LRR TIRES VS WINTER TIRES HIGHWAY TESTED!

[Phase]

I decided to see what difference low rolling resistance tires make versus higher rolling resistance tires in steady state highway driving. We all know they make a difference in city and lower speed driving. But what about highway speeds when aerodynamics matter?

I decided to do a test and actually see if tires make a diff on the highway since it doesn’t seem like there are ANY tests done on YouTube or other forums or any tire companies?!?

I chose a dry day with no wind. Ambient temps of about 42 degrees and sunny.

The test road is about 8 miles going west on highway 26 and 8 miles coming back east and completely flat

My high grip tires were the Bridgestone blizzak winter/snow tires inflated to 38 psi

The more miles I drive, the more stable my mpg average since my ioniqs hybrid system alternates between engine and battery then averages those together. There is no instant mpg like Toyota hybrids.

Going west from one marker to another, I averaged 58.5 mpg and then looping back the TOTAL mpg for the trip with the extra miles was 54.2 mpg

I then went to Costco, dropped my car off and got my winter tires taken off and my all season eco tires put on. Process took less than an hour

My low rolling resistance tires are the Bridgestone ecopias. Inflated them to 38 psi also

I went out and did the exact same stretch

Going west I averaged 59.5 mpg. I was scratching my head thinking “ seriously only a 1 mpg jump? Doesn’t seem worth the tire change… let’s continue and see what the average does with more miles”

Then going east and back to the check point, the TOTAL mile average was 62.5!

What was funny is even though the two first half of the trip averages were almost the same, doubling the miles, the winter tires averaged down for mpg and the lrr tires averaged up

Also a side note, the winter tires had thinner treads and about 40,000 miles on them and I had to throw them away today. They were over 2 years old

The ecopias were purchased new less than a year ago and have a deeper tread. So the gap between the tires fuel economy probably would’ve been even bigger if they were both new tires with the same wear

I’m now over inflating the ecopias to 41 psi and will probably add my wheel skirts back on next week.

Also the tests were done at 65 mph with cruise control set. Maybe the rolling resistance difference closes tighter at higher speeds like 80-90 mph when aero pretty much takes over completely.

Either way, my steady state highway test results show that low rolling resistance tires make a difference even at highway speeds for the average driver!

[CapriRacer]

A couple of thoughts:

I'll bet your second test had a headwind in the first leg, which became a tailwind on the second leg.

Rolling resistance varies considerably. I don't have a good handle on winter tires, but the variation in regular all season tires is on the order of 50%.

Don't forget that the general rule is that tires with better RR are worse for traction and/or wear.

[Phase]

Originally Posted by CapriRacer

A couple of thoughts:

I'll bet your second test had a headwind in the first leg, which became a tailwind on the second leg.

Rolling resistance varies considerably. I don't have a good handle on winter tires, but the variation in regular all season tires is on the order of 50%.

Don't forget that the general rule is that tires with better RR are worse for traction and/or wear.

Nope same wind direction which was a 3 mph cross wind coming from the south

And yes I know the traction isn’t going to be as good. Wouldn’t take them out in a heavy snow storm or drive on ice.

[Nissandriver]

What are you using to measure your mileage? Is it the car computer´s measurement? There´s no way I can get good reliable measurement´s for such short trips in my old cars.

I´m curious as to how your car´s computer mileage measurements compare to what you see if you use the number miles traveled divided by the pump´s number of gallons to refill.

As for rolling resistance, the difference can be significant. I had a 2001 Nissan Frontier XE (2.4L I4) that always got 30-31 mpg for 1-2 years. Most of the driving was 65 mph on the highway. I needed to replace the front tires so I bought two used tires. After that tire replacement I could never get the truck to average more than 28 mpg. I burned one tank never exceeding 55 mph and tried my best to increase the mileage and I still got 28 mpg. Those tires were louder too. I started paying a lot more attention to rolling resistance after that pair of tires.

[Phase]

Originally Posted by Nissandriver

What are you using to measure your mileage? Is it the car computer´s measurement? There´s no way I can get good reliable measurement´s for such short trips in my old cars.

I´m curious as to how your car´s computer mileage measurements compare to what you see if you use the number miles traveled divided by the pump´s number of gallons to refill.

As for rolling resistance, the difference can be significant. I had a 2001 Nissan Frontier XE (2.4L I4) that always got 30-31 mpg for 1-2 years. Most of the driving was 65 mph on the highway. I needed to replace the front tires so I bought two used tires. After that tire replacement I could never get the truck to average more than 28 mpg. I burned one tank never exceeding 55 mph and tried my best to increase the mileage and I still got 28 mpg. Those tires were louder too. I started paying a lot more attention to rolling resistance after that pair of tires.

I was using the cars on board trip meter. The total run was 16-20 miles for each set of tires. I’ve seen some people on this forum with their scan gauges do a ONE MILE section and then mention their mpg numbers. Maybe that instant read out works for their old ice cars, but in my hybrid, definitely not. I mean I can feel the difference on rolling resistance too. Especially in the city

The main point of my test was to see if the tires make a diff on the highway. Seems like they do

I also did my usually drive to mount hood and back which is 150 miles round trip. With my winter tires, I usually averaged 48-50 mpg round trip. Yesterday with the new tires I got 55 mpg round trip. Not as quite the leap as the other test. But there are a lot of factors too during that trip like heat use, how fast I accelerate up a hill and so on.

From timberline lodge on mount hood back to Beaverton it’s a 79 mile drive. I reset the trip mpg from the top. Averaged 92.5 mpg back to Beaverton over that whole drive. The uphill drive is what tanked the mpg and brought the overall day average to 55