Sidewall question

[Old Codger]

I am looking at 2 similar tires from the same manufacturer. One is a 315/70 - 17 load range D and the other is a 35 x 12.50 x 17 load range E2. Both tires have 2 ply sidewalls. Will the sidewalls on the E2 tires be tougher/less likely to be torn by rocks than the D rated tires? I assume the higher load capacity will have thicker plies in the sidewalls to carry the higher load, which may make them more tear resistant. But, I also know enough about engineering and materials to question that assumption. Any thoughts one way or the other?

I understand both are overkill in terms of load capacity on a Bronco. I am not asking about assumed ride quality differences.

thanks

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[DriveAllNight]

I'm not a tireologist but are you sure the 35 inch E rated tire is only 2 ply?
That doesn't sound right to me.

 

[Old Codger]

@DriveAllNight, I agree but that's what the manufacturer's description for this tire name says (not tied to this specific size).

 

[Brian_B]

Well E vs D is a load rating so it doesn’t directly correlate to puncture/tear resistance - but you can infer if a tire is rated for higher pressure/load it had to do something to strengthen the side wall to support that.

Commonly that’s more plies - it it can also be something like Kevlar or thicker material.

Doesn’t provide any guarantee mind you - because again, it’s a load rating. But I would bet a sidewall on an E would hold up better to abuse than a D (even if it’s just marginally)

An E rating would also be more prone to slipping a bead at lower tire pressure than D rating due to (probably) stiffer and/or thicker sidewalls, and it will tend to weigh more due to the additional material.

So pros and cons

 

[SuperDave150]

Way old background info: they’re actually called “pneumatic tires” because the air holds the load. The sidewalls (carcass) don’t hold up the weight - they hold the air pressure inside and that air holds up the weight.
This is the 21st century; tire engineer have figured out how to contain high pneumatic pressures without the necessity of utilizing umpteen layers of material.

 

[Old Codger]

Thanks @SuperDave150 for politely reminding me of the obvious thing I knew at some level but had not thought through. Makes the decision much easier. No value adder for the E rated tire in this case, only weight penalty.

 

[dgorsett]

Well, you said it...."weight penalty". Meaning, the E has more stuff. It's the same height and width, so the more stuff must be thickness. More thickness=puncture resistace.

 

[Canyon Coolers]

I got to sit in on a few hours of Kenda's tire school recently. Ply count is deceptive since they can be of any thickness and any material. I would not over think it, but instead source a brand you trust in the right application and load rating for your vehicle since it is designed to ride a certain way and have a certain footprint under a certain load.

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