[johnung]

Hoping to hear some tire pressure suggestions. Recommended tire pressure for my stock runflat Pirellis 225/45-18 is 32psi front, 38psi rear. Just mounted same exact size in goflat winter Michelin X-ICE Xi3.

Should I still use 32/38 pressures or something else? Thanks in advance.

[johnung]

Originally Posted by johnung

Hoping to hear some tire pressure suggestions. Recommended tire pressure for my stock runflat Pirellis 225/45-18 is 32psi front, 38psi rear. Just mounted same exact size in goflat winter Michelin X-ICE Xi3.

Should I still use 32/38 pressures or something else? Thanks in advance.

Any tire pressure suggestions? Gotta be some tire pyrometer guys out there? Thanks!

[johnung]

Originally Posted by johnung

Any tire pressure suggestions? Gotta be some tire pyrometer guys out there? Thanks!

What tire pressures do you guys run in goflat winter tires? Stock size 225/45-18

[kern417]

Run the same. You can bump up the fronts to 34-35 to help it cut through snow, but otherwise just follow the suggestions.

[rambleon84]

Some manufactures suggest a bit higher psi in the winter but i would suggest testing that out yourself. Next time you see a bunch of snow, fill your tires up to the door sticker suggested psi and go driving. Then run several psi higher and note if you feel any differences over the same conditions.

https://www.tirerack.com/tires/tiret...jsp?techid=168

[johnung]

Originally Posted by rambleon84

Some manufactures suggest a bit higher psi in the winter but i would suggest testing that out yourself. Next time you see a bunch of snow, fill your tires up to the door sticker suggested psi and go driving. Then run several psi higher and note if you feel any differences over the same conditions.

https://www.tirerack.com/tires/tiret...jsp?techid=168

Thanks for the link. I wonder how much that changes if your reference point is runflats? Doesn't seem like TireRack considered that in this recommendation

My stock runflats recommend 32 front & 38 rear. That's what I used the other day when they were mounted. It seems to be riding pretty stiff like the tires are definitely full of air compared to the summer Michelin PS4S that have a soft summer compound.

Just thinking out loud...
Front 35-37 and Rear 41-43 just seems so high.

[Gen13 F36]

I run 36 and 38 on my 19" with indy 500

[kern417]

Originally Posted by johnung

Thanks for the link. I wonder how much that changes if your reference point is runflats? Doesn't seem like TireRack considered that in this recommendation

My stock runflats recommend 32 front & 38 rear. That's what I used the other day when they were mounted. It seems to be riding pretty stiff like the tires are definitely full of air compared to the summer Michelin PS4S that have a soft summer compound.

Just thinking out loud...
Front 35-37 and Rear 41-43 just seems so high.

Again, run the same, or bump up the fronts if you feel like it improves performance. I didn't say anything about bumping up the rears.

The pressures are based on weight balance and promoting even treadwear. I run less pressure in the summer for traction and more in the winter for inclement weather. It's up to you to find the sweet spot. But the manufacturers recommendation work for OEM tire sizes. whether they're runflats, all seasons, whatever.

You should be determining your best tire wear anyway. If you always drive with a car full of family/kids, it'll wear differently than someone that typically rides alone. It all just depends. Check your tread depth every 5k and make sure it's wearing evenly. Then adjust pressures if necessary.

[Gen13 F36]

Actually some tires get noisier when inflated too much

[johnung]

Originally Posted by johnung

Hoping to hear some tire pressure suggestions. Recommended tire pressure for my stock runflat Pirellis 225/45-18 is 32psi front, 38psi rear. Just mounted same exact size in goflat winter Michelin X-ICE Xi3.

Should I still use 32/38 pressures or something else? Thanks in advance.

UPDATE:
I received the email response at the bottom of this post from TireRack. The bottom line is to JUST SET WINTER TIRE PRESSURES +3LBS (assuming winter tire size is the same as stock tire size).

If you care about the details why, or you are fighting insomnia, then keep reading.
Hope this helps!

My interpretation of the TireRack email that I received is:

1) If the tire size is the same, then use the manufacturer's tire pressure recommendation regardless of whether a tire is a runflat or non-runflat.

2) The often repeated advice to "increase pressures in winter tires" isn't actually intended to increase the recommended pressure settings. It is to ensure that actual driving pressures during the course of daily driving do not drop below the recommended levels.

Laws of Physics make pressures drop inside tires when temperatures drop. Often the coldest time of a winter day is early morning, right when most people get in their cars to drive to work. So the concern is that the pressure inside the tires may have dropped to below the recommended levels in the cold early morning, reducing the effectiveness of your winter tires when you most need it driving to work.

Recommended tire pressures are always "cold" pressures, meaning to always check them when the car has been sitting for hours. Driving around causes tires to warm up and their inside pressure to rise.

