# Toyo Open Country M/T question



## Balrog (Jan 7, 2017)

I am running the above mud tires on a F150 quad cab pick up.  Just put them on about 500 miles ago.  As expected, this has hurt highway gas mileage some.  The tires are rated for a max PSI of 65.  

Those with experience with this or other mud tires, what pressure are you running them when on the highway.

I ran them at a little over 50 PSI on a trip back from Florida last week and I got about an extra 1.5-2 miles/gallon on the return trip when compared to running at about 40 PSI on the way down.


----------



## T-N-T (Jan 7, 2017)

Max psi will help mileage 
It will hurt ride quality 
It will also likely wear the middle of the tread faster than the sides on light truck


----------



## Oldstick (Jan 7, 2017)

Only thing I can add is I have the Open Country H/T's (Highway) on my truck and they are superb.  Very quiet and smooth ride and excellent tread wear so far, but still with good tread for occasionally off-road use.  I knew that my needs would be 90% on the road, so that is why I chose those.


----------



## TecRsq (Jan 7, 2017)

Here's what I've always done to get sweet spot for front/rear normal operating pressure.

Note: these will change some from summer to winter

- Go to a place like a big industrial Park or rural straightaway.

- Allow tires to cool and with tires just below max inflation, apply large application of sidewalk chalk, completely across tread of each tire.

- Drive straight for a short distance, get out and note chalk pattern.

- You want to let air out in small increments and drive another short distance. Again noting chalk pattern on tread.

- Objective is to reduce pressure until you see the chalk wearing off evenly across the tread blocks.

* Once you find the sweet spot. Make a note for front and rear pressures.

Don't be surprised if it's a little lower than you normally run your tires. Adjust for summer and winter accordingly and also for load carrying or trailering.

I've run Toyo MT's on multiple 1 Ton trucks and Jeeps, along with 33 to 42 inch tires of various brands.

The above steps for finding sweet spot, along with truing tires, regular rotations and the like. Will assure much more mileage per tire, throughout the life of their respective use cycle.

Regards


----------



## GoldDot40 (Jan 7, 2017)

FWIW, any/all tire manufacturers will tell you to run the pressure in accordance to the decal in the door jam regardless of the size and load rating of the tire. Max pressure on the sidewall is exactly that...maximum recommended pressure (cold usually) @ the specified max weight capacity of the tire.

I've ways run 8(D) and 10(E) ply tires at the pressure spec on the door jam decal and tires have always worn even and my fuel mileage hasn't altered enough to notice. Still 20mpg on the hwy.

Just put a set of Kumho AT51 (all terrains) on my truck just yesterday. They're phasing out the KL78 all terrain which is what I took off with 48K miles on them and we're still at 7/32 tread depth.


----------



## Balrog (Jan 8, 2017)

GoldDot40 said:


> FWIW, any/all tire manufacturers will tell you to run the pressure in accordance to the decal in the door jam regardless of the size and load rating of the tire. Max pressure on the sidewall is exactly that...maximum recommended pressure (cold usually) @ the specified max weight capacity of the tire.
> 
> I've ways run 8(D) and 10(E) ply tires at the pressure spec on the door jam decal and tires have always worn even and my fuel mileage hasn't altered enough to notice. Still 20mpg on the hwy.
> 
> Just put a set of Kumho AT51 (all terrains) on my truck just yesterday. They're phasing out the KL78 all terrain which is what I took off with 48K miles on them and we're still at 7/32 tread depth.



Running mud tires at 35 PSI dropped me from about 19 miles/gallon on the highway down to less than 15.


----------



## GoldDot40 (Jan 8, 2017)

Ain't ever seen fuel mileage drop THAT much with lowering air pressure...unless they were nearly flat.

Mine call for 80psi max cold. Running them at 35psi per the OE specs didn't effect fuel mileage at all. Maybe it's all-terrain vs mud? Never seen the benefits of running a mud tire on the hwy anyway.


----------



## Beagler282 (Jan 10, 2017)

Had those tires on my Tundra when I had it with a 20" wheel. I run 50psi in the front and 42psi in the rear. They wore properly for me like that.


----------



## Balrog (Jan 10, 2017)

GoldDot40 said:


> Ain't ever seen fuel mileage drop THAT much with lowering air pressure...unless they were nearly flat.
> 
> Mine call for 80psi max cold. Running them at 35psi per the OE specs didn't effect fuel mileage at all. Maybe it's all-terrain vs mud? Never seen the benefits of running a mud tire on the hwy anyway.



There is no advantage of mud tires on the highway.

Incidentally I have bumped the pressure to 50 psi in all 4 tires and it helped gas mileage by about 1.5 mpg.  Still not too great.


----------



## pine floor (Jan 17, 2017)

Balrog, if you come from Lousiana where I did, no body went much farther than to work without mud tires. Thats if you worked from blacktop.

That being said, I have run abouut some of the best and worst of MT.. Buckshots,Nito Grappler,Thornburg or whatever them beast were called. The best were, well their is no best.

