OT - Tire Air Pressure Question

[Nittany Ziggy]

I just bought new tires for my car and have a question regarding the air pressure. I will be driving quite a bit in the next week and want to be sure I am not wearing them out unnecessarily. The tires are Bridgestone Turanza EL 440 and the size is 235/40 92V. The recommendations on the inside of the driver’s door are 38 psi for the front and 36 for the rear. The tires say 40 psi is the max. The very reputable tire company that installed my tires have them at 40 psi all the away around.

I normally have tire change outs taken care of at the dealer but they were swamped due to the pandemic. The dealer has always followed the recommendations on the label inside the driver’s door. My new tires were installed on Thursday and the tire shop is closed from Friday through Monday so I cannot get an answer from them. I am driving to Chicago tomorrow and want to ensure I am not wearing them out with incorrect pressure.

Any advice on the best air pressure for these tires is welcome.

 

[Nitt1300]

Go with the car mfg recommendations- but within 2 lbs is close enough (I say this, but I'm anal about tire pressures myself even though I know better)

 

[fairgambit]

I just bought new tires for my car and have a question regarding the air pressure. I will be driving quite a bit in the next week and want to be sure I am not wearing them out unnecessarily. The tires are Bridgestone Turanza EL 440 and the size is 235/40 92V. The recommendations on the inside of the driver’s door are 38 psi for the front and 36 for the rear. The tires say 40 psi is the max. The very reputable tire company that installed my tires have them at 40 psi all the away around.

I normally have tire change outs taken care of at the dealer but they were swamped due to the pandemic. The dealer has always followed the recommendations on the label inside the driver’s door. My new tires were installed on Thursday and the tire shop is closed from Friday through Monday so I cannot get an answer from them. I am driving to Chicago tomorrow and want to ensure I am not wearing them out with incorrect pressure.

Any advice on the best air pressure for these tires is welcome.

I'm no tire expert, but if the recommendations are 38, it seems like the max must be more than 40.

 

[ILLINOISLION]

There’s too much pressure to answer this question correctly, so I’ll respectfully decline.

 

[fairgambit]

There’s too much pressure to answer this question correctly, so I’ll respectfully decline.

You're treading lightly on this topic?

 

[Waltwam]

I just bought new tires for my car and have a question regarding the air pressure. I will be driving quite a bit in the next week and want to be sure I am not wearing them out unnecessarily. The tires are Bridgestone Turanza EL 440 and the size is 235/40 92V. The recommendations on the inside of the driver’s door are 38 psi for the front and 36 for the rear. The tires say 40 psi is the max. The very reputable tire company that installed my tires have them at 40 psi all the away around.

I normally have tire change outs taken care of at the dealer but they were swamped due to the pandemic. The dealer has always followed the recommendations on the label inside the driver’s door. My new tires were installed on Thursday and the tire shop is closed from Friday through Monday so I cannot get an answer from them. I am driving to Chicago tomorrow and want to ensure I am not wearing them out with incorrect pressure.

Any advice on the best air pressure for these tires is welcome.

I remember my tire specialist in Erie gave me some info years back, but I cannot remember exactly what he said about the information recommended on the car being incorrect. I believe there is information on the inside of the tires with correct specifications. Never made sense to me , so I suggest checking with a specialist as soon as possible to get the correct information. Sorry I cannot tell you more.

 

[Agoodnap]

Always go with the auto manufacturer's spec.

 

[Nittany Ziggy]

I'm no tire expert, but if the recommendations are 38, it seems like the max must be more than 40.

Yes - That was a surprise to me also. I only noticed it after taking a picture of the sidewall so I could provide accurate info in my OP.

Always go with the auto manufacturer's spec.

I would generally agree but I remember reading Click n Clack and they stated that the auto manufacturers are providing the air pressure for the best ride, not the best mileage. This is why I am asking.

