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#1 2010-11-29 20:04:13

kornfeld
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Compilation of Tips on Buying Used Tires

I've been going through the process of looking for a set of new or used tires for winter use.  Obviously, new tires would be the best solution, but in the interest of saving money I've been looking for a used set.  While researching how to examine used tires, I found a lot of useful information on both used and new tires, so I figured I'd compile some of what I found into a single post.  If you feel like you already know most of the stuff you'd need to know about tires, then skip down to the "age" section in this post.  It might have some info that's new.  So without further ado, here's what I've found on what to look for in used tires:

Size

First thing to look at is size.  Tire Rack has a guide here on how to read tire specs, so I won't go into that.  The useful thing I discovered in my searching is that most tires on Tire Rack's site include a recommended rim width for that particular tire.  This will tell you if that size tire will work on the rims that you have.  To get to that information, go to the page for the tire you're interested in; click on "Specs"; then look in the "Rim Width Range" column.  It'll give you a range of acceptable rim widths.  This site is also useful for comparing two different sized tires.

Tread Depth

Second thing when looking at tires is to check tread depth on each tire individually, and then compare the tread depth of the tires as a group to make sure they're all similar. Based on what I've read, most new tires of the size and type you'd use on a 9-2x start with somewhere around 10/32" to 12/32" of tread depth, and are no longer legal (or safe) to use when they have less than 2/32" of tread left.  This means that tires we'd use have between 8/32" and 10/32" of tread to use over their entire life....and this means that a tire with 6/32" of tread left may actually only have 50% of its life left. 

Tire rack did a very interesting comparison test of stopping distances with varying depth of tread on the tires.  Good stuff starting at 1:21, and then a scary comparison at 1:55:



The most accurate way to measure tread depth is with a depth gauge, as explained here. An easier (but less accurate) way to measure depth is with a coin as explained here.  In short, you use a penny or a quarter to ballpark the depth of the tires.  To do so, insert a penny into the treads like this:

http://www.tirerack.com/images/tires/tiretech/pennyfront.jpg

If part of Lincoln's head is covered by the tread, you have more than 2/32". Slightly more depth can be measured with a quarter:

http://www.tirerack.com/images/tires/tiretech/quarter.jpg

If part of Washington's head is covered, there is at least 4/32" of tread left.  And finally, again with a penny:

http://www.tirerack.com/images/tires/tiretech/pennyback.jpg

If part of the Lincoln Memorial is covered, you have more than 6/32" of tread left.

So the amount of tread you'd like to have left on a set of used tires is up to you and how much they cost.  The only thing to be sure of on our cars is that the tread is of equal depth on all four tires because we have AWD.  I'm not sure what an acceptable difference is in tread depth...but I'm guessing that you don't want much more of a difference than 2/32" between any two tires. 

Also, be sure to check the tread depth across the width of the tire in multiple spots, and around the circumference of the tire.  This will tell you about the next thing, which is...

Tread Quality

A single tire might have good depth in one spot, but be bald in another spot...which means that getting a measurement in a single spot is kind of meaningless.  So measure across the width and along the circumference in multiple spots.  You can also run your hand along the circumference of the tire to feel if some areas feel rougher or smoother than others.  Ideally, the tire should feel uniform everywhere.  The rubber of the tread should also be examined for excessive cracking.  Rubber degrades over time, so if the tire is old (more on this later) or has been exposed to excessive temperature swings, sunlight, or ozone, it will start to dry up and crack.  I don't know how much cracking is excessive cracking, but I have read that if the cracks are wide or open, or if the rubber is discolored around the cracks, then the tire is no longer good.

Punctures/Broken Belts

You can't directly see the inside of the tire unless it's off the wheel, and you can't see the condition of the metal belts within the rubber of the tires unless you have special tools that allow you to do so.  If the tire is not mounted, then be sure to examine the inner surface for patches (or holes), and any signs of broken belts.  Assuming the tires are mounted on wheels, you can see clues to the internal condition of the tires.  Look along the tread carefully for any signs of a puncture, or of a plug or patch.  Be sure to look in the grooves between the tread blocks as well as on the blocks themselves.  Also look for any bubbles/bulges or dents in the rubber.  All of these things are signs that the tire may be damaged from something that happened in the past, so it's probably not a tire worth buying.

