[FIRE UP]

Hey Gang,
While on a Jeep run the other day with a couple of buddies and their wives, we stopped for lunch and were talking about tires. One of them is on the lookout for some. He stated he's thinking about 35s for his '17 Recon. I told him I've got the Hancook Dynapro 315 70 17 A/T and they've been absolutely flawless in all aspects, on or off road. He stated a 35 12.50 is a truck tire whereas, a 315 70 is more of a passenger car tire. I'm not smart enough to debate one way or the other.
I did look up a 35 12.50 17 and it came up as a load range C, D and E, with different load ratings. But, when I looked up a 315, all I get is "Load Index". And, from what I gathered, with a "load index", the same tire has different load ratings, based on pressure. What say you tire experts?
Scott

 

[WebDevDan]

Size and load rating have nothing to do with each other. 315/70R17s come in load ranges C/D/E as well. Just go to tirerack.com and search for 315/70/17 and you'll see the same load index/range ratings on both sizes

 

[ScaldedDog]

OP, your friend is assuming that all metric size tires are P-metric, which is incorrect. Some, including yours in that size (you have the ATM, right?) are LT, just like all 35s. You can google the difference between p-metric and LT easily enough, and tiresize.com will show you whether a particular tire in a particular size is P or LT.

That said, I never understood why anyone would buy a 315/70 over a 35. They are generally a quarter of an inch shorter. If you want a 35, buy a 35, right?

Mark

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[jadmt]

OP, your friend is assuming that all metric size tires are P-metric, which is incorrect. Some, including yours in that size (you have the ATM, right?) are LT, just like all 35s. You can google the difference between p-metric and LT easily enough, and tiresize.com will show you whether a particular tire in a particular size is P or LT.

That said, I never understood why anyone would buy a 315/70 over a 35. They are generally a quarter of an inch shorter. If you want a 35, buy a 35, right?

Mark

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I have had both 35’s and 315’s and I don’t think there is enough difference to worry about either way. Some/most manufacturers don’t make various models in both sizes so if you are stuck on a particular model ie say cooper st maxx you can only get the 315/70’s. Granted some have both.

 

[ScaldedDog]

I have had both 35’s and 315’s and I don’t think there is enough difference to worry about either way. Some/most manufacturers don’t make various models in both sizes so if you are stuck on a particular model ie say cooper st maxx you can only get the 315/70’s. Granted some have both.

That makes sense.

Mark

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[FIRE UP]

Hey gang,
Thanks for the answers. When I was outfitting our '15 JKUR, I was learning about metric sizes of tires. In all the other EIGHT Jeeps we've owned, I dealt with standard sizes, i.e. 31s, 33s, and 35s. But, in cruising around on this forum, so many had gone to the "315s" to be used as 35s, instead of actually purchasing 35s, I figured, what the heck, must be good or, they wouldn't be getting them. Well, I don't recall all the specific difference between the 315s and actual 35s I (and Discount Tire) was looking up at the time but, if I remember anything (which isn't much), they're close to identical.

But, as for my buddy, and his dilemma, well, I'll do some more digging to see if I can prove to him that both will do the job. Thanks again.
Scott

 

[NickMOAB]

In my hunt for 35" bfg I came across a killer deal on the 315. I am not disappointed.

 

[FIRE UP]

In my hunt for 35" bfg I came across a killer deal on the 315. I am not disappointed.

My one BIG regret when I originally outfitted ours with the 315 A/Ts from Hancook was/is, they're "D" rated which, is a slightly heavier and, harsher ride than a C rated tire. I needed to not be so hasty and do a tad more research on either 35s or 315s to find out which model/brand had/has load range C so I could have gotten a better ride. Oh well, these will wear out in time and I'll do better next time.
Scott

 

[NickMOAB]

Mine are load range C and when I bought my jeep it had E rated MT's. The ride is night and day while still maintaining great trail manors.

