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Pay Attention To Your Tire Ratings!


hutchman
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My "adventure" vehicle is a 2007 GMC Sierra 1500 with the Z71 Off Road Package. This Off Road Package includes the so called "on/off" road P265/70R17 blackwall tire. The tires on my truck are a Goodyear with a tread pattern that is more aggressive than a straight highway tire, but much less aggressive than a typical mud tire like a BFG Mud Terrain. They seemed to be a decent compromise between off road performance and a quiet highway tire.

 

On our recent visit to the Midwest, I suffered a cut tire on a gravel road in southern Missouri. I replaced it with the spare and headed back to WA State, where I ordered a replacement tire and had it installed. All seemed well and good until two days ago when my son and I were looking at the new tire. He noticed the tire rating and stated that it was a standard load rated tire...........really only a PASSENGER CAR RATED TIRE! I had not paid that much attention.......Hmmmmmmm, this could cause some real problems when up in the mountains on Forrest Service Roads. There is a lot of sharp gravel in the mountains, which is very similar to the gravel on the road in MO. These sharp rocks can and will puncture a tire easily if the tire is not build for heavy duty service.

 

Back in the day, bias ply tires had a "ply" rating based on the number of "plies" or layers of rubber in the casing. A 2 ply tire had 2 layers and was less strong than a 4 or 6 ply tire. It was easy to tell how tough a tire was by the number of layers of rubber. You could feel every pebble on the street on true 10 ply tires!

 

Today it is not as easy to know how tough your tire might be. Due to modern manufacturing techniques, tires toughness is no longer indicated by counting plies as in the past but by an equivalent rating based on the old ply system. Here is a link to some good basic info on how tough the tire is you might be purchasing:

 

http://www.tirerack.com/tires/tiretech/tec...e.jsp?techid=55

 

The "on/off" tires on my truck are really no more than 2 ply passenger car snow tires in toughness. They are not good off road tires.......period. It kind of makes you wonder why they would be installed with a so called "off road" package..........

 

When I replace these tires, I will purchase a much heavier LT rated aggressive tire which should resist punctures much better and be a better back country tire. These are the type of tire that should be include in the Z71 Package, but probably aren't due to cost. But what do I know?!?! Maybe most people using this type of truck never leave the pavement and therefore do not need a true LT rated tire.

 

There are of course, disadvantages to this type of tire.........fuel economy. These tires are much heavier and have more rolling ressistance than the passenger car tires and because of this, will cause a reduction in fuel economy, drivability, and be noisier. There are trade offs to deal with in tires as in life!

 

Just remember that when driving in the back country that all of your equipment must be up to the task. It can be a long walk out!

 

 

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My "adventure" vehicle is a 2007 GMC Sierra 1500 with the Z71 Off Road Package. This Off Road Package includes the so called "on/off" road P265/70R17 blackwall tire. The tires on my truck are a Goodyear with a tread pattern that is more aggressive than a straight highway tire, but much less aggressive than a typical mud tire like a BFG Mud Terrain. They seemed to be a decent compromise between off road performance and a quiet highway tire.

 

On our recent visit to the Midwest, I suffered a cut tire on a gravel road in southern Missouri. I replaced it with the spare and headed back to WA State, where I ordered a replacement tire and had it installed. All seemed well and good until two days ago when my son and I were looking at the new tire. He noticed the tire rating and stated that it was a standard load rated tire...........really only a PASSENGER CAR RATED TIRE! I had not paid that much attention.......Hmmmmmmm, this could cause some real problems when up in the mountains on Forrest Service Roads. There is a lot of sharp gravel in the mountains, which is very similar to the gravel on the road in MO. These sharp rocks can and will puncture a tire easily if the tire is not build for heavy duty service.

 

Back in the day, bias ply tires had a "ply" rating based on the number of "plies" or layers of rubber in the casing. A 2 ply tire had 2 layers and was less strong than a 4 or 6 ply tire. It was easy to tell how tough a tire was by the number of layers of rubber. You could feel every pebble on the street on true 10 ply tires!

 

Today it is not as easy to know how tough your tire might be. Due to modern manufacturing techniques, tires toughness is no longer indicated by counting plies as in the past but by an equivalent rating based on the old ply system. Here is a link to some good basic info on how tough the tire is you might be purchasing:

 

http://www.tirerack.com/tires/tiretech/tec...e.jsp?techid=55

 

The "on/off" tires on my truck are really no more than 2 ply passenger car snow tires in toughness. They are not good off road tires.......period. It kind of makes you wonder why they would be installed with a so called "off road" package..........

 

When I replace these tires, I will purchase a much heavier LT rated aggressive tire which should resist punctures much better and be a better back country tire. These are the type of tire that should be include in the Z71 Package, but probably aren't due to cost. But what do I know?!?! Maybe most people using this type of truck never leave the pavement and therefore do not need a true LT rated tire.

 

There are of course, disadvantages to this type of tire.........fuel economy. These tires are much heavier and have more rolling ressistance than the passenger car tires and because of this, will cause a reduction in fuel economy, drivability, and be noisier. There are trade offs to deal with in tires as in life!

 

Just remember that when driving in the back country that all of your equipment must be up to the task. It can be a long walk out!

 

I discovered the same thing last year when I got a flat in the Nevada desert. I think the manufacturers put the lighter duty tire on the trucks because 1.) like you said, most never make it off the pavement and 2.) they get better mileage.

 

Like you, I will likely go with the LT rated tire when it comes time to replace mine. In a perfect world I would have the LT's on one set of rims and another set of rims with the passenger tires and switch them based on driving needs. I haven't won the lotto yet so I have to compromise and go with a single set of tires.

 

Roadhound

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