Sidewalls

Next up is to examine the sidewalls.  Make sure they aren't damaged from being run into curbs, make sure they aren't dented or bulging anywhere, and make sure they don't have any signs of punctures or patches.  Excessive curbing is easy to spot because the black rubber will be scraped off, and you'll see a lot of exposed white rubber.  Any sidewall punctures are bad signs...I've read that very small punctures can be repaired, but it's a bad idea to do so...so it's probably best to say that if there is any damage to the sidewall then the tire isn't safe.  Also examine the rubber of the sidewalls for cracking, which is indicative of old or degraded rubber.  As mentioned earlier, rubber degrades over time, so if the tire is old or has been exposed to excessive temperature swings, sunlight, or ozone, it will start to dry up and crack.  I don't know how much cracking is excessive cracking, but I've read that if the cracks are wide or open, or if the rubber is discolored around the cracks, then the tire is no longer good.

Age

Here's the section that was totally new to me: the age of the tire.  This applies to any tire you buy, whether it's used and from someone's backyard or brand new from a store.  The tread on a tire may be of ample depth and all of the other signs may be good as well, but the rubber might be so old that it isn't safe anymore.  All tires are stamped with a code that tells you the year the tire was made, as well as the week it was made during that year.  Here's what a sample code looks like, it says "DOT U2LL LMLR 5107":

http://www.tirerack.com/images/tires/tiretech/determining_age/Post_2000_Full_Dot.jpg

The last four digits of that code tell you the age of a tire.  The first two digits are the week they were made.  In this case, this tire was made in the 51st week.  The last two digits tell you the year.  In this case, the tire was made in 2007.  So this tire was made in the 51st week of 2007.  This code will be stamped on at least one of the sidewalls of every tire you look at.  If it isn't on the first sidewall you look at, look on the other side of the tire and it will be there...unfortunately it might be stamped on the inner sidewall, which means you'll potentially have to climb under the car to read the code.  If there are only three numbers at the end of the code, then the tire was made before the year 2000, which means it's very old and should not be used under any circumstances. More detail on this can be found here.

There are two categories of tire: those that have never or rarely been used but stored for a long time, and those tires that may be low mileage but have been heavily abused during their short life.


     How age affects tires that have only sat on a rack at a store and never been used, or tires that have been used very infrequently and stored in someone's garage the rest of the time


There is varying opinion on what the expiration date of a tire is, because it depends on the conditions under which a tire was stored.  Ideal conditions would be in a cool, dry location that is out of the sun, and with no weight on them.  The tires should not be stored with weight on them, because "long-term inactivity is more harmful to tires than weekly drives that flex the tires and help maintain oil dispersion within the rubber compounds."  (That was copied from here.) Less than ideal conditions would be if they've been sitting in a garage that gets very hot in the summer, and then very cold in the winter; or sitting out in the sun; or stored with weight on them.  Under ideal conditions, tires are good for a maximum of around 6-8 years based on what I've read.  Under less than ideal conditions, that number goes down to 4-5 years.  In other words, even if the tire has perfect tread and perfect sidewalls and looks brand new....if it's older than 8 or so years, it isn't safe to use anymore.  And if you're unsure of how it's been stored, 4-5 years is pushing it.

There have been at least a few instances of "brand new" tires that are actually very old being sold from stores.  So the tire has never been used before, but the rubber is so old that the tire is no longer safe.  Here's a scary video about this exact issue (it gets particularly scary at ~2:05, but seriously, the whole things is really worth watching).



Here's an excellent example of a deceptive set of tires that I almost bought:

http://lh6.ggpht.com/_qGvlGpcQ1_M/TPKqnQTWWwI/AAAAAAAAAJc/EkQOI__t6-U/securedownload.jpg

http://lh3.ggpht.com/_qGvlGpcQ1_M/TPKqntoyIpI/AAAAAAAAAJg/sWR7S40m1OA/securedownload2.jpg

These tires look awesome, right?  Unfortunately, they were made in mid-2003, which puts them at almost 7.5 years old....so there's a good chance that they're no longer safe even though there is plenty of tread depth and the sidewalls look immaculate.

     Tires that may be low mileage, but were heavily used or abused in one way or another over their life

Scargo had this to add about tires that were used over their life as opposed to being stored:

Scargo wrote:

For tires that are regularly abused (i.e. autocross, or canyon carving every week), they age out considerably more quickly for their intended purpose.  Most lose their elastomers within a year or at most 2 years, which means an extreme loss of grip.  They'll still be safe, but their intended use is lost.