 

[massimoManca II]

I just bought new tires for my car and have a question regarding the air pressure. I will be driving quite a bit in the next week and want to be sure I am not wearing them out unnecessarily. The tires are Bridgestone Turanza EL 440 and the size is 235/40 92V. The recommendations on the inside of the driver’s door are 38 psi for the front and 36 for the rear. The tires say 40 psi is the max. The very reputable tire company that installed my tires have them at 40 psi all the away around.

I normally have tire change outs taken care of at the dealer but they were swamped due to the pandemic. The dealer has always followed the recommendations on the label inside the driver’s door. My new tires were installed on Thursday and the tire shop is closed from Friday through Monday so I cannot get an answer from them. I am driving to Chicago tomorrow and want to ensure I am not wearing them out with incorrect pressure.

Any advice on the best air pressure for these tires is welcome.

You’re fine at 38psi on all four... I’m actually impressed your retailer set all four to 38 , these clowns can be sloppy and I’ve had shops do all sorts of kooky stuff / setting random pressures / variances on each corner

safe motoring to you.

 

[massimoManca II]

I'm no tire expert, but if the recommendations are 38, it seems like the max must be more than 40.

Say What?!??

i’d be worried only if it were the other way around

 

[Nittany Ziggy]

You’re fine at 38psi on all four... I’m actually impressed your retailer set all four to 38 , these clowns can be sloppy and I’ve had shops do all sorts of kooky stuff / setting random pressures

safe motoring to you.

Thanks for the kind words. My retailer set all four to 40 psi, not 38 and 40 is what the tires say is the max recommended. I also envision the pressure increasing tomorrow when I am on the Turnpike at high speed in 90+ degrees weather.

 

[PSU65]

I assume there’s no longer a requirement to stay under a certain speed for a period of time on new tires?

 

[massimoManca II]

Thanks for the kind words. My retailer set all four to 40 psi, not 38 and 40 is what the tires say is the max recommended. I also envision the pressure increasing tomorrow when I am on the Turnpike at high speed in 90+ degrees weather.

you’re fine at 40... that pressure delta at operating temp is negligible

i typically run 38psi on all corners for max mpg - even though mfr specs are 32psi.... I do not mind the slightly stiffer ride

 

[PearlSUJam]

you’re fine at 40... that pressure delta at operating temp is negligible

i typically run 38psi on all corners for max mpg - even though mfr specs are 32psi.... I do not mind the slightly stiffer ride

The discussion about 2 psi is hilarious. If the temp outside goes from 50 degrees to 90 in a day there's more than 2 psi change all in one day. Make sure to check your psi every day! Lol

 

[ILLINOISLION]

I assume there’s no longer a requirement to stay under a certain speed for a period of time on new tires?

That’s a great question, always heard that subject raised in regard to breaking in a new car.

 

[PearlSUJam]

I'm 45 and have changed my own oil and rotated my tires and understood psi for the last 34 years and find this thread hilarious. You all bitch about the younger generations but this is really a discussion?

 

[fairgambit]

Say What?!??

i’d be worried only if it were the other way around

My Rx-8 runs on Bridgestone Potenzas and the recommended inflation is 36. The max is 51. Ziggy says his recommended is 38 and the max is 40. What am I missing? 40 for max psi seems low.

 

[massimoManca II]

My Rx-8 runs on Bridgestone Potenzas and the recommended inflation is 36. The max is 51. Ziggy says his recommended is 38 and the max is 40. What am I missing? 40 for max psi seems low.

While I agree that 40psi sounds low as far as a maximum rating, as long as he’s at/below that pressure the point is moot ... the Michelins on my Motorhome are rated 70psi max and everything I read is that you need to run at that pressure or you will lose control and die... have had no issues nor would i lose sleep running at max psi

 

[RedBankerEngr]

There’s too much pressure to answer this question correctly, so I’ll respectfully decline.

or …,so I'll respectfully deflate.

