My23 cars and efficiency

[jpk]

I've read quite a few posts on here around how larger wheels affect efficiency, can anyone supply some science to collaborate this as if the overall diameter remains the same how can the efficiency change. I ask this as it's now confirmed that the my23 cars will come with larger rims but the ranges haven't been modified to reflect any efficiency changes.

 

[siteguru]

If the overall circumference is the same then I can't see how efficiency can be affected.

Maybe smaller sidewall tyres increase the rolling resistance?

 

[mg4mc]

Maybe smaller sidewall tyres increase the rolling resistance?

They certainly decrease pothole resistance!

 

[TheHypnoToad]

If the overall circumference is the same then I can't see how efficiency can be affected.

Larger rims almost always increase overall wheel weight, even with lower profile tyres, which would result in an efficiency drop.

 

[Eber]

The width should be more relevant as it increases rolling and air resistance.

 

[Ian Key]

I'd have thought that a larger overall circumference would increase efficiency as for each revolution of the axle you travel further, or am I missing something?

 

[Eber]

I'd have thought that a larger overall circumference would increase efficiency as for each revolution of the axle you travel further, or am I missing something?

The circumference would have to be identical for every approved set of wheels, otherwise your speedometer would be incorrect.

Bigger rims require tyres with a different cross section.

 

[Kithmo]

I'd have thought that a larger overall circumference would increase efficiency as for each revolution of the axle you travel further, or am I missing something?

The larger the radius the more effort is required to turn the wheel.

 

[Ian Key]

The larger the radius the more effort is required to turn the wheel.

So why not fit smaller wheels. Less effort to turn, smaller lighter and cheaper tyres

 

[JuziWomble]

MY23 cars - I heard that the only My23 car that was going to be different (excusing paintwork) was the dual motor'd 4 - Larger Wheels and larger calipers / Rest of line up stayed the same - But thats all subject to 'hearsay'

 

[Deleted member 10041]

I'd have thought that a larger overall circumference would increase efficiency as for each revolution of the axle you travel further, or am I missing something?

I'm sure they did a test recently of family hatch back EVs, on the efficiency part of it the basic model Mégane 18inch wheels didn't give as good figures as the higher spec 20 inch wheels.
Can't remember where I saw it, mg4, Id3, Mégane, Born were all in it. Different Models and battery size of each car were in it also (51 and 64 mg4) (58 and 77 Id3 and Borns)

 

[richlove]

I've read quite a few posts on here around how larger wheels affect efficiency, can anyone supply some science to collaborate this as if the overall diameter remains the same how can the efficiency change. I ask this as it's now confirmed that the my23 cars will come with larger rims but the ranges haven't been modified to reflect any efficiency changes.

Where have you seen this confirmed, out of interest?

 

[Robf]

I've read quite a few posts on here around how larger wheels affect efficiency, can anyone supply some science to collaborate this as if the overall diameter remains the same how can the efficiency change. I ask this as it's now confirmed that the my23 cars will come with larger rims but the ranges haven't been modified to reflect any efficiency changes.

Err Google it? e.g.

How Does Wheel Size Affect Performance?

One of the first and easiest modifications to a car can be to slap some larger wheels on, but what what affect does it have on acceleration and overall performance?

www.carthrottle.com

or

How does wheel size condition the performance of your car?

We are using the word “wheel” here deliberately to refer to all the components of this crucial part of our car, from the alloy rim to the tyre, and all its feat

www.pirelli.com

In addition, larger dia needs greater force to initate and maintain speed (its a lever thing). This being offset by greater distance per revolution. Its hitting that sweet spot alluded to in the Pirelli article

 

[Pazmeister]

The 17 vs 18 inch wheels...EXACTLY same circumference the tyre profile of 18 is slimmer which means more unsprung weight eg weight before suspension comes into play. This means a bumpier less smooth ride as the tyres help soak up bumps and the handling is slightly effected. So 18s actually worse......is this going to be noticed be a race driver...yes...will normal Joe Public notice probably not. As for range difference if any not even measurable

 

[Lucky5]

Also, as diameter is increased, profile lowered then width increases normally. Door pillar on my trophy has 18 inch spec at 235 cross section not 215 as per 17s. Guess this increases drag too

 

[Ian Key]

The 17 vs 18 inch wheels...EXACTLY same circumference the tyre profile of 18 is slimmer which means more unsprung weight eg weight before suspension comes into play. This means a bumpier less smooth ride as the tyres help soak up bumps and the handling is slightly effected. So 18s actually worse......is this going to be noticed be a race driver...yes...will normal Joe Public notice probably not. As for range difference if any not even measurable

That I can relate to. My brother had a SLK and went for the smaller rim option with deeper profile tyres to improve the ride quality as he was using it for driving around France not racing and he valued his spine.

 

[Kithmo]

So why not fit smaller wheels. Less effort to turn, smaller lighter and cheaper tyres

Mainly vanity, people don't like the look of smaller wheels, I prefer them TBH.

 

[jpk]

Where have you seen this confirmed, out of interest?

Miles confirmed it around 23 minutes into the latest podcast

 

[richlove]

Miles confirmed it around 23 minutes into the latest podcast

Which podcast?

 

[jpk]

Which podcast?