315/70r17 + stock gears + OTT tune

Regarding the 3rd Gen Tacoma Double Cab Long Bed configuration, equipped with a 3-inch lift, skid plate, rock sliders, and a tonneau cover, I can offer the following insights based on my experience with 315/70r17 tires, stock gear, and with OTT tune.

Initially, concerns regarding the need for regearing were present; however, the current setup provides sufficient power for optimal tire performance. Transitioning from 285/70r17 tires, where an average of 18.2 mpg was observed, the Ultraguage calibration for the 35s surprisingly indicates an average of 19 mpg.

This data reflects driving conditions that include both hilly highway routes and city driving.

I am interested in understanding your experiences with a similar setup.

Could you provide potential explanations for the increased fuel efficiency observed with the 35s compared to the 33s?

Your insights and experiences are highly appreciated.

 

Different tires will have different rolling resistances.
What are the specs on the new vs. old tires? (brand? model? load range?)

 

Old tires were 285/70r17 Toyo RT Trail C rated
New tires are 315/70r17 Nitto Ridgegrappler E rated

 

Interesting that the E is the one doing better...
I will say though, I have Toyos on mine now (M/T 285/75R17-E), they seem like they have the most rolling resistance of any tires I've had. There's a long very gradual downslope on a street near me and most vehicle/tire combos I've had will very gradually pick up a little bit of speed while coasting down it in neutral... These Toyos OTOH will very slowly lose speed on that same street. Given what I paid for them (and the tread getting torn up from going offroad), they've been a bit of a disappointment.

If I was to guess, Nitto has a more compliant carcass they make their tires from, so they roll easier down the pavement.

 

That's interesting feedback. I'm sure the tread patterns could mess with the rolling resistance. But going from a lighter tire to a heavier one, I thought it'd be the other way around.

 

I should also add that the 35s appear to have smoother gear changes compared to my 33s.

 

If your talking about the toyo MT that is one of the heaviest tires around.

Yoko g003 285/75r17 63

Toyo mt 285/75r17 69

What i want to know is how long has the test period been? Has the regular route changed much ? Did you change wheels with the tires? Have you always manually calculated mpg or gone off the dash/ultra gauge? I dont think this math is mathin. You can't add 14lbs of rolling mass per corner and not take a bigger hit.

Nitto ridge grappler 315/17r17 E
70


Toyo rt trail 285/70r17 c
56