PJSnow

I seem to be getting vibrations between 90-100+ mph. I don't recall this before but maybe it has just gotten more significant. I feel it mainly in the dead pedal and I guess in the body. I am assuming the wheels will need to be rebalanced but is there anything else that can be causing this kind of issue? Loose bolt somewhere? Worn brakes/rotors? Suspension?

chriso5573

I have the same thing. I asked my friend who does some of the work I don't have time for on my car/motorcycle and he said he's positive its the tires. Apparently when they aren't balanced it will cause vibrations at higher speeds. I'm close to getting new tires so I just deal with it since it's subtle.

PatrickISF

How are your tires? Are they wearing evenly? Are they near the wear bars? Those issues can cause vibrations. I had some vibrations at higher speeds and the tire shop removed all the weights on the wheels and re-did the balance, which helped a lot. I also installed Figs LCA bushings which actually helped some of the vibrations I had before as well. I would start with getting a re-balance which is the easiest thing to do.

lobuxracer

iTrader: (2)

Might be tires, might be a bent/cracked wheel too. I had a crack in the rear wheel on my Supra that only showed up over 135 mph. It was easily repaired.

ssis300

iTrader: (2)

Assuming all of our speed testing is done in Mexico .....which is where we experienced some vibration around 85+ mph speeds in the wife's FX50. Ironically, this came right after a tire rotation, so we just had all four corners re-balanced this weekend and everything is backto being smooth as silk.

Drive safely, my friends.

DreDilla

Slightly off topic... but how does the acceleration and power of the FX50 compare to the IS F?

Weapon F

Road force balancing, I aways use this method when mounting new tire for first time. I've been doing this for few yrs now. First time I used Road force balancing, I had tires on for few months two standard wheel alignment and wheel balanced still had a vibration issue until I Road force balanced tires that's solved my problem. Here some info its little long but may provide you with some useful information regarding the differences between a standard Wheel Balance and Road Force wheel balance.

Driveshaft and axle failures, suspension wear or failure, improper wheel alignment, brake wear or failure, wheel bearing wear, tire/wheel assembly imbalance, out-of-round tire or wheel, or the force variation of a tire.

Since the introduction of the modern spin balancer, most tire/wheel assembly balancing equipment has been able to accurately diagnose and correct both dynamic and static imbalance. However, balancers can only fix balance problems. Even the most sophisticated balancers cannot eliminate vibrations from a bent wheel or an out-of-round or irregularly worn tire.Vibrations can come from several different areas driveshaft and axle failures, suspension wear or failure, improper wheel alignment, brake wear or failure, wheel bearing wear, tire/wheel assembly imbalance, out-of-round tire or wheel, or the force variation of a tire.

All tires have some amount of static and dynamic imbalance. Whether it causes any problems is a function of the amount of imbalance, the wheel and tire combinations, and how the tire/wheel assemblies interact with the vehicle.

Static imbalance makes a tire/wheel assembly vibrate up and down. Dynamic imbalance causes the assembly to shimmy from side to side.

Since the introduction of the modern spin balancer, most tire/wheel assembly balancing equipment has been able to accurately diagnose and correct both dynamic and static imbalance. However, balancers can only fix balance problems. Even the most sophisticated balancers cannot eliminate vibrations from a bent wheel or an out-of-round or irregularly worn tire.

Adding balancing weights can only correct weight differences; it will not compensate for other problems. In fact, in attempting to come up with a balance solution, balancer electronics all start out with the assumption that a tire/wheel assembly is within a certain maximum deviation from round. If an assembly is too far out, the balancer will probably not even be able to make a proper weight correction.

In addition to whatever imbalance it may have, because of the construction of a pneumatic tire, all tires have some variation in sidewall stiffness. It may be best explained by thinking of tires as if they were built with a series of springs in the sidewalls. Some of these imaginary springs are stiffer than the others.

When one of the stiffer springs (the stiffer part of the sidewall) is in position between the wheel and the road, the wheel is pushed up away from the road with more force than when a weaker spring (the softer portion of the sidewall) is between the road and the wheel.

This creates a vibration, undetectable with a normal spin balancer, as the car moves along the road. Whether the variation is noticeable (and by how much) varies with the particular vehicle and its tire and wheel assemblies.

The number of stiff points in a tire/wheel assembly is called the harmonic order; and there may well be more than one. A tire/wheel assembly with one stiff point has a radial first harmonic or R1H. If there were two stiff points, it would be R2H. Three stiff points and its R3H, and so on.

Both the stiffness of a tire’s sidewall and the lateral (side to side) and radial (variation from true round) runout of the wheel combine to determine the harmonic order. While repositioning the tire on the wheel can minimize first harmonics, second and third harmonics are more difficult to correct without wheel or tire replacement.

The radial force produced by variations in sidewall stiffness is called ‘road force variation’ and it cannot be corrected by balancing. Unfortunately, many tires have serious variations in road force that are visually undetectable.

All tire manufacturers test tires at their manufacturing facilities for uniformity, including road force variation, conicity (the tendency to roll like a cone), ply-steer (the tendency to crab sidewise) and balance. Acceptable levels of uniformity vary among manufacturers, tire lines and the planned distribution channel for the tire.

As part of their uniformity measurements and to help with balancing, manufacturers usually place red or yellow marks (or both) on the sidewalls of their tires. The red mark indicates the point of maximum radial force variation (the stiffest point and effective “high spot”) and should be aligned with the wheel’s point of minimum radial runout (the wheel’s “low spot”), which is generally indicated by a colored dot or a notch somewhere on the wheel.

Car manufacturers have been using road force wheel balancers for decades because even the best tires are not perfect. It’s done at the factory on every tire/wheel assembly to create that ever so important new car ride.

So what does a road force balancer actually do? Road force balancers, in addition to performing a traditional spin balance, measure both the wheel and tire by pressing a large roller against the tread of the spinning tire. The roller applies 1,200 to 1,400 pounds of pressure to simulate the weight of the vehicle on the tire as it rolls down the road.

A computer in the machine, along with various sensors, determines variations of tire stiffness, radial runout and anything in the tire’s construction (such as inconsistencies in the belt package) that would prevent the tire from rolling smoothly when it is weighted by the car. By measuring both the wheel and tire, the road force balancer tells the technician where to move the tire around on the wheel until the effective high spot of the tire (when it is rolling on the car) matches the low spot of the wheel – a more sophisticated method of match mounting.

PJSnow

It sounds like the consensus is the tires/balancing. I am planning to get new tires by the end of the summer so hopefully a Road Force balancing and alignment will get rid of the vibration. Thanks for the responses!
I'm hoping I don't have a cracked or bent wheel. Any way to check for that?

lobuxracer

iTrader: (2)

The easy way is when the wheel is on the balancer. When the wheel is spinning it will be pretty obvious if it is out of round or out of true.