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Load Range E1 vs E2


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#1 Foy

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Posted 16 April 2017 - 04:48 PM

In the "just when I thought I had an understanding of this" column!

 

Now comes a comparison of E1 vs E2 load range. As I feebly understand Discount Tire's own material, E-rated tires sized 305 and up carry an E-2 load range and a max inflation of 65 psi while E-rated tires sized below 305 carry an E-1 load range and a max inflation of 80 psi.  It is apparently entirely possible to run an E-1 or an E-2 tire having the same max load capacity, etc, so the primary (sole?) difference would seem to be overall sidewall stiffness and related handling situations.  I admit it's funny to use "handling" and "8,000 lb pickup truck" in the same sentence, but I have to say I've noticed a meaningful improvement in driving/handling when running E1 rated tires at 75-80 psi.

 

Has anybody run E2s on a truck formerly running E1s and noticed any decline in handling characteristics?  I would think the taller tire (305 to 315) running 65 psi max would have to feel squishier than the same tire in a 285 size running 80 psi, with each tire being from the same manufacturer, tread design, and operational application.

 

Bottom line for me is I'd like a touch more tall (315/75R16) than the size I'm running now (285/75R16) but I don't want to give up sidewall stiffness and "handling". I still chuckle when I write that.....my truck "handles" like a Porsche with 4 flat tires.........and that's on a good day.

 

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#2 Squatch

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Posted 16 April 2017 - 05:43 PM

New one on me. But I'm guessing this is the "new" flotation tires in metric sizes. Slowly replacing the old 35x12.50x15 ect.


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#3 craig333

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Posted 16 April 2017 - 10:25 PM

Never heard of that either. 


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#4 smlobx

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Posted 17 April 2017 - 11:48 PM

I wonder if the "new" E2 rating is a marketing ploy for the old standard "D" rated tires with a 65 psi max rating??
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#5 PJorgen

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Posted 18 April 2017 - 02:59 AM

Great questions and the same things I asked my tire guy when I went to bigger tires on my GMC 2500HD.  What I learned is:

 

Any truck tire 305mm (11.5") or wider is considered a "flotation" tire and will have a C2, D2 or E2 load range.  These tires have a max inflation less than the C, D or E range tires.  In the case of the E vs E2 it's 80 vs 65 psi.  

 

Load INDEX is equally important in determining weight capacity as load RANGE.  For instance, a load range E, load index 121 tire at 50 psi can carry 2470lbs, whereas a load range E2, load index 121 tire at 50 psi can handle 2755lbs.  However, either tire at max pressure, 80 psi and 65 psi respectively, can carry 3195lbs.  Very simple, right?  BTW - all this info is straight from the Discount Tire document.  

 

With my truck I went from 285/65/18 to 305/60/18 so that I could use flotation tires and air down to lower pressures while still maintaining the weight capacity since I have a FWC on the back and gross weight of about 8700lbs.  I've noticed no change in handling but an improvement in ride quality due to the lower tire pressures.  

 

Note that 305 or 315 refers to width, not height.  You mention that the 305 or 315 is a taller tire.  Only true if you stay with the same aspect ratio (the second number in the tire size).  My 305/60/18s are actually a tiny bit shorter than the original 285/65/18s.  

 

Got all that?


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#6 Foy

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Posted 18 April 2017 - 08:51 AM

Yep, got it, and many thanks for relating your direct, on-point experience.

 

I am aware that 305-315, etc relates to width.  A touch more width is among my goals. The size I'm focused on at present (315/75R16) is within the same aspect ratio as the 285/75R16 I'm currently running.  Conversion charts show the 315/75 to be 1.8 " taller and 1.2" wider than the 285/75s, and it's the bump in diameter/height which is my primary goal. 

 

It's particularly great to hear of your experience in the handling and ride comfort departments.  I look favorably upon keeping handling "no worse than it is now" when laden while enjoying a somewhat smoother ride.

 

I am also focused on the load index numbers more than the load range rating.

 

Good stuff!  Thanks!

 

Foy 


Edited by Foy, 18 April 2017 - 09:08 AM.

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#7 ntsqd

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Posted 19 April 2017 - 01:49 AM

It wasn't complicated enough, some lawyer had to make it more so? Yeash!

 

We went from OEM size 265/something(70?)R16's to GY DuraTrac 315/75R16's to Yoko A/T-S II 315/70R17's on our truck. The 17's are slightly better in the handling dept., but that could also be the different mfg's. Both 315's go down the road at 50 psi. Any higher and they start lifting the tread edges. Both our Polar Moment and our inertia is high, but I'm happy with the handling from either tire.


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#8 JaSAn

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Posted 19 April 2017 - 03:20 AM

I am also focused on the load index numbers more than the load range rating.

 

 

Both are important, just depends on how you plan to use your truck.  Load range is a rating of the resistance of the sidewall to puncture: E = 10 ply rated, D = 8 ply rated.  Actual number and construction of plys are molded into the tire sidewall.  So if you go off road ply rating is important.

 

Load index relates to maximum load.  Index number is used because it is used for both Europe, Asia (Kg.) and US (lbf.) max loads.

 

Didn't know the difference between E1 and E2.

 

https://en.wikipedia.../wiki/Tire_code

 

jim


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#9 Foy

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Posted 20 April 2017 - 01:05 PM

I've overlooked a rather meaningful detail in all of this:  My truck has OEM 7.00 x 16.00 inch wheels.  Discount Tire says the narrowest wheel they want to mount a 315/75R16 tire on is 7.5" and they recommend at least an 8" wheel.  Dunno if that's policy or a strong recommendation, but I'm ponderin' nonetheless. I'm not particularly interested in buying 4 wheels, but keeping the original wheels and the tires on them and running them parts of each year for the next several years isn't an altogether bad idea.  Hmmmm........

 

Foy


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#10 Squatch

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Posted 20 April 2017 - 03:24 PM

I've been running flotation sizes in C rated for years. The trick to good handling is to have the tread flat on the surface of the pavement. Too narrow a wheel can make the tires feel squirrely and will greatly lessen tread life. if you are going wider go for the recommended wheel width.


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