Michelin LTX MS2 Mileage Compared With Agilis Tires

[booster]

We added another data point to earlier watching of what the MS2 tires, size 265-70-17, mileage was going to be compared to the Agilis 265-75-16 tires we last had.

All these trips were on routes that gave nearly right on 14.5mpg every time over the years with the Agilis. On the exact same routes and speeds, the MS2 tires are consistently .5-.6mpg higher. Today's 300 mile trip came in at 15.16mpg compared to the 14.5mpg the Agilis gave on that day trip, which we do often and have good history on it.

 

[Asphalt Addict]

Hello Booster, Did you have the computer recalculated to match the larger tires? Or are you doing it old school with math.

 

[booster]

Hello Booster, Did you have the computer recalculated to match the larger tires? Or are you doing it old school with math.

I still have the now old HPtuner tuner that I used to reprogram the shift points and lockup speeds, so reprogrammed it myself with the tuner.

Not as easy as some others like my old Buick where can set revs per mile which is a common tire spec. There were to cryptic settings that had to change at the same time and it wasn't a numerical calc you could do, so lots of trial and error. I do have a discussion on it here on the forum someplace, including I think the settings for the 265-75-16 tires we had then, which are the same revs per mile as the 265-70-17 tires we have now.

You can't get the GM dealers to do that change as they don't have that size tire in their tuning software because it is not an OEM size used on the vans. A speed shop or truck performance shop could do it for a fee.

 

[cowxie]

Are they really larger tires?
Tire size calculator shows that the two have a circumference that differs by 0.1% - basically the same revs per mile.
So could you truly say that the tires are the reason for the ~4.5% increase in fuel consumed?
I suspect so. Unless there was a unusually brisk headwind for the new tire trip

 

[booster]

Are they really larger tires?
Tire size calculator shows that the two have a circumference that differs by 0.1% - basically the same revs per mile.
So could you truly say that the tires are the reason for the ~4.5% increase in fuel consumed?
I suspect so. Unless there was a unusually brisk headwind for the new tire trip

The two tire sizes do have the same circumference and mentioned the identical rev/mile for them in the post above.

The first post mentions the two tire sizes that are the rev/mile that is the comparison done, so I am missing how the change in gas mileage could be because of the tire change in rolling distance on the trip.

I am pointing out that the change in mileage is in the change in tire model, and probably much less influence from the change in aspect ratio.

I had been wondering on the mileage ever since we put the Agilis tires on as the mileage dropped then from the identical size LTX MS2 tires of the time period. Now we got that mileage back, it appears, with a change away from the Agilis. Time will tell if it continues for years or not.

Different tires can get large differences in mileage depending on construction and tread profile. Some manufacturers even list rolling resistance as a sort of spec, but only a number of stars rating system comparing to other tires. Some tire reviewers also do a repeated route to compared mileage between tested tires. OEM tires are said to be sourced as the lowest rolling resistance they can find so the get the best mileage rating in the qualification testing. Many OEM tires also often don't handle very well as the two things can be contrary.

 

[ks@yvr]

Are they really larger tires?
Tire size calculator shows that the two have a circumference that differs by 0.1% - basically the same revs per mile.
So could you truly say that the tires are the reason for the ~4.5% increase in fuel consumed?
I suspect so. Unless there was a unusually brisk headwind for the new tire trip

I think it would be 4.5% decrease in fuel used as better mileage with new tires.

 

[booster]

I think it would be 4.5% decrease in fuel used as better mileage with new tires.

Tires usually give an APPARENT increase in mileage as they get old because the rolling diameter gets smaller, increasing revs/mile so the odometer reads higher miles traveled.

In this case the Agilis were not worn enough to make a difference and if they were, it would have made them look like they did better than they did.

 

[Boxster1971]

I’ve found that wind has a significant impact on mileage and could easily account for the variation you are seeing.

 

[booster]

Wind certainly makes a difference, as does speed, so I am careful about that for stuff like this, but on long trips there is usually a pretty consistent result do to averaging out, with the major variable being freeway vs rural highway mileage split and how many slowdown towns we go through. On all trips for the 3 years the Agilis were on the van, almost every trip came in at 14.5mpg which was kind of odd, I thought. That is why the one day test loop we did on two occasions was used as it limits the variables. It is also a scenic route we drive at least once and usually twice a year for fun.

Two of the trips were a round trip route all in the same day and same wind direction, so no real affect IMO. The other trips were round trips with one as a same day one on separate days, but all gave nearly identical numbers so very likely something real there. We have a 900 miler coming up soon and it will be spread out over about 10 days with one day out and one day back being 90+% of the miles. That trip last year was the same miles and timing and was consistent with the others. We will see if it does it again or not.

As I mentioned, more trips over more miles will confirm or disprove it all, and the mileage may must change as the tires age also. Too few data points right now to know for sure.

 

[Boxster1971]

What tire pressures are you running in these comparisons? How did you determine the tire pressures to run in each case?

