Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Testing rolling resistance of the Various Tires of the Suzukiclone Fleet (RE92 wins)

rmay635703 · 12-09-2012, 05:27 PM

Well, I had a few issues with this thread from the getgo so I figured I would post my scientific (lol) set of data points for comparison on another totally different vehicle.

In any event my testbed was a Miles ZX40 EV, its top speed determined by the 48v motor and single gear is 30mph summer and 28mph winter (clean road)

I did a test in front of my folks house to see how far the car would coast from 5mph to a stop.

I tested the stock Powermax 769 - 155x65r13 and some randomish Honda 115x70x14 space savers, last year at this same time I was running some antique Goodyear continentals 155x80r13's and will include a bit of antidotal from them. All tires were tested at 60psi. I did want to test some 125/80r13's (because I have always had excellent luck with them) but I had none that fit the miles lug pattern.

In any event on flat ground and a huge 30 degrees, wind was nearly calm with a couple MPH here and there with a very thin layer of slime on the road

Powermax 769 155x65r13s coasted a whopping
35' 3" (both runs were only a few inches off, must have been dumb luck) These are the stock tires from miles

Honda 115x70r14 space savers on front only a whopping
39' average (1' variation, 2nd run was further)

I then tested top speed, unlike any other vehicle on the road the Miles ZX40 cannot change gears or increase power output and tire changes are easy to test based on WOT top speed.

Results
Powermax - 28mph (on the normal stretch we run everyday)
Spacesavers up front - 29mph (same place)
Old Goodyears - 29mph (speedo corrected but also at 5-10% higher energy draw due to the size change no doubt)

So given the set of tires I have available I noted no significant difference besides a bit of traction difference and of coarse some major road noise on the spacesavers (rather agressive tread for a bald tire actually).

Also before size is brought up although the space savers "should" be a smaller diameter (1/3") I did note the car sat higher because the tires are more like old balloon tires, car sat a bit higher on the space savers than with the regular tire and side to side comparison off the vehicle same deal, look more like moped style tires. It is also worth noting that the car is about 2400lbs and actually has a tad more weight to the rear.

Ah well. When summer comes along maybe I can do a more convincing test with clean roads and warm temps.

Something worth noting is that the Miles Zx40's alignment is not significantly affected by the space savers, I have noticed some space saver designs when put on my cobalt or commuta caused visible deflection due to the really strange offset on the rim, I would think this would have more affect on how far you coast than the RR because it messed up your alignment. But I digress.

Happy coasting.

12-09-2012, 05:27 PM	#35 (permalink)
rmay635703 home of the odd vehicles Join Date: Jun 2008 Location: Somewhere in WI Posts: 3,891 Silver - '10 Chevy Cobalt XFE Thanks: 506 Thanked 867 Times in 654 Posts	Well, I had a few issues with this thread from the getgo so I figured I would post my scientific (lol) set of data points for comparison on another totally different vehicle. In any event my testbed was a Miles ZX40 EV, its top speed determined by the 48v motor and single gear is 30mph summer and 28mph winter (clean road) I did a test in front of my folks house to see how far the car would coast from 5mph to a stop. I tested the stock Powermax 769 - 155x65r13 and some randomish Honda 115x70x14 space savers, last year at this same time I was running some antique Goodyear continentals 155x80r13's and will include a bit of antidotal from them. All tires were tested at 60psi. I did want to test some 125/80r13's (because I have always had excellent luck with them) but I had none that fit the miles lug pattern. In any event on flat ground and a huge 30 degrees, wind was nearly calm with a couple MPH here and there with a very thin layer of slime on the road Powermax 769 155x65r13s coasted a whopping 35' 3" (both runs were only a few inches off, must have been dumb luck) These are the stock tires from miles Honda 115x70r14 space savers on front only a whopping 39' average (1' variation, 2nd run was further) I then tested top speed, unlike any other vehicle on the road the Miles ZX40 cannot change gears or increase power output and tire changes are easy to test based on WOT top speed. Results Powermax - 28mph (on the normal stretch we run everyday) Spacesavers up front - 29mph (same place) Old Goodyears - 29mph (speedo corrected but also at 5-10% higher energy draw due to the size change no doubt) So given the set of tires I have available I noted no significant difference besides a bit of traction difference and of coarse some major road noise on the spacesavers (rather agressive tread for a bald tire actually). Also before size is brought up although the space savers "should" be a smaller diameter (1/3") I did note the car sat higher because the tires are more like old balloon tires, car sat a bit higher on the space savers than with the regular tire and side to side comparison off the vehicle same deal, look more like moped style tires. It is also worth noting that the car is about 2400lbs and actually has a tad more weight to the rear. Ah well. When summer comes along maybe I can do a more convincing test with clean roads and warm temps. Something worth noting is that the Miles Zx40's alignment is not significantly affected by the space savers, I have noticed some space saver designs when put on my cobalt or commuta caused visible deflection due to the really strange offset on the rim, I would think this would have more affect on how far you coast than the RR because it messed up your alignment. But I digress. Happy coasting.