The same applies to Snow tires that regularly get hot (lots of highway, for example). They also age much more rapidly than the expected "freshness" date.  I have noticed a noticeable loss of (mostly) wet grip within typically 3 years of use, usually with plenty of usable regular (as opposed to snow) tread depth left.   

Again, they'll remain safe, but for their intended use, they're no longer of much value.  Makes buying used snows not worth it, IMHO.

Last edited by kornfeld (2010-11-30 19:38:57)


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#2 2010-11-29 20:05:09

kornfeld
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Re: Compilation of Tips on Buying Used Tires

Saved for future use....and if anyone has any other information to add to this post, or if anything posted here looks incorrect, please let me know so it can be fixed.


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#3 2010-11-29 20:19:51

SaabRX
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Re: Compilation of Tips on Buying Used Tires

DUDE , THANK YOU SOOOO much for this very INFORMATIVE POST!!

  eek

embeer cool

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#4 2010-11-29 20:31:57

ryrules1
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Re: Compilation of Tips on Buying Used Tires

+ 1  embeer Age is a bitch in life and in tires.

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#5 2010-11-29 20:34:38

Psybin
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Re: Compilation of Tips on Buying Used Tires

Wow, I didnt know about the expiration dates, good post!  up

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#6 2010-11-29 22:34:23

krazykarguy
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Re: Compilation of Tips on Buying Used Tires

up Thanks for posting!


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2014 Ford Mustang GT Premium 6MT - Sterling Gray Metallic

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#7 2010-11-29 22:41:57

Justin80
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Re: Compilation of Tips on Buying Used Tires

Deserves a sticky. up

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#8 2010-11-29 23:23:52

Topher
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Re: Compilation of Tips on Buying Used Tires

Justin80 wrote:

Deserves a sticky. up

Completely agree!

Stickied.


Thanks

up


And here come the one uppers  arrow-down

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#9 2010-11-30 08:47:19

SaabRX
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Re: Compilation of Tips on Buying Used Tires

Welcome to the sticky Club  Phil..  lol

[The sticky bandits strike again]  lol

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#10 2010-11-30 09:03:46

Silently
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Re: Compilation of Tips on Buying Used Tires

Thank you embeer

arrow-left Runs outside to check the tires I bought last month as brand new...


1/2 of a Volvo S40 and my own two feet

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#11 2010-11-30 09:42:53

Psybin
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Re: Compilation of Tips on Buying Used Tires

Hahah yea I came across this thread last night about 830 and went and checked all the cars.
Figures the tires on the GFs jJetta had the markings on the inside.
The wagons are 2010, Jettas 09, STIs 08. The oldest tires I have are the Michelin Alpine Winter tires I have mounted on the OEM BBS wheels and they are 2005.

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#12 2010-11-30 10:38:05

Linear Man
aka Boxer4dad
From: Brighton, MI
Registered: 2005-10-05
User Number: 837
Posts: 3527

Re: Compilation of Tips on Buying Used Tires

Good stuff.  Had to learn about the dates when I bought my used Hoosiers.  I got late '06 tires, but some available were 2004s.  That was in '09, so while the 2006s weren't new (as expected), the 2004s would have definitely been lacking.  The date gives you a negotiating point.


Had>>>> 05 Black Linear 5MT, Prem. Package

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#13 2010-11-30 10:42:18

deliverator
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Re: Compilation of Tips on Buying Used Tires

I'd put the bit about age at the top because it's new information to a lot of people.

If someone reads through it as-is and sees a couple of paragraphs that cover stuff they already know they may skip the rest.

Apart from that suggestion, good writeup.

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#14 2010-11-30 10:44:41

tlow98
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Re: Compilation of Tips on Buying Used Tires

The date trick is awesome, glad you posted it!


05 MT, cold, sport...black

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#15 2010-11-30 10:57:32

Scargo
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Re: Compilation of Tips on Buying Used Tires

BTW the age issue is assuming normal use and normal conditions (i.e. like the stated OCI's in most manuals).

For tires that are regularly abused (i.e. autocross, or canyon carving every week), they age out considerably more quickly for their intended purpose.  Most lose their elastomers within a year or at most 2 years, which means an extreme loss of grip.  They'll still be safe, but their intended use is lost.

The same applies to Snow tires that regularly get hot (lots of highway, for example). They also age much more rapidly than the expected "freshness" date.  I have noticed a noticeable loss of (mostly) wet grip within typically 3 years of use, usually with plenty of usable regular (as opposed to snow) tread depth left.   facepalm

Again, they'll remain safe, but for their intended use, they're no longer of much value.  Makes buying used snows not worth it, IMHO.


