Curious to know if anyone else has observed the same. I switched to 20" T Sportline turbine style rims with Michelin Pilot Sport AS 3+ tires (non staggered) about a week ago. I have a Model 3 Performance (no PUP) which I was previously driving with uncovered aero 18" rims. My efficiency with the aero rims was 270 kw/hr over the previous 12k miles. Since switching, with my standard daily commute of 90 miles roundtrip, I have observed an average energy usage of 330-340 kw/hr! Tire pressures 43 psi. I definitely expected some loss of range and efficiency in making the switch but this strikes me as excessive. The only other factor I can think of that might be effecting it is the weather which has been pretty wet this past week. The rain and road conditions may worsen efficiency but, if anything, I would expect the increased traffic and lower average speed on my commute attributed to the wet conditions to at least cancel out the increased friction and drag of the road conditions and weather??? More curious to see if anyone is experiencing this significant of a drop in range or if there's something else I should be thinking of.
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60 kw/hr loss of efficiency in switching to 20" T Sportline from 18" aero (uncovered)
- Thread starter Gtrain
- Start date
jelloslug
Active Member
It's the new tires. Once the break in a bit, you will see the consumption go down. It won't go down all the way though as the new tires you installed have a higher rolling resistance than the ones you removed.
Wow, watch those units. "kw/hr" makes no sense at all. It reports in Wh/mile. Is that what you mean?
Also I think your results are about as expected.
Also I think your results are about as expected.
Yeah, sorry, Wh/mile is what I meant - typing in haste. OK, well, I guess it sounds like what I'm seeing is in line with what others have observed. Bigger hit than I imagined but I guess that's the way it goes. I love the look of the rims but the range sacrifice may not be worth it. Will follow over time to see if it improves (fingers crossed).
you’re comparing to an average over 12K miles, which means that most of those miles were driven in far more favorable temperature and weather conditions.
We know that heating takes a significant amount of energy and so does rolling over water (it does take quite a lot of energy to displace it). That’s where your loss comes from.
The new wheels have the same aerodynamic cross-section, their spoke design should not be any more drag-inducing vs the uncovered 18s and the slight increase in rotational mass has no measurable effect in the context of freeway driving. You’ve also switched to a sickier but still A/S tire compound and are running high pressure, which minimizes sidewall deformation.
All of the above points to the fact that the new wheels/tires are a minor part of your energy consumption increase. Check again in May and I bet your average will be barely higher than the one you measured with the original 18s.
He's in Newport Beach CA. Don't think it's temperatures. My guess is, his tire switch is accounting for about 10%. The rest are, new tires, maybe a little heat and rain. After 12K miles I think he would have a good feeling of where he should be.
lbowroom
Plaid, white on black, CF, 8/27/21, Track Pack
Not clear to me that wheel mass is really a factor in efficiency. First, it would only be an effect while accelerating, not at steady state. Then, the extra mass would pay back some dividend in regen braking. The extra rolling resistance of the tires is where the efficiency is lost. Also, while a 20" wheel may be heavier, the tire is usually lighter. It's the sum that counts
The 20" wheel/tire combo is most assuredly heavier than 18". Requires more energy to accelerate and you only get back ~60% with regen (my SWAG) unless it is cold enough that you have to use brakes then you get back 0. Aerodynamic drag probably more because wheels are larger diameter turbine. Tire to road drag may be higher due to tire difference.
I'd suggest trying 45 lbs of air in tires cold. It made a diff in my MPS4 tires on my performance. Can't wait to get some 18" wheels on my car.
I'd suggest trying 45 lbs of air in tires cold. It made a diff in my MPS4 tires on my performance. Can't wait to get some 18" wheels on my car.
Maybe I’ll try no covers to see what that hit is first. I think 19 OEM’s look great.
Note I’m already taking a hit for AWD. Lifetime is 268 with 3800 miles. 2.5 months of that is cold weather.
Thanks for the data point.
TANGO SUKKA
Member
I have the stock 20" Performance w/ PUP tires and I'm constantly in the 310~340 Wh/mi rating on the freeway. My 12k lifetime average is 311 Wh/mi.
I have a long commute, 195 mi, and I can make it to work if I keep it under 75, but usually with < 10% charge remaining. I do have a high elevation 1500' elevation gain right at the start of my trip as well. I've been seriously thinking of getting some 18" wheels, but I'm not sure I'll really make up that much in efficiency.
I have a long commute, 195 mi, and I can make it to work if I keep it under 75, but usually with < 10% charge remaining. I do have a high elevation 1500' elevation gain right at the start of my trip as well. I've been seriously thinking of getting some 18" wheels, but I'm not sure I'll really make up that much in efficiency.
Please say 195 miles is round trip. Still that's insane. My commute is 5 miles (one way), no traffic lights, no highway, 2 stop signs
Please say 195 miles is round trip. Still that's insane. My commute is 5 miles (one way), no traffic lights, no highway, 2 stop signs
Hah, nope! I commute to work a couple of days and I work from home the rest. 360 Wh/mi was my average today.
