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Effect of wider tires on range

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I can recommend highly the 265/30 Pilot Sport on the front even though it is not a Tesla spec tire in other words it does not have the somewhat different tread composition and acoustic foam. I got mine at Tire Rack. Of course like all the Pilot Sport 4S tires especially 30 series they're not cheap and who knows what the supply chain issues are right now with any of these things but the tire itself is great. I can't tell that it's really any noisier than the stock 235/30 Tesla spec which was originally the OEM tire on the car. Unfortunately for reasons that may have to do more with cost and perhaps rolling resistance they went to a Pirelli Pzero Tire on the performance models, which is by comparison a piece of crap. And they also went to that ridiculously heavy 9 in wide wheel which offers really no benefits for handling over the original 8.5 in wheel and is even heavier than the original OEM turbines. We got an enormous Improvement in ride just from swapping out the boat anchors for lightweight forged wheels. Saved an average of 6 lb a corner relative to the 2018 OEM wheels. And those wheels are significantly wider than the stock wheels they replaced so that's 6 lb saved on a much wider rim. The VS14 forged rims combined with the MPP adjustable suspensions literally transformed the cars.
I have thought about changing rims and I have some time to consider that while I run my current tires. I do like the look of the ubers but they definitely are stupid heavy so they are probably gonna go at some point. I may do my changes in stages since I'm going to have the car for a long time and it will let me try different things out.
 
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I have thought about changing rims and I have some time to consider that while I run my current tires. I do like the look of the ubers but they definitely are stupid heavy so they are probably gonna go at some point. I may do my changes in stages since I'm going to have the car for a long time and it will let me try different things out.
Yeah for sure you have to play the long game on all the upgrades unless you've got a stupid amount of money to spare. We did it in stages. First the rims, then the MPP suspension bits. But all the effort is worth it in the end. Our cars are just so responsive and ride better to boot. And since my wife wanted a softer ride she got the Comfort adjustable kit and I took the Sport kit. Both are great
 
The big problem with 275s on the front is that I would have to push the offset way out to clear the front steering knuckle which of course affects your energy consumption and range fairly dramatically- and you're also going to have to run more negative camber to get the tire tucked into the wheel well with those changes. As it is, I've got basically a stock offset on a 9.5 inch wheel and essentially a stock scrub radius at least on the front which is desirable. People who are obsessed with the flush look don't realize that they are changing the scrub radius of the suspension with uncertain effects in terms of how the tire patch behaves at the limit. There's also the question of what the change in scrub radius does to suspension stability in the event of a catastrophic Tire failure or blowout. I don't know myself but I'm pretty confident I don't want to mess with it too much.
Not that dfwatt will see this, but lots of people that race their cars run 275's with a 35 offset. I have 2 sets myself. It's very close, but most tires do fit. Those that don't only interfere by 1-2 mm, so you only need a 3mm spacer. This is far from "push the offset way out" - 3mm is nothing. Logically, if a 265 fits, any 275 will fit with 5mm offset change.

5mm of scrub radius change is also irrelevant. Lots of people racing run 15mm offset difference in order to fit properly wide 295+ tires.

That being said, 265 is plenty on the street, and is a good compromise. But it absolutely does use more energy- I generally see about 360 wh/mi at 70 MPH on level ground. Also, if you are squeezing 35K or even 20K miles out of tires, then just go 245's- you're not driving in a way that you'll ever notice or care about 245's vs 265's. 265's are for drivers that are happy to get 10K miles.
 
One of the problems with this discussion is that people assume that your range loss is simply due to the wider Tire which may be contributing both in terms of rolling resistance and in terms of aerodynamic drag. But a huge issue that is very hard to measure is the effects of the wider Wheels which oftentimes are not designed from the standpoint of aerodynamics but more from the standpoint of looks. A big part of why the model 3 with a 18-in Wheels is so efficient is the Aero wheel covers. They're worth at least 10 to 15 watt hours per mile on the highway. It's a shame that nobody's making aero wheel covers that can be snapped on to various custom aftermarket wheels because I bet they would make a significant difference in range.
 
I've never really considered this, so why is this? In most hard surface machines like ball bearings, less contact area is better.

I'm not well versed on hard surface rolling resistance, but if you had a constant load, wouldn't going to a larger bearing improve efficiency?

With tires, almost all of the energy loss is from deforming the tire as you roll. A wider tire has more rubber, but it deforms proportionally less vertically. For reasons beyond my complete understanding, the net results is usually an improvement. We all tend to imagine that rolling resistance is from surface-surface interactions, like the tire actually sticking to the road and so on, and there is some of that but its negligible.

Of course there is an aerodynamic penalty though!
 
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I'm quite certain wider tires increase rolling resistance. Look at any car built around maximum efficiency and you will find the thinnest tires. Wider tires are simply to increase grip when it's needed. The more rubber you have on the ground (with all other variables the same) the more energy loss you have with each rotation, not even accounting for the decreased aerodynamics of the wider tire at high speeds.