 

[psuro]

The Ideal Gas Law is in play here.

PV=nRT

 

[BW Lion]

I just bought new tires for my car and have a question regarding the air pressure. I will be driving quite a bit in the next week and want to be sure I am not wearing them out unnecessarily. The tires are Bridgestone Turanza EL 440 and the size is 235/40 92V. The recommendations on the inside of the driver’s door are 38 psi for the front and 36 for the rear. The tires say 40 psi is the max. The very reputable tire company that installed my tires have them at 40 psi all the away around.

I normally have tire change outs taken care of at the dealer but they were swamped due to the pandemic. The dealer has always followed the recommendations on the label inside the driver’s door. My new tires were installed on Thursday and the tire shop is closed from Friday through Monday so I cannot get an answer from them. I am driving to Chicago tomorrow and want to ensure I am not wearing them out with incorrect pressure.

Any advice on the best air pressure for these tires is welcome.

Max inflation pressure for that tire per Bridgestone is 51 psi. I’d set them all at 37-38 psi cold.

https://www.caranddriver.com/news/a15341871/tread-rightly-why-tire-pressure-matters/

 

[GTACSA]

It would seem that increased wear on tires over a 1,000 mile trip resulting from a difference of 2 psi would be negligible at the extreme, and probably 99% less than that.

 

[dmallory7]

You didn't ask for the best milage rather you wanted to ensure no excessive wear. Over inflation will wear the center of the tire and under inflation the tire edges. Go with 38 lbs not the 40. In the heat range of July your tire pressure will rise dramatically with high speed driving. Protect the tire center by not over inflating and you can protect the edges by not cornering at fast speed.

 

[ChandlerPearce]

My Rx-8 runs on Bridgestone Potenzas and the recommended inflation is 36. The max is 51. Ziggy says his recommended is 38 and the max is 40. What am I missing? 40 for max psi seems low.

The OP didn't state the car.....and 92v is not a tire size.....that is a load and speed rating. Your tires are 235/40R19...and those tires are rated for a max of 51 pounds. Remember many auto manufacturers state low tire pressure for maximum ride comfort...eg my STS Cadillac says 30 psi for a 235/55r17 which is ridiculous......I run 35 for better mileage, wear, and handling. I personally would run 40psi and then YOU decide how it feels and fuel mileage.

 

[KnightSlayer]

I checked with Tom Brady's House of Tires and they recommend running all 4 tires at 22 psi.

 

[Nitt1300]

I checked wit Tom Brady's House of Tires and they recommend running all 4 tires at 22 psi.

almost ruined my keyboard

 

[JmmyW]

I just bought new tires for my car and have a question regarding the air pressure. I will be driving quite a bit in the next week and want to be sure I am not wearing them out unnecessarily. The tires are Bridgestone Turanza EL 440 and the size is 235/40 92V. The recommendations on the inside of the driver’s door are 38 psi for the front and 36 for the rear. The tires say 40 psi is the max. The very reputable tire company that installed my tires have them at 40 psi all the away around.

I normally have tire change outs taken care of at the dealer but they were swamped due to the pandemic. The dealer has always followed the recommendations on the label inside the driver’s door. My new tires were installed on Thursday and the tire shop is closed from Friday through Monday so I cannot get an answer from them. I am driving to Chicago tomorrow and want to ensure I am not wearing them out with incorrect pressure.

Any advice on the best air pressure for these tires is welcome.

Ziggy, go with the car manufacturer recommendations. That takes into account the weight of your car on each tire and will ensure the tires have the proper contact patch with the road - and you’ll get the best mileage, lowest tread wear, and proper handling and braking.

The difference between 40 and 38 isn’t much so if you’ve already left on your trip, you’ll be OK.

