[derf]

This is why I wonder about gearing ratio. Based on the infamous chart, which if I am correct references true tire size, a 35 which is actually 33.5" under load, 4.10 would be about perfect, but then you have people who claim their 4.10 is under geared with 35s. I would think 4.10's and a small and light 35 like KO2 or Duratrac would be a perfect combo.

That's why a gear ratio calculator is better than the chart. When you can put in the actual tire size you get a much more accurate result.

 

[15RubieJK]

This is why I wonder about gearing ratio. Based on the infamous chart, which if I am correct references true tire size, a 35 which is actually 33.5" under load, 4.10 would be about perfect, but then you have people who claim their 4.10 is under geared with 35s. I would think 4.10's and a small and light 35 like KO2 or Duratrac would be a perfect combo.

I have 4.10s and mtr 35s which are considered light. The 4.10s are ok but I wouldn't mind going 4.56s ect. It's very subjective in what feels right to someone. My goal would be getting back the stock ratio ect.

 

[SoCalRubicon]

?

So you are having a "shrinkage" problem?

Been in cold water recently?

J/K.

Which "35 inch" KO2's do you have?

The 315/70R17's or the 35x12.5R17's?

Because the 315/70's are actually listed as 34.4" which will be even smaller when mounted.

 

[SRG]

This is why I wonder about gearing ratio. Based on the infamous chart, which if I am correct references true tire size, a 35 which is actually 33.5" under load, 4.10 would be about perfect, but then you have people who claim their 4.10 is under geared with 35s. I would think 4.10's and a small and light 35 like KO2 or Duratrac would be a perfect combo.

Are you taking into account what motor (3.8 or 3.6)? I can see a 3.8 being undergeared with an unloaded 35" tire (true 34"ish measured height) and 4.10's but I'd think the 3.6 with an automatic would be pretty good match for both on and off-road.

Gear Ratio RPM Chart Calculator

There's a good gear calculator that already specs out JK models and transmissions. All you have to do is mess with the numbers in the calculator to see the affects.

 

[TxJprs]

I've run a few Jeeps and tires over the JK years. I've always used a Procal.

GY Duratrac 315/70R17 entered 33.75" into the ProCal
BFG KM2 35x12.50R17 entered 33.75" into the ProCal
Mickey Thompson ATZP3 315/70R17 entered 33.75" into the ProCal
BFG KO2 35x12.50R17 entered 33.75" into the ProCal

All measured on the Jeep with 29 PSI and rounded to nearest quarter inch. So I'd say my measurements are +/- 1/8".

Note the KM2's have a more rounded edge which makes them look smaller. Tires with a more square edge appear taller. A buddy just got a set of Toyo MT's in 35x12.50R17. I'll have to ask him what he measured them out to be.


Side note:
And Since I've run a number of tires, let me throw in that I've also run GY MTR in 285's and Cooper STT in 33's. All that said, I have no intentions of running any other tire brand but BFG going forward. They balance, ride, last and perform the best. Loved the KM2's. The KO2's are great so far. If I ever go back to a MT, I'll wait for the KM3's in supposedly 2017.

Second side note.
Some of them those I ran on JKUR with 3.6/4.10's and some on a 3.6/3.73's. Both downshift with a good headwind on the highway. Both downshift on hills with a decent grade. Ultimately I do not feel there is much of a difference to my butt in seat. So, I say get you'll be satisfied with either and in either case, to get back to stock performance you need to go to 4.56 (4.88 if you don't run highway much or have thoughts of 37's).

 

[TxJprs]

Buddy confirmed he measured his Toyo MT's out to 35" on the Jeep, so at least some manufactures are true to size.

 

[nknacd]

according to BFG's website your 315's are 34.4 or 34.5 in overall diameter, or your 35s are actually 34.5

If you are like me i research everything before buying All-Terrain T/A KO2 | BFGoodrich Tires

knowledge is power

 

[derf]

according to BFG's website your 315's are 34.4 or 34.5 in overall diameter, or your 35s are actually 34.5

If you are like me i research everything before buying All-Terrain T/A KO2 | BFGoodrich Tires

knowledge is power

Speaking of knowledge is power...

Most tires never actually measure out to the advertised OD. My 315/70R17 tires are advertised at 34.4" in OD. On my Jeep (and on many others) they actually measure 33.5" in real life.

 

[TurkTTR]

With tire sizing being different than the nominal size indicates, I always figured it was a "close enough is good enough" thing. But for whatever reason, with lumber, it always drives me crazy that the nominal size is different from the actual size. I have been dealing with tires for longer than I've been buying lumber though, to be fair.

I only learned about lumber sizing a few years ago- the hard way, after drawing up extensive plans and a full cut list for a build, only to later find out nothing fit together the way it should have because a 2x4 is not 2" x 4".

I have since adjusted my plan-making skills accordingly. I am happy to hear that Lowe's has to list actual size along with nominal size though, because remembering dimensions is tough while standing in the hardware store sometimes. I think it's a bit overkill that it took a lawsuit to put that in motion though...

 

[swab]

My 305/70/17 terra grapplers measure 33.25" at 30 psi.

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