The Art of Purchasing Used Tires

The Art of Purchasing Used Tires
Everybody wants a bargain, so the first step in buying used tires is determining your bargain. In other
words, spend a little time searching online retailers and local retailer websites in an attempt to
determine the right tire for your vehicle. There are many factors to consider when choosing a tire that
are well beyond the scope of this article, but once you have chosen the right tire type, note a realistic
ballpark retail price and … keep on reading!
Items to consider; requirements to establish:
Tread life
Tread pattern
o Winter (Noise, Snow, Ice, Highway, Stud-able etc.)
o All Season (Touring, Noise, Fuel Consumption, Dry/Wet Performance etc.)
Speed and load rating
Finding your vehicle’s tire size
PLEASE read your owner’s manual. It is full of useful information – including your tire size.
Your vehicle will also have a tire placard (see Figure 1). Usually the placard is on the driver’s door jamb
or under the gas cap cover.
Figure 1 Typical tire placard
Most common place to look for used tires
Local online classified ads such as:
How to search for tires on these sites
Always search by tire size, if you drive a Hyundai Accent with P175/70R13 tires, do not search for:
“Hyundai Accent tires”. Instead type “ P175/70R13” into the search window. Many vehicles share the
same tire sizes, don’t miss out.
Sort through the results to find tires that meet your established requirements in terms of tread pattern,
Below is an example of what you might find.
The ad states:
The asking price for these 4 tires is $150 private sale – so taxes are not applicable.
Choosing alternative tire sizes
Note: different tire diameters require different size rims. Different tire width may require different
size rims.
You may be tempted to install different size tires on your vehicle. As a general rule, do not install a
different size tire unless explicitly listed by the manufacturer as a viable option. Figure 1 shows that
P175/70R13 and P185/60R14 are both viable options for this vehicle.
When in doubt, you may go to: to determine if
two tire sizes are similar enough to allow for trouble free operation (assuming they fit over your brake
and steering components).
Figure 2 shows a screenshot obtained by using the tire size calculator found at
Figure 2 Tire size calculator
The calculator shows that the two suggested tire sizes have a diameter variance of 0.42%. This example
should allow you to appreciate the importance of selecting the right size tire for your vehicle.
Determining new tire tread depth
Tire tread depth is commonly measured in 32nds of an inch.
You will need to browse around. Not all websites will offer this information, but it is out there. Figure 3
shows a screenshot from for the tires found in the ad.
Figure 3 Firestone Winterforce Tire specifications
Above we can note that the new tire tread depth is 12/32nds of an inch.
Evaluating a used tire – Price
Using the same site as you found the original tire tread depth, in this case, obtain a realistic
price for the specific tire in question. Figure 4 below shows that I can realistically expect to purchase 4
Firestone Winterforce tires for $321.76 + tx in Montreal Quebec.
Note: If this price differs significantly from the prices obtained when doing your initial research,
compare to another retailer for the specific tire.
Figure 4 Winterforce tire costing
These are the same tires as in the ad.
Calculate the percentage in savings
Formula = (New-Old)/New
Refer to Figure 4 above
New Tires
New tire = 321.76+15% (quick estimate for sales tax in Quebec) = 321.76+48.15= 369.15
New tire = 369.15/4 = 92.29
Note: Tires in Quebec are also subject to a $3 recycling fee at the time of purchase (not included).
Used tires
150/4 = $37.5, exempt from sales tax
Percentage saving – buying used VS buying new
(92.29 – 36.5)/92.29 = 61%
Assessing tire condition
Remaining tread on the tire
Often the seller will supply the remaining tread on the tire; it is your responsibility to know its
Legally in Quebec, a winter tire must have a minimum of 1.6mm1, rounded to 3/32nds, of tread. You
should subtract this number from the starting tread depth researched earlier.
Note: although 3/32 is the strict legal minimum, a tire is commonly considered worn out at 4/32. A
garage may refuse to install a tire that is at 4/32 or less tread depth.
Recall we found that the new tire has a tread depth of 12/32nds.
12/32 – 3/32 = 9/32
Therefore the 175/70R13 Firestone Winterforce tire has 9/32 of usefull tread during its usefull lifetime.
Final checks
The age of the tire
Do not purchase a tire that is over 5 years old. The tire begins to crack and the rubber deteriorates.
Conflicting information is available but one reliable source, Cooper tires, recommends discarding a tire
that is over 10 years old, period2.
Figure 5 Tire sidewall
When looking at a tire sidewall, look for the DOT marking. These will be embedded in the rubber on one
side only of the tire. The last four numbers indicate when the tire was manufactured. The tire in Figure 5
was manufactured in the 26th week of 2010.
Measuring tread depth
You will need a tire tread depth gauge.
Figure 6 Tire tread depth gauge
Do not use a piece of change or a ruler to try to establish a rule of thumb. The industry has adopted this
method of measuring for a reason. The tool is worth $3.99 at Canadian Tire.
Measure the tread depth of the tire(s) you are thinking of purchasing.
Figure 7 Tread depth gauge on tire
Figure 8 Reading tread depth on gauge
The measured tread depth is between 7/32nds and 8/32nds, let’s just say it’s at 7 for argument sake.
Recall that the Firestone Winterforce tire has 9/32 of usefull tread.
Calculate the remaining tread wear of the tire in percentage.
Formula =1- (New-Old)/New
1- (9-7)/7 = 78%
Decision time
In this particular case with the Firestone Winterforce tires, we would be paying 61% less for a tire that
still has 78% of its useful life remaining. A good deal.
As a rule of thumb, if the two percentages sum to more than 100%, you are making a good purchase. If
the two percentages sum to 1, you are breaking even and should buy new to get the warranty.
In this particular case, we are actually 39% better off buying used tires when only cost is calculated.
There just isn’t any warranty against defects.