Take bicycles for example, high efficiency road bikes have extremely thin tires to minimize contact with the ground to reduce rolling resistance.
 
I'm quite certain wider tires increase rolling resistance. Look at any car built around maximum efficiency and you will find the thinnest tires. Wider tires are simply to increase grip when it's needed. The more rubber you have on the ground (with all other variables the same) the more energy loss you have with each rotation, not even accounting for the decreased aerodynamics of the wider tire at high speeds.

Take bicycles for example, high efficiency road bikes have extremely thin tires to minimize contact with the ground to reduce rolling resistance.

Wider bicycle tires also have less rolling resistance (all else equal, there being some complexity in optimum tire pressures in each case and so on). In fact in recent years, starting around ~2015 or so road bike tires have been growing wider, as people have learned more about the net benefits of rolling resistance vs aero drag. Basically they figured out if you make the rim a little wider to match the wider tire, and design the fork around it wider tires and rims, you can negate most of the aerodynamic penalty and just enjoy better grip, comfort, and rolling resistance. In the year 2000 a time trialist would likely be on 19-20mm wide tires while today 25mm is almost a bare minimum. (My wife and I used to be bike racers, me a cat 3, her a professional)

With cars the net total resistance improves with skinnier wheels and tires, but rolling resistance in isolation doesn't get better. Rolling resistance goes up linearly with speed, while aerodynamic drag is supra linear. At 70mph the net win goes solidly towards aero improvements over minor changes in rolling resistance.
 
Looks like @jackmott is right here. This is a page on bicycle tires, and rolling resistance goes down with width due to less deformation. However, aero quickly dominates at higher speeds, even on bikes, so it's a tradeoff. Given cars tend to want to maximize highway range, aero is what they minimize even though it does technically increase rolling resistance.

 
All anecdotes suggest on the order of 5-15% (about 20-40 fewer actual highway miles).

Personally I think offset plays a bigger role than I have seen considered—specifically, going from a 1-inch tuck to flush probably adds a lot of turbulence around the wheel wells, beyond just an inch more width on the rubber.

But, I have no data to support and do not care enough to bother. Everything I have done—lowered (+ efficiency), wider tires (- efficiency), wheel spacers (- efficiency), front lip (+ efficiency) has largely been a wash. Though, at 75mph I found the difference between no AC and max AC to be about 100wh/mi, or about a 25-30% hit… so if you are really concerned about getting to your destination, just take off your pants in the car :p .
One interesting note:

I recently purchased an identical wheel set to my race set, and mounted the same size tires but from the “Grand Touring” category. Anecdotally, I think I saw about a 10% increase in efficiency between daily-driving on 200-TreadWear race rubber and these 600-Treadwear highway tires.

They are 275/35R19 all around on very flush 19x9.5+22 (daily driving at race camber to make them fit). I am very happy to look back at this in every parking lot if it means a few extra minutes at every supercharger ;) .

4791CD35-D25B-46C3-B678-6EF93C6F137A.jpeg
 
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Wider bicycle tires also have less rolling resistance (all else equal, there being some complexity in optimum tire pressures in each case and so on). In fact in recent years, starting around ~2015 or so road bike tires have been growing wider, as people have learned more about the net benefits of rolling resistance vs aero drag. Basically they figured out if you make the rim a little wider to match the wider tire, and design the fork around it wider tires and rims, you can negate most of the aerodynamic penalty and just enjoy better grip, comfort, and rolling resistance. In the year 2000 a time trialist would likely be on 19-20mm wide tires while today 25mm is almost a bare minimum. (My wife and I used to be bike racers, me a cat 3, her a professional)

With cars the net total resistance improves with skinnier wheels and tires, but rolling resistance in isolation doesn't get better. Rolling resistance goes up linearly with speed, while aerodynamic drag is supra linear. At 70mph the net win goes solidly towards aero improvements over minor changes in rolling resistance.
So there are some reasons behind what you are saying and what I am saying which I think can make us both simultaneously correct for different reasons because we are talking about different things in a way.

Rolling resistance is different than drag coefficient and the two have no direct dependency on each other other than both being effected by tire width. Rolling resistance is caused mostly by sidewall deformation which effects the surface contact patch. Wider tires create higher friction than thinner tires which is due to an increase on rolling resistance due to more rubber being in contact with the ground. Deformation is caused by the interaction of the PSI (pounds per square inch) of air pressure pushing against the contact patch of the tire against the surface and that interaction with the weight of the vehicle.

