Vibration over 65 mph?
08-27-13, 07:38 PM
#1
The pursuit of F
Thread Starter
Vibration over 65 mph?
Over 65 mph or 105 km/hr, when maintaining that speed with light throttle input or accelerating to a higher speed, I feel a high frequency vibration in the car. Any passenger feels it. If I let go of the accelerator to coast down to 65, no vibration during that time. 
I sense it has to do with the power delivery and possibly the AWD system instead of tires wheels balancing issues which would vibrate regardless of throttle input or not.
Before I remove my 5mm spacers to troubleshoot and subsequently bring it in to my dealer, anyone else with this issue?
I sense it has to do with the power delivery and possibly the AWD system instead of tires wheels balancing issues which would vibrate regardless of throttle input or not.
Before I remove my 5mm spacers to troubleshoot and subsequently bring it in to my dealer, anyone else with this issue?
08-27-13, 07:46 PM
#2
Lexus Test Driver
It definitely cannot be your wheel balancing since your car is almost brand new. I doubt getting it re-balanced will fix the issue.
That leaves your tires and considering Lexus decided to put the biggest pile of cr*p Bridgestone on their sportiest sedan right now so it must be due to your tires unevenly wearing out. A phenomenon known as "cupping". When the tire blocks don't evenly wear out on each front and back, it results in the tread blocks hitting the pavement with different force resulting in vibrations.
You can google "tire cupping" and read up more about it.
http://www.cherokeesrt8.com/forums/s...ad.php?t=29184
You should take your car to a tire shop and have them run their hands over your tires to see if they are getting "cuped".
That leaves your tires and considering Lexus decided to put the biggest pile of cr*p Bridgestone on their sportiest sedan right now so it must be due to your tires unevenly wearing out. A phenomenon known as "cupping". When the tire blocks don't evenly wear out on each front and back, it results in the tread blocks hitting the pavement with different force resulting in vibrations.
You can google "tire cupping" and read up more about it.
http://www.cherokeesrt8.com/forums/s...ad.php?t=29184
You should take your car to a tire shop and have them run their hands over your tires to see if they are getting "cuped".
08-27-13, 08:06 PM
#3
The pursuit of F
Thread Starter
Thanks 05rollaxrs. However I don't see this being a tire issue since my 3IS only has 320 km and the vibration is not there if I let go of the accelerator at high speed. I even doubt it's the spacers because again the vibration would be present even without throttle input at that speed. I'm thinking it's an off-balanced drive shaft?
08-27-13, 09:24 PM
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Avoid all conclusions
There are pitfalls ... it seems that if a tire is out of balance, that if it shimmies at a certain speed, it should do so at that speed no matter if the accelerator pedal is pressed. That seems reasonable enough. But, isn't the same going to be true of drive shafts and other parts of the drivetrain?
Nothing obvious jumps out, but what are the odds that it would?
One possibility to consider, notwithstanding that it does not seem consistent with the observed behavior, is a time with uneven "road force". This was explained on an episode of Goss' Garage a year or so ago, and I had never heard of it before then. What can evidently happen is that the stiffness of the side wall is not uniform all the way around the tire. When the tire rolls, the center of the tire, and the axle, lift up and down slightly, varying in accordance with the variation in side wall stiffness. He showed a special balancing machine where the tire is actually pressed against a big roller as it spins, to simulate actual installation on the car. Again, this does not seem consistent with what you observed, but it will be difficult to find anything that is consistent with that behavior.
Evidently, somewhere there is some part that vibrates ordinarily but that stops vibrating when the accelerating force is removed. It would seem more likely to encounter the opposite, i.e., for a vibration to be damped when the part that is vibrating is less able to move freely. When the drive axle is exerting torque at the wheel, there is contact force against the big ***** in the CV joint, that will not be present when the accelerating force is removed. I don't think that helps at all, but I'm just sort of thinking out loud. The same occurs at the other end of the drive shaft. When the accelerating force is removed, the drive shaft loosens up at both ends, and is more free to vibrate. But you are experiencing the opposite. The only way it seems likely to me that that would happen is if some part is improperly machined, which would surprise me immensely.
