about 90K miles on my car. But I've always driven it safe and sane on the streets and haven't raced it... yet.
Overall, the feeling here is excessive runout on the rims, not neccesarily the tires. My hope is to just eliminate the steady background shake by just doing the right thing and running the proper sized rims. So D.T. said they would take the rims back and refund my money but I want to know what my options are as far as a nice 17x8.5 or 17x9" rim in the 4.25" bolt pattern that aren't known for vibes.