The winter wheel and tire shuffle can be a test of patience, attention to detail

I recently bought a very high-mileage 2004 BMW X5 with the rare combination of a six-speed manual transmission, the sport package, and the towing package. The intent was to have a vehicle that I wouldn’t hate daily-driving and could also use, if necessary, to hitch a rented U-Haul auto transporter and tow another car home, enabling the crimes of opportunity that have resulted in my little I-don’t-call-it-a-collection.

After replacing one bad lower control arm in the X5, I transferred the registration and plates from my BMW E39 530i sedan onto it and began the daily-driving experiment. But the next issue was what to do about winter tires. Granted, the X5’s all-wheel drive gives it a huge advantage over the rear-wheel drive in the sedan it’s replacing (which, on all-season radials, once almost stranded me in a nearly flat snow-covered parking lot, and which, even when shod with snows, couldn’t back out of the slightly-downward slope of my driveway once the tread depth had worn down).

There’s a commonly-held belief that cars with all-wheel drive don’t need snow tires. It’s a question of degree (or degrees, if you want to make climate-centric puns). If you live where it doesn’t snow, they don’t. If there’s sporadic light snow, you’ll probably be fine. But if it snows often and you commute consistently, there’s no doubt that you’ll be safer with snow tires.

Here’s the issue: A car needs to go, turn, and stop. There’s zero question that all-wheel drive is better than rear-wheel or front-wheel drive at the going part of the equation, and even without snow tires, it’s going to do a better job of getting you up inclines, as well as in and out of snow-rutted parallel-parking spaces. But, in low traction conditions, it’s really not much better at turning, and it’s definitely not better at stopping. The most hazardous vehicle I’ve ever driven in the winter was a big 1992 Ford F250 dually four-wheel drive pickup. Sure, I could drive it over snowbanks, but if you were headed down an incline and around a curve toward an intersection in snowy weather, it was absolutely terrifying. To improve turning and stopping, you need—taDA!—snow tires.

With that, some folks go hard the other way and say, “If you don’t pony up for new snow tires in the winter, you’re an idiot who is endangering the life of your family and others.” I’m not one of those people. The world is gray, not black and white. When my wife and I bought her 2013 Honda Fit, the fact that she regularly commutes in it meant that good winter rubber was a must. And, since the car’s little 185/55R16 tires were skinny, new snow tires mounted and balanced on steel wheels and shipped to my door were orderable from The Tire Rack for something like $500.

However, since I work from home, I don’t have a commute. The economics of winter wheels and tires on the X5 are different than on the little Honda. This car has 18-inch wheels, so snow tires start at about $155 each through The Tire Rack. The tires it currently wears are decent Continental CrossContacts with about 30K miles on them and tread depth ranging from 9/32 inches to 7/32 inches, so I hate to pay the $100–$140 to pull them off and have new snows mounted and balanced, then pay again to remount them in the spring. Plus, the X5 is currently wearing the correct sport package-specific wheels; decorum dictates that I allocate those wheels to non-winter tires and get another set of wheels for winter.

But doing that adds up quickly: $620 for four new snows and another $125-ish for mounting and balancing. And even if I found a decent set of used wheels for $150, that’s $900 total. So, when the car has all-wheel drive, good all-season rubber, and I have zero commute, you’ll forgive me if I decide against spending that much money. The way to do that is, if possible, buy a set of used winter tires already mounted on wheels. Craigslist and Facebook Marketplace are rife with ads for winter tires and wheels.

It seems like I go through this every winter I have a new car. I hate it, but I do it anyway. When it comes to buying used winter wheels and tires, it usually boils down to these things:

Used Wheels

Wheels must fit a car correctly. That comes down to five parameters: bolt pattern, diameter, width, offset, and center bore.

Bolt pattern: Bolt pattern is the number of wheel lugs or studs and their circular spacing. Generally, for European cars, it’s specified in millimeters (e.g., 5×120 is five lugs on a 120mm circle), and for American cars, it’s in inches (e.g., 5×4.75). Without the bolt pattern being correct, the wheel won’t even attach to the hub. Some aftermarket wheels are drilled for more than one bolt pattern to make them more universal.