Presumably it is unrelated to braking, or you would have mentioned that.
Engine torque undergoes fluctuation or perturbation over each 720 degrees. This inherently induces vibration. Ordinarily this is suppressed by the flywheel, but the flywheel only smooths out the torque fluctuations that would transmit into the chassis via the reaction, at the drive axles, to the application of accelerating force at the contact patches. The engine itself vibrates in mode that is specific to the fluctuation in torque, in addition to the vibration associated with piston motion. During acceleration, the torque reaction causes the engine to press against the engine mounts on one side of the engine. This could have the effect of suppressing vibration, although it seems more likely, once again, that the effect would be the opposite.
I don't know. I'm just sort of thinking out loud.
Nothing obvious jumps out, but what are the odds that it would?
One possibility to consider, notwithstanding that it does not seem consistent with the observed behavior, is a time with uneven "road force". This was explained on an episode of Goss' Garage a year or so ago, and I had never heard of it before then. What can evidently happen is that the stiffness of the side wall is not uniform all the way around the tire. When the tire rolls, the center of the tire, and the axle, lift up and down slightly, varying in accordance with the variation in side wall stiffness. He showed a special balancing machine where the tire is actually pressed against a big roller as it spins, to simulate actual installation on the car. Again, this does not seem consistent with what you observed, but it will be difficult to find anything that is consistent with that behavior.
Evidently, somewhere there is some part that vibrates ordinarily but that stops vibrating when the accelerating force is removed. It would seem more likely to encounter the opposite, i.e., for a vibration to be damped when the part that is vibrating is less able to move freely. When the drive axle is exerting torque at the wheel, there is contact force against the big ***** in the CV joint, that will not be present when the accelerating force is removed. I don't think that helps at all, but I'm just sort of thinking out loud. The same occurs at the other end of the drive shaft. When the accelerating force is removed, the drive shaft loosens up at both ends, and is more free to vibrate. But you are experiencing the opposite. The only way it seems likely to me that that would happen is if some part is improperly machined, which would surprise me immensely.
Presumably it is unrelated to braking, or you would have mentioned that.
Engine torque undergoes fluctuation or perturbation over each 720 degrees. This inherently induces vibration. Ordinarily this is suppressed by the flywheel, but the flywheel only smooths out the torque fluctuations that would transmit into the chassis via the reaction, at the drive axles, to the application of accelerating force at the contact patches. The engine itself vibrates in mode that is specific to the fluctuation in torque, in addition to the vibration associated with piston motion. During acceleration, the torque reaction causes the engine to press against the engine mounts on one side of the engine. This could have the effect of suppressing vibration, although it seems more likely, once again, that the effect would be the opposite.
I don't know. I'm just sort of thinking out loud.
08-29-13, 04:25 PM
#7
The pursuit of F
Thread Starter
^^^^^ Appreciate the brainstorming of ideas. Lots of possibilities.
UPDATE: I removed my 5 mm spacers and it's now more difficult to tell if the vibration is there. I did feel the vibration but not as consistently and as intense as before. I suspect the spacers simply exacerbated the underlying issue which I still believe one exists.
I brought it in for servicing and they'll run some tests overnight into tomorrow. They mentioned it's possible a wheel is not perfectly balanced and I do recall one of the rear wheels had around 8 -10 individual weights attached!
Fingers crossed they find the source so I can put the spacers back. BTW, got a '13 ES 350 as a loaner and it's a smooth, powerful, and quiet cruiser. Nice straight-line vehicle, not so much on the curves.
UPDATE: I removed my 5 mm spacers and it's now more difficult to tell if the vibration is there. I did feel the vibration but not as consistently and as intense as before. I suspect the spacers simply exacerbated the underlying issue which I still believe one exists.
I brought it in for servicing and they'll run some tests overnight into tomorrow. They mentioned it's possible a wheel is not perfectly balanced and I do recall one of the rear wheels had around 8 -10 individual weights attached!