 

[FIRE UP]

Well Gang,
To finish this thread up, my buddy ended up ordering (5) 315 70 17 B.F. Goodrich KO2s from Discount tire. Not sure what he's paying for them but, he did tell me they're LOAD RANGE C. Now, in my recent search, it seems that about 99.999% of the 315s out there have what's called a "load Index". And, according to Discounts website, about 99.9999% of the 315s have a load index of 121. That number represents what kind of weight it can carry. When I looked up a bunch of 315s, the lowest "load index" for any 35" tire was the B.F. Goodrich KO2 which, was 113 instead of 121. Now, on Big-Os tire website, they have the KO2 at load range C for $242 each. If my Hancooks were a bit older and or more worn, I'd probably be heading down to them unless I could find them cheaper.
Scott

 

[jwt873]

The load range is just a complicated way of telling you the maximum number of pounds the tire will support. A 121 tire can support 3197 Lbs at its maximum inflation pressure. There's a chart in this link that decodes the load ranges: https://www.tiresplus.com/tires/tire-buying-guide/tire-load-index-chart/

The E rated 121 KO2 will have something like "Maximum Load 3197 Lbs @ 80 PSI" written on the sidewall.

The C rated 113 KO2 will have something like "Maximum load 2535 Lbs @ 50 PSI" written on the sidewall.

It's the air pressure in a tire that suports all the weight of a vehicle. (If you let all the air out, an E rated tire will be just as flat as a C rated tire).. The E rated KO2 is able to carry more weight because of the extra 30 PSI of pressure that it can hold.

 

[aldo90731]

OP, your friend is assuming that all metric size tires are P-metric, which is incorrect. Some, including yours in that size (you have the ATM, right?) are LT, just like all 35s. You can google the difference between p-metric and LT easily enough, and tiresize.com will show you whether a particular tire in a particular size is P or LT.

That said, I never understood why anyone would buy a 315/70 over a 35. They are generally a quarter of an inch shorter. If you want a 35, buy a 35, right?

Mark

Sent from my SM-G935V using Tapatalk

Only that 35s are not really 35s...they are only 34.5s, as for example BF Goodrich likes to do —which is really owned by Michelin.

On the other hand, my 315/70-17 KO2s measure 12.7 across; that’s 0.2” wider than a 35x12.5. Since I live near snow-covered mountain areas where tire flotation is a key advantage, I’ll pick the tire with the bigger footprint.

 

[aldo90731]

Well Gang,
To finish this thread up, my buddy ended up ordering (5) 315 70 17 B.F. Goodrich KO2s from Discount tire. Not sure what he's paying for them but, he did tell me they're LOAD RANGE C. Now, in my recent search, it seems that about 99.999% of the 315s out there have what's called a "load Index". And, according to Discounts website, about 99.9999% of the 315s have a load index of 121. That number represents what kind of weight it can carry. When I looked up a bunch of 315s, the lowest "load index" for any 35" tire was the B.F. Goodrich KO2 which, was 113 instead of 121. Now, on Big-Os tire website, they have the KO2 at load range C for $242 each. If my Hancooks were a bit older and or more worn, I'd probably be heading down to them unless I could find them cheaper.
Scott

I bought a set of 315/70-17 KO2s from Discount Tire about four months ago, for $242 as well, and they are clearly labeled C range.

Having said that, the 34x10.5 KO2s on my 2015 JKU Sahara were D rated and rode more smoothly than these 315/70-15 C range.

Which goes to show that, all things being equal, ride quality is affected by many factors besides load range. Tire width will have as much or more impact.

 

[ScaldedDog]

Only that 35s are not really 35s...they are only 34.5s, as for example BF Goodrich likes to do —which is really owned by Michelin.

On the other hand, my 315/70-17 KO2s measure 12.7 across; that’s 0.2” wider than a 35x12.5. Since I live near snow-covered mountain areas where tire flotation is a key advantage, I’ll pick the tire with the bigger footprint.

Actually, absent Interco and Pitbull, the average 35" radial for 17" wheels has a diameter of 34.8", and a weighted rolling diameter (WRD) of 33.7", with the smallest and largest measuring 34.4"/33.1" and 35"/34", respectively. (N=37) I excluded Interco because their radials have a much larger differential between diameter and WRD than the industry average (6.6% vs 3.1%). I suspect, but do not know, that they use less steel than most manufacturers, causing their radials to have a larger crown. I excluded Pitbull because they don't publish rev/mile numbers for their tires.

Incidentally, BFGs in that size, not counting the Krawler KX, which hardly anyone on here runs, average 34.6"/33.6", so they are a couple of tenths smaller than average.

The average 315/70-17 (N=44) has a diameter and WRD of 34.5" and 33.4", respectively, making them 0.4" or 0.3" smaller than a 35, depending on which attribute you choose to measure.

