Running higher tyre pressure?

Mike KL · March 21

On the UX250h F-sport 18" tyres, its recommended to run on 2.3bar/33psi. However I found it a bit too soft sometimes and I want to bring it up to 2.5bar/36psi.

Does anyone do this and how do you feel? thanks

Don C · March 21

6 hours ago, Mike KL said:

On the UX250h F-sport 18" tyres, its recommended to run on 2.3bar/33psi. However I found it a bit too soft sometimes and I want to bring it up to 2.5bar/36psi.

Does anyone do this and how do you feel? thanks

It might not make much difference but you stand the chance of needing new tyres prematurely.

fourbanks · March 21

My dealer sets the uxs at 25 bar for everyone

Duggie B · March 21

2 hours ago, fourbanks said:

My dealer sets the uxs at 25 bar for everyone

Both our GS300h and GS F tyres are set at 2.5 bar.

schroder · March 21

3 hours ago, fourbanks said:

My dealer sets the uxs at 25 bar for everyone

25 bar?? That's 362.594 PSI which I feel is a tad high. The car would float into the air 🤣

fourbanks · March 21

4 minutes ago, schroder said:

25 bar?? That's 362.594 PSI which I feel is a tad high. The car would float into the air 🤣

Having hit that large pothole, they may have helped serious damage recently?

Lmafudd · March 21

And in which parallel universe is Air lighter than Air?

schroder · March 21

8 minutes ago, Lmafudd said:

And in which parallel universe is Air lighter than Air?

Any gas when heated at atmospheric pressure becomes lighter than air.. even air can be lighter than air and this is the basis of the hot air balloon. The equation governing this is the equation of state (for ideal gases- that is not very dense gases)

This one!

Lmafudd · March 21

Clever.

Good luck with fitting the heater in your tyres, I'll wave hello when you fly over one day!

gdamorini · March 22

On 3/21/2024 at 1:14 AM, Mike KL said:

On the UX250h F-sport 18" tyres, its recommended to run on 2.3bar/33psi. However I found it a bit too soft sometimes and I want to bring it up to 2.5bar/36psi.

Does anyone do this and how do you feel? thanks

I keep the tyres inflated at 2.5 bar, recommended is 2.3 bar. This way the car handles better and it should improve a bit mileage. I own a 250h non F-sport with 17" tyres.

Mike KL · March 22

8 hours ago, gdamorini said:

I keep the tyres inflated at 2.5 bar, recommended is 2.3 bar. This way the car handles better and it should improve a bit mileage. I own a 250h non F-sport with 17" tyres.

Just did it for a day and drive around 70miles, 2.5bar front and 2.4bar rear. The car feels better, steering is sharper and less spongy but still comfortable. Mpg doesnt change but the road feed back is satisfying. Gonna keep this configuration.

GMB · March 23

We lived in a very hilly area and the consensus of opinion in these places - garages/competent drivers etc - was to inflate the tyres about 10% higher than the book values. They said it prevents undue tyre wear from all those sharp corners, less tendency to rub the sidewalls and gives better cornering grip due to less roll. It certainly worked for us, and no noticeable extra tyre wear in the centre area. I still slightly overinflate the tyres because the low profile tyres always look flat at the right pressure! PS - less road noise too. I am sure that someone on here will point out the error of my ways very soon😝

Lmafudd · March 23

8 hours ago, GMB said:

PS - less road noise too. I am sure that someone on here will point out the error of my ways very soon😝

I ran mine at a higher pressure until I swapped the run-flats for ordinary tyres for that very reason. Tyre noise significantly reduced which makes sense as there would be less contact with the tarmac, I assume!

DavidCM · March 23

On 3/21/2024 at 5:52 PM, schroder said:

Any gas when heated at atmospheric pressure becomes lighter than air.. even air can be lighter than air and this is the basis

This all sounds like a lot of hot air to me.

fourbanks · March 23

49 minutes ago, Lmafudd said:

I ran mine at a higher pressure until I swapped the run-flats for ordinary tyres for that very reason. Tyre noise significantly reduced which makes sense as there would be less contact with the tarmac, I assume!

I got a large nail in my run flat and only lost a few bars over a week, so I'm keeping mine

levensnevel · May 24

Interesting discussion.

Cause I'm wondering. All of our previous cars ran with 2.8 bar pressure. And we experienced no excess wear and tear nor a bumpier ride. Since the 18th of May we are the proud owners of a my2020 UX300E on 18inch wheels.