Fingers crossed they find the source so I can put the spacers back. BTW, got a '13 ES 350 as a loaner and it's a smooth, powerful, and quiet cruiser. Nice straight-line vehicle, not so much on the curves.
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08-29-13, 05:50 PM
#8
Lexus Test Driver
I think I somehow I missed this post before. Glad that there is some progress for the vibration issue. If you observe one wheel has much more tape weights than the others, it means that particular wheel was not the best out of the batch. Usually a wheel balancing would solve the issue but maybe it just requires a balancing of greater precision by a better tire shop. Taking the car to the dealership is always the first step, considering the car hasn't been driven much. My past experience tells the even a shop points you to a wheel balancer with the display "0.00" and "0.00", it does not necessarily mean the wheel is perfectly balanced because if the tire is not seated properly with the wheel, no matter how many times the shop attempts to balance the tire, vibration still occurs. This happened to me two decades ago. You can PM me if you need a good tire shop if the dealership has a hard time troubleshooting the issue.
08-29-13, 07:27 PM
#9
The pursuit of F
Thread Starter
I think I somehow I missed this post before. Glad that there is some progress for the vibration issue. If you observe one wheel has much more tape weights than the others, it means that particular wheel was not the best out of the batch. Usually a wheel balancing would solve the issue but maybe it just requires a balancing of greater precision by a better tire shop. Taking the car to the dealership is always the first step, considering the car hasn't been driven much. My past experience tells the even a shop points you to a wheel balancer with the display "0.00" and "0.00", it does not necessarily mean the wheel is perfectly balanced because if the tire is not seated properly with the wheel, no matter how many times the shop attempts to balance the tire, vibration still occurs. This happened to me two decades ago. You can PM me if you need a good tire shop if the dealership has a hard time troubleshooting the issue.
08-30-13, 06:28 AM
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Balancing isn't adequte without checking road force.
I want to emphasize once again that conventional dynamic balancing of a tire is not sufficient, because it does not detect "road force variation". I suggest reading this:
http://www.motorweek.org/features/go..._balancing_act
It is reasonable to expect stronger likelihood of this potential problem with run-flat tires than with regular tires, due to the stiffer side walls. Whenever a tire is correctly balanced on a conventional tire balancing machine but still vibrates when mounted on the car, road force variation is the most likely explanation.
And of course it is true that if the tire is not centered exactly the same on the balance machine as it is on the wheel hub of the car, the balance will be different and it will vibrate. But this is obvious, and is not likely to occur. However, if there is any debris on the wheel or on the surface of the wheel hub, which might alter the way that the tire rests against the surface behind it, this as well will mess up the balance. And the same thing will occur if the spacer is not completely uniform in thickness all the way around. I havn't seen the spacer so I can't speculate much here, but assuming it is one large disc with holes for the studs, then if it is even slightly thicker at one point than at the opposite point, this as well would ruin the balance of that wheel. And I will try to explain exactly why this would occur.
To explain why this would occur, I need to explain the difference between static balance and dynamic balance. Tire balancing machines check for dynamic balance. Consider the example of balancing a crankshaft, but suppose that in place of the actual crankshaft, we are balancing a simple circular shaft, i.e., a long, straight cylinder, circular in cross section. Assuming that the density of the shaft is uniform and that there are no imperfections, then as long as it is mounted such that the rotation axis is aligned with the centerline of the shaft, it will achieve static balance. What this means is that, under the influence of gravitational force (or any similar acceleration), it will not rotate all on its own. And if you give it a spin, it will eventually come to a stop, and the point where it does will be completely random. Statically, it is balanced. Now suppose that very close to one of the shaft you attach a small mass, and then the same distance from the other end you attach an identical mass, but opposite by 180 degrees. The shaft will still be statically balanced. As before, it will have no tendency to rotate on its own, under the force of gravity or similar acceleration, and if you spin it, it will come to a stop at a random point. But, it lacks dynamic balance. As it rotates, the angular momentum vector, which is directed approximately along the length, is skewed due to the two weights, and as it rotates, the angular momentum vector constantly changes direction. Here you have static balance but do not have dynamic balance. It wobbles when it rotates. This is why when you watch a tire being balanced, the machine tells the technician not merely where to rotate the tire when placing the weight, but also the proper location for the weight in the other dimension, along a line between the front of the wheel and the rear of the wheel. If that part of it is not done correctly, the wheel will end up statically balanced but not dynamically balanced, and it will wobble.
