Dr Teeth
08-26-2007, 09:23 PM
OK, here's my dilema. I bought a set of rims from Discount Tire Direct in early June. After I put them on I had a vibration at about 80 KPH, enough to make the steering wheel visibly shake, so I took the car to a local tire store and had them balanced. No difference.
Next I took the car to a local specialty tire store (Harper's Tire) had the road force balance done. Their machine said that two of the tires were marginal, but they managed to balance them anyway. That seemed to do it. No more shake at 80 KPH and 110 or 120 was OK too. I was completely happy, until my local LX club (Alberta LX) had a big M&G at an acerage about 250 K north of here. Driving home I tucked in behind a buddy's Charger. Everytime he and I hit 140 KPH I got a wicked vibration through the car. OK, here we go again.
I called Discount Tire and explained what was going on. They felt the problem was likely due to the marginal tires, so they sent two more up, and I booked another appointment with Harper's tire to have them installed.
The morning of the install I took the car out for a run so I could describe the exact symptoms. To my surprise I could take it to 180 KPH without any vibration! I have no idea why it vibrated above 140 earlier on the highway. Anyway, I figured I had the tires anyway, so I may as well get the marginal ones replaced.
After Harper's replaced the two marginal tires and re-road force balanced the other two rims I took it for a spin. CRAP! The vibration and steering wheel shake I had at 80 KPH before was back, only now between 90 and 100. So last night I decided to do some self diagnostics. I swapped the right front for the right rear. No change. Then I swapped the left fornt and left rear. Still no change. Finally I decided to put the stock rims and tires back on. Bingo, no more vibration. Today, just to see if the vibration might somehow have been caused by the stiff sidewall on the aftermarket rims, I decided to increase the inflation on the stock tires to 51 PSI (the max on the sidewall). They now ride as stiff as the 20 inch Falkens, but still no vibration, so it's not a sidewall stiffness issue.
Obviously the aftermarket tires and or rims are the cause, but I'm still confused. Whay would the vibration above 140 KPH vanish without doing anything? And the new vibration (with the two new tires) would come and go on a straight stretch, almost like something was going in and out of phase, yet on a straight stretch the tires should rotate at the same speed, so they shouldn't go in and out of phase.
I'll be calling Discount Tire tomorrow morning, as well as Harper's tire, but in the meantime does anyone have any idea what the problem might be.
PS: I made sure all the hucentric adapters were still present (and the right size), the lug nuts show an even wear pattern all around the shoulder, so the shoulder angle seems correct; and I torque everything incrementally with a torque wrench. The rims are 5 on 115, not 114.3 (or at least that's what Discount Tire said when I bought them)
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Next I took the car to a local specialty tire store (Harper's Tire) had the road force balance done. Their machine said that two of the tires were marginal, but they managed to balance them anyway. That seemed to do it. No more shake at 80 KPH and 110 or 120 was OK too. I was completely happy, until my local LX club (Alberta LX) had a big M&G at an acerage about 250 K north of here. Driving home I tucked in behind a buddy's Charger. Everytime he and I hit 140 KPH I got a wicked vibration through the car. OK, here we go again.
I called Discount Tire and explained what was going on. They felt the problem was likely due to the marginal tires, so they sent two more up, and I booked another appointment with Harper's tire to have them installed.
The morning of the install I took the car out for a run so I could describe the exact symptoms. To my surprise I could take it to 180 KPH without any vibration! I have no idea why it vibrated above 140 earlier on the highway. Anyway, I figured I had the tires anyway, so I may as well get the marginal ones replaced.
After Harper's replaced the two marginal tires and re-road force balanced the other two rims I took it for a spin. CRAP! The vibration and steering wheel shake I had at 80 KPH before was back, only now between 90 and 100. So last night I decided to do some self diagnostics. I swapped the right front for the right rear. No change. Then I swapped the left fornt and left rear. Still no change. Finally I decided to put the stock rims and tires back on. Bingo, no more vibration. Today, just to see if the vibration might somehow have been caused by the stiff sidewall on the aftermarket rims, I decided to increase the inflation on the stock tires to 51 PSI (the max on the sidewall). They now ride as stiff as the 20 inch Falkens, but still no vibration, so it's not a sidewall stiffness issue.
Obviously the aftermarket tires and or rims are the cause, but I'm still confused. Whay would the vibration above 140 KPH vanish without doing anything? And the new vibration (with the two new tires) would come and go on a straight stretch, almost like something was going in and out of phase, yet on a straight stretch the tires should rotate at the same speed, so they shouldn't go in and out of phase.
I'll be calling Discount Tire tomorrow morning, as well as Harper's tire, but in the meantime does anyone have any idea what the problem might be.
PS: I made sure all the hucentric adapters were still present (and the right size), the lug nuts show an even wear pattern all around the shoulder, so the shoulder angle seems correct; and I torque everything incrementally with a torque wrench. The rims are 5 on 115, not 114.3 (or at least that's what Discount Tire said when I bought them)
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