Are BFG KM3's running true to listed diameter (1 Viewer)

[Blasst]

I usually look at tiresize.com.......but lately I am not sure they are reliable. I have heard they are running an inch under stated diameter. But that may be diameter from the Goodrich site which I haven't looked at.

Looking at other sites the diameter is listed the same...but the weight difference on some sites is 10 lbs or more.....wayyyy crazy. Suppose I should consult The Goodrich site.
Anyone bought KM3's and actually checked the diameter??

Jim


LT 35X12.50R17 34.5 in diameter...
[URL='https://tiresize.com/tires/BFGoodrich/Mud-Terrain-TA-KM3-315-70R17.htm']LT 315/70R17 34.4 diameter......[/URL]

 

[TeCKis300]

They are reliable. The tire industry has a agreed upon methodology which is mounted on wheel, inflated, and unloaded. Measuring any other way is inaccurate and not particularly useful, as it invites a number of variables into the equation.

"Overall Diameter"
A tire's overall diameter is the outer diameter of the tire measured in the center of the tread. This measurement is made without any load placed upon the tire and after the tire has been properly mounted on its industry assigned measuring rim and has been inflated and reset to its test pressure after 24 hours."logy to measure tire sizes.

More discussion here - Tire Size vs. True Size

 

[Blasst]

great explanation, Thanks. I have been wondering exactly how they do it.

 

[Blasst]

not sure why some sites list a 10 lb difference in those two tires I listed....and some sites don't. The size and all specs are almost identical.
BF Goodrich site doesn't have their tire specs link operational for the KM3 yet.

 

[TeCKis300]

Are they all Load Range E? It might be a P-metric/XL vs an LT construction.

 

[Blasst]

Yup...all the specs seem ....except the weight. Somebody goofed or they may be constructed differently as you said. I'll call somewhere tomorrow.


LT 315/70R17
121Q E BSW 34.4" 12.7" 8-11" 9.5" 18/32" E 10 ply 3195 lbs 65 psi 99mph 65.8 lbs

35X12.50R17LT
121Q E BSW 34.5" 12.5" 8.5-11" 10" 18/32" E - 10 ply 3195 lbs 65 psi 99 mph 74.4 lbs

 

[Taco2Cruiser]

If you look at BFGs website, it lists the

315/70r17 at 73.66 pounds
35x12.5e17 at 74.38 pounds

Still never got why BFG keeps making two tires so close in specs, when there are so many more key sizes missing when these things are first released. They did this on the KO2 also.

 

[gaijin]

Yup...all the specs seem ....except the weight. Somebody goofed or they may be constructed differently as you said. I'll call somewhere tomorrow.


LT 315/70R17
121Q E BSW 34.4" 12.7" 8-11" 9.5" 18/32" E 10 ply 3195 lbs 65 psi 99mph 65.8 lbs

35X12.50R17LT
121Q E BSW 34.5" 12.5" 8.5-11" 10" 18/32" E - 10 ply 3195 lbs 65 psi 99 mph 74.4 lbs

Well, for starters the Tire Load Limits at pressures below the Max 65psi are different for those two tire sizes.

LT315/70R17 Load Range E:
Minimum 35psi - 2535 lbs (Recommended Cold Tire Inflation Pressure for LC200 and LX570)
40psi - 2685 lbs
45psi - 2915 lbs
50psi - 3195 lbs
55psi - 3195 lbs
60psi - 3195 lbs
Maximum 65psi - 3195 lbs

35X12.50R17LT Load Range E:
Minimum 25psi - 1875 lbs
30psi - 2155 lbs (Recommended Cold Tire Inflation Pressure for LX570)
33psi - 2305 lbs (Recommended Cold Tire Inflation Pressure for LC200)
35psi - 2405 lbs
40psi - 2625 lbs
45psi - 2840 lbs
50psi - 3000 lbs
55psi - 3065 lbs
60psi - 3130 lbs
Maximum 65psi - 3195 lbs

This hints strongly at different construction for the two tires to meet the different specs for LT-Metric vs. High Floatation designs.

HTH

 

[Blasst]

Thanks guys.... I had a feeling it was just my ignorance...or missing something. Good catch @gaijin. I agree. I think the 35x12.50 is different construction. It is listed on BF site under 4x4 tires....and is $30 dollars more per tire.

Rob how in the hell did you find the weight on BF's site? Dayum dude....I looked for 2 hours and gave up. Yeah it is strange those 2 tires are so close in size. I may look for a lighter tire. Mid 70's is heavy and 34" or a hair less is what I want.

I was disappointed in the sizes offered in the KM3. Looking at Toyo and Cooper now.......

Jim

 

[bjowett]

The K02 All Terrains I have dealt with run quite small. BFG spec's the 34/10.5R17 at 33.5", it is only 33.1" on a Rock Warrior Wheel. Hopefully the KM3 runs a bit more true to size.

BFG KO2 34x10.5r17lt

 

[Markuson]

My 285/70/17's were barely 32"

My 35x12.5x17 Nitto Ridge Grapplers are just a smidge taller than 34"...off the truck.
If I crank them to their maximum allowable pressure...off the truck...they come close to 35. But no one actually runs then like that.

So ya...there's an explanation...and ya...they qualify by industry standards...
...but ya, it's frustrating when you are trying to figure out *in advance* what will rub and what won't and where...when mere fractions of inches make the difference.

That...has a lot to do with the reason we end up with SOOOO many "will it fit?" threads.

 

[TeCKis300]

That...has a lot to do with the reason we end up with SOOOO many "will it fit?" threads.

If it doesn't fit, just cut or beat it out of the way. Which is not far from the truth of how it is done.

 

[Markuson]

If it doesn't fit, just cut or beat it out of the way. Which is not far from the truth of how it is done.

Heh... Believe me...I’ve cut, hammered and more. Just wish it was easier to predict when getting down to nitty gritty dimensions.

But...It will always be tricky whenener we push the limits.

**And that’s where it’s really on us.**
If we all stuck to more normal parameters...it’s really pretty easy. But we don’t. So we really can’t complain too much.

 

[Blasst]

It will fit ok....I've already made preparations for that. But I'm not driving with 75 lb tires. Planned all along for 34's in the 65-68 lb range on RW's. I have been stalling waiting for the KM3's to see what their like. The guy installing my 40 gallon tank said all the KM3's were running an inch under stated size. He has been selling quite a few.

Mark, I immediately thought of your Nitto's when he told me that. I remember it well. Crazy how they put out specs...or their lack of ability to do it accurately. WTF?

 

[TeCKis300]

Crazy how they put out specs...or their lack of ability to do it accurately. WTF?

It's not crazy. It's a difference of methodology.