I hope this makes sense, and that it reveals why an imperfect spacer could be the cause of the problem. It does not seem likely that this would be the cause, but it is within the realm of possibility. And there still is no apparent explanation for why the vibration goes away when you take your foot of the accelerator pedal, which is mysterious.
http://www.motorweek.org/features/go..._balancing_act
It is reasonable to expect stronger likelihood of this potential problem with run-flat tires than with regular tires, due to the stiffer side walls. Whenever a tire is correctly balanced on a conventional tire balancing machine but still vibrates when mounted on the car, road force variation is the most likely explanation.
And of course it is true that if the tire is not centered exactly the same on the balance machine as it is on the wheel hub of the car, the balance will be different and it will vibrate. But this is obvious, and is not likely to occur. However, if there is any debris on the wheel or on the surface of the wheel hub, which might alter the way that the tire rests against the surface behind it, this as well will mess up the balance. And the same thing will occur if the spacer is not completely uniform in thickness all the way around. I havn't seen the spacer so I can't speculate much here, but assuming it is one large disc with holes for the studs, then if it is even slightly thicker at one point than at the opposite point, this as well would ruin the balance of that wheel. And I will try to explain exactly why this would occur.
To explain why this would occur, I need to explain the difference between static balance and dynamic balance. Tire balancing machines check for dynamic balance. Consider the example of balancing a crankshaft, but suppose that in place of the actual crankshaft, we are balancing a simple circular shaft, i.e., a long, straight cylinder, circular in cross section. Assuming that the density of the shaft is uniform and that there are no imperfections, then as long as it is mounted such that the rotation axis is aligned with the centerline of the shaft, it will achieve static balance. What this means is that, under the influence of gravitational force (or any similar acceleration), it will not rotate all on its own. And if you give it a spin, it will eventually come to a stop, and the point where it does will be completely random. Statically, it is balanced. Now suppose that very close to one of the shaft you attach a small mass, and then the same distance from the other end you attach an identical mass, but opposite by 180 degrees. The shaft will still be statically balanced. As before, it will have no tendency to rotate on its own, under the force of gravity or similar acceleration, and if you spin it, it will come to a stop at a random point. But, it lacks dynamic balance. As it rotates, the angular momentum vector, which is directed approximately along the length, is skewed due to the two weights, and as it rotates, the angular momentum vector constantly changes direction. Here you have static balance but do not have dynamic balance. It wobbles when it rotates. This is why when you watch a tire being balanced, the machine tells the technician not merely where to rotate the tire when placing the weight, but also the proper location for the weight in the other dimension, along a line between the front of the wheel and the rear of the wheel. If that part of it is not done correctly, the wheel will end up statically balanced but not dynamically balanced, and it will wobble.
I hope this makes sense, and that it reveals why an imperfect spacer could be the cause of the problem. It does not seem likely that this would be the cause, but it is within the realm of possibility. And there still is no apparent explanation for why the vibration goes away when you take your foot of the accelerator pedal, which is mysterious.
08-30-13, 08:04 AM
#11
Lexus Test Driver
Thanks AndyL for the background. I believe the dealer has access to the Hunter Road Force balancers and I'm hoping that will suffice if it's the wheel(s) in the first place. Will post tomorrow as I'll know then. Here's a pic I found of the wheel with at least 8 weights.
I am told repeatedly by a few tires shops that Hunter Road Force balancer is not the best in the market. (My dealership also uses that as well. ). The tire shop that I go to use Hoffman machine (forgot the exact model) and it is more accurate for more demanding wheels. I believe some BMWs in our local area use Hoffman machines as well.
http://www.hofmann.ca/default.asp
And don't forget to check carefully about the rim condition when you get back the car. F-Sport wheels are so precious.
