Tire load rating ?

[speyrod]

Ok, I thought I had an understanding of tire load ratings, high load rating roughly = more plys Here we have a LT BFG and a Yoko P series, how does P series have a higher load rating than the LT? Does the load rating not align with the number of plys? I more concerned with bad forrest road punctures, this always equalled more plys, have I been looking at this all wrong?

SIZE​

UTQG​

MAX. LOAD​

MAX. INFLATION PRESSURE​

TREAD DEPTH​

TIRE WEIGHT​

RIM WIDTH RANGE​

MEAS. RIM WIDTH​

SECT. WIDTH​

TREAD WIDTH​

OVERALL DIAM.​

REVS. PER MILE​

COUNTRY OF ORIGIN*​

LT285/70R17 116/113S C​

None​

2,755 lbs​

60 psi​

15/32"​

58 lbs​

7.5-9"​

8.5"​

11.5"​

9.3"​

32.8"​

635​

Country of Origin "US" = UNITED STATES OF AMERICA US​

P285/70R17 117T ​

600 A B​

2,833 lbs​

51 psi​

13/32"​

45 lbs​

7.5-9.5"​

8.5"​

11.2"​

8.5"​

32.8"​

633​

TH​

 

[gaijin]

Ok, I thought I had an understanding of tire load ratings, high load rating roughly = more plys Here we have a LT BFG and a Yoko P series, how does P series have a higher load rating than the LT? Does the load rating not align with the number of plys? I more concerned with bad forrest road punctures, this always equalled more plys, have I been looking at this all wrong?

SIZE​

UTQG​

MAX. LOAD​

MAX. INFLATION PRESSURE​

TREAD DEPTH​

TIRE WEIGHT​

RIM WIDTH RANGE​

MEAS. RIM WIDTH​

SECT. WIDTH​

TREAD WIDTH​

OVERALL DIAM.​

REVS. PER MILE​

COUNTRY OF ORIGIN*​

LT285/70R17 116/113S C​

None​

2,755 lbs​

60 psi​

15/32"​

58 lbs​

7.5-9"​

8.5"​

11.5"​

9.3"​

32.8"​

635​

Country of Origin "US" = UNITED STATES OF AMERICA US​

P285/70R17 117T​

600 A B​

2,833 lbs​

51 psi​

13/32"​

45 lbs​

7.5-9.5"​

8.5"​

11.2"​

8.5"​

32.8"​

633​

TH​

Number of plys is no longer a thing. Load Index is what you should be looking at. If you want better abrasion/puncture resistance, you are better off with a LT-Metric tire with a high Load Range. In your case, you should be looking at the Load Range E tires in LT285/70R17.

Here's a breif extract from TireRack that may help:

TIRE TECH: LOAD RANGE / PLY RATING IDENTIFICATION
(Lea en español)
The load range/ply rating branded on a tire's sidewall identifies how much load the tire is designed to carry at its industry specified pressure. Passenger tires feature named load ranges while light truck tires use load ranges that ascend in alphabetical order (letters further along in the alphabet identify stronger tires that can withstand higher inflation pressures and carry heavier loads).

Before load ranges were adopted, ply ratings and/or the actual number of casing plies were used to identify the relative strength with higher numeric ratings or plies identifying tires featuring stronger, heavier duty constructions.

Today's load range/ply ratings do not count the actual number of body ply layers used to make up the tire's internal structure, but indicate an equivalent strength compared to early bias ply tires. Most radial passenger tires have one or two body plies, and light truck tires, even those with heavy-duty ratings (10-, 12- or 14-ply rated), actually have only two or three fabric plies, or one steel body ply.

In all cases, when changing tire sizes or converting from one type of size to another, it is important to confirm that the Load Index in the tire's service description of the new tire is equal to or greater than the Load Index of the original tire and/or that the new tire's rated load capacity is sufficient to carry the vehicle's gross axle weight ratings.

HTH

TireRack source: Tire Tech: Load Range / Ply Rating

 

[speyrod]

Thanks, so in with the above examples does the Yoko P with the higher load rating imply that in this case the Yoko would have a greater puncture resistant than this particular BFG?

 

[gaijin]

Ok, I thought I had an understanding of tire load ratings, high load rating roughly = more plys Here we have a LT BFG and a Yoko P series, how does P series have a higher load rating than the LT? Does the load rating not align with the number of plys? I more concerned with bad forrest road punctures, this always equalled more plys, have I been looking at this all wrong?

