Wider Pilot Sport 4S tires on stock 18-inch wheels installed and tested

[AlanSubie4Life]

The difference in efficiency between P3D & P3D+ has to do with the different wheel more than the different tire compound.

If you look at Troy's calculations, there is a 7% different between the areo wheels (without the covers) and the sports wheels even though both are on all-season tires. This is mostly due to the weight of the wheels.

Tesla Model S/X/3 range at 55/60/65/70/75/80 mph

The tires are both all season, but they are not the same tire manufacturer. You'd have to use exactly the same tire compound to control the experiment to check impact of the wheel size. If anything, I think this 7% projected impact shows that the specific tire matters a lot.

https://www.tirerack.com/tires/tire...&tireModel=Primacy+MXM4&partnum=345VR8MXM4PV3
https://www.tirerack.com/tires/tire...reModel=ProContact+RX&partnum=34WR9PCRXXLCOSI

FWIW, the Tire Rack specifically calls out low rolling resistance for the MXM4 but not for the ProContact (though I am sure they aren't bad).

On my Spark EV, I experienced about 13-20% range reduction when going to RE-71Rs from the stock Ecopias. This is an extreme case. However, nothing else changed - wheels are the same - (and I have two Spark EVs, one with the stock tires, and one with the sticky tires), so it's relatively easy for me to see the (large) difference.

Certainly a little bit of extra wheel weight (looks like 7lbs per wheel for P3D/P3D+ difference) won't help, but rolling resistance and stickiness is very likely the main contributor to the efficiency loss. It would be great to get firm data, but it is hard to control the experiment. Estimate is 10-20% loss, but usually people change the width, the aspect, diameter, the wheel, aeros, driving habits, etc., so it's hard to control for all the variables.

The good news is that there is a huge stopping benefit & handling benefit to going to Summer tires.

 

[StellarRat]

The tires are both all season, but they are not the same tire manufacturer. You'd have to use exactly the same tire compound to control the experiment to check impact of the wheel size. If anything, I think this 7% projected impact shows that the specific tire matters a lot.

https://www.tirerack.com/tires/tire...&tireModel=Primacy+MXM4&partnum=345VR8MXM4PV3
https://www.tirerack.com/tires/tire...reModel=ProContact+RX&partnum=34WR9PCRXXLCOSI

FWIW, the Tire Rack specifically calls out low rolling resistance for the MXM4 but not for the ProContact (though I am sure they aren't bad).

On my Spark EV, I experienced about 13-20% range reduction when going to RE-71Rs from the stock Ecopias. This is an extreme case. However, nothing else changed - wheels are the same - (and I have two Spark EVs, one with the stock tires, and one with the sticky tires), so it's relatively easy for me to see the (large) difference.

Certainly a little bit of extra wheel weight won't help, but rolling resistance and stickiness is very likely the main contributor to the efficiency loss. It would be great to get firm data, but it is hard to control the experiment. Estimate is 10-20% loss, but usually people change the width, the aspect, diameter, the wheel, aeros, driving habits, etc., so it's hard to control for all the variables.

The good news is that there is a huge stopping benefit & handling benefit to going to Summer tires.

I think the weight of the tires is probably a factor as well. Do you know how your tires compare in weight on the Sparks? Also, is there a source of objective info on difference in rolling resistance between the Ecotopia and the MXM4? I noticed a substantial range hit when I went from Ecotopia to MXM4 on my Leaf. For rolling resistance and noise CR rates the Bridgestone Ecopia EP422 Plus pretty highly and they do have the right size for the M3. It does appear that they are not rated for over 118 mph. That might be a factor for people in Germany, LOL.

 

[luvnMyTS]

On my Model S, I went with a 275/30/21 instead of the stock 245/35/21. The lower series kept the diameter the same, yet gave me a wider patch on the road, while keeping the same height and not impacting speedometer readings.

I've never been a fan of the smaller/narrower tire on a wider trim, looking like the tire is too small for the wheel. Unfortunately, all Tesla's are this way. Likely because it trims it out to offer a minuscule advantage in range. But, I think this is partially what leads to so many people getting wheel rash. Naturally, people driving their cars into curbs is the cause of it and if they wouldn't do that, they wouldn't get wheel rash!! LOL, but with the tires so pulled in, there's no margin for error. With the 275's, the tire is sticks out just a little, but looks straight up when standing a foot or two away. Knock on wood, I've never curbed a wheel before, but, feel like if I did now, there's at least a small margin of error. I got new wheels and it drove me nuts. Had to go buy new tires, despite the ones that were on it being new.

See photos below for comparison......They are custom wheels, but same width wheel as stock.

Most importantly for me though, I think it looks like it fits the wheel now and to me, looks MUCH better.

Appears the same concept could be done on the Model 3.

Model 3 stock 18" is 235/45/18. A 265/40/18 is the exact same 26.3 diameter. Same exact 4.2" sidewall height, so ride quality shouldn't be impacted at all. Yet, the tire is 1.1" wider.

If you have 19's, 235/40/19 stock is 26.4 with a 3.7 sidewall. 265/35/19 is 26.3 with a 3.7 sidewall.