08-30-13, 08:10 AM
#12
Lexus Test Driver
I want to emphasize once again that conventional dynamic balancing of a tire is not sufficient, because it does not detect "road force variation". I suggest reading this:
http://www.motorweek.org/features/go..._balancing_act
It is reasonable to expect stronger likelihood of this potential problem with run-flat tires than with regular tires, due to the stiffer side walls. Whenever a tire is correctly balanced on a conventional tire balancing machine but still vibrates when mounted on the car, road force variation is the most likely explanation.
And of course it is true that if the tire is not centered exactly the same on the balance machine as it is on the wheel hub of the car, the balance will be different and it will vibrate. But this is obvious, and is not likely to occur. However, if there is any debris on the wheel or on the surface of the wheel hub, which might alter the way that the tire rests against the surface behind it, this as well will mess up the balance. And the same thing will occur if the spacer is not completely uniform in thickness all the way around. I havn't seen the spacer so I can't speculate much here, but assuming it is one large disc with holes for the studs, then if it is even slightly thicker at one point than at the opposite point, this as well would ruin the balance of that wheel. And I will try to explain exactly why this would occur.
To explain why this would occur, I need to explain the difference between static balance and dynamic balance. Tire balancing machines check for dynamic balance. Consider the example of balancing a crankshaft, but suppose that in place of the actual crankshaft, we are balancing a simple circular shaft, i.e., a long, straight cylinder, circular in cross section. Assuming that the density of the shaft is uniform and that there are no imperfections, then as long as it is mounted such that the rotation axis is aligned with the centerline of the shaft, it will achieve static balance. What this means is that, under the influence of gravitational force (or any similar acceleration), it will not rotate all on its own. And if you give it a spin, it will eventually come to a stop, and the point where it does will be completely random. Statically, it is balanced. Now suppose that very close to one of the shaft you attach a small mass, and then the same distance from the other end you attach an identical mass, but opposite by 180 degrees. The shaft will still be statically balanced. As before, it will have no tendency to rotate on its own, under the force of gravity or similar acceleration, and if you spin it, it will come to a stop at a random point. But, it lacks dynamic balance. As it rotates, the angular momentum vector, which is directed approximately along the length, is skewed due to the two weights, and as it rotates, the angular momentum vector constantly changes direction. Here you have static balance but do not have dynamic balance. It wobbles when it rotates. This is why when you watch a tire being balanced, the machine tells the technician not merely where to rotate the tire when placing the weight, but also the proper location for the weight in the other dimension, along a line between the front of the wheel and the rear of the wheel. If that part of it is not done correctly, the wheel will end up statically balanced but not dynamically balanced, and it will wobble.
I hope this makes sense, and that it reveals why an imperfect spacer could be the cause of the problem. It does not seem likely that this would be the cause, but it is within the realm of possibility. And there still is no apparent explanation for why the vibration goes away when you take your foot of the accelerator pedal, which is mysterious.
http://www.motorweek.org/features/go..._balancing_act
It is reasonable to expect stronger likelihood of this potential problem with run-flat tires than with regular tires, due to the stiffer side walls. Whenever a tire is correctly balanced on a conventional tire balancing machine but still vibrates when mounted on the car, road force variation is the most likely explanation.
And of course it is true that if the tire is not centered exactly the same on the balance machine as it is on the wheel hub of the car, the balance will be different and it will vibrate. But this is obvious, and is not likely to occur. However, if there is any debris on the wheel or on the surface of the wheel hub, which might alter the way that the tire rests against the surface behind it, this as well will mess up the balance. And the same thing will occur if the spacer is not completely uniform in thickness all the way around. I havn't seen the spacer so I can't speculate much here, but assuming it is one large disc with holes for the studs, then if it is even slightly thicker at one point than at the opposite point, this as well would ruin the balance of that wheel. And I will try to explain exactly why this would occur.
