Huge difference in consumption between tires

[d00d]

Range drops when temperature drops, and rain, wider or under inflated tires also decrease range.

I went from;
21" Mission E Design Wheels
Front: 9.5 J × 21 ET 60 wheels with Continental ProContact RX (AS) 265/35 R21 tires
Rear: 11.5 J × 21 ET 66 wheels with Continental ProContact RX (AS) 305/30 R21 tires

...to;
20" Taycan Turbo Aero Wheels
Front: 9.0 J × 20 ET 54 wheels with Continental ProContact RX (AS) 245/45 R20 tires
Rear: 11.0 J × 20 ET 60 wheels with Continental ProContact RX (AS) 285/40 R20 tires

Saw maybe a 5% range increase in similar conditions.

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[l33cher]

Hello again,

I want to thank everyone for taking the time to write. My initial intention for this thread was to have a healthy discussion that might help me understand what I’m experiencing with my tires. I don’t want this to turn into an argument.

I understand @prj’s point of view, and arguing with science is pointless. I just believe there may be another variable in the equation.

After reviewing the invoices for my tires, I found that the proper model for the summer (problematic) tires is the Continental SportContact 7, 21". The winter tires are GRIPMAX SureGrip Pro, 21", which is different from what I previously stated.

For now, I’ll continue to gather more data since I drive the same route every day. When I have something that can provide clear evidence for my claim I will write again.

 

[69Mach390]

Hello again,

I want to thank everyone for taking the time to write. My initial intention for this thread was to have a healthy discussion that might help me understand what I’m experiencing with my tires. I don’t want this to turn into an argument.

I understand @prj’s point of view, and arguing with science is pointless. I just believe there may be another variable in the equation.

After reviewing the invoices for my tires, I found that the proper model for the summer (problematic) tires is the Continental SportContact 7, 21". The winter tires are GRIPMAX SureGrip Pro, 21", which is different from what I previously stated.

For now, I’ll continue to gather more data since I drive the same route every day. When I have something that can provide clear evidence for my claim I will write again.

I’ve seen this over the years on other EV forums.

One of the issues is that people use the wrong “measuring stick” for calculating efficiency.

Using the displayed estimated range in the dash or the % charge change is NOT an accurate measuring stick.

We call those the “guess o meter” because they’re a complete guess by the computer.

Instead you need to measure miles traveled per kWh.

Then remove other variables like temperature, wind, speed etc to compare. Really hard to compare summer to winter temps and make any conclusions though.

 

[Rik_CT4s]

Range drops when temperature drops, and rain, wider or under inflated tires also decrease range.

I went from;
21" Mission E Design Wheels
Front: 9.5 J × 21 ET 60 wheels with Continental ProContact RX (AS) 265/35 R21 tires
Rear: 11.5 J × 21 ET 66 wheels with Continental ProContact RX (AS) 305/30 R21 tires
?

...to;
20" Taycan Turbo Aero Wheels
Front: 9.0 J × 20 ET 54 wheels with Continental ProContact RX (AS) 245/45 R20 tires
Rear: 11.0 J × 20 ET 60 wheels with Continental ProContact RX (AS) 285/40 R20 tires

Saw maybe a 5% range increase in similar conditions.

I am doing the same. From 22 HF5 Vossen to current 21 Cross Turismo design wheels for the winter on Pilot Alpin 5 tyres, to this spring to 20" turbo s aeros with 245 / 285 tyres on Michelin PS4, mainly for comfort.
To make it look acceptable on a turbo s cross I add some spacers 15mm all around.

 

[kern417]

It's all about rolling resistance. Summer tires are stickier, therefore they take more effort to turn over. It will impact your range due to the compound alone.

 

[69Mach390]

It's all about rolling resistance. Summer tires are stickier, therefore they take more effort to turn over. It will impact your range due to the compound alone.

Actually the opposite is true.

Better traction and rolling resistance aren’t mutually exclusive. In fact a lot of summer tires have very low rolling resistance and typically better than all seasons or winter tires.

Source- https://tirecraft.com/summer-tires-vs-all-seasons-3-reasons-to-invest-in-performance-tires/

 

[kern417]

Actually the opposite is true.

Better traction and rolling resistance aren’t mutually exclusive. In fact a lot of summer tires have very low rolling resistance and typically better than all seasons or winter tires.

Source- https://tirecraft.com/summer-tires-vs-all-seasons-3-reasons-to-invest-in-performance-tires/

If it's a stickier summer tire then it has more friction. The only time that could be the case is if you aren't getting them up to temp. But the tire that OP posted is a 240tw. It's going to wear way faster than an all-season with everything else being equal because of the added resistance.

EV tires are like Touring tires - designed to reduce resistance to improve efficiency. So the moment you swap them out for something more performance oriented, it's normal to see efficiency go down.