Part of the deal was a fresh set of front tyres [non run-flats]. For which I returned to the workshop a few days back. Had an interesting discussion there with the mechanic who changed the tyres. He told me that Lexus advised 2.4 bar for our electric UX. But that from experience they augmented the tyre pressure to 2.6 bar. And he advised against 2.8 bar. So now all tyres are on 2.6 bar.

Shall we keep it the tyre pressure on 2.6 bar, or.....

Anyone?

Mike KL · May 24

8 hours ago, levensnevel said:

Interesting discussion.

Cause I'm wondering. All of our previous cars ran with 2.8 bar pressure. And we experienced no excess wear and tear nor a bumpier ride. Since the 18th of May we are the proud owners of a my2020 UX300E on 18inch wheels.

Part of the deal was a fresh set of front tyres [non run-flats]. For which I returned to the workshop a few days back. Had an interesting discussion there with the mechanic who changed the tyres. He told me that Lexus advised 2.4 bar for our electric UX. But that from experience they augmented the tyre pressure to 2.6 bar. And he advised against 2.8 bar. So now all tyres are on 2.6 bar.

Shall we keep it the tyre pressure on 2.6 bar, or.....

Anyone?

I have been running F 38psi R 36psi after I opened this topic, got roughly 1500 miles. I like it better than factory recommend pressure, less squishy and body roll. In my experience, it's not the cold tire pressure you need to concern about, its the peak tire pressure increased in your daily routine. Make sure it won't reach 3bar when hottest and you are fine.

Don C · May 24

10 hours ago, levensnevel said:

Interesting discussion.

Cause I'm wondering. All of our previous cars ran with 2.8 bar pressure. And we experienced no excess wear and tear nor a bumpier ride. Since the 18th of May we are the proud owners of a my2020 UX300E on 18inch wheels.

Part of the deal was a fresh set of front tyres [non run-flats]. For which I returned to the workshop a few days back. Had an interesting discussion there with the mechanic who changed the tyres. He told me that Lexus advised 2.4 bar for our electric UX. But that from experience they augmented the tyre pressure to 2.6 bar. And he advised against 2.8 bar. So now all tyres are on 2.6 bar.

Shall we keep it the tyre pressure on 2.6 bar, or.....

Anyone?

The dealer isn’t always right, it’s usually an opinion of the person telling you. The sticker on the door was put there by Lexus who spent millions developing and testing the car. Unless someone showed me a bulletin from Lexus, I can’t think of a single reason to even ponder over changing it.

Mike KL · May 25

3 hours ago, Don C said:

The dealer isn’t always right, it’s usually an opinion of the person telling you. The sticker on the door was put there by Lexus who spent millions developing and testing the car. Unless someone showed me a bulletin from Lexus, I can’t think of a single reason to even ponder over changing it.

I agree but not all, it's a recommended pressure but not a must. Especially on a SUV with not much power like ours, they always go for a recommended figure that gives greater comfort.

Its always good to experience your tire pressure +- a bit as long as you don't go anywhere close to the tire manufacturer's pressure limit. The recommended number is a good place to start with, then try +1-2 psi in both front or both rear or even all 4 tires see how it feels but make sure both tires on the same axle must be equal.

Don C · May 25

22 hours ago, Mike KL said:

I agree but not all, it's a recommended pressure but not a must. Especially on a SUV with not much power like ours, they always go for a recommended figure that gives greater comfort.

Its always good to experience your tire pressure +- a bit as long as you don't go anywhere close to the tire manufacturer's pressure limit. The recommended number is a good place to start with, then try +1-2 psi in both front or both rear or even all 4 tires see how it feels but make sure both tires on the same axle must be equal.

Most tyre pressure gauges are only accurate to that kind of range so with that in mind there seems little point adjusting them.

Bill Dawes · May 28

I have always found that dealers put higher tyre pressures in, as they do with higher oil level, a less desirable habit than higher tyre pressure I would have thought.

Your tyre pressures will increase will increase/decrease anyway with ambient temp and running friction.

Gas density wiil increase by ratio of absolute temperature if the gas is constrained in a vessel, this is why pressure increases. A tyre as a vessel is elastic so probably not to the same extent as a relatively rigid vessel. If free to expand it will of course decrease in density by inverse ratio of absolute temperatures.

Just returned from a 900 mile holiday from Somerset to Norfolk, 56.3 mpg, temperature as we know not too high so a few more degrees would have probably gained another couple of mpg.

Bill D.