Tire PSI - use tire or door rating?

[Pearl]

If you're really heavy (200lbs.+), add 2-3lbs of psi to the left-side tires for more even tire wear. Also consider getting an alignment done with you in the car. Never go by the max listed on the tire's sidewall. Start from the door jamb sticker and fine tune from there.

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[tacthecat]

If you're really heavy (200lbs.+), add 2-3lbs of psi to the left-side tires for more even tire wear. Also consider getting an alignment done with you in the car. Never go by the max listed on the tire's sidewall. Start from the door jamb sticker and fine tune from there.

Neither is recommended nor necessary for a street automobile - if it was then what should you do when your 110# girlfriend by herself, or you and your 3 rugby buddies, decide to pile in and take a road trip?

 

[Gavnzdad]

I keep mine in the 35-40 range. Always have, been fine.

 

[tacthecat]

I keep mine in the 35-40 range. Always have, been fine.

Most people running those pressures (3 - 8 psi above auto mfg. COLD recommendations) on OEM size tires usually wear out the center of the tire well before the entire width. Are you able to get "even wear across the tread" at these pressures for the life of the tire?

 

[Gavnzdad]

Most people running those pressures (3 - 8 psi above auto mfg. COLD recommendations) on OEM size tires usually wear out the center of the tire well before the entire width. Are you able to get "even wear across the tread" at these pressures for the life of the tire?

The tires usually weather crack up before the tread wears out. I dont drive as much as some people. Tires will last me a few years. They always wear just fine.

 

[ArnoldLayne]

I had to repair a flat last week, and the tech that helped me out said I should run my tires at 36-38 PSI cold vs 32 PSI. I have 11k miles on the car, and he showed me how the outside is wearing faster than the center, due to under-inflation.

My EX-T door jam says 32 PSI all the way around. The tires are rated to 44 max.

Does anyone know how Honda comes up with their PSI? Any recommendations for preferred PSI? I do mostly solo highway driving.

This has always confused me, anyone have some good, fact based info about using the car vs tire recommendations?

Honda's recommendations are probably based on room temp at 78deg.

Mine are inflated at 36 psi all around to account for the heat. I do mine at Costco (its free) and they inflate it to 36 psi on all tires and I check and inflate every month when I stop by at Costco.

The first time I did the nitrogen deflation/inflation at Costco, the guys inflated it at 32 psi and within 2 days I got 'Low Tire Pressure' warning from TPMS.

If you are a Costco member, do a Nitrogen swap on your tires. I think its around $12-13. Nitrogen fills are free for life for all Costco members and you can check and inflate your tire pressure every month to keep your tires properly inflated with Nitrogen. And the guys at Costco tire center are pretty good and have the right equipment to do it in min.

It does not get any better than that provided you are a Costco member.

 

[tacthecat]

Honda's recommendations are probably based on room temp at 78deg.

Mine are inflated at 36 psi all around to account for the heat. I do mine at Costco (its free) and they inflate it to 36 psi on all tires and I check and inflate every month when I stop by at Costco.

The first time I did the nitrogen deflation/inflation at Costco, the guys inflated it at 32 psi and within 2 days I got 'Low Tire Pressure' warning from TPMS.

If you are a Costco member, do a Nitrogen swap on your tires. I think its around $12-13. Nitrogen fills are free for life for all Costco members and you can check and inflate your tire pressure every month to keep your tires properly inflated with Nitrogen. And the guys at Costco tire center are pretty good and have the right equipment to do it in min.

It does not get any better than that provided you are a Costco member.

Door post inflation recommendations are for cars at ambient temperature and undriven for several hours, usually overnight. It doesn't matter if the ambient is -20 or +105 degrees. Driving more than a mile just before checking will skew the results. If you don't have an inflator at home then fill them wherever and check after car has been parked overnight. That said 36 psi is probably okay. Be sure to reset your TPMS each time you change the air or nitrogen pressure. And it's common for the TPMS to come on in our '12 Si in the Fall the first time the temp drops into the teens (tire pressure changes about 1psi for each 10 degrees F change in ambient temperature).

 

[tacthecat]

I had to repair a flat last week, and the tech that helped me out said I should run my tires at 36-38 PSI cold vs 32 PSI. I have 11k miles on the car, and he showed me how the outside is wearing faster than the center, due to under-inflation.

My EX-T door jam says 32 PSI all the way around. The tires are rated to 44 max.

Does anyone know how Honda comes up with their PSI? Any recommendations for preferred PSI? I do mostly solo highway driving.

This has always confused me, anyone have some good, fact based info about using the car vs tire recommendations?

See posts 5 & 6

 

[gheezycivicx]

Honda's recommendations are probably based on room temp at 78deg.

Mine are inflated at 36 psi all around to account for the heat. I do mine at Costco (its free) and they inflate it to 36 psi on all tires and I check and inflate every month when I stop by at Costco.