Diameter and width: These are almost always specified in inches and are usually stamped either in the wheel’s center or on the backside. It’s common for a car to be available with one set of wheels for the standard option package, and another larger wider set for the sport package. For example, on my 2004 X5, the stock wheel is 17×7.5, but the sport package uses 18×8.5 wheels. If you’re looking for winter wheels and tires, you can usually save some coin by using the smaller non-sport size.

Center bore size: You’d think that if you found a wheel with the correct bolt pattern and diameter and width, it’d fit on the hub, but there’s another crucial parameter, and that’s the center bore size—the diameter of the hole in the center of the wheel, which fits over the hub. If the center bore is too small, the wheel simply won’t fit. If it’s too big, it will fit, but you may have vibration and balance issues unless you use a set of hub-centric rings that properly center the wheel’s larger bore to the smaller hub. If you’re staying within a particular marque, the hub-centric rings you need are usually easy to research and buy, but for more obscure combinations, figuring out what you have and what you need can be challenging.

Offset: This is how “inboard” or “outboard” the wheels are. It’s specified as the distance—usually in millimeters—from the inside of the mating face to the center line of the wheel. Most newer cars have a positive offset, which means that the wheels are inboard of the center line. On European cars, the original wheels are usually stamped with the offset, preceded by the letters “ET,” so “ET40” means a 40mm positive (inboard) offset. Offset can be tricky because, unlike bolt pattern and center bore, it’s not always a binary fits-or-doesn’t-fit. The wheels may bolt on and the car may drive, but if the offset is wrong, rubbing or clearance problems may present themselves during turning. Spacers can be employed to move wheels further outboard, but it’s best to use wheels that fit correctly.

Straightness: These days, I assume that all used wheels are bent, because they almost always are. The question is how badly. On vintage cars, you usually do okay by putting the straightest two wheels on the front and the worst-bent ones on the back, but modern cars tend to transmit all wheel vibrations to the driver. Unfortunately, when buying used wheels, your eye can only see the most glaring dents and flat spots. You really need to put the wheels on a car and spin them to judge how straight they are. I cannot overstate the degree to which “caveat emptor” (buyer beware) applies to buying any used wheels. When I look at used wheels for a rear-wheel drive car, I drive there in the car, take a floor jack and stands with me, pull off the car’s two rear wheels, slap on the wheels I’m considering buying (two-at-a-time on the back), run the engine, and spin them to see how straight they are. Unfortunately, on an all-wheel drive car like the X5, you can’t do that without raising all four wheels off the ground.

Used Tires

Wear: Low wear is far more important when buying used snow tires than it is for regular tires. This is because many snow tires have two different rubber compounds, with the softer outer compound engineered to remain flexible in cold weather. Unfortunately, this compound wears quickly. And, obviously, as the tire wears, the tread can’t bite into and squeeze out as much snow. For these reasons, The Tire Rack recommends that snow tires be replaced when they’re down to 6/32 inches of tread. That’s very different than “they’re good down to the 2/32-inch wear bars” rule of thumb that’s often used for other tires. So unless your climate and usage profile shows very little snow exposure, do the math of what new snows will cost, look for the best newest set of snows you can find, and decide what tradeoff you’re willing to accept in time spent, wear, and savings. My rule: “Two hours to get nearly new tires for half off is pretty good.”

It’s imperative that you use a tread depth gauge to get an accurate measurement. Check each tire. Uniform tread depth is particularly important with all-wheel drive cars, as uneven wear can put strain on the AWD systems.

