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Tire Balancing
I have a new set of Nitto 555G2's 245x17 and 315x17 and can't get them balanced. I've tried 4 dynamic balances and 2 Road Force balances. The tires are true and I haven't had a balance issue in 29,000 miles on my Goodyear F-1's which were balanced several different times when swapping out a bad tire (twice).
The steering shakes and shimmies between 65-75 and sometimes as low as 45 depending on road surface. Any ideas would be helpful. :CRY: |
I'd get the car aligned as you may have some wear and settings have changed after 29k.
Toe-out and Neg camber issues may not rear its head on one tread tire VS another. Lowering of positive caster is not common with wear so probably not suspect. Kuhmo doesn't make the 555G2 but Nitto does. Nittos aren't known for being problematic, Kuhmo has had several quality issues over the years and nothing on a nationwide level in 4-5 years. |
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Sorry spdbrake, yes their Nitto.
I suspected alignment. I have a guy that I've had do it four times. Two were because I worked on the rear and moved the snail adjusters. This last was a four wheel alignment and the rears were right on and the front toe in was slightly off. The symptoms were exactly the same driving t the shop 15 miles as driving home......No change. The Road Force (twice) showed the tires were true and I witnessed this myself as they spun them up on the last balance. |
So the tyres have no radial or axial runout?
And the alignment is good now, but it still does this? Have you got another set of tyres to try? Gary |
No Gary, but like I said the Goodyears were perfect when I swapped them for the Nitto's and they had 30K on them and were 10 years old.
No previous shimmy for 10 years New Nitto's perfectly round....well as close as I've ever seen alignment made no difference running 26 PSI.....tried 35, 30, 26, 22, and 20..... 26 cold seems to be best but not a cure. |
Could it be a case of some cars don't like certain brands of tyres?
One of my cars was a completely different car with a Falken directional tyre versus another cheap brand. Are the Nittos directional or asymmetrical etc? |
Not to give you a science project but.... If you jack the car and put the front wheels on the back and spool them up while on jacks and they're smooth as glass...
You've got something loose or worn in the front end, be it steering, rodend, caster plate, A-arm bearing, ball-joint. |
So if they balanced out on the machine 2-3 times, they're balanced. To keep balancing them on the same machine and expecting a different result is one of the definitions of insanity. :)
Same thing with the alignment. If you've checked the alignment a couple of times, and it's spot on, move on to something else. Something's loose, broken, or worn out. Gradually increase the car's speed in one gear, and pay attention to the speed and rpm that the vibration starts and stops. Check it in at least 2 gears. Do that 2-3 times to check for consistency. Then get the car up above the speed that it vibrates, like 80-85mph. Put it in neutral, and let it slowly coast down to about 35mph. Write down the speeds that the vibration starts and stops. Do that 2-3 times to check for consistency. If it vibrates most under power, it's driveline. If it vibrates most coasting, it's suspension. |
Adding to Bob's info above, I'll tell you a story about wheel balancers.
We had a new Balancer installed a few years back. My argument with the tech who showed us how to use it was: "You have got 2 zeros, so remove the wheel and refit it to the balancer, and it should spin up zeros again". He says no. Sure enough the machine says the wheel is wrong now, so rebalance again. So, in which instance was the wheel correct, if ever? Thank god, my type of work didn't involve using it. On rear wheel drive cars, your front wheels should rotate by hand and then stop on their own at different places, if they slow and then roll the other way, that is a heavy spot. |
I had the same problem...it was the pins.... needed to be VERY carefully centered and torqued and the tire pressures needed to be lowered to 18 psi.....no really....
I hate those fing pin wheels ....now I have fake ones with lug nuts and the car is as smooth as the proverbial baby's bottom... You have my sympathy, used to piss me off to have a 75 thousand dollar bucket list car that used to annoy me every time I drove it... There are a few places that can balance the tires on the car.... good luck.. |
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I had a hiway speed vibration problem that was solved by installing hub centric rings. You might also look at swapping out your front ball joints, as these have been known to be low quality parts from the factory.
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You might want to try a run-out check on your wheels since this started when the new tires were mounted. Even the best tire tech can bend one on a machine from time to time.
Don't ask me how I know. Bill |
I had the same problem!
I suggest one of you new tires is not round. They are balanced, but not round. I struggled with it for years! Road force balanced by 2 different shops and they swore it was right. Finally found the right tech and he found one of my rims was slightly out. I thought the road balance machines should show this but it didn't on my case. Fat tires on a lightweight car, they seem to be more sensitive and the normal tech thinks its within tolerance! |
Hey randy...where did you get the hub centric rings for Superformance wheels?
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Here's the latest.
I jacked the car up and used my dial indicator on the center of the tread at 30lbs. pressure. The readings were .083 and .085 on the fronts and .075 and .070 on the rear. I also used the dial on the sidewall bead and there was less that .010. I say less but it was virtually undetectable. The flat spots can be seen but Nitto would not give me a number for "out of round" I did go to the dealer with these numbers but he doesn't know anything!!!! He gave me Nitto's number and I initiated a case with them. I would expect .030 runout but .083 seems high but I don't know if my odd ball method of measuring is valid to determine true run out. I expect an answer from Nitto before the days end. By the way..... The low speed shimmy at around 45 when the car first rolls out of the barn is normal according to Nitto. I need to mention that after about 3 miles it doesn't shake at below 60 again. He said typical of the soft compound of these tires............. When it shimmied at 35-45 the few times I've driven it with these new Nitto's I thought I was loosing my mind. Good to know I'm not the only one experiencing this phenom. |
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Randy tagged it for you! If you have an SPF with 29,000 miles and SPF balljoints that is your problem. Replace them with the Cobra Valley balljoints and your issues will disappear. Ed |
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Tom, I'm running the same tires as you. I don't get the high speed shimmy, but these tires sure do flat spot when sitting for long.
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