This website provides an easy way to compare tire sizes.....

Tire Size Comparison

BEFORE 245/35/21

AFTER - 275/30/21

 

[AlanSubie4Life]

I think the weight of the tires is probably a factor as well. Do you know how your tires compare in weight on the Sparks? Also, is there a source of objective info on difference in rolling resistance between the Ecotopia and the MXM4? I noticed a substantial range hit when I went from Ecotopia to MXM4 on my Leaf.

It's 21 pounds (RE-71R) vs. 17lbs (Ecopia). Note I also went wider due to lack of availability of RE-71R at the stock size.

https://www.tirerack.com/tires/tire...e&tireModel=Potenza+RE-71R&partnum=05VR5RE71R
https://www.tirerack.com/tires/tire...ewall=Blackwall&partnum=855TR5EP150&tab=Specs

As far as I can tell, the Ecopias are really efficient. They're also like driving on banana peels and every start is nearly a burnout. They have extremely low stickiness in addition to low rolling resistance. (If I get a chance, I'll do an instrumented 60-0 braking distance comparison between the Ecopias and the RE-71Rs (actually it'll be a Direzza ZIII now since the RE-71Rs are now in the dumpster, but it's a similar comparison). I expect at least a 20% difference in braking distance.)

However, looking at the basic numbers, rotational weight:
Tires - 25-23 pounds (R19s are lighter than R18 for stock Model 3). Wheels - 21.6-25.6-28.75 pounds, Rotors ~20 pounds.
These aren't the only rotational components (though probably the dominant ones due to their contribution to the moment of inertia). In any case it's about a 3% change in rotating weight. This is not a calculation of the moment though.
That's certainly not good for handling, but as far as efficiency is concerned, some of the rotational kinetic energy can be reclaimed through regeneration. However, rolling resistance losses cannot be recovered.

 

[StellarRat]

It's 21 pounds (RE-71R) vs. 17lbs (Ecopia). Note I also went wider due to lack of availability of RE-71R at the stock size.

https://www.tirerack.com/tires/tire...e&tireModel=Potenza+RE-71R&partnum=05VR5RE71R
https://www.tirerack.com/tires/tire...ewall=Blackwall&partnum=855TR5EP150&tab=Specs

As far as I can tell, the Ecopias are really efficient. They're also like driving on banana peels and every start is nearly a burnout. They have extremely low stickiness in addition to low rolling resistance. (If I get a chance, I'll do an instrumented 60-0 braking distance comparison between the Ecopias and the RE-71Rs (actually it'll be a Direzza ZIII now since the RE-71Rs are now in the dumpster, but it's a similar comparison). I expect at least a 20% difference in braking distance.)

However, looking at the basic numbers, rotational weight:
Tires - 25 pounds. Wheels - 21-28 pounds, Rotors ~20 pounds.
These aren't the only rotational components (though probably the dominant ones due to their contribution to the moment of inertia). In any case it's about a 5% change in rotating mass.
That's certainly not good for handling, but as far as efficiency is concerned, some of the rotational kinetic energy can be reclaimed through regeneration. However, rolling resistance losses cannot be recovered.

Thanks for that info. I see that the Ecopias are not rated as performance tires...so, I guess the bottom line is: How do you drive? And how much range do you need? For me the thrill of fast driving and hard cornering is long gone. Stopping could be a factor. I think of my car as tool to get from point A to B. The M3 LR gives me the most A to B range with the greatest luxury. I wonder how much further the M3 LR could go with Ecopias?

 

[AlanSubie4Life]

Thanks for that info. I see that the Ecopias are not rated as performance tires...so, I guess the bottom line is: How do you drive? And how much range do you need? For me the thrill of fast driving and hard cornering is long gone. Stopping could be a factor. I think of my car as tool to get from point A to B. The M3 LR gives me the most A to B range with the greatest luxury. I wonder how much further the M3 LR could go with Ecopias?

You should try - everyone wants to know! - if you can find ones with the correct load rating. However, be very cautious about stopping and increase following distance accordingly. 20 feet in stopping distance from 60 MPH could mean a pretty costly accident. On the upside, the chances of getting rear-ended are reduced. For full disclosure, to be clear - the Ecopias are *terrible* tires for pretty much everything except ride comfort (they have super soft sidewalls) and efficiency.

 

[StellarRat]

You should try - everyone wants to know! - if you can find ones with the correct load rating. However, be very cautious about stopping and increase following distance accordingly. 20 feet in stopping distance from 60 MPH could mean a pretty costly accident. On the upside, the chances of getting rear-ended are reduced. For full disclosure, to be clear - the Ecopias are *terrible* tires for pretty much everything except ride comfort (they have super soft sidewalls) and efficiency.

That's interesting because Consumer Reports didn't rate them too badly on performance related items. HOWEVER, they are not rated in the performance tire category by CR, just the plain old tire category. I'd probably have to have a really good reason to switch to the Ecopias. And, since I just got my Model 3 in July it's going to be a long time before I need new tires, so even if I was willing, no info for a long time from me. My feeling is that this should be a math problem if someone can get the correct rolling resistance data for the tires. There is some old rolling resistance data in the Wikipedia, but it's 15 years old. Apparently this isn't an easy thing to find.

