Diagnosis? Vibration After Wheel Change

I just had my front 2 wheels changed with mounting and balancing. In addtiion the new to me (used) fronts and the existing rears were all refinished.

A new slight vibration/noise has started up when the car is coming to a halt--I noticed when applying the brakes. It seems to be coming from the front, possibly the passenger side but I'm not positive. The car is otherwise driving well and no issues at higher speeds. I am certain that it's related to wheel swap as this was never an issue before.

What are the most likely causes--loose nut, or inappropriate balancing/mounting? The wheel guy told me not to touch the rims for 24 hours so as not to tarnish the finish but I will check the nuts after that. I want to be educated on whats the the likely problem before I take it back to the shop or ideally solve it beforehand.

I'm running 18/19 M5s with Stoptech BBK (just clears in fronts). On a Zanardi suspension. Thanks.

any centering rings(hubcentric)?

I am not 100% sure as I wasn't present at the initial install. I have a picture here -- and if you look closely there are 2 black layers. Maybe one is a centering ring? Excuse my ignorance on the topic.

I was going to suggest the same thing as docjohn. You wouldn't really be able to tell based on that picture, I am pretty sure you probably have to pull the wheels off. SOS has some metal ones, I would suggest those over the plastic ones if you don't have them.

http://www.scienceofspeed.com/products/exterior_performance_products/NSX/aluminum_centering_rings/

Second pic you can see the red hub centric rings through the center cap hole. My guess is something brake related if its only at slowing down not specific speeds... Hard to diagnose without seeing in person or driving. They may have sprayed brake cleaner on the rotors or?

Another possibility since the fronts are new to you, is to check for a slight bend in one of them.
Less likely is that when being refinished they painted (powdercoated?) the machined lug faces, not allowing them to torque down evenly.

Brian

Do you have another set of wheels/tires you could swap onto the car? That would let you narrow it down to something on the car (brakes, suspension) vs something with the wheels/tires (imbalance, bent, lack of hubcentricity/rings, etc).

Unfortunately, I suspect your options for swapping are limited with a big brake kit...

Are the front tires new. If not, were they swapped left to right/right to left or left as they were? I've noticed some tires after a period tend to cup on the inside, sometimes the outside. When they are swapped left to right/right to left they will give a slight vibration as your braking because your transferring the cars weight to the front, loading up the front tires and that's when you feel the tire wear {cupping}. This has happened to me on mine before.

Uneven tire wear, vibrations, and cupping are all different things.

It's common for the NSX to wear the insides of the front tires first. You won't feel it as vibrations.

"Cupping", also known as "scalloping", is an uneven wear pattern, pictured in the photo below. It occurs when tires aren't rolling smoothly down the road. The most common causes are suspension problems (bushings, bearings, etc) or tire balancing problems. However, you won't feel a cupped wear pattern as a vibration, at least not unless the wear is so far gone that they should have been replaced long ago. (But if the cupping is caused by a balancing problem, then you will feel that problem as a vibration.)

I would have the tires rebalanced just to rule that out. I would also be very careful about re-mounting the wheels, making sure to snug the lugs first then tighten them before the full weight of the car is lowered onto them. And yes, metal centering rings will help. Unfortunately, when wheels aren't hubcentric (don't have the matching hub diameter for the car), vibrations are common and can be difficult or impossible to eliminate completely.

Is there any vibration if you decelerate without using the brakes? If no, then its almost certainly the brakes.

Possibilities:
Warped rotor
Cracked rotor (not all that uncommon with drilled rotors)
Pad material desposited on rotor. (You wouldn't be able to visually detect this but it is a very common problem caused by parking while pads are still hot. Often mis-diagnosed as warped rotors).