 

[69Mach390]

If it's a stickier summer tire then it has more friction. The only time that could be the case is if you aren't getting them up to temp. But the tire that OP posted is a 240tw. It's going to wear way faster than an all-season with everything else being equal because of the added resistance.

EV tires are like Touring tires - designed to reduce resistance to improve efficiency. So the moment you swap them out for something more performance oriented, it's normal to see efficiency go down.

Again, traction/grip and rolling resistance aren’t mutually exclusive. Did you read the link I posted?

Maybe more evidence will help-
https://www.hananiaacuraoforangepar...mer tires,time enjoying the summer adventures.

“Reduced Rolling Resistance: Summer tires are engineered to have lower rolling resistance compared to all-season tires. This means less energy is lost due to friction between the tire and the road. As a result, your car experiences less drag, allowing for more efficient power delivery and potentially improved fuel economy.”

https://www.continental-tires.com/a...lated-use-phase-emissions/rolling-resistance/

“ Generally, summer tires have lower rolling resistance than winter tires.”

 

[d00d]

As Johnny Carson would say, I did not know that.
Start here to find the EU label that shows rolling resistance (enter United Kingdom);
https://www.continental-tires.com/products/b2c/tire-knowledge/eu-tire-label-search/

 

[69Mach390]

As Johnny Carson would say, I did not know that.
Start here to find the EU label that shows rolling resistance (enter United Kingdom);
https://www.continental-tires.com/products/b2c/tire-knowledge/eu-tire-label-search/

Honestly it surprised me too. Sometimes physics doesn’t work out the way you think it would. Common sense would tell you that traction= sticky = friction = worse rolling resistance. But in reality, that’s really not the case.

Or how about this one?

Wider tires can have LESS rolling resistance!
https://velo.outsideonline.com/road...ling-resistance-than-their-narrower-brethren/

Kinda like how longer/wider snow skis are faster.

So why don’t cars use wider tires for efficiency? Because of other physics at play. In particular unsprung weight.

 

[d00d]

Makes sense for skinny bike tires, but maybe not for car tires?

 

[AutoX]

Ya same specs but haven’t done a manual measurement.

I got them from America’s Tire

They’re OEM now FWIW https://www.hankooktire.com/us/en/company/media-center/media-detail.630161.html

Not OEM for 21" Mission E wheels with 315 width.

 

[daveo4EV]

Range drops when temperature drops, and rain, wider or under inflated tires also decrease range.

I went from;
21" Mission E Design Wheels
Front: 9.5 J × 21 ET 60 wheels with Continental ProContact RX (AS) 265/35 R21 tires
Rear: 11.5 J × 21 ET 66 wheels with Continental ProContact RX (AS) 305/30 R21 tires

...to;
20" Taycan Turbo Aero Wheels
Front: 9.0 J × 20 ET 54 wheels with Continental ProContact RX (AS) 245/45 R20 tires
Rear: 11.0 J × 20 ET 60 wheels with Continental ProContact RX (AS) 285/40 R20 tires

Saw maybe a 5% range increase in similar conditions.

yes tires matter

https://www.taycanforum.com/forum/t...miles-range-edit-i-think-its-the-tires….6787/

 

[69Mach390]

Makes sense for skinny bike tires, but maybe not for car tires?

The physics is the same.

It’s just waaaaay easier to measure with bike tires.

And even with bike tires, rolling resistance is only one part of the equation. Weight and even wind resistance (from wider tires) come into play. The same would be true for cars.

Trying to measure what is doing what when it comes to efficiency in EVs is nearly impossible……. Unless it’s a MAJOR change (like losing 30% of your range in very cold temperatures).

A few percentage points from a tire swap would be very difficult to measure as you can’t get rid of all the other variables (wind, traffic, temperature, etc) and account for such a small change in efficiency.

 

[kern417]

Again, traction/grip and rolling resistance aren’t mutually exclusive. Did you read the link I posted?

Maybe more evidence will help-
https://www.hananiaacuraoforangepark.com/5-reasons-why-your-car-needs-summer-tires/#:~:text=Reduced Rolling Resistance: Summer tires,time enjoying the summer adventures.

“Reduced Rolling Resistance: Summer tires are engineered to have lower rolling resistance compared to all-season tires. This means less energy is lost due to friction between the tire and the road. As a result, your car experiences less drag, allowing for more efficient power delivery and potentially improved fuel economy.”

https://www.continental-tires.com/a...lated-use-phase-emissions/rolling-resistance/

“ Generally, summer tires have lower rolling resistance than winter tires.”

i'm speaking from engineering background and personal experience. saying grippier tires have less rolling resistance does not make sense. everything about them from tire temp, grip, and increased wear indicate the opposite of what you're linking. and lines up exactly with OPs experience.

have you ever switched to summer tires and gotten better fuel efficiency?

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