How Tires Can Tell a Lot About How a Used Car Was Treated
Tires can say a lot about that prospective Craigslist buy.
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When contemplating a prospective used car, no matter where it's for sale, it's important to get a solid idea of its overall health. An initial test drive is crucial, no matter what some new forms of online car buying might have you think. Looking for leaks, misaligned panels, body damage, and everybody's favorite patina, rust, is key, as is checking the health of the tires.
Examining the tires can determine how the car has been driven, how often it's been driven, how safe it is to drive, and how it's been maintained. There are exceptions, but it's amazing what the tread pattern can reveal, like when a miniscule forensic detail blows the lid off of a murder case. With that, let's cue up a classic tv intro on repeat and get to work outlining what to look for beneath the arches.
An Easy Way To Measure Tread Depth
First, to set a good baseline, figure out how much tread is left on each tire. Looking at the wear bars between the tread blocks can determine if they've got some mileage left or are in need of replacing. Are the wear bars even with the surface of the tread? If so, they need replacing.
Another is to use a penny—insert a penny into the tread groove, with the top of Lincoln's head aimed downward. If his head is fully revealed over the tread block, the tire is at less than 2/32 inch depth and should be replaced. You could also use a quarter, as mentioned in our previous post How To Check Tire Tread By Yourself.
This condition marker is really easy to figure out, though it seems like a lot of people overlook it. People who list their ultra-clean vintage cars often forget to touch on it in their high-end auction listings, too, but that's a discussion for another day.
Old tires are dangerous. The general rule of thumb is that you should be closely inspecting ones that have been in existence for five years or more, but that doesn't mean they absolutely require replacement. The code is easy to decipher: The first two numbers are the week the tire was made, the third and fourth are the year.
Date codes can also indicate how much a car has been driven and maintained throughout the past couple of years. If they're four years old, yet there is plenty of tread left, it shows that the car might not have been driven much. This is a good opportunity to ask about fluid intervals, and if they've been regular, or if the car potentially has two-year-old oil sitting in its pan.
Which Tires Are More Worn?
If it's a front-wheel-drive car and the front tires are significantly more worn than the rears, this could indicate two things: neglected basic maintenance in the form of tire rotation or the car's been driven hard.
If it's a rear-wheel-drive car, it's the opposite. In my personal experience, if it's a high-end car with staggered wheels, meaning the rear wheels are wider than the fronts, this is especially important to look for. The wider the tire, the higher the price to replace them—the previous owner might have cheapened out on maintenance and upkeep here, potentially in other areas as well.
If the tire's inner steel belt is starting to poke through, that's a major red flag and should be addressed immediately.
There are varying opinions on this aspect. Personally, I find if all of the tires are in good condition, it's not necessarily a knock against the condition of the car if they're mismatched. At least in more mild climates that don't see as much rain and snow as other parts of the world. Though, if one or more are expired, there are vastly different kinds of tires, or vastly different treadwear ratings, such as 200-tw vs. 450-tw, that would be cause for concern.
The ideal scenario is that all tires are of the same brand and model and have generally the same wear across all four. This indicates that the owner's paid attention to their tires, and there's a good chance they've had regular services done by qualified individuals, too. But then, that should also be qualified with service receipts.
Chunks that have been taken out of the sidewall or bubbles that have popped up are immediate red flags and indicate that those tires shouldn't be driven around on. Some people might have a higher tolerance than others for this sort of thing, but it's best to play it safe and treat it as a major safety hazard. Also, if it looks like the tire's been driven around on with this sort of damage for a while, that's just simply unsavory automobile ownership.
If you see this type of damage, it's an opportunity to use it to your advantage in negotiation. But do yourself a favor and either have the car towed or throw a spare on there if you drive it home.
Cracking and Dry Rot
Cracks are an indicator that the tire's materials are breaking down. Over time, the rubber loses its ability to safely expand and contract, as well as grip the road. This could be due to a tire being driven in a temperature range that it wasn't meant for, like driving 200-tw tires around in cold conditions or overheating them. Or, the tires have been sitting in the direct sun for too long. The tires might have also been exposed to harmful chemicals. This is less common with new tires, but you should still be on the lookout.
Dry rot is essentially extreme cracking. There's overwhelming visual proof that the materials are compromised and pose an immediate safety risk if you drive on them.
Alignment, Pressure, and Balance Wear
Tire pressure, alignment, and tire wear can reveal a lot about how a car's been treated. If there's significant uneven wear across each tire, this could mean the owner's neglected to have the car properly aligned, which might've accelerated wear on other components, such as ball joints, tie rods, and bushings. Or, it might've been in a crash and it can't be properly aligned.
Digging deeper, the way uneven wear appears can tell a lot about an alignment. Inside shoulder wear indicates either too much toe-out or way too much negative camber. If the tread is smooth on one end and sharp on the other, this is also an indication of toe wear.
Tire pressures also come into play. If there's more wear in the middle of the tire, they've spent some time overinflated with air. If there's more wear on the outside, they've spent more time underinflated.
If there are patchy wear spots, this could mean they've been flat-spotted, meaning the car came to a hard, abrupt stop and either the car is old enough to not have ABS, or their ABS wasn't functioning properly. So, make sure to inquire about the car's brakes and braking system. Alternatively, this could indicate that the tires have been out of balance or sitting for some time.
What About Wheels?
Although the car doesn't roll down the road with its wheels touching the ground (at least it shouldn't be) some minor condition details about them might also help determine how the car's been treated.
Significant curbing, meaning the rim of the wheel's ground up against curbs and other road features, might indicate ownership neglect. Some curbing, though, I wouldn't necessarily write the car off immediately. Cars like the Fiesta ST have very thin sidewall tires and rims that are at ultra-high-risk for curbing—a little curbing is almost inevitable.
If the wheels are covered in brake dust, this might indicate that the owner isn't too keen on regular washes and light detail sessions. Though, if the brake dust is baked on or has corroded the wheels' finish, that could indicate ownership neglect. If they let this very visible thing go bad, how are things looking under the hood?
How Will You Be Driving the Car?
As far as how serious of a matter each of these are, it depends on your individual threshold. If you're buying a car that's been driven in autocross or at a track day, the car might have a little toe or camber wear, and therefore, personally, I'd be more concerned with other aspects, like ensuring the car's had regular or shortened service intervals and stays cool under performance driving scenarios.
It's important to know if the car's been driven enthusiastically. And if you intend to drive it the same way, it's reasonable to encounter some wear that's mildly outside of what your local tire shop down the street might call normal. But still, this could be a point of negotiation.
If you're buying the car to solely be a reliable A-to-B commuter, I'd want to ensure the tires are aligned within factory spec. Don't be afraid to point out any of these issues and use them for negotiation purposes.
Again, all of this is assuming that the car has done some mileage on the set of wheels you are seeing. If the tires were recently replaced before it was put up for sale, you can't draw conclusions based on tire data.
Let's open this up for discussion: What do you look for in tire condition when buying a car?