Mark

 

[rednroll]

I have 315/70/R17 KO2's Load E rated and for DD use I run them at 35psi. I never knew my load E tires road harsh until someone on the inter forums who has never ridden in my JKU told me they road harsh. In other words it's really subjective. I preferred the load E tires due to they have more/thicker plies which not only provides higher tow ratings since they can be inflated with higher PSIs but adds to the durability to resist punctures when offroad and more durabilty seemed like a good thing to me since I go offroad. Where as ride comfort if it was really a harsh ride, that can be adjusted by riding at a lower on road PSI. Many ride at 30 PSI on E rated tires. I run my E's at 35psi and feel the ride is fine. Maybe that's just because I prefer a firmer ride or maybe that speaks to the ride quality of my Mopar 2in lift with Fox shocks? I really don't know. I just know an E rated tire could be adjusted for through tire pressure for increased ride comfort but a C rated tire couldn't be adjusted to increase tow capacity and durability.

My 315/70/R17 E rated KO2s were also purchased through Discount Tire.

In my hunt for 35" bfg I came across a killer deal on the 315. I am not disappointed.

My one BIG regret when I originally outfitted ours with the 315 A/Ts from Hancook was/is, they're "D" rated which, is a slightly heavier and, harsher ride than a C rated tire. I needed to not be so hasty and do a tad more research on either 35s or 315s to find out which model/brand had/has load range C so I could have gotten a better ride. Oh well, these will wear out in time and I'll do better next time.
Scott

 

[YnotAJeep]

I scored my BFG KO2's 315-70-17C back when 4WD was selling them for 200 each no tax and free shipping. They have been great tires. I run them at 30psi cold.

 

[JTPhoto JK]

I had 35x12.50x17 Pitbulls and they were true to size. They dwarfed other 35s.
I then moved up to 37x12.50x17 Pitbull Rocker Radials again true to size and dwarfed other 37s.
You CAN’T go by manufacturer specs. They are all different.
As for the metric tires. A 315 is the metric version of a 35. The 305 metric of a 33 hence most manufacturers don’t make both a metric and SAE.
Here is a brand new 37x12.50x17 Mastercraft against a very well worn 37x12.50x17 Pitbull Rocker radial (a half inch of tread worn off these Pitbulls at this point. New they would be another inch taller).

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[rednroll]

I did a similar test. I parked my 315/70/R17s KO2s next to another JK with 35 x12.5 KO2s. I could not tell a difference in size with them side by side.


Going by tiresize.com it shows these as the measurements

315/70/R17 KO2 Height= 34.4in, width=12.7in
35x12.5 KO2: Height=34.5in, Width=12.5in


So what does this mean? I think it doesn't mean a damn bit of difference, so get the one that cost the least which in the U.S. is typical the tire in metric sizes. Why do the metric sized tires often cost less? Personally, I think it's because they are taking advantage of people in the U.S. who are unfamiliar with the metric measurements and too lazy to figure out how to convert the metric size to standard size. Hardly anyone on this forum from the U.S. ever posts a thread, "Looking for 315/70s", they all say "looking for 35s". I believe the 315/70/R17 KO2 is the exact same tire as the 35x12.5xR17 KO2s just with different measurement stamps printed on the side walls.

 

[JTPhoto JK]

I did a similar test. I parked my 315/70/R17s KO2s next to another JK with 35 x12.5 KO2s. I could not tell a difference in size with them side by side.


Going by tiresize.com it shows these as the measurements

315/70/R17 KO2 Height= 34.4in, width=12.7in
35x12.5 KO2: Height=34.5in, Width=12.5in


So what does this mean? I think it doesn't mean a damn bit of difference, so get the one that cost the least which in the U.S. is typical the tire in metric sizes. Why do the metric sized tires often cost less? Personally, I think it's because they are taking advantage of people in the U.S. who are unfamiliar with the metric measurements and too lazy to figure out how to convert the metric size to standard size. Hardly anyone on this forum from the U.S. ever posts a thread, "Looking for 315/70s", they all say "looking for 35s". I believe the 315/70/R17 KO2 is the exact same tire as the 35x12.5xR17 KO2s just with different measurement stamps printed on the side walls.

I totally agree with you. On occasion you will find a manufacturer that will build the metric 315/70R-17 in D rated and then produce a 35x12.50x17 as an E Rated Tire, but physically they are still the same size.

It’s crazy when think about it that with most manufacturers you have to buy a “37” just get a true 35” tire.


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