 

[booster]

I have been running an adjusted to ambient range 61 front and 75 rear as the larger 265 size's extra load capacity still very easily covers our weight. I set the pressure before we go and shoot for those pressures at the the midrange temp for the day or trip and calculate by allowing 1.2psi front and 1.5psi rear for every 10 degrees off of my arbitrary 70*F reference temperature for the tires. On longer trips that accuracy is not as close as on a one day one as temps and especially winds vary more, but I haven't seen any real amount of mileage difference from longer trips to the testing day trips as things seem to average out for the daily variations. The 1.2 and 1.5* are not exact, but close enough for this kind of stuff over a narrow temp range. If I wanted to be more accurate I could use this crib sheet that I calculated the pressures using the actual formula at 5 degree steps, using the absolute temperature if I did all the math correctly. The handling stays good over that same +/-20* range although midrange is best.

An oddity is that I have found that selecting tire pressures that I like for handling calculate out to having the same tire patch contact area with the road for the front and rear. Even the old standard 65-80 psi that many users like for the 245/75/16 tires has a less than 2# per square inch difference so there may be something to the whole idea of using that for figuring out starting points for tire pressures on SRW class B vans.

Front tires​	​	​	​	Front tires​	Rear tires​	​	​
Reference P​	Reference Temp​	New Temp ​	Pressure change​	New Pressure​	Reference P​	New temp​	Pressure change​
61​	70​	75​	0.61​	60.39​	75.52​	75.00​	0.76​
​	​	80​	1.22​	59.78​	​	80.00​	1.51​
​	​	85​	1.83​	59.17​	​	85.00​	2.27​
​	​	90​	2.44​	58.56​	​	90.00​	3.02​
​	​	95​	3.05​	57.95​	​	95.00​	3.78​
​	​	100​	3.66​	57.34​	​	100.00​	4.53​
​	​	105​	4.27​	56.73​	​	105.00​	5.29​
​	​	70​	0.00​	61.00​	​	70.00​	0.00​
​	​	65​	-0.61​	61.61​	​	65.00​	-0.76​
​	​	60​	-1.22​	62.22​	​	60.00​	-1.51​
​	​	55​	-1.83​	62.83​	​	55.00​	-2.27​
​	​	50​	-2.44​	63.44​	​	50.00​	-3.02​
​	​	45​	-3.05​	64.05​	​	45.00​	-3.78​
​	​	40​	-3.66​	64.66​	​	40.00​	-4.53​
​	​	35​	-4.27​	65.27​	​	35.00​	-5.29​
​	​	30​	-4.88​	65.88​	​	30.00​	-6.87​
​	​	​	​	​	​	​	​
​	​	​	Good shortcut​	​	​	​	​
​	​	​	1.2psi per 10*F @ 60psi​	​	​	​	​
​	​	​	1.5psi per 10*F @ 75psi​	​	​	​	​

 

[Mr. Merk]

Did you find these tires in Load Range E?

Got curious and looked at Tirerack. I only see them in XL which max load is pretty close to the weight of our vans with max pressure of only 50psi.

Surely I'm missing something

Edit: yep. You are on 17s. I see it now!

 

[booster]

Did you find these tires in Load Range E?

Got curious and looked at Tirerack. I only see them in XL which max load is pretty close to the weight of our vans with max pressure of only 50psi.

Surely I'm missing something

Edit: yep. You are on 17s. I see it now!

Yeah, they actually have about 370# per tire more load capacity than the stock Roadtrek 245/75/16 tires.

 

[youngnretired]

After getting our 210 popular weighed just after leaving town on our trip a couple months ago, I'm going to investigate load range F tires in stock configuration for our next replacements, or at least something with greater than 3040lb max load. I'm quite confident one of the rears was over max load at various times, or continually.

 

[booster]

After getting our 210 popular weighed just after leaving town on our trip a couple months ago, I'm going to investigate load range F tires in stock configuration for our next replacements, or at least something with greater than 3040lb max load. I'm quite confident one of the rears was over max load at various times, or continually.

You can also just go up to the 265 tires and wheels and get 70# per wheel more load rating.

Be aware that if the tires are overloaded it is also likely the rear axle is overloaded as they are rated the same capacity.

 

[youngnretired]

The scale said the rear axle was 6000lbs, front at 4040. At 6000lbs, it's 80lbs below max rating. We had used 2-3 gallons of fuel when we got weighed and probably moved some water from front or rear fresh tank to the black and Grey tanks. I can't remember specifics.

After we weighed, I started a proactive pattern of not filling the fuel tank, or making sure the interior fresh tank wasn't full to try to manage the weight on the rear axle a little smarter.

Here in a few days, we're going to fill both fresh tanks, propane and not have any tools, clothes etc, just the normal pots, pans, glasses etc that go with us on trips and get a weight to know.

I'll do more research on tires as I get closer to needing them.

