• 24
We've always found that our tires get squirrely in the wet before they fail the old penny test for tread depth. The Tire Rack, supplier of black round things and other accessories, are suggesting that the price of your safety has appreciated by 24 cents. For years, the penny test has been a quick way to turn a common item of pocket detritus into a tread-depth gauge. Hold Abe upside down, and if the tread clears the top of his noggin, you've got at least 2/32nds of an inch of tread. When tread gets down that low, however, things start to get hairy. 2/32nds is the minimum depth that warranties on the tires will be honored, but that doesn't make it wise to cruise around on rubber that tired. We were once treated to a nasty little bit of unexpected oversteer when taking an off-camber turn downhill during a rainstorm with tires that barely passed the penny test.
The Tire Rack is encouraging drivers to use a quarter instead of a penny. Using George's melon as a guide in the same way as the penny, the minimum tread is 4/32nds, double the penny test. It could be argued that there's a lot of miles to be had during that 2/32nds delta, but your life, and that of your passengers, is far more valuable than a few miles on a set of tires. In Tire Rack tests, the "quartered" tires had significantly better grip and shorter stopping distances in the wet. The hope is that awareness will increase and lives will be saved. There's no need to wear your tires so low – it's not like they're slicks – and it's one of the cheapest measures you can take to ensure the safety of you and your cargo.

[Source: Tire Rack]

UPDATE: The Tire Rack also offers up this video to show the difference in stopping distances between new tires, tires worn down to a quarter's measurement (4/32"), and tires worn down to a penny's measurement (2/32"). The difference between all three is pretty dramatic, especially the "quartered" and "pennied" that are separated by only 2/32" of tread life.


Tire Rack experts seek change in tread-depth limits

SOUTH BEND, Ind., JULY 23 /PRNewswire/ -- Quarters are safer than
pennies when it comes to checking your tires, according to new tests
conducted by The Tire Rack, the country's largest independent tire tester.
With much of the summer travel season remaining and a change of season
looming, now is especially important for drivers to be aware of their
tires' condition.
(Photo: http://www.newscom.com/cgi-bin/prnh/20070723/CLM024A )
For decades the tire industry has taught drivers to use the so-called
Penny Test as a simple way to tell when tires were worn out. But experts at
The Tire Rack say that popular lesson is outdated, compromises safety, and
should give way to the Quarter Test.
In the old Penny Test, seeing the top of Lincoln's head while holding a
penny upside down in a tire tread groove indicated a tread depth of
2/32-inch (1.6mm) or less, and that the tire needed replacing. Instructions
on how to properly check tire tread depth can be found at
In driving tests conducted by The Tire Rack, a late-model pickup truck
riding on tires that passed the Penny Test -- legal in most states --
averaged 499.5 feet to stop from 70 miles per hour on wet pavement. That's
equal to about 12.5 school busses, or nearly a tenth of a mile.
However, the same vehicle riding on tires that passed Tire Rack's
proposed Quarter Test stopped almost 122 feet (24%) shorter. These tires
had treads measuring 4/32-inch (3.2mm) deep, as measured from the edge of a
quarter to the top of Washington's head. Not only were braking distances
significantly reduced, overall grip noticeably improved. Dramatic footage
comparing Penny- and Quarter-Tested tires is available online at
"The Penny Test was an indirect result of tire warranties," explained
John Rastetter, director of tire information at The Tire Rack. "It is to
that depth (2/32") that most warranties remain valid, encouraging drivers
to drive longer on tires that don't provide enough wet-weather traction."
Tire Rack tests showed that doubling the tread depth at which warranties
are voided will improve safety by cutting braking distances and improving
traction in the wet. "We know these changes won't happen overnight so we're
encouraging drivers to pay more attention to their tires now," he said.
Wet/Snowy roads + Worn tires = A real problem
In 2005 584,000 car crashes occurred in the rain, causing 169,000
injuries and 2,914 fatalities, according to the most current data from the
National Traffic Highway Safety Administration (NHTSA). Another 264,000
crashes occurred in snow and sleet, accounting for another 53,773 injuries
and deaths.
Rastetter and his team feel many of these incidents were likely related
to worn tires since NHTSA data also show some 20 million vehicles have at
least one bald tire. In addition, less than one in three (31%) drivers
doesn't know how to tell if their tires are bald, according to the Rubber
Manufacturers Association, a tire industry trade group. A bald tire is one
with less than 2/32-inch of tread depth.
Tire companies spend millions of dollars developing tread patterns that
channel water away from under a rolling tire. This channeling allows the
tire to stay in contact with road surfaces, especially at highway speeds.
As tires wear, their ability to displace water and grip snow is
diminished, increasing the chance of hydroplaning. Hydroplaning occurs when
tires are forced up off the pavement by water trapped under the tire. The
result is a complete loss of traction that leaves drivers helpless to
control their vehicles. By the time a tire is near the end of its service
life it can displace a tiny fraction of the water, and grip little of the
snow, it could when new.
"Riding on worn or bald tires in rain and snow is like trying to ice
skate in dress shoes," said Rastetter, "you're going to lose control."
About The Tire Rack
Founded in 1979, the family-owned Tire Rack has become America's
largest independent tire tester and consumer direct source for tires,
wheels and performance accessories. A team of more than 80 test drivers
test tires from every major tire manufacturer on a state-of-the-art,
10-acre test facility at the company's headquarters in South Bend, Indiana.
Findings are posted free on the company's website, http://www.tirerack.com,
where consumers can thoroughly research a purchase. The Tire Rack also
posts data collected from more than 119,000 consumer surveys representing
more than two- billion miles of real-world tire information; the largest
known cache of such information anywhere.

