Dialing up to 50 PSI for improved efficiency

[Dolemite]

Just sharing an experience - I daily 19" Michelin PS4Ss in 265 all-around. Today I decided to crank all my pressures up to 50 PSI (maximum labeled on the sidewall) just to see if that would change anything. Efficiency improved dramatically. Average Wh/mi never went above 300, even with a few episodes of 75+ mph highway & "spirited driving" - although the car definitely felt more skittish. Will be doing this on longer trips going forward vs. swapping back to the hateful MXM4s.

 

[Rice&Curry]

how was the ride quality? after driving for some time the tire pressure will go up beyond 50 psi. I am not sure if this is safe as you will be driving above the rated tire pressure.

 

[Dolemite]

how was the ride quality? after driving for some time the tire pressure will go up beyond 50 psi. I am not sure if this is safe as you will be driving above the rated tire pressure.

It's probably fine - they test these things ad infinitum for every moronic scenario imaginable. Most people probably don't even know the pressures on the placard are COLD pressures. Actually... most people probably don't even know where to find their tire pressures. Went up to ~54 during driving, I don't care/not worried. The one thing you DO have to be cognizant of is that the car does handle differently at the limit vs. when I run them at 42, at which point it feels like it's on rails. And these sizes are completely pointless for street driving, but a lot of fun. If that's your thing.

Ride quality was absolute *sugar*. It's also considerably noisier. But you get to save watts!

I also wouldn't do it outside of long-distance driving because you'd likely end up prematurely wearing out the center rib.

 

[Feathermerchan]

It is safe to inflate your tires to the recommended COLD tire pressure on the sidewall and then drive them. Yes the tire pressure increases when the tires warm up but that's OK. NEVER let air out of a hot tire unless you have a really good reason to. Underinflated tires overheat and fall apart. Inflating over the OEM recommended pressure normally just reduces traction and results in a stiffer, more bouncy ride.

 

[bjrosen]

What are you averaging for trips, 300Wh/mile is terrible. I've averaged 227Wh/mile over the last 7200 miles and 235 for the life of the car. I keep my tires at 44PSI.

 

[Dolemite]

What are you averaging for trips, 300Wh/mile is terrible. I've averaged 227Wh/mile over the last 7200 miles and 235 for the life of the car. I keep my tires at 44PSI.

Lifetime average is about 280 - from what I've heard on here, that's fairly normal.

 

[afadeev]

Lifetime average is about 280 - from what I've heard on here, that's fairly normal.

It is, for a TM3P. Mine is 288-ish, though it drops in the winter (winter tires effect) and is presently on the upswing (on PS4Ss).

Over-pressurizing the tires will distort and elongate the contact patch. This, actually, helps with traction in standing water, but compromises traction on dry surfaces.
Since you picked PS4Ss as your tires, I take you prioritize performance handling and traction over cost and efficiency. As do I.

I run my PS4Ss at 42 psi all around.
Anything higher, and the ride quality begins to degrade.

YMMV,
a

 

[Dolemite]

It is, for a TM3P. Mine is 288-ish, though it drops in the winter (winter tires effect) and is presently on the upswing (on PS4Ss).

Over-pressurizing the tires will distort and elongate the contact patch. This, actually, helps with traction in standing water, but compromises traction on dry surfaces.
Since you picked PS4Ss as your tires, I take you prioritize performance handling and traction over cost and efficiency. As do I.

I run my PS4Ss at 42 psi all around.
Anything higher, and the ride quality begins to degrade.

YMMV,
a

Yep, P here, also. I am also quite intimate with my right foot, unlike some others on here.

 

[Sasmf]

Yep, P here, also. I am also quite intimate with my right foot, unlike some others on here.

Are you guys running the normal Michelin PS4s or the Tesla specific Michelin version (the one supposedly with the foam inside)? I've heard the Tesla specific PS4s only come in the 18 and 20 spec sizes. How is the noise of the PS4s at "normal" pressures?

