Piston Slap: To Love, To Hate Aftermarket Rimz

Sajeev Mehta
by Sajeev Mehta
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piston slap to love to hate aftermarket rimz
Lance writes:

Hey Sajeev,

A long time (since roughtly 2006ish) TTAC reader, I thought you might be able to help me out a bit, or point me in the right direction. My car (2007 Honda Civic Si Sedan, 17300 miles when bought used off lease, now currently around 39000 miles) vibrates terribly at highway speed. Starts around 55mph, continues to increase until about 80-85 where it begins to smooth out again.

Oddly, the vibration seemed (at the time, about a year ago or so) to have cropped up “overnight” (I don’t drive on the highway often, maybe once or twice a month) and at the time I hadn’t had the car up to those speeds in quite some time, probably about 3 weeks or so. I certainly didn’t recall any vibration the previous trip I took with any highway speeds, but there sure was one obvious then, and it’s gotten a little bit worse since I first noticed it. I’ve been living with it ever since, but I’m getting fed up.

The vibration is not felt in the steering wheel (aside from the steering wheel being a part of the interior of the car, the wheel dosn’t shake side to side or anything like that), it is felt throughout the entire interior of the car as if the vehicle is sitting in a giant paint shaker. Riding in the car at highway speeds feels as if the car was built with the purpose of being a mobile massage chair. As I can’t really drive everywhere at speeds in excess of 80mph, I’d like to find the cause.

The car was aligned and the wheels balanced shortly after I first detected the issue. Of course, the honda guys told me they couldn’t guarantee a balance on aftermarket wheels (which came with the car when I got it, cheapie 18″ ICW racing wheels shod with brand new cheapie Fierce tires if it helps to know the makes/models). They did get the alignment right, the car did and still does track straight down the road as long as the road is smooth and flat and the steering wheel isn’t doing it’s tick/pulse thing (more on that below). I thought the balance would be the problem, but after that didn’t correct the issue I began inspecting the tires for wear patterns and was flabbergasted by what I found.

The wear pattern doesn’t look like any normal sort of wear that I’ve ever seen. It certainly doesn’t look like anything listed in the following image. The closest thing it resembles is an order of cupping, maybe with a side of camber wear… but it’s on both inside and outside edges, and the worn spots extend for about 6 to 8 inches or so, and do not always match up with a worn spot on the opposite side of the tire. If anything, they’re offset from each other a little, side to side. All 4 tires are worn in this manner to some degree. I don’t currently have any photos, the wear is hard to see in person because it’s spread out over a large area. The only way to tell is to notice that some of the shallower grooves in the tread disappear for a few inches before reappearing. Can’t really feel it by running my hand over the tire either. Very, very weird.

The car drives straight, handles fine. Nothing about the handling or alignment causes me concern from a driving-the-car perspective, but the weird tire wear must be caused by something.

That bit about the steering “tick”: The steering wheel has a little bit of a pulse, or tick to the right every so often at highway speed, but that is unrelated to the vibration, and it doesn’t always seem to be present. Minor annoyance, sometimes I don’t even notice it.

The only other thing of note: My family lives in the country, and visiting them means about 15 miles of unpaved road driving at the end of a 4 hour drive. When I first had the car I took that section pretty slow, but even 35-40ish mph was still a pretty hard hit on the tires in a couple places (an embedded chunk of rock I couldnt see which I hit with the tires on the passenger side, and an entrance onto a bridge that all 4 tires hit, which was VERY rough, enough to make me concerned that I might have damaged tires, wheels, even suspension parts, but the honda guys said everything looked ship-shape aside from the alignment. My dad thinks I may have shifted belts in the tires since they’re pretty cheap things and who knows how well they’re really made. My research online tells me this probably isn’t much of an issue but that’s why I’m writing to you!

If you have any ideas what might be the problem, I’d be glad to hear it. I’m thinking of putting lighter rims and new tires on shortly just to have a reprieve from driving a giant red massage chair on wheels. I’d hate to put new stuff on just to wear them out and be shakin’ shakin’ in 6 months or so though.

Help me Sajeev, you might be my only hope!

Sajeev answers:

I could be your only hope? No pressure there! Anyway, I think one (or more) of your wheels is out-of-round. It sounds like you hit enough bumps/potholes/sinkholes to do two things:

  1. Damage the suspension enough to cause a wear item to prematurely wear and eat up the tire tread in that funny manner.
  2. Bend your crappy, cheapie wheel.

Aftermarket wheels are such a hit or miss, but you often get what you pay for. The photo above is my Fox Body 1988 Mercury Cougar XR-7. I shelved my factory 15×7″ turbine wheels ( same as the Mustang GT of the era) because they were impossible to clean, needed refinishing, and are so outdated that I could no longer buy a decent summer tire for it. And the way I drive, I want summer tires!

So I upgraded to 1993 Cobra style wheel, reproductions (probably) from China. At 17×8.5″ these Rimz are a huge upgrade from stock but with a factory look: they get compliments all the time , even if people regularly say that I need to “modernize” to a different wheel. I wanted a period correct restomod upgrade, and I got it. Case closed? Not. These Rimz are stupid heavy, I don’t even want to know the increase in unsprung weight. Even worse, they occasionally wobble on certain wavy roads and certain speeds…immediately after I did the wheel swap.

So my Cougar has the same problem as your Civic! Wheel balance? Nope. High quality, brand name summer tires? Not helping. Numerous suspension checks with plenty of new parts? No dice.

I gave up. The Cougar looks awesome (to me) and I love the extra grip, and I’m not super concerned with the occasional wobble, because I know exactly where its coming from. If this was a track car, I’d either get new Rimz or have a wheel shop professionally machine them to perfection. If that’s even possible! Is it possible?

Well, now that I’ve thoroughly confused myself, off to you Best and Brightest.

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.

Sajeev Mehta
Sajeev Mehta

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2 of 70 comments
  • Ranwhenparked Ranwhenparked on Mar 29, 2013

    Sounds a lot like what my brother did to his E46 3-Series years ago when he decided the stock rims were too boring and swapped in a set of the cheapest, gaudiest looking things ever to come out of China. The car hasn't driven right since, and in 5 years, he hasn't been bothered to put the factory ones back on. I suspect they were just totally out of round to begin with and no amount of balancing is ever going to fix them.

  • Carlos Danger Carlos Danger on Apr 10, 2013

    Belts, belts all the way down. The giveaway is the pattern and the suddenness of the onset. Rims or struts may have contributed to shifting, but....belts.

  • Art_Vandelay I wish. Love the 70 series
  • Pco65752756 Why is this not on the High Mile Cars List?
  • SCE to AUX "But we can all go pound sand in North America, unfortunately"In reality, that would be about 1000 people who can go pound sand, which is why this isn't coming to North America.
  • MaintenanceCosts You could probably make this thing satisfy US emissions standards, although it wouldn't right now, but there is no way on God's green earth you could make it satisfy US safety standards.
  • MrIcky Haven't these been out for a while? Is the news just that Japan gets them now too?