This discussion reminded me of my vehicle dynamics class at PSU. Professor told the class, there’s a fully loaded tractor trailer properly set-up to handle the load. Then, it delivers its cargo. Can it stop faster or slower now that it weighs 30,000 pounds less? The interesting answer was, the unloaded rig will (usually) take more distance to stop. See, the tire pressures were set so they had a proper contact patch when the trailer had its cargo. After unloading the cargo, there was a significant decrease in weight, and only the center of the tires were now in contact. This led to reduced traction, and (slightly) increased braking distances.

 

[91Joe95]

The Ideal Gas Law is in play here.

PV=nRT

Nerd.

 

[91Joe95]

Ziggy, go with the car manufacturer recommendations. That takes into account the weight of your car on each tire and will ensure the tires have the proper contact patch with the road - and you’ll get the best mileage, lowest tread wear, and proper handling and braking.

The difference between 40 and 38 isn’t much so if you’ve already left on your trip, you’ll be OK.

This discussion reminded me of my vehicle dynamics class at PSU. Professor told the class, there’s a fully loaded tractor trailer properly set-up to handle the load. Then, it delivers its cargo. Can it stop faster or slower now that it weighs 30,000 pounds less? The interesting answer was, the unloaded rig will (usually) take more distance to stop. See, the tire pressures were set so they had a proper contact patch when the trailer had its cargo. After unloading the cargo, there was a significant decrease in weight, and only the center of the tires were now in contact. This led to reduced traction, and (slightly) increased braking distances.

So you're saying if Ziggy exceeds the manufacturer's expected load rating he should go with the 40 psi?

 

[JmmyW]

So you're saying if Ziggy exceeds the manufacturer's expected load rating he should go with the 40 psi?

I am saying he should go with the car manufacturer recommendations.

From Ziggy’s OP, they are: “The recommendations on the inside of the driver’s door are 38 psi for the front and 36 for the rear”

 

[MtNittany]

It depends. Are the floor mats soaked in ether?

 

[JoeBot409]

Put 45psi in

 

[fastlax16]

40 hot or cold?

 

[Lion84]

Is he filling them with Nitrogen and does that make a difference.

 

[psuro]

Nerd.

Hey!

No four letter words allowed on this board!

 

[HartfordLlion]

Nerd.

Riches guys in the world are nerds.

 

[Post_ShockTherapy_MackDaddy]

The discussion about 2 psi is hilarious. If the temp outside goes from 50 degrees to 90 in a day there's more than 2 psi change all in one day. Make sure to check your psi every day! Lol

PV=nRT

The beauty of chemistry

 

[Post_ShockTherapy_MackDaddy]

The Ideal Gas Law is in play here.

PV=nRT

Just saw your post. Kudos.

 

[PearlSUJam]

PV=nRT

The beauty of chemistry

 

[psufan44]

I just bought new tires for my car and have a question regarding the air pressure. I will be driving quite a bit in the next week and want to be sure I am not wearing them out unnecessarily. The tires are Bridgestone Turanza EL 440 and the size is 235/40 92V. The recommendations on the inside of the driver’s door are 38 psi for the front and 36 for the rear. The tires say 40 psi is the max. The very reputable tire company that installed my tires have them at 40 psi all the away around.

I normally have tire change outs taken care of at the dealer but they were swamped due to the pandemic. The dealer has always followed the recommendations on the label inside the driver’s door. My new tires were installed on Thursday and the tire shop is closed from Friday through Monday so I cannot get an answer from them. I am driving to Chicago tomorrow and want to ensure I am not wearing them out with incorrect pressure.

Any advice on the best air pressure for these tires is welcome.

Follow the tire pressure label on the vehicle- I am assuming you replaced the tires with the exact same size which was on the vehicle. The pressure was developed to optimize all the vehicle parameters (safety, handling, ride, NVH, fuel economy, traction, etc......). In my former life, I worked for a major auto manufacturer in Chassis with responsibility for tires.

Add: The tire pressure monitoring system which alerts you when tire pressure is to low is set up based on the released pressures.