DJLikwid

I'm an extreme newbie, so pardon the lack of knowledge.

I'm going to buy some rims & tires (probably today) and the seller said in his ad that the rims come with... "Falken tires 205/40/17 the tread is still good. don't know % left."

I can obviously eyeball the rims to see if theyre in good condition, but how do I tell how much % is left on the tires? This is my first time buying tires.

St Jimmy

There are "wear bars" all along the tires, when they go to those bars its usualy 1/8th of an inch tread left which is the legal limit. Check to see how far away from the wear bars the tread is.

nsxtasy

Before I answer your question, I should mention that a lot of people OVERestimate the percentage left when selling tires. So when you're buying, ask them to tell you the tread depth, rather than the percentage remaining.

Measuring Tread Depth

The easiest way to specify is to have the seller measure the tread depth, using a ruler or any thin object (e.g. toothpick) on which you can draw markings and then hold it up to a ruler or tape measure to measure. Tread depth is usually measured in 32nds of an inch, but it's easy enough to convert between mm and inches. (1 inch = 25.4 mm, 1 mm = 1.26/32 inch)

At Discount Tire, they gave me a card (made of cardboard, the size of a credit card) that had printing on it to use as a gauge in measuring tread depth. It was FREE.

It's usually, but not always, the same depth across the tread (if it's not, then measure in multiple places and say where each number is).

Calculating Percentage Left

If you really want to calculate an accurate percentage of the tread left, once you know the tread depth, here's how to do it.

First, look up the specs of the tire, either on the manufacturer's website or on the website of a retailer like the Tire Rack, to find out the tread depth when the tire is new. Not all tires come with the same tread depth when new. For example, supersticky tires like the Falken Azenis RT-615 come with 8/32" when new, many summer tires like the Yokohama ES100 come with 10/32", many all-seasons with 12/32", and many winter tires have even more tread depth when new.

All street-legal tires sold in North America have treadwear indicator bars molded into the tread. These are strips about 1/2 inch wide, going across the tread, about every foot or so around the circumference. Take a close look at any tire and you'll see them. These strips are 2/32" more shallow (less deep) than the rest of the tread. As a result, when the tread depth gets down to 2/32", the treadwear indicator bars appear flat across the tread. At this point, tires must be replaced, by law, as they are no longer street legal.

Some people replace tires before they reach 2/32" of tread depth, because when they're worn down to, say, 3/32" or 4/32", they're not as good in rain as with deeper tread. But for purposes of your computation, you can assume the tires will be replaced at 2/32".

Then, it's just a matter of interpolating tread depth between the number when new, and 2/32".

For example, let's look at the Yokohama ES100, a popular tire for Integras, in the 195/55-15 size that's stock on the GS-R. According to the specs on the Tire Rack website, it comes with 10/32" of tread depth when new. Thus, the difference between new tread depth (10/32") and replacement tread depth (2/32") is 8/32". And each 1/32" of tread depth is 1/8, or 12.5 percent, of the tread life:

If the tread depth is 9/32", it has 87.5 percent remaining.
If the tread depth is 8/32", it has 75 percent remaining.
If the tread depth is 7/32", it has 62.5 percent remaining.
If the tread depth is 6/32", it has 50 percent remaining.
If the tread depth is 5/32", it has 37.5 percent remaining.
If the tread depth is 4/32", it has 25 percent remaining.
If the tread depth is 3/32", it has 12.5 percent remaining.
If the tread depth is 2/32", it has 0 percent remaining.

