# Tire Testing for Mileage-Contest



## spdas (Nov 28, 2009)

Aloha, all. 
I have been running 195/50/15 Nitto wide tires on mags on my Yaris Zilla/Warp9/44Calb180's for the last 4 months and have been getting on average 210 watth per mile going 60-70mph @ 3/4 freeway of my typical 73 mile journey. I also get 190 watth keeping it to 45-50mph. 

I changed over to my original 185/60/15 Potenza's to test so we will see the difference. It will be the exact distance although I expect my odometer to say about 69 miles using these taller tires.

Here is a contest with no prize:

What do you think my watth per mile will be?


francis


----------



## Salty9 (Jul 13, 2009)

The energy use/tread width ratios would be interesting.


----------



## spdas (Nov 28, 2009)

RESULTS: very surprising.

Nitto 195-50-15 @ 40% tread. 300 treadwear PSI:43 all around

Ride on grooved freeway: noticeably better
Ride on smooth freeway and newly paved ashphalt: noisier
Handling/cornering: Superior
Watts used on average 72.3 mile journey. @corrected 60 mph:: 210watts/mile
Driving pleasure: Superior with these much wider lower profile tires.


Bridgestone Potenza 185-60-15 75%tread 160 treadwear PSI 43
(I believe these were used on the early Prius for LRR, but Bridgestone Ecopia seems to be the favorite for Hybrids now).

Ride on grooved freeway and bumps: Noticeably harsher
Ride on smooth freeway and newly paved asphalt: much quieter
Handling/cornering: mushy
Watts used on average corrected to 72.3 mile journey. 60 mph:: 217watts/mile.
Driving pleasure: Less sporty.


All driving and weather conditions were the same and I mostly drove using indicated amps and which pegged the speed at 60mph. With the shorter Nitto tires I mostly drove at an indicated 64-65 mph for the same amp draw.

I totally did not expect these results. From what I understood, I thought that going with narrow and taller tires gave less rolling resistance, but I just read an article claiming that wider tires will give better mileage. I will be going to the junkyard to find some 205-50-15 to recheck these results in the future.
francis


----------



## PZigouras (Jun 5, 2010)

One thing I noticed is that the stiffness of the tire and the tire compound has more to do with the rolling resistance than the actual size of the tire.

I went from 225/60-15 to 185/80-15 (almost half the width) and it did almost nothing... just like your test. 

Goodyear FuelMax seems to do the best in terms of rolling resistance -- regardless of the tire size.


----------



## DIYguy (Sep 18, 2008)

Apparently, the best tire is the Michelin Energy Saver AS. I replaced my 235/50 R18 with 205/65 R16 Energy Savers. The ride is much better, handling not as good, but the efficiency is 10% better overall. I'm still adjusting to the change in coasting distance. These are incredible. The truck just keeps rolling now. I have some higher efficiency numbers at lower speeds and lower numbers at higher speeds, which makes sense as aerodynamics plays a bigger role at higher speeds.


----------