 

[AlanSubie4Life]

Yeah, for CR, not sure, but maybe for within their class. Like I said, if I get a chance I'll do an instrumented stopping distance comparison for the Sparks, and that will give you a very good idea how they compare to performance tires.

I saw someone saying somewhere that the load rating might not be high enough, but it looks like 94 (1477lbs/670kg) is available for Ecopia, so that should be fine, as the 20" Model 3 stock tire has a load rating of 92, AFAIK.

 

[StellarRat]

Yeah, for CR, not sure, but maybe for within their class. Like I said, if I get a chance I'll do an instrumented stopping distance comparison for the Sparks, and that will give you a very good idea how they compare to performance tires.

I was going to ask you, do you like the Spark? They are very low priced for an electric but tiny. I looked at those, but decided on the Leaf because it was a much roomier car. You must see something in them since you own two. How's the reliability been?

 

[zhu-]

The 245s on the stock aero rims look to be a much better fit than the 235. As your co-workers mentioned, definitely looks more powerful albeit subtle.

 

[Ciditad]

I was going to ask you, do you like the Spark? They are very low priced for an electric but tiny. I looked at those, but decided on the Leaf because it was a much roomier car. You must see something in them since you own two. How's the reliability been?

Not to hijack your question but I loved my Spark EV when I had it. Changed the Ecopia tires to MXM4 and the torque was more under control (lost maybe 8% range). The only issue I had with the Spark is the car came from an Econobox and interior is pretty low end. Even with the batteries and lower CG, the car felt a bit unstable at highway speeds and runs out of steam after 60MPH. It's definitely a pocket rocket for short range trips.

 

[lozza]

Thanks for the info on the wider tires... Has anyone tried the 265/40/18 size in the aero rims for the Model 3? Really like the advice around this. Thinking of Pilot Sport 4S, but don't want to make a $1000 mistake in size!

Model 3 stock 18" is 235/45/18. A 265/40/18 is the exact same 26.3 diameter. Same exact 4.2" sidewall height, so ride quality shouldn't be impacted at all. Yet, the tire is 1.1" wider.

 

[spesler]

@lozza 265 width on an 8.5” wide rim would be an improper fitment. Plenty of people do it, but 255 is the max width that is correct for the factory wheels.

 

[lozza]

@lozza 265 width on an 8.5” wide rim would be an improper fitment. Plenty of people do it, but 255 is the max width that is correct for the factory wheels.

Thanks for the thoughts. Just trying to understand what the consequences of improper figment means? I actually would like the sidewall to stick out slightly from the edge of the rim (I don’t really like the fact the rim protrudes more than the side wall on the stock 18” rims). With the 265 will I get a similar look like the photo shown above? Also really want to keep the calibration of the size vs. speedo the same, so this size seems to be the right calculation for that.

 

[zhu-]

Thanks for the thoughts. Just trying to understand what the consequences of improper figment means? I actually would like the sidewall to stick out slightly from the edge of the rim (I don’t really like the fact the rim protrudes more than the side wall on the stock 18” rims). With the 265 will I get a similar look like the photo shown above? Also really want to keep the calibration of the size vs. speedo the same, so this size seems to be the right calculation for that.

Possibly uneven wear? A 265 tire on a 235 wheel might cause the center of the tire to have more wear than the edges since the sidewall is being pushed inwards by the smaller wheel.

 

[spesler]

With an oversized tire, the sidewalls will flex more than when mounted in a rim of the correct width. This will make the tire “balloon” and could result in less precise handling, loss of pressure, or tire damage. It could also be just fine, as I said, people do it all the time. IMO it’s best to stay within mfg specs when possible. For these wheels that would mean tread widths between 235 and 255.

 

[WarpedOne]

... and still no pics of 245s on stock 18"?

 

[oripaamoni]

Anybody see these tires yet? Pilot Sport 4 claims to be Tesla OE with the acoustic dampening. Sporty quiet tire? I might give these a shot.
https://www.tirerack.com/tires/tire...odel+3&autoModClar=Dual+Motor+All-Wheel+Drive

 

[gilscales]

... and still no pics of 245s on stock 18"?

See post #6 of this thread, they look good.

 

[gilscales]

Will definitely be doing this one I eat through my stock tires. I wonder if 255's would be overkill. Will probably do 245's to get a good balance of range and performance.

I have decided to be the guinea pig for 255/40/19" tires, I chose this size as I want the widest recommended size and did not want to step down in diameter, this tire is 27" vs. 26.4" for stock diameter so should provide a more comfortable ride as well

the only ones that are not over 25 lbs. I could find are
https://www.tirerack.com/tires/tire...9DWS06XL&vehicleSearch=false&fromCompare1=yes

These tires get good reviews and another site listed them at 24.8 lbs. while all others on tire rack in this size are 27 to 28 lbs. or more, I have to wait a few months though to scrub off my stock rubber!