The overworked (and poor) Lincoln penny measurement

So much of this comes down to not wasting time chasing worn-out tires. You can look at tread photographs or take someone’s word on number of seasons and mileage, but nothing beats a tread-depth gauge. However, most sellers don’t have one. It’s something of a tradition to use a Lincoln-head penny with the head upside-down in the tread to judge depth. At least everyone has a Lincoln penny, so you can ask someone who’s running an ad to put a penny head-down in the tread and ask what it covers. Unfortunately, this tradition stems from the non-snow-tire world, where tires are considered worn out if there are 2/32 inches of tread, and that’s roughly the top of Lincoln’s head being exposed. As I said, for snow tires, you need way more tread than that. Unfortunately, using Lincoln’s head is not a great test because Lincoln’s facial features aren’t in the center of the penny, and the facial features don’t line up evenly with 1/32-inch boundaries.

But if you need to use Lincoln’s head, here are some better metrics: 9/32 inches of tread comes to the good former president’s nose; 8/32 inches is about even with his brow; 6/32 inches is close to where his forehead meets his hair; and 4/32 inches covers his hair about halfway.

Using the Lincoln monument on the back of the penny (upside-down in the tread) is actually better because it’s centered. The top of the pillars is about 10/32 inches, the top of the monument is about 8/32 inches, and halfway between the “E Pluribus” and “Unum” lines is about 6/32 inches, and 4/32 inches doesn’t even reach to “E Pluribus.”

Just one more penny example: Below is a pic of one of the Blizzaks for my BMW E39 5 Series sedan. The tread looks OK to the eye, but the tire gauge measures it at 5/32 inches. The penny measurement has Lincoln’s hair covered. The takeaway message for this one is that I would’ve put this tire back on the sedan for one more season if I hadn’t bought the X5, but I wouldn’t pay money for it.

Size: Obviously, you need tires that fit the wheels and the car. Every tire is specified by its width, aspect ratio, and diameter. These are almost always embossed on the tire sidewall as “width/aspectR/diameter” (e.g., 255/55R18). Recommended winter sizes, however, may differ slightly. I go to The Tire Rack’s website, which lists a standard size winter tire to fit the original wheels and an alternate size if you want to go to a smaller wheel. For example, for the X5, it’s 255/55R18 for the original 18-inchers, and 235/65R17 or 255/60R17 for a non-sport-package car.

Damage: Thoroughly inspect the sidewall of any used tire for damage. Tires with any cracking (dry rot), cuts, gouges, or bubbles should be rejected. If the tires are off the rim, run a gloved hand inside each one to check for plugs (repaired punctures) in the tread. These aren’t necessarily flat-out (bad pun) grounds for rejection, but they’d have to be an awfully good deal to be considered.

Age: Every tire sold in the United States since 2000 should have a string of characters on the sidewall that starts with “DOT” and ends with four digits. Those last four digits are the week of manufacture and the last two digits of the year. So if the last four digits are “4317,” the tire was manufactured in the 43rd week of 2017. How old is too old? You can find recommendations online that say to replace tires after six years. Other sources say 10. Personally, I look at it more as a question of overall condition, price, and how much you use the car.

Searching tips

I try to find winter tires already mounted on wheels, since, in theory, that saves the $100–$140 for mounting and balancing. To me, the perfect ad would say, “Winter tires and wheels from 2004 BMW X5. Original Style 57 wheels mounted with 235/65R17 Pirelli Scorpion snow tires. Wheels have no visible dents and are straight enough not to vibrate the car at highway speeds. Tires have two easy seasons on them, tread depth is 9/32 inches, no punctures or sidewall gouges… $500 or best offer.” That lists all the information you’d need. However, you rarely see it listed like that.

Instead, what I find too often are ads that say, “BMW wheels,” don’t list which model they’re for, don’t state the wheel and tire size, and have maybe one photo. Because of this lack of specificity, I’ll try searching for:

• Car make and model
• Tire size
• Tire brand and model

It’s frustrating and time-consuming, but often you can find the best deals through ads with the least specificity. I’ve sometimes searched simply “BMW,” recognized wheels as those I’m looking for, and then downloaded the photos and blown them up to read the tire size on the sidewall.

