"Optimal" tire pressure

[CuriousGeorge]

If you are with 40/37 PSI you are 5 PSI above factory recommendation just read this and with directly temperature affects tire pressure for every 10 degrees increase temperature your air pressure will increase by 1 PSI as you are driving in 100’F. Weather your tires will be at 43/40 PSI which is just dangerous and high way speed of 70 M/Hr.increase PSI higher.As I keep my 16” Hankooks at 35/32 PSI as many people complain about wearing mine as new with 16000 miles View attachment 23301

I think that you need to reread this thread.

40/37 is only 2 (not 5) psi over the 38/35 recommended (for stock 17" tires) by MINI USA. It is 2 psi under the recommended (in the UK*) pressure for "ECO". It is 10 psi under the maximum pressure limit for the tire.

As well, nobody here is so naive (I hope) as to not realize that tires heat up when a car is driven (especially when underinflated), and that unless otherwise specified any values mentioned (including by manufacturers) refer only to pressures when cold.

*When I was in London quite a few years back I was struck by the number of billboards carrying public service reminders to check your tire pressures frequently, to help fight climate change. When was the last time you saw anything like that in the US?

 

[CuriousGeorge]

Just a small update: while my intent of testing higher pressures was to determine the effects on handling, not range, the latter seems to be up by 5-10%. At some point rolling resistance would be expected to actually increase, but at least on the surfaces on which I drive, that "breakpoint" is apparently higher than the recommended pressure.

Range normally isn't an issue for me, but still worth knowing what the benefit might be of inflating to higher-than-recommended pressure before, e.g., a road trip. I'm still not sure where I will settle for daily use, though - the stiffer sidewalls at the higher pressure means that the tires are less likely to complain during hard cornering, but I don't get many chances to push that hard, and the ride quality is definitely worse.

Again, Pirelli P7s in 17"...

 

[Puppethead]

I inflated my tires (17" Goodyear Eagle F1s) to the "ECO" 42/39 psi from the UK chart posted previously and had immediate results, easily went over 6 mi/kWh with 80% freeway driving in mid mode.

***********************************
Sep 30, 2024 at 18:47 ** 75°F ** Wind: 15.348 mph from NW ** Humidity: 47% ** Driven: 89.8 Mi ** Start-Batt: 100% ** End-Batt: 49% ** Mi / kWh: 6.09 ** GOM Reading: 59 Mi ** Range Left: 86.24 Mi ** Total Range (From 100% charge): 176.04 Mi ** Total Range (From 100% charge): 176.001 Mi

At least I think I got the tires inflated to 42/39 psi according to my gauge although the wheels may have been too warm, the TPMS said it was lower. When I get a chance I'll double check. I did notice the stiffer ride but I like it, I have better feel of the road.

 

[SameGuy]

My next drive down to Plattsburgh (75 miles each way) I will try the UK Eco setting. Last week in mild weather the F1s at 38/35 I got there with 49% left, but the return trip involves slightly more uphill driving, and a slight headwind, so I stopped for a few kWh about 30 miles from home. It is supposed to remain mild for the rest of this week, so if I can make it down to Plattsburgh with more than about 53% left (I will never get a calculated 176 miles lol), I will try to nurse it back home without stopping. I have my choice of fast chargers along the last 15 miles if I need to bail.