Currently running Goodyear Wrangler Duratracs on a 2500 diesel. Seconnd set so far just did not need all the traction I needed out in La. Got over 62,ooo on the last set so decided on the same . 65 psi on the front and 50 on the back.. Not a MT by any standard but some outer lugs with a sweet middle AT.

Been stuck with the best of all MT also. LOL.

Try some different air pressure also. You get what you desire with these beast.. Kinda like a army tank versus a caddy ( tracks) (tires)

Good luck.

PF


----------



## lonewolf247 (Jan 18, 2017)

Basically, the tires list the max operating pressure on the sidewall, and as mentioned, that's all it is. You can't operate them above that pressure. 

The door jam decal list the tire pressure that you should operate your tires at. You should go by this. Now when choosing new tires, you have to make sure that the tires you are buying, are compatible and designed to run at the pressure your vehicle calls for, and also, meet the load range it calls for as well. Operating at much higher or lower pressure would cause your tires to wear prematurely and possibly set off your tire pressure monitoring system, if you go too high or low on pressure.

I've run several MT and AT tires over the years, and that alone shouldn't kill your mileage drastically provided you didn't change your tire size. Did you stick with the stock size tire, or did you increase the overall height of your tire? What size tires came on your truck, and what are you running now?


----------



## Balrog (Jan 18, 2017)

lonewolf247 said:


> Basically, the tires list the max operating pressure on the sidewall, and as mentioned, that's all it is. You can't operate them above that pressure.
> 
> The door jam decal list the tire pressure that you should operate your tires at. You should go by this. Now when choosing new tires, you have to make sure that the tires you are buying, are compatible and designed to run at the pressure your vehicle calls for, and also, meet the load range it calls for as well. Operating at much higher or lower pressure would cause your tires to wear prematurely and possibly set off your tire pressure monitoring system, if you go too high or low on pressure.
> 
> I've run several MT and AT tires over the years, and that alone shouldn't kill your mileage drastically provided you didn't change your tire size. Did you stick with the stock size tire, or did you increase the overall height of your tire? What size tires came on your truck, and what are you running now?



I don't have the numbers in front of me, but the mud tires are at most about an inch greater in diameter.


----------



## lonewolf247 (Jan 18, 2017)

^Yeah I figured you probably went up in tire size as well. I always do too.  Your gear ratio is effectively different now, and the engine rpms are not running at optimum conditions, so your fuel mileage is going to suffer somewhat. 

However, your speedometer is also effected, so it may not be quite as bad as it seems. You would show less miles on your odometer than you actually travel.


----------



## tree cutter 08 (Jan 20, 2017)

For best millage stick with factory size tires. I always upgrade tire sizes a bit but don't bother to check the milage because it always suffers some.


----------



## Jeffriesw (Jan 21, 2017)

My 2011 F250 came with Michelin 275/18/70 on it I think. They wore out about 75,000 miles. I replaced them with Cooper
http://us.coopertire.com/Tires/Light-Truck/DISCOVERER-S-T-MAXX.aspx?gclid=CLTj2bC109ECFY08gQodUuYGFQ

305/60R18

I run them about 55 psi

I lost about 1.0 to 1.5 MPG going with the larger size tire and my speedometer reads about 4 mph less than it is actuall going at 60 mph.


----------



## GoldDot40 (Jan 21, 2017)

Swamp Runner said:


> My 2011 F250 came with Michelin 275/18/70 on it I think. They wore out about 75,000 miles. I replaced them with Cooper
> http://us.coopertire.com/Tires/Light-Truck/DISCOVERER-S-T-MAXX.aspx?gclid=CLTj2bC109ECFY08gQodUuYGFQ
> 
> 305/60R18
> ...



Your speedometer reads "about" 4 mph less? So your odometer is turning slower as well. How do you know which equation to use to figure your mpg? Without a precise change, you won't ever be able to know for sure. And actual road speed of 56 mph when your truck says 60 = 6.67% difference, btw.

A lot of people swear they lost substantial mpg when they switch to a size or so up, but ultimately realize, it's nowhere near as bad or didn't change at all after they have their speedometer recalibrated for the oversized tires.

I went from a factory 31" tire to a 33" tire. With the speedometer fix...I didn't lose any mpg whatsoever.


----------



## T-N-T (Jan 21, 2017)

GoldDot40 said:


> Your speedometer reads "about" 4 mph less? So your odometer is turning slower as well. How do you know which equation to use to figure your mpg? Without a precise change, you won't ever be able to know for sure. And actual road speed of 56 mph when your truck says 60 = 6.67% difference, btw.
> 
> A lot of people swear they lost substantial mpg when they switch to a size or so up, but ultimately realize, it's nowhere near as bad or didn't change at all after they have their speedometer recalibrated for the oversized tires.
> 
> I went from a factory 31" tire to a 33" tire. With the speedometer fix...I didn't lose any mpg whatsoever.



Yep.  My last tires were significantly larger than stock.  To calculate based off odometer looked bad.
To calculate mileage off gps came out much different


----------



## Jeffriesw (Jan 22, 2017)

Never thought about it, I will see if I can get someone to recalibrate based on the new tire size and see what it reads then
My calcs were based upon just hand figuring mileage and fuel used while fueling up.


----------

