Looks vs Logic - Tire size ??

[RoseLane4]

I owned a ‘22 BD 7MT (4:46 diffs) with the stock 32” Generals.. 35’s would have been great & easily handled by the 4:46’s!

Now I have a ‘24 BL’s 7MT (4:70 diffs) with 35’s and can easily handle 37’s!

Point: Go for the 35’s!!

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[kodiakisland]

That is not entirely true......such is the case with the 2.3 7MT, if it's geared wrong for the taller tires, it spends a LOT of time in boost on the highway, especially at over 70 MPH, and in a head wind, THUS using a LOT more gas (MPG goes way down)......IMO, its all about being correctly geared for the tire size, and I dont want to change gearing.

All depends which gear you are in. Use the gear that keeps you out of boost. I get better highway mileage with my 37s than I did with my 35s.
Shift points are based on engine rpm, not speed. You should be in an rpm range that is not in boost regardless of speed.

As far as looks vs function, I leave the looks to the dudes running 20s.
Use the size tire you need, unless looks are more important to you than function, then go with whatever.

 

[kodiakisland]

If you are spending time in boost ~you~ are in the wrong gear. This may mean that 6th gear is useless, and maybe even 5th gear.

I get ~better~ mileage on the freeway cruising at 70-80 with 38s than I did with 35s, even though the wheel weighs 10 lbs more. And I'm in 4th or 5th gear doing it, depending on the headwind and/or traffic around me.

Yep, just got back from a 4K mile round trip after going to the 37s. I got better mileage than I did from the 35s.

RPMs is what matters, not speed or gear the vehicle is in. I don't care what gear I'm in as long as I'm in the rpm range I want to be in. The actual gear used is irrelevant.

 

[23OBX2.7]

There are a few tire models out that were designed to look the off-road business and function very well on pavement....

 

[timhood]

So.......the age old tire size dilemma.......did you go strictly LOOKS or did you choose LOGIC??

For my 2025 Base 7MT -

LOOKS tells me go with 315/70/17 on a +30 offset wheel (FP Everglades)
LOGIC tells me go with a 285/70/17 on a +55 offset wheel (BD steelies)

The 33" tire is LOGICALLY a better tire for a 4.46 geared 2.3 7MT
BUT the 35" tire LOOKS really good and I know I will give up not only MPG but acceleration as well.

What say you ??

I’m going to assume you have a 4-door, because 33s look great on a 2-door. Since we can weed out off-road needs, we’re looking at looks vs. cost. I was inclined to tell you to go for the 35s even though I have the 2.7, so can’t account for the gas mileage difference you’ll get.

I actually went the other direction and drive on slightly smaller tires on-road, mainly to save my expensive tires for actual off-roading and to get better gas mileage with day-to-day driving. I will probably be getting 35s when my KO2s wear out, but only for increased off-road capability.

 

[JL8jeff]

If you go with the factory Sas Goodyear MT's (315/70/17), it's really a 34" tire compared to the other brands in that size and being C rated is pretty light. Here's a comparison someone on here posted showing the factory Goodyear 315/70/17 next to a 285/75/17 (I think) and a 37/12.5/17 tire.

 

[Deleted member 64921]

I’m going to assume you have a 4-door, because 33s look great on a 2-door. Since we can weed out off-road needs, we’re looking at looks vs. cost. I was inclined to tell you to go for the 35s even though I have the 2.7, so can’t account for the gas mileage difference you’ll get.

I actually went the other direction and drive on slightly smaller tires on-road, mainly to save my expensive tires for actual off-roading and to get better gas mileage with day-to-day driving. I will probably be getting 35s when my KO2s wear out, but only for increased off-road capability.

I have a 2 door

 

[Deleted member 64921]

If you go with the factory Sas Goodyear MT's (315/70/17), it's really a 34" tire compared to the other brands in that size and being C rated is pretty light. Here's a comparison someone on here posted showing the factory Goodyear 315/70/17 next to a 285/75/17 (I think) and a 37/12.5/17 tire.

Agree, I may just go with the Goodyear MT 315/70/17 - I like it because for the size, it's still fairly light. I had them on my 24 BD

 

[HowieLong]

If you go with the factory Sas Goodyear MT's (315/70/17), it's really a 34" tire compared to the other brands in that size and being C rated is pretty light. Here's a comparison someone on here posted showing the factory Goodyear 315/70/17 next to a 285/75/17 (I think) and a 37/12.5/17 tire.

For comparison to other popular 315/70R17 tires: Goodyear lists the Territory MT as 34.41 outside diameter, Toyo lists both the AT III and the RT Trail as 34.4, Falken lists the A/T4W at 34.7 and BF Goodrich lists both the KO2 and KO3 as 34.4. All manufacturers list the RPM at 604 except the Falken at 602.

 

[Tonka Bronka]

Yes, but I did not forget about, I was considering that size, BUT, not a lot of options and they are all HEAVY due to load rating, many more choices in the 285/70 size and lighter tires as well.

They are not all heavy. The six ply C's in a 34" are only slightly heavier than the stock 285/70, which are also six ply.

 

[Jazer]

The 33" tire is LOGICALLY a better tire for a 4.46 geared 2.3 7MT
BUT the 35" tire LOOKS really good and I know I will give up not only MPG but acceleration as well.

What say you ??

That's why I went with a 34

 

[BobbySaggz]

"Ferdinand Alexander Porsche was of the opinion that form should not follow function, but that the two aspects should instead be weighted equally. According to him, form and function can only develop their effect through the interplay with one another, with each aspect given meaning by its counterpart."

"Porsche Design follows a clear design philosophy: optimize function. Reduce the form right down to the essentials."

"If you analyze the function of an object, its form often becomes obvious."

Flipping that last one around, if you analyze the form of an object, its function also becomes quite obvious. If you have a brick with a body-on-frame design equipped with off-road tires, using that as a high speed highway commuter is pretty nonsensical.

I have aerodynamic, firm suspension equipped street cars optimized for higher speeds, and I have my off-road oriented box that isn't any of those things. Each vehicle has its own use case, and the form and function of each is intrinsically linked. My Bronco hasn't had a license plate mounted on it since I trailered it off the lot over a year ago.

 

[KABQ]

With 37s on mine it drives slightly worse on road, but it makes me happier. There's certainly some logic in that.

 

[Mike leggiero]

i found a light weight 37 i ran on my base 7 speed the tarre max rt in a d rate 60 pounds per tire they say 37 12.50 17 but its more of a 37 10 50 17 i also run them on my black diamond with 4.46 and a auto both get 19 hi way.

 

[Guzzler22]

Do what appeals to you-you’re the one paying for it.

I totally agree!
As much as I complain about poor MPG that goes hand in hand with Sasquatch and 4-DOOR "penalties" I went with looks - that for now at least I'm willing to accept - until it's time to look at replacing tires. I cannot justify going bigger/heavier.
But you do you. Be Happy!

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