I missed Summer Tire & Temperature Efficiency

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Jelle v/d Meer
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Joined: Sat Apr 28, 2018 7:43 pm
Location: Tilburg / Netherlands

I missed Summer Tire & Temperature Efficiency

Post by Jelle v/d Meer » Thu Apr 01, 2021 9:54 am

I recently got my summer tyres fitted again and yesterday with warmer temperatures (18-24 degrees) I experienced again the massive positive impact those 2 have on the efficiency and range.
Looking through the data from last winter (trips >60km with avg speed >80km/h) I averaged 212wh/km at avg 90km/h.

Yesterday I made 5 trips (2 long & 3 short) on the first long trip I got 171wh/km at 85km/h and on the 2nd long trip 147wh/km at 84km/h.
I left fully charged and pre-conditioned with GOM showing 397km - 245km later I arrive home with still 54% SoC and 235km range left :D.

3.JPG

I-pace S + HUD + Drive Pack + Light Oyster Sport Seats + Tailgate I Ceasium Blue | 18" wheels
Infotainment 20C + Telematics 19.2 | ODO 67,900km | 2020 Efficiency 199watt/km @ avg 74km/h

RS1980
Posts: 15
Joined: Thu Nov 12, 2020 4:04 pm
Location: Germany

Re: I missed Summer Tire & Temperature Efficiency

Post by RS1980 » Fri Apr 02, 2021 9:01 pm

Lucky you! As mine is a company car, I am stuck with winter tires from Oct-March no matter real temperatures nor conditions.
Can't wait for the switch in one week.
I-Pace S MY21

Grunt
Posts: 94
Joined: Fri Aug 07, 2020 12:39 pm
Location: Belgium

Re: I missed Summer Tire & Temperature Efficiency

Post by Grunt » Thu Apr 15, 2021 3:31 pm

Jelle v/d Meer wrote:
Thu Apr 01, 2021 9:54 am
I recently got my summer tyres fitted again and yesterday with warmer temperatures (18-24 degrees) I experienced again the massive positive impact those 2 have on the efficiency and range.
Looking through the data from last winter (trips >60km with avg speed >80km/h) I averaged 212wh/km at avg 90km/h.

Yesterday I made 5 trips (2 long & 3 short) on the first long trip I got 171wh/km at 85km/h and on the 2nd long trip 147wh/km at 84km/h.
I left fully charged and pre-conditioned with GOM showing 397km - 245km later I arrive home with still 54% SoC and 235km range left :D.
Jelle,

Your efficiency results are astonishing, as always. I remember your post last year where you achieved 565km of range on a single charge at 85kmh. And now this...
Even your average winter efficiency of 212Wh is impressive. 171Wh in good conditions, well done. But 147Wh... :shock: :shock: :shock:
You comfortably exceed WLTP results. Do share all secrets, please!

So, basics: you run 18" wheels.
Eco-driving parameters I take as given - keep steady speed, leisurely accelerations, look ahead, avoid braking. Earlier I read your explanation that you keep the power meter at the letters - no lower than the C from Charger, no higher than the R from Power. Anything else that you feel makes a meaningful difference?
What tyres do you run? I saw you chew through a lot of km, so I assume these are no longer OEM?
What tyre pressure do you run at?
Do you always (when feasible) do a full preconditioning, battery and cabin?
Do you have a (heated) garage?
How do you handle HVAC? Off, manual or auto control, chosen temperature...?
What sort of roads do you travel on? What speed do you stick to, on motorways and outside? 85kmh on average can mean steady driving at 90kmh with minimal time off the motorway, or half at 130kmh and half at 40 through traffic for instance...
Anything else you feel that helps?

Thanks for educating all of us :-) 99% of days personally I do not care one bit about consumption; but on occasion it is great to have the entire arsenal of tips & tricks available to extract the last bit of range...

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ianipace
Posts: 324
Joined: Sat Nov 09, 2019 9:11 pm
Location: Cardiff, UK

Re: I missed Summer Tire & Temperature Efficiency

Post by ianipace » Thu Apr 15, 2021 4:26 pm

Boys, boys on this side of the 'pond' we spell those black roundish things TYRES!!
I know Google likes to influence you with the American spelling, but you can tell it to offer you English (UK)!

Stay safe and meant in good humoUr!

Ian
MY2019 SE in Caesium Blue. Panoramic roof and Gloss Black 18" wheels. Ohme Smart charger.

