Driver side tires have more tread than passenger

[David]

So i am working my way into a automotive technician and during my time on the lube rack I came across a car with tread wearing more on one side of the car. Was just wondering if there was any particular reason of this. The left or driver two tires were at 5/32″ while the passenger side was at 4/32″. This was a 2014 chevy cruze by the way. I read something on torque steer and how the two drive shafts are different lengths so more torque is applied to the shorter shaft and during hard acceleration the scrub rate is higher on one side or something like that? but didn’t really understand how it all worked. Anyone know why this would happen or what would cause this?

Thanks in advance
Dave

Topic

[zero]

Typically, whichever side has the sorter shaft will spin as more of the torque is actually put to the road. At least in a straight line. It’s most likely an indication of poor maintenance, either by the owner, or the person actually responsible for rotating the tires.

[David]

gotcha, I did notice in the online catalog at work it says to rotate tires front to rear and then rear tires go on the opposite sides of the front, where as at work we are told to rotate all tires just by switching the tires on the one side with the other. So it probably does have to do with rotating them improperly. Doesn’t seem like a major issue, I mean its just 1/32 of an inch. They looked like they were worn normally, just was curious as to why more on one side.

I know if I was working on my own at work I would take the time to rotate them the way there suppose to be but other people would probably freak out trying to change the way its done while were getting slammed with cars with rotations all the time. And I wouldn’t want to say anything and be that guy trying to do everything the correct way over minuscule details.

[Cameron]

[quote=”dburns87″ post=164301]So i am working my way into a automotive technician and during my time on the lube rack I came across a car with tread wearing more on one side of the car. Was just wondering if there was any particular reason of this. The left or driver two tires were at 5/32″ while the passenger side was at 4/32″. This was a 2014 chevy cruze by the way. I read something on torque steer and how the two drive shafts are different lengths so more torque is applied to the shorter shaft and during hard acceleration the scrub rate is higher on one side or something like that? but didn’t really understand how it all worked. Anyone know why this would happen or what would cause this?

Thanks in advance
Dave[/quote]

The wear may have very little or nothing to do with torque application at each front wheel but due to other factors. It depends where you took your measurements. If you checked across each tire, the wear is unlikely to be uniform in any event due to inflation and alignment issues.

If the tires were run for long periods at different inflation pressures (quite likely) the wear will not be the same. You can get more wear in the central part of the tire with a higher level of inflation and more on the edge sections with a lower inflation level.

Then you can get uneven wear across the tread if the toe setting on the wheel is out of spec and it is likely that the toe settings on both wheels were probably not the same during the wear life of the tire unless the owner took the car in for frequent wheel alignments. You can have one wheel close to spec and the other side knocked out of spec. Too much toe in or too much toe out will wear one side of the tire more than the other side of that tire.

The soundness of the shock absorbers on each side can also affect tire wear on that corner of the vehicle.

Typically many owners are slack when it comes to checking tire pressures on their cars and most of them don’t even know what the optimum pressures are for their vehicle to obtain good tire wear. Then they adjust the pressures on them when the tires are hot rather than cold and frequently with inaccurate tire gauges. How many of them even bother getting wheel alignment checks every 12 – 15000 miles as they should? I’m sure many don’t bother with wheel alignments until they buy a new set of tires and after that the car rarely sees another alignment.

So I suspect the different wear possibly had much more to do with lack of owner maintenance than anything else.

[David]

The reason I was thinking it may be related to torque steer is because I could see this guy racing around in his little turbo charged cruze and peeling out or just accelerating quickly maybe causing more wear on one side. I always take measurements in the most center of the tire also being sure to note any wear indicating over inflation, under inflation, or alignment related wear, feathered wear indicating a bad shock absorber and so on.

This guy is pretty picky he also brings in a z06 corvette and is always reminding us to check the tire pressure. Normally what I will do is look at the placard in the door and as long as its above those pressures around 6psi or more I figure its probably good. Sometimes I will get a car with pressure under the spec to where I will inflate it just to whats on the door. Hard to gauge what to set tires if you know the customer has just been driving it, definitely don’t want to let out all the hot air.

I did notice in the cruze on the dash all the tires were at 35psi which is right where they should be cold so he must set his tires when they are hot or someone did. They were all the same pressure though.

Good point about the alignment. I didn’t realize that is how often that needed to be checked.

[Author]

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