The first time I did the nitrogen deflation/inflation at Costco, the guys inflated it at 32 psi and within 2 days I got 'Low Tire Pressure' warning from TPMS.

If you are a Costco member, do a Nitrogen swap on your tires. I think its around $12-13. Nitrogen fills are free for life for all Costco members and you can check and inflate your tire pressure every month to keep your tires properly inflated with Nitrogen. And the guys at Costco tire center are pretty good and have the right equipment to do it in min.

It does not get any better than that provided you are a Costco member.

I am going to try 36 psi as well. Ever since I went down to 32 psi, i've had the low tire pressure warning even after calibration. 32 psi was fine on a 1300 mile round trip, averaging 42 mpg, but the tire pressure warning is annoying.

 

[tacthecat]

I am going to try 36 psi as well. Ever since I went down to 32 psi, i've had the low tire pressure warning even after calibration. 32 psi was fine on a 1300 mile round trip, averaging 42 mpg, but the tire pressure warning is annoying.

If the warning is coming on after a good calibration and you don't have a tire leaking air, you're likely not inflating all tires to the same (+- 1psi) pressure, or you're inflating them after driving more than 1 mile after they've sat for 3+ hours (ie cold). Best, for most people, to run the recommended (door sticker) pressures. The poster above you most likely has an alignment issue, not a tire pressure issue - or he drives/corners aggressively.

 

[BarracksSi]

Sometimes I wish we could up-vote answers on these forums like they do on Stack Exchange.

Anyway...

What PSI? Go by the door jamb first, and do it when the tires are cooled down to ambient temperature after driving. As tacthecat said, it doesn't matter if the weather is 100 degrees or 0 degrees, because this is a mechanical thing we're talking about -- the amount of sidewall flex and tread shape depends on internal pressure (the air behaves like a spring). It might be worth it to raise the pressures all around -- evenly -- if you're going to be heavily loaded. Check the owner's manual, too.

The manufacturer arrives at these specs based on how much weight the tires carry, the tires' width, and their sidewall depth. This is why, on our cars, the specs call for 35 PSI in front and 32 in the rear -- there's more weight in the front of the car.

Outliers:
Drag racing -- you can lower the pressure in the drive tires to let them behave more like proper drag slicks with soft sidewalls. I got my best 60' times with 20 psi. Lower than that, though, and the internal air becomes softer than the sidewalls, and the tire "cups", which means that the center of the tread tucks inward and doesn't get a good grip.

Autocross/track -- you can alter the pressures to keep the tires from "rolling over". It's really better to take care of this through alignment and other suspension settings, but if you're running in stock class, and/or you're tweaking things between runs, adjusting tire pressures is the way to go. The end of the car with harder pressures will slide more: high PSI in the back can help rotate in a turn (which is what we'd want in our FWD cars); high PSI in the front can avoid too much roll-over, but it also reduces front grip (which is what we don't want).

Sidewalls that are a lot thinner/fatter than stock -- I never deviated very far from stock, so I haven't read up on this. You may need to experiment and closely monitor treadwear with these if you want the longest tire life. Say you run 15s: I'd check the PSI rating for the LX models and their 16" wheels. 20" wheels and above? Go with higher PSI, I've heard, which helps with rim protection just as much as treadwear.

 

[BarracksSi]

If you're really heavy (200lbs.+), add 2-3lbs of psi to the left-side tires for more even tire wear. Also consider getting an alignment done with you in the car. Never go by the max listed on the tire's sidewall. Start from the door jamb sticker and fine tune from there.

Autocross guys like to do this. If you take it to a shop and they don't want you sitting in the car while it's on the alignment machine, you can use some weights (dumbbells, plates, whatever) in the driver's seat instead.

 

[HayaiKuruma]

Swapping out my OEM 17" to the OEM 18" from the Sport HB. Noticed in the manual it says 35 psi front and 33 psi rear. I forgot to look at the door jamb sticker to compare. Is this what I should run? I'm sure I'll have to calibrate the TPMS because of the swap. What psi are you foks running on the 18"? Also an important fact, I didn't put the OEM Conti's on my 18", I put Michelin Sport A/S3+ 235/40ZR18 95Y XL on there. Thanks

 

[BarracksSi]

Swapping out my OEM 17" to the OEM 18" from the Sport HB. Noticed in the manual it says 35 psi front and 33 psi rear. I forgot to look at the door jamb sticker to compare. Is this what I should run? I'm sure I'll have to calibrate the TPMS because of the swap. What psi are you foks running on the 18"? Also an important fact, I didn't put the OEM Conti's on my 18", I put Michelin Sport A/S3+ 235/40ZR18 95Y XL on there. Thanks

My door jamb sticker says 35f/33r, too. 235/40-18, as you know.

(and 60 psi for the spare)

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