Unfortunately, searching for used tires locally on Craigslist or Facebook Marketplace is a special pain because, unlike on eBay where width, aspect, and diameter are database-searchable parameters, CL and FBM both search for your query exactly as you type it. Thus, if I’m looking for 255/55R18 tires, I’ll search for not only “255/55R18,” but also “255/55/18,” “255 55R18,” and “255 55 18,” as the four will generally yield different results. Like I said, it’s a pain.

One trick is to use wheels and snow tires from a less-popular model, provided that research shows they’re compatible. Also, snow tire sizes don’t need to be an exact match provided that they’re close. There are a number of online calculators you can use to judge how bad the speedometer error will be if you change the tire size (google “speedometer error calculator”), but I generally assume that, if the width stays constant, you can go down half a size in aspect ratio (e.g., from 235/65R17 to 235/60R17) with tolerable speedometer error.

Another is to buy tires that are mounted on generic aftermarket or steel wheels. However, as I said, you need to be very careful with offset and center bore. Even if the seller swears they were used on your exact model car, you may still have fitment issues.

Really, you need to verify everything. If you’re not going to test-mount all four and drive them (and who is in the dead of winter?), you need to be sure the wheels and tires actually are what the seller says. I’ve seen ads where things are mislabeled, and sellers swearing things are compatible when they’re not. At a minimum, show up with a tread depth gauge, check the size and offset numbers (if they exist) on the back of the wheels, verify that all four tires are the same make, model, and size, and measure the center bore with a ruler. If you have any doubt on fitment, jack up one corner of the car and try one on.

So, with that, let’s run through a few actual ads:

“Used Wheels BMW X5: Blizzak wheels off BMW X5, set of 4, $100.” That’s the entire description. Photos show a set of aftermarket Moda wheels, and the 255/55R18 tire size is photographed, as is the tread, but the tread looks pretty worn. This is the sort of ad I would’ve jumped at a few years ago, but the location is an hour from me, and my request to take the penny picture went unanswered. The smart move would be to go only if I assumed the tires were junk and wanted only the wheels.

“235 65 17 Winter Continental tires and wheels for 2005 BMW X5: 17-inch winter tires and wheels for 2001–06 BMW x5, ready to install, tires like new, $400.” No photos; tires are about 45 minutes from me. I texted the seller asking for photos, including the penny pic. He complied quickly. Wheels are OEM for a 2005 X5, but a rather odd style. Penny pic has camera angle and shadow issues. Where exactly does the tread come to? Lincoln’s eye? If so, could have as much as 9/32 inches of tread depth. If they were 15 minutes from me, I would certainly have a look.

But then the holy grail of winter wheel and tire ads appeared that showed that good things can come to those who wait:

“4 BMW OEM Style 209 Wheels with Michelin X-Ice 2 235/60/18: These are OEM and came off a 2010 X5. Excellent shape. Need to be cleaned. Only one or two very small road rash. Picture attached. Tires are in good shape, 10mm tread depth, good for 2–3 more seasons. Manufactured December 2017. Package deal only. All 4 wheels with 4 tires mounted, $200.”

Boy, the actual BMW wheel style number, tire size, date code, a deep tread depth measurement, a photo of the tread depth gauge in one tire verifying the claim, and a very low price. What’s not to jump at? Now, there are differences in bore size and offset between a 2010 X5 and my 2004, but I verified the offset is within 2mm, and that the larger bore size can be adapted with 74.1-mm-to-72.6-mm hub-centric rings. The tire size was non-standard, but a look on the forums showed that some folks prefer this skinnier size, and a speedometer error calculator verified that, at 70, the speedo error is with one mph.

I messaged, I came, I saw, I bought, I smiled. Needless to say, I dragged the tires home in the back of the X5 they’re about to be mounted on.

May your used winter tire and wheel shopping be as productive as mine.

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Rob Siegel has been writing the column The Hack Mechanic™ for BMW CCA Roundel magazine for 33 years and is the author of five automotive books. His new book, Resurrecting Bertha: Buying back our wedding car after 26 years in storage, is available on Amazon, as are his other books, like Ran When Parked. You can order personally inscribed copies here.