John32
Posts: 172
Joined: Thu May 18, 2017 7:28 pm

Re: I missed Summer Tire & Temperature Efficiency

Post by John32 » Thu Apr 15, 2021 8:30 pm

Has anyone ever compared Summer tyres to all-weathers regarding consumption? With the strange winters we’ve had lately, I consider switching to 4season tyres when the current set runs out

Gtquan
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Joined: Wed Mar 04, 2020 3:28 pm
Location: Canada

Re: I missed Summer Tire & Temperature Efficiency

Post by Gtquan » Thu Apr 15, 2021 10:50 pm

My average over the last 10 wks has been 25.6 Kwh/100km on winter 18s. That's over 4300km. Average speed 44kph. Most trips highway committing 90-120kph.

My summer 22s are worse so far this year but hasn't warmed up that much in Toronto yet.

Jelle v/d Meer
Posts: 1439
Joined: Sat Apr 28, 2018 7:43 pm
Location: Tilburg / Netherlands

Re: I missed Summer Tire & Temperature Efficiency

Post by Jelle v/d Meer » Fri Apr 16, 2021 8:36 am

Grunt wrote:
Thu Apr 15, 2021 3:31 pm
Eco-driving parameters I take as given - keep steady speed, leisurely accelerations, look ahead, avoid braking. Earlier I read your explanation that you keep the power meter at the letters - no lower than the C from Charger, no higher than the R from Power. Anything else that you feel makes a meaningful difference?
Yes - ECO mode and high regen.
Relative to I-pace capability YES leisurely accelerations however compared to most ICE cars at traffic lights I am still pretty much past the intersection before other cars move.
Also I found personally that I am more efficient if I slowly decelerate so when possible (=look ahead) start earlier and slowly lift the power pedal instead of releasing it at once. As you wrote indeed try to keep the charge/power meter between the letters once you are driving.
Grunt wrote:
Thu Apr 15, 2021 3:31 pm
So, basics: you run 18" wheels.
What tyres do you run? I saw you chew through a lot of km, so I assume these are no longer OEM?
Yes for both summer and winter I run 18" and for summer I am still on my original OEM tyres (Pirelli Scorpion Verde All Seasons - 235/65 R18 110V XL) and for winter they fitted Michilin Latitude Alpin LA2 235/65 R18 110H XL. With the last tyre change the feedback was that both had approx 5,000-8,000km life left in them - the lease company won't give new ones till old are warn out, they even fixed a puncture in 1 of my summer tyres.
My summer tyres have efficiency A and my winter tyres efficiency C which I also see translated in consumption. Temperatures dropped again to near freezing at night and 7-10 degrees during the day but now on summer tyres almost all short trips (<10km) stay below 200wh/km and most between 170-190wh/km where previous on winter tyres in similar temperatures it was rare to below 200wh/km om shorter trips.
Interestingly with my winter tyres the car registers just less of 1% too few km, with my summer tyres that is closer to 3%. Last year during my range record attempt the tripmeter showed 556.8km but GoogleMaps showed 572.6km. My odometer now says 68,432km but real km I probably just exceed 70,000km
Grunt wrote:
Thu Apr 15, 2021 3:31 pm
What tyre pressure do you run at?
I asked for maximum pressure when the tyres got changed - I tend to run at slight above advised PSI.
Grunt wrote:
Thu Apr 15, 2021 3:31 pm
Do you always (when feasible) do a full preconditioning, battery and cabin?
Do you have a (heated) garage?
If I remember it I try to pre-condition the cabin 15-25 minutes before departure. The battery only when range matters as if not needed I try to avoid 100% SoC, this because I really like one pedal driving and when near 100% SoC there is barely any regen.
I have a garage but it is not heated but it also never has seen a car parked in it - my car is always parked on the driveway.
Grunt wrote:
Thu Apr 15, 2021 3:31 pm
How do you handle HVAC? Off, manual or auto control, chosen temperature...?
Most trips the climate control is off and if on the preferred setting is manual with fan at speed 2, temperature at 20 degrees and air blowing at windscreen and top part of cabin.
AC only gets put on if too hot or if moisture if fogging the windows.
Grunt wrote:
Thu Apr 15, 2021 3:31 pm
What sort of roads do you travel on? What speed do you stick to, on motorways and outside? 85kmh on average can mean steady driving at 90kmh with minimal time off the motorway, or half at 130kmh and half at 40 through traffic for instance...
Pretty much all kind of roads, longer trips involve mostly highways. From my home I can travel to 4 highways, 2 (direction S/SW/W & NE) take approx 8km and the other (direction NW/N & E/SE) approx 15km all with a mixture of speeds and traffic lights.
The max speed on Dutch highways was reduced in March 2020 to 100km/h between 6am and 7pm (I mostly drive during the day) - I tend to put the ACC on 104km/h (=100km/h real speed). When I have plenty of time, need range or trying to be efficiency I set the ACC to 90km/h.
Just checked with GoogleMaps and this particular return of 118.4km consist of 9.0km of 30/50km/h, 21.5km 60/80km/h and 87.9km highway so roughly 75% highway.