You might want to start by carefully inspecting each of the front rotors. You should be able to spot any small cracks through the rims.
Then I would re-torque all the lug nuts to factory spec. (80 ft/lb?) You can do this without touching the rims. If you don't have a torque wrench borrow or buy one. Loosen and re-tighten each lug nut in a star pattern, drive the car a few miles, then recheck torque on each lug nut. Improperly torqued lug nuts will cause disk brake rotors to warp. The only fix is to resurface them or replace them.

You can also check for warpage yourself by testing the run-out on each rotor but this will require removing the rims of course.

Thanks for the advice. The tires are old but less than 2k miles on them--and I don't know if kept them on the same rims. I will drive the car a bit more but I noticed the issue when braking and coming to a halt at a slow speed. I will have to test it out to see if it also occurs without braking. The BBK installation is new--also less than 2k miles driven on it and I didn't have any issues prior to the wheel swap. The parts are essentially new in terms of usage.

I will try some of those suggestions. The shop that did the work (actually they subcontracted it to a wheel refinisher) says they will take a look at it and hopefully it can be remedied. I would say it's less of a vibration and more of a noise but seems like it's coming from some irregular contact of 2 surfaces/structures.

Easy test for me would to go thru a brake bed in procedure. On my BBKs I sometimes get deposits that cause such things. A bed in removes them clean. Not always a the problem.. but a quick test nontheless.

you can simply remount each wheel yourself and see if that helps.

nsxtasy said:

Uneven tire wear, vibrations, and cupping are all different things.

It's common for the NSX to wear the insides of the front tires first. You won't feel it as vibrations.

"Cupping", also known as "scalloping", is an uneven wear pattern, pictured in the photo below. It occurs when tires aren't rolling smoothly down the road. The most common causes are suspension problems (bushings, bearings, etc) or tire balancing problems. However, you won't feel a cupped wear pattern as a vibration, at least not unless the wear is so far gone that they should have been replaced long ago. (But if the cupping is caused by a balancing problem, then you will feel that problem as a vibration.)

I would have the tires rebalanced just to rule that out. I would also be very careful about re-mounting the wheels, making sure to snug the lugs first then tighten them before the full weight of the car is lowered onto them. And yes, metal centering rings will help. Unfortunately, when wheels aren't hubcentric (don't have the matching hub diameter for the car), vibrations are common and can be difficult or impossible to eliminate completely.

Click to expand...

This is much better worded than my post. :redface:

i would swap the front wheels and go for a test in dry weather (in case the tires are directional). if the noise has moved to the other side then it has to be the wheel.

docjohn said:

you can simply remount each wheel yourself and see if that helps.

Click to expand...

Just talked to Ozone, not the wheel.

The passenger side wheel just barely is touching the stoptech caliper. He's going to try a 3mm spacer. I believe Synth19 is running same spec model 5's up front possibly with a small spacer as well?

I think I figured it out. The noise only comes on braking and not just slowing down. As Chris and tof noted if it's only on braking, then it must be a brake issue. And brakes were working fine prior to install.

So I was driving on the way to the shop and noticed the sound better today (definitely a clashing of 2 substances) -- again occurring while braking to a halt. Getting near the shop, I decided to pump the brakes harder and I started hearing a grinding noise. I had a suspicion of what it was (it occurred to me yday actually but I wasn't sure)--lack of proper clearance of BBK. I checked the Stoptech caliper and noticed a tiny scuff where the inner aspect of the wheel was probably rubbing on it.

I talked it over with the shop owner and he concurred that symptoms were due to improper clearance. On the way home, I was able to modulate the brakes gingerly and avoid the noise/rubbing. The caliper on the driver side is fine and it seems to clear OK. Driving at higher speeds, I have no symptoms. I think that things should be symmetrical but I guess there's always some variation? Does this make sense?

I probably just need a couple MM, so do you guys recommend 3MM, 5MM spacers or anything else I could do that wouldn't necessitate the use of spacers?

Also, are 3MM spacers universal or car specific? SOS is getting 5MMs next week but the weather is so great, I really want to drive this car ASAP.