 

[Dolemite]

Are you guys running the normal Michelin PS4s or the Tesla specific Michelin version (the one supposedly with the foam inside)? I've heard the Tesla specific PS4s only come in the 18 and 20 spec sizes. How is the noise of the PS4s at "normal" pressures?

Yeah there's no such size in T0 spec - I'm running the generic PS4S. NVH @ 42 all-around is definitely worse than the OE MXM4s.

 

[Gasaraki]

how was the ride quality? after driving for some time the tire pressure will go up beyond 50 psi. I am not sure if this is safe as you will be driving above the rated tire pressure.

The max rated tire pressure on the tire is at set temperature and takes in to account that the pressure will increase some more due to temperature increase when running the tire.

 

[charlieaf92]

What are you averaging for trips, 300Wh/mile is terrible. I've averaged 227Wh/mile over the last 7200 miles and 235 for the life of the car. I keep my tires at 44PSI.

Lol, well that certainly puts things in perspective. My 9k mile average is like 320. When I'm on the highway doing 75-80 it's more like 340+

 

[Feathermerchan]

The OEM tires on the performance are sticky with high rolling resistance. I don't run them or the silly 20" wheels. I need sidewall so I have 18" forged wheels. With the MXMV tires, my lifetime avg is about 270.

 

[ODWms]

My lifetime average on the 20” PS4s is 277, over 41,000 miles. I keep my pressures at about 48-50 cold. Ride quality difference is barely noticeable for me.

 

[Zcd1]

First road trip of any significant distance I took in the car traversed an especially bad section of pavement in Wisconsin.

Tire pressures were at the original recommended 48+ PSI. Couldn't stand the ride quality - truly unpleasant.

Lowered the pressures to ~40 PSI cold and have never looked back... (Tesla-specific OEM Michelin PS4S tires)

 

[afadeev]

I'm running the generic PS4S. NVH @ 42 all-around is definitely worse than the OE MXM4s.

Same here, my second set of PSS4's is of plain-vanilla variety.

Since my old set of OEM PS4S's was pretty worn (between 2-4/32), and the new tires are definitely quieter. But that comparison misleading, since new full tread tires are always quieter.

Non-foam PS4S's are not only lighter and ~$110 cheaper/set, but I had a puncture in the OEM set that required dismounting the tire, scraping off the foam layer, then re-installing and re-balancing. Thus a typical $25 15-minute puncture repair turned into $95 and a few hours of waiting. Not worth it for me.

 

[Feathermerchan]

Just plug em like the rest. I can't tell you how many plugged tires I have worn out. No trip to the tire place and you can usually plug them on the car. Safer and faster than jacking and removing.

 

[ODWms]

Same here. I was sold on plugging decades ago. I keep them in every car, and have worn out tires, years after I’ve plugged them.

 

[roblab]

Everyone should have a plug kit in their frunk or trunk. It's whistling past the graveyard not to, as you're gonna need to fix a flat some day. With a plug kit you don't have to take it to a repair shop, nor even to your own garage. Just pull over (into a store parking lot rather than on the side of the road may be preferable) and push a plug into the hole. It is also wise to have a small pump you can plug into the lighter outlet so you can refill the air your tire lost.

Either way, buy a plug kit, at least. I've plugged a tire on the side of the road and never got my pants dusty, and then again in a parking lot or in my garage. Some of these were on trucks I used to own, large box trucks. All of 'em never saw a tire repair shop. Little things like doing your own flat repair add up, and it's a skill worth learning. With a hammer to pound in the plug "needle", even small woman can fix a tire, though I never let my little wifey do it.

 

[Feathermerchan]

A week after we picked up our Y, the left rear went low. I plugged it in the driveway.
I have plugging kits and compressors in each of our Frunks. The compressor is a Milwaukee M12 unit. Allows you to set the pressure you want and start it. Stops on its own.