To explain why this would occur, I need to explain the difference between static balance and dynamic balance. Tire balancing machines check for dynamic balance. Consider the example of balancing a crankshaft, but suppose that in place of the actual crankshaft, we are balancing a simple circular shaft, i.e., a long, straight cylinder, circular in cross section. Assuming that the density of the shaft is uniform and that there are no imperfections, then as long as it is mounted such that the rotation axis is aligned with the centerline of the shaft, it will achieve static balance. What this means is that, under the influence of gravitational force (or any similar acceleration), it will not rotate all on its own. And if you give it a spin, it will eventually come to a stop, and the point where it does will be completely random. Statically, it is balanced. Now suppose that very close to one of the shaft you attach a small mass, and then the same distance from the other end you attach an identical mass, but opposite by 180 degrees. The shaft will still be statically balanced. As before, it will have no tendency to rotate on its own, under the force of gravity or similar acceleration, and if you spin it, it will come to a stop at a random point. But, it lacks dynamic balance. As it rotates, the angular momentum vector, which is directed approximately along the length, is skewed due to the two weights, and as it rotates, the angular momentum vector constantly changes direction. Here you have static balance but do not have dynamic balance. It wobbles when it rotates. This is why when you watch a tire being balanced, the machine tells the technician not merely where to rotate the tire when placing the weight, but also the proper location for the weight in the other dimension, along a line between the front of the wheel and the rear of the wheel. If that part of it is not done correctly, the wheel will end up statically balanced but not dynamically balanced, and it will wobble.
I hope this makes sense, and that it reveals why an imperfect spacer could be the cause of the problem. It does not seem likely that this would be the cause, but it is within the realm of possibility. And there still is no apparent explanation for why the vibration goes away when you take your foot of the accelerator pedal, which is mysterious.
The other person who has discussed this topic with me and who can converse so well about the difference between static and dyanmic balance, road force vibration is the owner of the tire shop that I go to.
Many years ago, I had some wheel vibrations with my first car and ever since I learned about this subject from the tire shop which I still go to.
08-30-13, 03:27 PM
#13
The pursuit of F
Thread Starter
No problem. Let us know how it turns out. The sooner it gets fixed, the better is for your tire wear.
I am told repeatedly by a few tires shops that Hunter Road Force balancer is not the best in the market. (My dealership also uses that as well. ). The tire shop that I go to use Hoffman machine (forgot the exact model) and it is more accurate for more demanding wheels. I believe some BMWs in our local area use Hoffman machines as well.
http://www.hofmann.ca/default.asp
And don't forget to check carefully about the rim condition when you get back the car. F-Sport wheels are so precious.
I am told repeatedly by a few tires shops that Hunter Road Force balancer is not the best in the market. (My dealership also uses that as well. ). The tire shop that I go to use Hoffman machine (forgot the exact model) and it is more accurate for more demanding wheels. I believe some BMWs in our local area use Hoffman machines as well.
http://www.hofmann.ca/default.asp
And don't forget to check carefully about the rim condition when you get back the car. F-Sport wheels are so precious.
I got the car back. Rims are undamaged. The right rear wheel was not perfectly balanced. They had to add a 0.25oz weight. The number of individual weights went down from 8 to 4 now. My ride home was smooth on the little bit of "non-traffic-infested" highway I was blessed with! I'll put the spacers back on only at the rear since if there will be a problem, I suspect it's from there. If all good, will put them on the front. Will test and update.
Last edited by corradoMR2; 08-30-13 at 03:31 PM.
08-30-13, 04:53 PM
#14
08-30-13, 06:54 PM
#15
The pursuit of F
Thread Starter
as the car vibrates slightly at highway speeds.One thing I noticed when I removed the spacers yesterday before servicing the car at Lexus is they had an imprint of the rim because the spacers are aluminum. (See pic) This "softness" may be what is messing up the ride. I suspect when I hand torqued the lugs, it takes one lug to be slightly more torqued than the other four to make a slightly deeper imprint in the spacer at that spot. This would result in a rotational axis that is not perfectly straight, creating a slight wobble, and hence the vibration.
My last attempt at this is find spacers made of steel and give it a shot...