1995.5 Audi //S6, Black/Ecru; MRC Stage 2, Eibach/Bilstein, RS2 BBK, HID's, Eurotails
2005 Saab 9-2X Aero Satin Grey; Cobb STX tune/Cobb 25 mm FSB, 22mm solid adj RSB/H6 upgrade/Noltec Camber Plates/STI Pinks, Koni Inserts/Whiteline Rear Stress Bar/Izixhood/Stromung DP, Crucial HF Kitty, STi catback, Hella MicroDE fogs, color keyed/polished roof rails.

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#16 2010-11-30 12:58:42

kornfeld
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Re: Compilation of Tips on Buying Used Tires

Thanks for the feedback everyone.   up embeer

I split the age section into two groups: one for those tires that have seen little or no use but are old, and another category for those that may be low mileage or relatively young but were heavily used. 

Let me know what you think or if it might be clearer in some other format.


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#17 2010-11-30 13:17:56

Silently
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Re: Compilation of Tips on Buying Used Tires

SilentlyAmazing wrote:

Runs outside to check the tires I bought last month as brand new...

2910 banana


1/2 of a Volvo S40 and my own two feet

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#18 2010-11-30 17:32:06

kornfeld
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Re: Compilation of Tips on Buying Used Tires

Scargo wrote:

The same applies to Snow tires that regularly get hot (lots of highway, for example). They also age much more rapidly than the expected "freshness" date.  I have noticed a noticeable loss of (mostly) wet grip within typically 3 years of use, usually with plenty of usable regular (as opposed to snow) tread depth left....Makes buying used snows not worth it, IMHO.

This is actually exactly why I want used tires....I think they're gonna get destroyed PDQ with how I'm going to use them.  The weather in SF rarely gets below the low 40's during the winter at the coldest, and there's never snow.  The only reason I need them is for trips up to Tahoe, which will happen once every week or two.  The vast majority of that drive is on the highway with no snow and relatively warm temperatures.  I'm not particularly interested in swapping back and forth between sets of tires that frequently, so the tires are going to spend most of their lives being driven in warm weather either in town or on the highway, and only occasionally in actual cold weather.

Looking at prices that have come up, I'm hoping to get a set already mounted on wheels that will last a year or two and will cost <1/2 the price of a new set including installation. 

Of course, the flip side of this is that there's a strong likelihood that I'll be buying a set that's already been abused by driving around on them in SF in years past.  So I'll probably end up getting a set of Continental DWS tires...they sound like they have the best set of characteristics for where I'll be driving.  I'll just keep my eyes open in the meantime.


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#19 2010-11-30 17:33:41

tlow98
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Re: Compilation of Tips on Buying Used Tires

excellent points Scargo, especially on the used winter tire issue.  i found that even my new blizzaks on my last car didn't seem that great by their third season.


05 MT, cold, sport...black

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#20 2010-11-30 19:06:54

Scargo
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Re: Compilation of Tips on Buying Used Tires

kornfeld wrote:

Thanks for the feedback everyone.   up embeer

I split the age section into two groups: one for those tires that have seen little or no use but are old, and another category for those that may be low mileage or relatively young but were heavily used. 

Let me know what you think or if it might be clearer in some other format.

up


1995.5 Audi //S6, Black/Ecru; MRC Stage 2, Eibach/Bilstein, RS2 BBK, HID's, Eurotails
2005 Saab 9-2X Aero Satin Grey; Cobb STX tune/Cobb 25 mm FSB, 22mm solid adj RSB/H6 upgrade/Noltec Camber Plates/STI Pinks, Koni Inserts/Whiteline Rear Stress Bar/Izixhood/Stromung DP, Crucial HF Kitty, STi catback, Hella MicroDE fogs, color keyed/polished roof rails.

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#21 2010-12-01 21:01:28

tekkheadd
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Re: Compilation of Tips on Buying Used Tires

Excellent Thread!


2005 Saab 9-2x Aero 5MT (world rally satin gray), PnP turbo, Factory Gauges, F1 Racing flywheel, 3'' Catless DP, DOM Tuned Stage II, Hella Micro DE fogs, Ixiz, Koyo Rad, Impreza trunk tray FTW!!
Stocker 16''s  Nokian Nordman2
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