SIZE​

UTQG​

MAX. LOAD​

MAX. INFLATION PRESSURE​

TREAD DEPTH​

TIRE WEIGHT​

RIM WIDTH RANGE​

MEAS. RIM WIDTH​

SECT. WIDTH​

TREAD WIDTH​

OVERALL DIAM.​

REVS. PER MILE​

COUNTRY OF ORIGIN*​

LT285/70R17 116/113S C​

None​

2,755 lbs​

60 psi​

15/32"​

58 lbs​

7.5-9"​

8.5"​

11.5"​

9.3"​

32.8"​

635​

Country of Origin "US" = UNITED STATES OF AMERICA US​

P285/70R17 117T​

600 A B​

2,833 lbs​

51 psi​

13/32"​

45 lbs​

7.5-9.5"​

8.5"​

11.2"​

8.5"​

32.8"​

633​

TH​

Further to my last:

There is no such metric as "load rating." There are Max. Load, Load Limit and Load Index. I'll assume you meant Max. Load.

When comparing Max. Load numbers, we must "normalize" to the same type of tire. In the case of P-Metric and LT-Metric, we must either increase the Max. Load of the LT-Metric tire by 10% or decrease the Max. Load of the P-Metric tire by 10%. Let's try the former:

LT285/70R17 Max. Load = 2,755 lbs X 1.1 = 3.031 lbs (normalized to P-Metric)

This shows the LT-Metric Max. Load (3,031 lbs) is actually higher than the P-Metric Max. Load (2,833 lbs).

Now the other way around:

P285/70R17 Max. Load = 2,833 lbs / 1.1 = 2,575 lbs (normalized to LT-Metric)

This shows the LT-Metric Max. Load (2,755 lbs) is actually higher than the P-Metric Max. Load (2,575 lbs).

HTH

 

[gaijin]

Thanks, so in with the above examples does the Yoko P with the higher load rating imply that in this case the Yoko would have a greater puncture resistant than this particular BFG?

No. Generally, due to the more robust construction and tougher rubber used in LT-Metric tires compared to P-Metric tires, even a Load Range C LT-Metric tire would be better than the P-Metric tire. Of course, a Load Range E (10 ply rating) would be even better.

HTH

 

[rscoleman]

Just a guess but I do not think puncture resistance is a function of plys or load rating these days. It is more likely material side wall is made of and what manufacture intended.

 

[catastrofe]

Further to my last:

There is no such metric as "load rating." There are Max. Load, Load Limit and Load Index. I'll assume you meant Max. Load.

When comparing Max. Load numbers, we must "normalize" to the same type of tire. In the case of P-Metric and LT-Metric, we must either increase the Max. Load of the LT-Metric tire by 10% or decrease the Max. Load of the P-Metric tire by 10%. Let's try the former:

LT285/70R17 Max. Load = 2,755 lbs X 1.1 = 3.031 lbs (normalized to P-Metric)

This shows the LT-Metric Max. Load (3,031 lbs) is actually higher than the P-Metric Max. Load (2,833 lbs).

Now the other way around:

P285/70R17 Max. Load = 2,833 lbs / 1.1 = 2,575 lbs (normalized to LT-Metric)

This shows the LT-Metric Max. Load (2,755 lbs) is actually higher than the P-Metric Max. Load (2,575 lbs).

HTH

Curious as to why the normalization is required, and why 10%? Why can't the published max load values be compared without adjustment?

 

[gaijin]

Curious as to why the normalization is required, and why 10%? Why can't the published max load values be compared without adjustment?

Basically, it's because the two tire types are different construction and Load Limits are specified differently by the TRA (Tire and Rim Association). As to why 10%, this has been covered ad nauseum in the various Tire Pressure threads, but I will refer you to the source document (start on page 11): Guide for the Application of Load and Inflation tables

HTH

 

[bloc]

Curious as to why the normalization is required, and why 10%? Why can't the published max load values be compared without adjustment?

The short answer is that euro and p-metric were originally designed for passenger cars and station wagons, but vans/trucks/SUVs have higher center of gravity and likelihood of being overloaded. Because of this they decided having a 10% buffer would be a good idea.

 

[catastrofe]

Basically, it's because the two tire types are different construction and Load Limits are specified differently by the TRA (Tire and Rim Association). As to why 10%, this has been covered ad nauseum in the various Tire Pressure threads, but I will refer you to the source document (start on page 11): Guide for the Application of Load and Inflation tables

HTH

Thank you. This is very interesting. . .one would think that the published max load value is "the gospel". Obviously that's not the case.