Tyres and efficiency

[dan_b]

We all know about lowering the rolling resistance of tyres to improve efficiency.
Seems someone's done a test of the various EV-specific tyres. Can't remember what are on my Model 3, will have to go have a look now!

https://electrek.co/2024/06/26/differen ... a-model-3/

[richbee]

We all know about lowering the rolling resistance of tyres to improve efficiency.
Seems someone's done a test of the various EV-specific tyres. Can't remember what are on my Model 3, will have to go have a look now!

https://electrek.co/2024/06/26/differen ... a-model-3/

Not EV specific, but I did read that the difference in fuel consumption between A rated and G rated tyres only amounts to about 1 tank of fuel over the life of the tyre - which is not a massive difference. The tyre / wheel size seems to make more difference. Big wheels definitely look better, but they hammer the fuel consumption (and tyre life)
I guess lots of small differences will add up across multiple components. We make wheel bearings for cars, and there is a huge focus on improving the friction and therefore energy loss. New seal designs, new grease types, changing the internal design to reduce preload - as well as reducing weight

[dan_b]

in that test it's showing a 10% variation in consumption across the tyres tested - sounds like that would give you more of a difference of £50/worth of fuel savings over a 20k mile lifespan?

But yes absolutely, wheel size/weight is also a factor - one of the things Bjorn Nyland is tracking on his many many efficiency tests is the different wheel sizes and their impact on efficiency (and noise).

I'm sure it's a factor on my Tesla M3P - even though it has the heat pump which my 2019 TM3 Long Range didn't (and so should be more efficient), it has the 20" wheels vs the 18s with aero caps, and it's actually a little bit less efficient. That and the sticker tyres I guess. Looks good though!

[Tinbum]

I remembering going from the OE Pirelli tyres on my Iveco van to some budget tyres made a huge difference on my fuel consumption and surprisingly it was for the better.

[nowty]

Not EV specific, but I did read that the difference in fuel consumption between A rated and G rated tyres only amounts to about 1 tank of fuel over the life of the tyre - which is not a massive difference.

29Wh difference per mile, so say 30000 miles that comes to 870000Wh or 870kWh.

8.9 kWh in a litre of petrol so its 97.7 litres or 21.7 gallons.

So unless I've got my sums wrong, a tankful is not far off.
A Humvee takes about 21.8 UK gallons.

[richbee]

in that test it's showing a 10% variation in consumption across the tyres tested - sounds like that would give you more of a difference of £50/worth of fuel savings over a 20k mile lifespan?

But yes absolutely, wheel size/weight is also a factor - one of the things Bjorn Nyland is tracking on his many many efficiency tests is the different wheel sizes and their impact on efficiency (and noise).

I'm sure it's a factor on my Tesla M3P - even though it has the heat pump which my 2019 TM3 Long Range didn't (and so should be more efficient), it has the 20" wheels vs the 18s with aero caps, and it's actually a little bit less efficient. That and the sticker tyres I guess. Looks good though!

I first became aware of the size affecting consumption with my previous Mondeo, which had 18" wheels (cos it looked good!). I was disappointed with the fuel consumption and did a bit of reading - apparently, with a bigger rim / smaller tyre wall, the rubber has to be softer to give the same kind of ride / bump absorption as a bigger tyre wall - hence worse fuel consumption.
Also probably explains the cheapo van tyres, which were probably harder, gave better fuel consumption.

[dan_b]

Good maths!

Not EV specific, but I did read that the difference in fuel consumption between A rated and G rated tyres only amounts to about 1 tank of fuel over the life of the tyre - which is not a massive difference.

29Wh difference per mile, so say 30000 miles that comes to 870000Wh or 870kWh.

8.9 kWh in a litre of petrol so its 97.7 litres or 21.7 gallons.

So unless I've got my sums wrong, a tankful is not far off.
A Humvee takes about 21.8 UK gallons.