I tend to loose time on highways but gain time off the highway compared to navigation and that is maybe another efficiency tip (not so much for highways) - maintain your speed.
In my experience it is good for efficiency, saves you time and in the I-pace fun to do. What I mean is try to minimize slowing down and carry your speed through corners, roundabouts, ramps/exits, speedbumps and traffic lights. My idea behind is that there is always energy loss with regen so if you carry more speed there is less regen and more importantly less acceleration needed.
Grunt wrote:
Thu Apr 15, 2021 3:31 pm
Anything else you feel that helps?
Sometimes if I really need range or trying to be efficiency I try to draft behind a big truck if it is fast enough (88km/h-100km/h) with the ACC set to minimal 1 bar distance.
Fair warning - be careful doing it as although the ACC keeps your distance it might be slower to react, luckily you can brake a lot faster than the truck. Also the police might pull you over (for not keeping enough distance) or you might anger the truck driver causing him to either deliberately slow down or drive partly/fully over the emergency lane throwing up all kind of dirt/gravel which than rains on your car and windshield.
I-pace S + HUD + Drive Pack + Light Oyster Sport Seats + Tailgate I Ceasium Blue | 18" wheels
Infotainment 20C + Telematics 19.2 | ODO 67,900km | 2020 Efficiency 199watt/km @ avg 74km/h

Grunt
Posts: 94
Joined: Fri Aug 07, 2020 12:39 pm
Location: Belgium

Re: I missed Summer Tire & Temperature Efficiency

Post by Grunt » Fri Apr 16, 2021 9:37 am

John32 wrote:
Thu Apr 15, 2021 8:30 pm
Has anyone ever compared Summer tyres to all-weathers regarding consumption? With the strange winters we’ve had lately, I consider switching to 4season tyres when the current set runs out
John32, it all depends on the rolling resistance coefficient (RRc) of the tyres (happy to oblige, @ianipace :lol: ). Some All Season tyres, like the Pirellis that Jelle mentions, do have an A label.

On the impact of the different tyres on range, I can offer a theoretical estimation...

Each tyre has an energy efficiency rating (nowadays A-E) that relates directly to the rolling resistance coefficient.
These ratings point to a range of measured RR coefficients, shown below:
A <=0.0065
B 0.0066-0.0077
C 0.0078-0.0090
D 0.0091-0.0105
E >=0.00106

(Until 2020 "D" did not exist, so the series was A.B.C.E.F and there was a G as well).

From this you can read that the rolling resistance difference between A and C tyres as somewhere between 20 and 40%. (Less, if the "A" is actually near the highest in its range (say RRc 6.5) and C is the lowest in its range (e.g. 7.8). More in the inverse case)
Lets assume 30% difference in RR.

How much that changes the consumption depends mostly on the speed.
Key variables deciding overall resistance are rolling resistance RR and aerodynamic drag AD.
Rolling resistance (per km) is almost a flat line, depending almost exclusively on the car weight. Aerodynamic drag depends on the speed (increasing with the square of the speed), the aerodynamic efficiency and the frontal area of the car (these last 2 are static, of course). It will be nearly 0 at very low speeds, bu increases exponentially with the speed.

At around 90kmh, typically these 2 factors (RR and AD) each make up roughly 50% of the overall resistance. At 50kmh, RR will be make up more than 70% of resistance. At 130kmh, RR will be less than 30%.

So the impact of a change like Jelle did (from C-rated winter tyres to A rated summer) could be estimated as:
At 50kmh: 30% of 70%, for a decrease in resistance of of 21%
At 90kmh: 30% of 50% for a decrease of 15%
At 130kmh: 30% of 30% or a decrease of 9%

So, quite a significant impact.

In reality the impact on consumption is likely to be a bit lower, because the car also has other elements that drive consumption, like use of heating, losses through acceleration, consumption running the onboard systems etc. Of course these are not affected by driving speed.

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MjrPayne
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Re: I missed Summer Tire & Temperature Efficiency

Post by MjrPayne » Fri Apr 16, 2021 2:53 pm

I've noticed that summer tires around zero degree has increased rolling resistance. They don't work that well below 5C. Consumption is 10-15% higher than with winter tires.
Blue HSE since 21.1.2019
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dernotte
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Joined: Tue Dec 24, 2019 2:34 pm
Location: Montreal, QC, Canada

Re: I missed Summer Tire & Temperature Efficiency

Post by dernotte » Fri Apr 16, 2021 8:41 pm

Sweet spot is +7c. Rubber structural thing.

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