A wider tire at the same PSI but otherwise identical as a thinner tire will have more area to spread the weight of the vehicle over more contact patch using the air pressure of the tire to support the weight on that contact patch causing less sidewall deformation so in that case it would be a decrease of rolling resistance, however if said decrease is a total net decrease would require overcoming the increased rolling resistance from increased friction as well as the added drag coefficient. The drag coefficient has an exponentially increasing effect with speed as you also said, therefore rapidly eliminating any sidewall deformation efficiency benefits that could may have been attained after friction losses.

An opposite to this is increasing PSI which will allow a tinner tire to support more weight on it's smaller contact patch due to less deformation. Also, centrifugal forces of high speeds on a thinner tire would eliminate even more of the sidewall deformation making it even less important. This case would also benefit from a decreased drag coefficient which would continue to benefit as speed increases.

In the case of bikes where speeds are relatively low, I'm not really convinced that the reasoning for widening the tires is for rolling efficiency and not for increased traction, smoothing the ride (comfort effects rider efficiency), and making the overall wheels less prone to damage. It's hard to win a race if you are on your ass lol. The old efficient tires were so damn thin and high PSI you had terrible traction which meant bad braking speeds and easy to lose stability in even mildly adverse conditions so they were a lot more dangerous. Road tires may have gotten wider but we are talking 5-6mm so, road tires are still crazy thin. If width was always better efficiency my old 29x2.6" downhill semi-slicks at 70PSI would be the ultimate in efficiency but those fatties were important because I was doing 60MPH+ on mountain roads with potholes and cracks and the efficiency loss was greatly overcome by safety/stability/resiliency benefits.

This all being said, the real true statement here would be less sidewall deformation is more efficient. Also that drag coefficient totally eliminates sidewall deformation benefits at automotive speeds.
 
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If you move to a wider tire and keep tire pressure constant, the area of the contact patch doesn't change. The shape of the contact patch changes, but not the area.

It is not the tire touching the road the is costing your energy, the is the energy spent deforming the tire. The casing, the tread blocks, any rubber that moves. Some of that energy is returned to you, like a spring, the rest is lost as heat/sound.
 
If you move to a wider tire and keep tire pressure constant, the area of the contact patch doesn't change. The shape of the contact patch changes, but not the area.

It is not the tire touching the road the is costing your energy, the is the energy spent deforming the tire. The casing, the tread blocks, any rubber that moves. Some of that energy is returned to you, like a spring, the rest is lost as heat/sound.
Beat me to it.
 
If you move to a wider tire and keep tire pressure constant, the area of the contact patch doesn't change. The shape of the contact patch changes, but not the area.
Ok, saying things differently yet thinking the same things still apparently. I am aware that two loaded tires of different widths but otherwise identical will have the same area of contact patch. Air pressure and vehicle weight dictate the area of the contact patch. Weight/PSI = Contact Area

I think I miswrote some of above because I kept getting distracted.

It is not the tire touching the road the is costing your energy, the is the energy spent deforming the tire. The casing, the tread blocks, any rubber that moves. Some of that energy is returned to you, like a spring, the rest is lost as heat/sound.
The tire itself deforming and any heat/sound generated while rolling is entirely because of the tire touching the road.


-Not that any of this really matters on a car because we still already know that drag effects so much as speeds increase that deformation doesn't even really matter in comparison.
 
A wider tire at the same PSI but otherwise identical as a thinner tire will have more area to spread the weight of the vehicle over more contact patch using the air pressure of the tire to support the weight on that contact patch causing less sidewall deformation so in that case it would be a decrease of rolling resistance,

As I understood it, rolling resistance comes from sidewall deformation and tread deformation, which may act in opposite directions. I can see the wider tire having lower sidewall deformation and energy dissipation, but worse tread deformation and dissipation. As the sidewall in a radial is usually floppy and the tread is stiff, I think it may mean more rolling resistance.

I look at the example of the BMW i3, where they chose a very tall tire (for a light car) and a very skinny one, it claimed it was done for lowering rolling resistance. Even at the cost of some handling and stability. I assume the BMW engineers have measured everything and made their choice.
 
As I understood it, rolling resistance comes from sidewall deformation and tread deformation, which may act in opposite directions. I can see the wider tire having lower sidewall deformation and energy dissipation, but worse tread deformation and dissipation. As the sidewall in a radial is usually floppy and the tread is stiff, I think it may mean more rolling resistance.

I look at the example of the BMW i3, where they chose a very tall tire (for a light car) and a very skinny one, it claimed it was done for lowering rolling resistance. Even at the cost of some handling and stability. I assume the BMW engineers have measured everything and made their choice.
Sure, deforming a thin flexible sidewall is less of a loss than the deforming of a thick stiff tread, but both a wide and a thin tire deform the tread and a thin tire would be deforming less total tread width but at a higher angle which is worse because the tire is losing more of it's shape.

Drag coefficient is still the biggest thing effected by tire width on a car overall and the main driving factor for using a thinner tire vs a wider tire and is why efficiency oriented cars use thinner tires.