Testing rolling resistance of the Various Tires of the Suzukiclone Fleet (RE92 wins)

[MetroMPG]

(ForkenSwift sporting the winning tire: Bridgestone Potenza RE92's, OEM low-rolling-resistance tire of the 1st generation Honda Insight.)

So, on the weekend as you may have seen already, I did some rolling testing of the six (6) different sets of tires that are currently in the Suzukiclone fleet. (Seven sets, if you count the spare tire donuts, which I also tested.)

I wanted to find out which tires had the best rolling resistance performance (and which ones had the worst).

This info probably may not be particularly useful to anyone else unless you have the same tires. (Which is unlikely, with the exception of the Bridgestone Potenza RE92's, which are still available. And maybe the Goodyear donuts. )

All the wheel/tire sets were mounted on the same car (ForkenSwift), which was rolled down a gentle hill onto a flat run-out.

Long story short, here's what I learned:



Order of testing - it was sort of an "A-B-C-D-E-F-G-H-A" test...



The how

• All testing was done by mounting the wheels/tires on the ForkenSwift

• Tires were set to 51 PSI

• I drove each car the same distance to an empty parking lot with a small downhill entrance/exit opening on a level run-out area

• Start: car was stopped with the hand brake at a marked position on the hill, transmission placed in neutral and the brake released

• Finish: after coasting to a stop (max speed < 10 km/h / 6 mph) each run's "end" position was marked on the road with chalk.

• 3 - 5 runs were done for each set of tires

• drove back to the shack, swapped the wheels/tires

• the hydraulic brakes were not used at all during the testing, to avoid as much as possible having the front brake pads dragging on the brake rotors after use

• rinse and repeat

Conditions:

24 C / 75 F - clear & dry
wind WSW 12 km/h (~7 mph)

Here's a pic of the test area, with an accurate representation of the RE92's average finish position compared to the average finish for the donuts (@ 70 psi):



You can see it wasn't that steep a hill. Maybe a 2 foot elevation change. (From: Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Poll Results )

[MetroMPG]

Moral of the story: obviously... tire choice can have an enormous impact on vehicle efficiency!

Stuff I learned:

• I was surprised how much better the RE92's were - not only did they have the best result overall, but they also had the biggest improvement when looking at the difference between each set of tires.

• I was surprised to see the big, beefy Michelin snow tires in 3rd place. With lots of deep-siped, blocky, squishy treads! (Then again, we know some snow tires can have LRR qualities - remember Chang Ho Kim's modified CRX winning the AMEC mpg rally with Nokian winter boots on?)

• The spare tire/donut performance surprised me. Part of me hoped they would have magical properties. Instead they were awful.

• PSI over 50 seemed to make little or no difference with the RE92s:

The next day I did a test of tire pressure vs. rolling resistance using the RE92's in the same parking lot. I went from 20 to 70 PSI in 10 PSI increments, 3 runs per increment. From 20-50 PSI, there was a measurable improvement each time. At 50, 60 & 70 PSI, there was no significant change in finishing position - the ending 9 chalk marks (3 PSI x 3 runs each) were mixed & clustered together along a 4.5 foot line.

I've done a test like that before: www.metrompg.com/posts/tire-pressure-rolling-resistance.htm

[Kodak]

Interesting test, and kudos to you for mounting and unmounting your wheels so many times just for some real data.

[MetroMPG]

Yeah, it took a stupid amount of time to do this.

Initially I just wanted to know if the RE92's were better than the Blackfly's Invictas. But then I just kept going

Oh well, it made for a neat picture.

[F8L]

I'd love to see these kinds of tests with current popular LRR tires like the Energy Saver A/S, Fuel Max, Ecopia EP100, dB Super E-Spec, ContiProContact w/EcoPlus, Nokian enTYRE, etc.

If only we were rich huh? lol

[MetroMPG]

Yup, that would be nice.

Supposedly official LRR ratings for new tires are coming for the US market - but I haven't been keeping up with the details.

[MetroMPG]

Originally Posted by MetroMPG

• PSI over 50 seemed to make no difference with the RE92s:

The next day I did a test of tire pressure vs. rolling resistance using the RE92's in the same parking lot. I went from 20 to 70 PSI in 10 PSI increments, 3 runs per increment.

FYI, I posted the details & charted the result of this test in this thread: Experiment: coast down distances (rolling resistance) @ various tire pressures

[BHarvey]

That's an awesome post.

Been looking at some Nokian Hakka C Van tires to replace my Kuhmo's.

[Gasoline Fumes]

Awesome job! But the "donuts" in the pic look a lot like yellow GTi wheels!

[MetroMPG]

Good eye. Yes, they look a lot like Suzuki Swift GTi wheels photoshopped to be yellow.

Aside from the pic below, I didn't take profile pics of the different wheel/tire combos...



from: Lower rolling resistance: space saver spare tire donuts @70 psi, or RE92's @ 51 psi?