HTH

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by St Jimmy &raquo;</TD></TR><TR><TD CLASS="quote">There are "wear bars" all along the tires, when they go to those bars its usualy 1/8th of an inch tread left which is the legal limit.</TD></TR></TABLE>

Nope. The wear bars are at 2/32", which is 1/16", not 1/8".

iH8RICERZ

iTrader: (1)

use a penny and insert it into the grooves of the tire...that'll give you a good reference on how much tread life is left. I usually guestimate in comparison to how they looked new...then provide pictures of me putting a penny inside the grooves to show the depth.

nsxtasy

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by iH8RICERZ &raquo;</TD></TR><TR><TD CLASS="quote">use a penny and insert it into the grooves of the tire...that'll give you a good reference on how much tread life is left. I usually guestimate in comparison to how they looked new...then provide pictures of me putting a penny inside the grooves to show the depth.</TD></TR></TABLE>

The "penny test" is described on the Tire Rack website. It's a good way of telling whether the tires have reached 2/32" of tread or not. But it doesn't give you enough information to calculate the percentage of tread depth remaining. As described in my previous post, you need to know the actual tread depth (not necessarily easy to tell from a photo), and the tread depth of the tires when new, in order to calculate a percentage accurately.

Hi-Psi

Yeah def the penny test is the best/easiest way.

DJLikwid

Here's a pic of the tires, not sure how easy it is to tell with this pic.

nsxtasy

It's impossible to tell from those photos (and from most photos).

Hi-Psi

Those look like 30 to 40% if that.

nsxtasy

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hi-Psi &raquo;</TD></TR><TR><TD CLASS="quote">Those look like 30 to 40% if that.</TD></TR></TABLE>

You really don't know much about tires, do you?

jomama

considering that you're a newbie, don't rush into things and buy whatever comes your way. don't buy anything based on rash decision making or else you may regret it. it's hard to say in the pictures you provided how much tread depth you have left. you're going to want to consider whether or not those are summer tires or all season tires (can't tell from photo) because if they're just for the summer, you're going to want to run another set of wheels with winter tires or all seasons due to the snow up in chicago - or have another car as a daily/beater car. if you need more help, i'm sure nsxtasy could help a lot since he's also from chicago and is known around H-T as the tire expert - no joke. good luck with your purchase.

jomama

those do look like falken 512s... which are an all season tire

DJLikwid

I have a set of all-season tires on the car right now with my blades. I was planning to put those on the ride during the winter and these during the summer.

nsxtasy

Yes, they look like the Falken Ziex ZE-512, which is an inexpensive all-season tire. Not exactly a great one, either.

My advice (which I also included in an IM) is, if you like these wheels at this price, then sure, go ahead and get them - because you like the wheels. Don't let the tires factor into your decision. These are cheap, inexpensive tires; a new set runs around $200 for all four, and a used set, depending on how much tread they have, are worth somewhere in the neighborhood of $0-100, which isn't a whole lot of money compared with the cost of the wheels. So if you like the wheels, get them, and if you want to use those tires, consider them a free bonus with the purchase of the wheels.

And, as others have suggested, keep in mind the differences between summer tires, all-season tires, and winter tires. Summer tires are designed to be used in moderate to warm temperatures, and usually outperform all-season tires in those temps, but they suck in snow and frigid cold. Winter tires are designed to be used in snow and frigid cold, and usually outperform all-season tires in those temps, but they suck on the occasional warm day in winter. All-season tires are compromise tires, better in winter than summer tires, but not as good as winter tires, and the rest of the year they're not as good as summer tires. If you get these and consider them your "nice" wheels (not using them in winter, when road salt can corrode them), that's fine; if and when you need to replace the tires, you can get better performance from a good summer tire (even an inexpensive one like the Kumho SPT or Avon Tech M500). And if you use your current wheels in winter only, and you want better grip when we get hit with our winter weather, you can consider getting a real winter tire like the Bridgestone REVO1 or Blizzak WS-50, Michelin X-Ice, etc.

I have summer tires and winter tires. I have a garage and change my tires myself, so I can wait until the first big snow to change them, and can change them back and forth any time I want; I usually change to winter tires around the second week in December, and change back around the second week in March. If I didn't have a garage and had to rely on paying a shop to change them for me, I would probably be changing them mid to late November and then the end of March.