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    • 1 Second Ago
      • 7 Years Ago
      My new tires Yoko Avid TRZ arrive today from great Indiana Tire Rack. My current tires are down to the last 1/34578th inch tread. ;)
      • 7 Years Ago
      Another sign how bad american drivers have become - they find oversteer frightening.
        • 7 Years Ago
        Oversteer when I want it is fun, when I'm just trying to go on my way, it's a little scary. Knowing how to recover is key, but even then, I defy you to keep your heart rate relaxed when the tail starts to come around unexpectedly.
        • 7 Years Ago
        Yea, unexpected over steer is pretty scary to anyone.

        ...and the American bashing is a little old.
      • 7 Years Ago
      Unless you're racing, which you shouldn't be doing in the rain in the FIRST place, tires that pass the penny test will do just fine. This is just a ploy put on by Tirerack to encourage reader to spend money on EXPENSIVE new tires. I'm sorry, but I'm not buying it.
        • 7 Years Ago
        $400 a year is expensive? When I buy/own a car, I kind of budget for those kinds of regular and predictable expenses.
        • 7 Years Ago
        And hence why you budget an emergency fund. You all seem to think TireRack is just trying to make an extra buck, but if you drive an average amount, you'll need new tires every year regardless. Some may buy higher performance tires, and thus will budget to buy them more often, some may buy higher tread wear rated tires. But TR's study is about regularly predicting to buy new tires at a certain point in time. I don't understand why people are complaining about price of a tire, as it's something you should have calculated when you bought the car. i.e. "over the next five years of owning this car I'll need to spend $6000 on gas, $2000 on tires, $5000 on insurance ... Oh wait, I don't have that kind of money, maybe I should take the bus."
        • 7 Years Ago
        True. I shouldn't but I have been known to run them to the cords and as long as you pay attention to standing water and do stuff like not drive in the ruts.. oh and don't drive with a phone glued to your face you should be fine. Bald is pushing it but you should be fine with the penny test or simply use the tread wear markers built into the tires for that matter, that is what they are there for. Sounds like good old TR is getting greedy. :) Speaking of TR.. they must love me.. I have been buying a set of tires from them every 8 months for the past 12 years or so. Not to mention race tires and tires for my wife. When do I get my discount? hahaha.
        • 7 Years Ago
        Right - because we can 100% predict everything that happens on the road, right? ;-) .

        The reason people should invest in high performance tires isn't because they're "racing" on the street - it's because stuff happens out there. Need to make an emergency maneuver in the rain? You don't want your tires sliding all over the place when you need to swerve at 65 MPH, right?

        Oh wait, yes, that's right... that'll never happen since we are capable of predicting what will happen at all times on the roads. I guess that explains why there are never traffic accidents either :-p
        • 7 Years Ago
        @James Sonne, why would we need new tires every year? Last I checked tires should last longer than 15k miles, which is probably right around the average.
      • 7 Years Ago
      'You all seem to think TireRack is just trying to make an extra buck, but if you drive an average amount, you'll need new tires every year regardless.'
      New tires every year? Are you mad? Average yearly driving is 15000 miles. If your tires can't last 15000 miles you buy some cheap ass tires or you are serioulsy in need of an alignment.
      I bought a used car on 10/05. Nice set of performance tires on the car. 21000 miles later they are still there and I can hardly see any tread loss. Yes I drive her everyday and no I haven't left any rubber anywhere.
        • 7 Years Ago
        It wouldn't be unusual for very sticky summer performance tires to only make it to around 20k (but only because of the very soft compounds they have). Personally, I prefer a high performance all season - a compromise between tread life and very high performance (both wet and dry).

        I live in Florida, so snow/ice isn't a big deal for me - I guess I'm lucky like that when it comes to tires.

        In fact, a lot of the cheapo OEM tires that come on cars these days tend not to make it much farther than 20-25k.
      • 7 Years Ago
      News flash: LLbean says winter's coming, and you don't want your kids to wait at the bus stop like shivering Dickens characters do ya? Buy some warm winter clothing for those kids before you kill them! It just so happens we've got a catalog around here somewhere...
      • 2 Years Ago
      "There's no need" Okay. Are you going to buy 4 new tires for my car? Cause, I can't afford it.
      • 7 Years Ago
      4/32 of an inch = 1/8 of an inch.... was the conversion so hard?
        • 7 Years Ago
        It sounds more authoritative when you say 4/32.
        • 7 Years Ago
        Well then, why stop there? Why not say 8/64 or 16/128ths? :D
      • 7 Years Ago
      It's all crap !!! To get the most out of your tires, drive them until they blow up one day, then you know you've gotten max life out of them.
      • 7 Years Ago
      Is the distance from the edge of the quarter to the top of George's head the same for old and new quarters?
      • 7 Years Ago
      First off it rarely rains here in AZ 11 months out of the year, so low tread is ok. And secondly this test is hard on most new cars that have negative camber and or toe out. I don't know about the rest of you but my tires always wear on the inside and some times the outside edge much more from cornering that in the center. Why use a coin at all it seems that all tires have wear bars between the treads.
      • 7 Years Ago
      We've been using quarters to check our tires in Canada for quite some time now...

      I don't know why you guys are still using pennies.
      • 7 Years Ago
      I use a $100 bill to check my tire tread. That's just how I roll...
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