 

[booster]

I figured I would bring this back up as we just finished a fall trip from the Minneapolis area to Copper Harbor, Michigan in the UP of Michigan. 850 miles total, with about 70 miles of 4 lane roads, about 100 miles of around hilly, curvy, very slow driving, Copper Harbor, and all the rest 2 lane rural highways with numerous small town slowdowns along the way. We used the trip to calibrate the new Scangauge 3 by using the entire trip fuel and mileage as one tank of fuel and comparing it to actual miles/gallons used hand calculation. Yes, our odometer has been calibrated to be very accurate by using GPS miles and highway mile marker data taken on a 100 mile length of freeway.

Broken into segments we got 15.69mpg going to the fill point just short of Copper Harbor. We got 13.0mpg in the area of Copper harbor. We got 15.91mpg from the fill point near Copper Harbor to home to fill at the same pump we started at.

Net hand calculated mileage for the entire trip came in at 15.42mpg which is about .9mpg, a bit over 6%, higher than we saw on the trips we had done on this exact same route multiple times with the Agilis tires when we got consistent 14.5mpg.

Winds were fairly high on the going segment with mostly cross, sometimes cross with a slight tailwind so not a lot of benefit or loss from wind, I think. Coming home on the last segment it was calm for about 3/4 of it with a small tail/cross wind for about 1/4 of it so we did get a bit of aid there which shows in the better mpg coming back.

The previous testing showed about 4% improvement over the Agilis with this test at 6% range so the small wind advantage on this trip is showing there, putting in most likely in the higher range of improvement over the Agilis.

All of this seems to be indicating someplace in the 4/5% increase in mpg with Defender LTX MS2 tires over the Agilis Crossclimate tires.

The MS2 tires continue to drive extremely well with excellent directional stability. I had the optimum pressure set at 65*F and we saw 40* to 83* on the trip and they worked well over the entire range. Temp rise of the tires was very low at probably 20* or less over ambient based on hand feel on the tires. The Agilis always felt very warm with the same test.

 

[romeo-ClassB]

I am following this thread since I maybe replacing my Bridgestone Dueler H/T tires soon (LT245/75R16). I always buy Michelin tires and would plan to continue with the brand.

I have recently discovered that I have slight scalloping on the front inside surface of the tires. This brings me to think about tire pressure. I have been running 60 psi in the front and 80 in the rear, as I think most RoadTreks do.

I have noticed that the door sticker shows 50 psi in the front and 80 psi in the rear. This brings me to the question of what is the rationale for running 60 psi in the front tires. Since I am on a journey to decrease the tendency to have "oversteer" or may be feeling of "light weight" on the front end during cornering, I am thinking the lower pressure in the front tires may help.

We are preparing for our trip to Yuma and I am starting to check tire pressures so its a good time to make adjustments.

Any thoughts?
Ron

 

[booster]

The 50 psi on the sticker is from the empty van when new and is, as I understand it, the minimum pressure needed to be able to handle max front axle weight. At 50 you can run an empty van for max comfort when light and still be safe at full load.

Any pressure of 50psi or higher will be safe, so folks chose what is the best balance of ride comfort and quality. I think most Chevies on stock size tires use 65psi but the range is from the 50 to 80 that we have seen on the forum. most are 60-65 psi.

IMO, just choose whatever pressure feels right to you driving and it can change between brands and also with tire age.

 

[booster]

We got one more data point on this, going over the same up and back trip along the Mississippi river in SE Minnesota from the Twin Cities. This is our annual trip to see the fall sites, not colors as it gets to busy, and pick up apples at our favorite orchard.

275 miles, a wind of about 10-15mph that gave about .6mpg difference in going compared to coming back. Lighter traffic than usual so allowed driving the many, steep, curvy hills more carefully and preventing downshifts which helps mileage some. About 30% on 4 lane 60mph and the rest at 50-55 on two lane with lots of 25-30mph little and moderate size towns.

We wound up with a light fill at the end do to a odd issue with a guy sitting at the pump we filled initially. We waited 10 minutes while he sat in his car, then exited and tried to get the pump to work direct from the phone. He failed so went back in the car again to fiddle with it and we used a separate pump. Calc showed 17mpg so surely wrong.

The sSangauge showed 16.4mpg but I expected that to not be correct as I only put the last correction to the Scangauge fuel comp in as an extra 1% instead of the 2% that the 900 mile trip showed it should be. I wanted to see if it would be another 1% off before adding it. My guess it was but the light fill masked confirmation.

When I did a calc to put the extra 1% in the mpg went to 16.1, which is very likely correct as it is based on the long trip data. It is also believable to me as it we would get about that driving carefully at those speeds when we had the old original MS2 tires, but never with the Agilis.

Right now, it appears the the early tests were on the low end of actual and the test on the longer trip was closer at and the longer legs of that trip were in the same range, but the slow section while in Copper Harbor and around it dragged down the overall.

So far all the new tire trips have been reliably higher than the Agilis got by at least .5mpg and mostly closer to 1mpg higher.

Interesting in the that the Scangauge 3 seems to need 5% fuel comp and the old Scangauge was closer to 3%.