Unexpected impact of bigger tires

[jadmt]

I run both mickey BBat's in pizza cutter 35's and in 37's and I have posted before (probably ad nauseam to everyone) and have done trips to moab with both and also longer trips throughout Montana, Idaho and washington switching back and forth and mpg has been essentially the same and my actual best has been with the 37's. I run psi that Mickey Thompson recommends for each and calibrate the speedo with a procal and my speedo and tripometer are spot on per stand alone gps and a speedometer phone app. lowly 3.6 auto and 4.10's. I do 6,7 and 8th gear on the highway depending on the wind and terrain..it is hilly coming and going any direction I go in from western Montana......I know science probably says not possible...

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[Terrymo]

I guess I’m just happy we’re still under $5/gallon.

I can’t complain I’m retired and don’t have a commute and my wife who is a school principal only drives 12 miles round trip….not in L.A. traffic.

They should put a “dry your tears” sign above the paper towels though.

 

[occasional_offroader]

The only logical thing to do is try 39s next.

 

[roaniecowpony]

I guess I’m just happy we’re still under $5/gallon.

There are going to be fewer refineries next year in CA. Combine that with the nearly non-existent pipelines coming into CA, and the fact that we've lost so many refineries that each one now supplies a significant percentage of fuel, and the loss of two more in the upcoming year amounting to about 20% of total production, and we'll feel a shortage and price spike estimated to rise to $8.43 in 2026. That's going to make milk and bacon (and Metalcloak stuff) cost a lot more. My bet is Metalcloak (and many others) will be forced to consider moving to remain competitive with mfrs in other states.

There'll be fewer cookies on the trail in the future.

 

[dstevens]

There's a lot of misinformation put out by the oil companies regarding their California operations. What they can not lie about is their securities reporting, which shows oil companies have quadrupled their profit in California in the last 6 years.

Cost of gasoline in California

$1.67 crude oil cost
$0.02 underground storage tank fee
$0.15 low carbon fuel standard
$0.22 cap and trade
$0.69 distribution margin
$1.02 refining margin
$0.18 federal tax
$0.10 state/county/city tax

For the refining margin the cost of refining, as reported to the SEC, is $0.20. The distribution margin for CA is double the national average. So around $1.70 of oil company margin for each gallon sold in California, where historically is was around $0.55, as it still is in the rest of the country.

tldr; Oil companies are responsible for $1.15 per gallon in CA compared to the rest of the country. CA taxes etc are $0.49, but many other locations have at least part of them.

 

[rickinAZ]

Does the transmission still reach 8th gear at highway speeds?

It easily reachs 8th gear

what did you use to calibrate for sizes? and how did you do it?

I used the standard method of a level on top of the tire, and a tape measure to the floor: 35.25". I recalibrated to that value using JScan

Still running the stock 3:73s

 

[Rubi392jp]

The 37in K02s are probably the same size or smaller then the 35in Mickeys. BFG always runs multiple inches smaller then what is on the sidewall.

Absolutely correct! My 37” K02s are just about 35.5 mounted on the vehicle and about 35.75 off the vehicle.

 

[rickinAZ]

Just to be clear about how I identified this improvement: being retired, I lead a fairly predictable life. I volunteer at Mayo three times a week, go to the shooting range, go out to lunch, my three children all live within five minutes, etc...

It’s a comfortable, consistent routine, and my fuel economy reflects that.

Over the five years I’ve owned the Jeep, my mileage has consistently been around 19 mpg (±0.5) according to the fuel economy computer. Two months ago, I added the 37s, and across the four tanks I’ve run since then, mileage has been between 21 and 22 mpg. It’s not a huge increase, but it’s certainly noticeable.

My take is that it's the better rolling resistance (much smoother) plus the implied higher "gearing" by going up 1.5" in diameter.

 

[R3TRO]

I run both mickey BBat's in pizza cutter 35's and in 37's and I have posted before (probably ad nauseam to everyone) and have done trips to moab with both and also longer trips throughout Montana, Idaho and washington switching back and forth and mpg has been essentially the same and my actual best has been with the 37's. I run psi that Mickey Thompson recommends for each and calibrate the speedo with a procal and my speedo and tripometer are spot on per stand alone gps and a speedometer phone app. lowly 3.6 auto and 4.10's. I do 6,7 and 8th gear on the highway depending on the wind and terrain..it is hilly coming and going any direction I go in from western Montana......I know science probably says not possible...

Woah talk about showing the difference between mounted vs not! That 37 looses what looks like close to 2" vs the 35 which maybe looses 1"? My guess would be the width and/or tire softness plays a big part here and how much the tire can squish.

 

[jadmt]

Woah talk about showing the difference between mounted vs not! That 37 looses what looks like close to 2" vs the 35 which maybe looses 1"? My guess would be the width and/or tire softness plays a big part here and how much the tire can squish.

the best measure is measuring from the bottom of your diffs to the cement on a level surface that will really show you how much you gain going 37 to 35 and vise versa...this is at 26psi on the 37's.

 

[R3TRO]

the best measure is measuring from the bottom of your diffs to the cement on a level surface that will really show you how much you gain going 37 to 35 and vise versa...this is at 26psi on the 37's.

Do you have same measurement with same pressure on your 35's?

 

[zouch]

it would be interesting to see how accurate your odometer is compared to the highway mileage markers next time you're out on the highway there for a while (10+ miles or so).

i've approached the adjustments a couple of different ways to kinda' verify each other, and adjusted the input 'tire size' value until it all lines up.
i'll usually start with GPS on the phone while at highway speeds (*without* the phone connected to the vehicle).
then i'll cross-check odometer against the highway mile markers over a long'ish drive.
i'll usually also try setting the Cruise Control at an indicated 60MPH and count how far i get against the highway mile markers before i can detect any variance from a mile-per-minute.

i'm using a Taser, but i'll have to check to see what the value is i ended up at.

i'm looking forward to doing it all again when i ditch the KM3s i've got on now for another pair of those Mickeys.

I used the standard method of a level on top of the tire, and a tape measure to the floor: 36.25". I recalibrated to that value using JScan

Still running the stock 3:73s

 

[MARTY J]

The 37in K02s are probably the same size or smaller then the 35in Mickeys. BFG always runs multiple inches smaller then what is on the sidewall.

That is odd. the 37" KM3 that I have measured 36.5 just like BFG list them as.

 

[roaniecowpony]

That is odd. the 37" KM3 that I have measured 36.5 just like BFG list them as.

I think some are measuring from the ground up to the center and multiplying 2x. I'm thinking that's not what the tire manufacturing spec is about.

 

[MARTY J]

I think some are measuring from the ground up to the center and multiplying 2x. I'm thinking that's not what the tire manufacturing spec is about.

measuring around the tire and dividing by 3.14 makes the most sense to me.

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