Knowing that no one, (haha, except possibly members from this forum) is going to go outside to adjust their winter tire pressure at 5am when it's 10 degrees F. or colder out, winter tire pressure recommendations get boiled down to "JUST SET WINTER TIRE PRESSURES +3LBS" to assure that they won't drop below recommended normal pressures at any time during the day.

You can occasionally double check when you start up your car in the morning by having your car read it's tire pressures from their TPMS system.

EMAIL RESPONSE FROM TIRERACK BELOW:
"Thank you for your inquiry. These tires being non-runflat does not factor into the pressure recommendation. The normal psi recommendation that I have found for your vehicle is 32/36. The goal in the winter is to make sure that the pressures do not drop below that level. Unfortunately, that tends to happen early in the morning, when people tend to be driving the most. Additionally, the pressure recommendations factor in an expected increase in pressure during driving due to heat build up in the tires. The ambient winter temperatures limit that build up. That is why it is best for most customers to increase the pressures in the winter.

I would start by increasing them by 3 psi over the normal recommendation. Monitor the fluctuations to the best of your ability, and be sure to check the pressures early in the morning. If you find that they are falling to or below the normal pressures, I would try them at 5 psi above normal. I am hesitant to start them too high initially. Higher pressures tend to diminish ride quality. Also, if there are extended periods of warm weather where the tires are able to generate more heat and pressure build up, the higher pressures can cause inconsistent treadwear."

[kern417]

You seem to keep skipping over my posts so I'll just say this one more time. Just run the recommendations. Running +3 on all 4 corners arbitrarily will likely cause uneven wear. Until you actually see uneven tire wear or pressures below the recommendation, you should not be increasing the pressure. Just check once a month and if it's low, add air. It won't always be exactly 32/38 and that's fine. When the tire heats up, it'll even itself out over time. IF you feel like your front tires aren't cutting into the snow, then you can add some air. But unless you want your tires to look like this after 10k miles, you need to only add pressure when there's an issue.

For reference, yes your tires heat up when driving. So if you run 35/41 cold, then it'll be more like 38/45 warm. That never makes sense, no matter what the temps are.

But it's up to you. Good luck.

[johnung]

Originally Posted by kern417

You seem to keep skipping over my posts so I'll just say this one more time. Just run the recommendations. Running +3 on all 4 corners arbitrarily will likely cause uneven wear. Until you actually see uneven tire wear or pressures below the recommendation, you should not be increasing the pressure. Just check once a month and if it's low, add air. It won't always be exactly 32/38 and that's fine. When the tire heats up, it'll even itself out over time. IF you feel like your front tires aren't cutting into the snow, then you can add some air. But unless you want your tires to look like this after 10k miles, you need to only add pressure when there's an issue.

For reference, yes your tires heat up when driving. So if you run 35/41 cold, then it'll be more like 38/45 warm. That never makes sense, no matter what the temps are.

But it's up to you. Good luck.

Sorry, didn't mean to give the impression that I was skipping over your posts. I should have acknowledged that what you are saying is a definite given. Was trying to make sense out of TireRack recommendations on my phone while dealing with four other things more important in my life. Typical day for all of us.

I agree with you that over inflation is a bad thing to avoid. When non-runflat winter tires were mounted last week I had them set cold pressures to the 32/38 stock recommendation. Then I had the car check the TPMS pressure settings.

Our outside temps haven't gotten into the 20's yet. I'll keep an eye on pressures to see if they drop below recommended values as outside temperatures drop. Same goes if we get an unusually warm day, making sure pressures aren't too high. Wish the TPMS system was more customizable to put minimum & maximum settings in to give me a heads up so I don't have to manually check. Man, that keyless ignition has really spoiled me! Take care.

[kern417]

Originally Posted by johnung

Sorry, didn't mean to give the impression that I was skipping over your posts. I should have acknowledged that what you are saying is a definite given. Was trying to make sense out of TireRack recommendations on my phone while dealing with four other things more important in my life. Typical day for all of us.

I agree with you that over inflation is a bad thing to avoid. When non-runflat winter tires were mounted last week I had them set cold pressures to the 32/38 stock recommendation. Then I had the car check the TPMS pressure settings.

Our outside temps haven't gotten into the 20's yet. I'll keep an eye on pressures to see if they drop below recommended values as outside temperatures drop. Same goes if we get an unusually warm day, making sure pressures aren't too high. Wish the TPMS system was more customizable to put minimum & maximum settings in to give me a heads up so I don't have to manually check. Man, that keyless ignition has really spoiled me! Take care.

It's all a part of maintenance. For example, I park in the same spot at work every day. So every day the tires on the right of the car have more pressure than the left. Why? Because the sun has been beating on them all afternoon, while my tires on the left have been in the shade. So don't expect it to be perfect. Just monitor your tire wear, keep up with tire rotations, and everything will wear evenly.

I keep my tire pressures at 32-33 all around. If it's ever below
30, I add pressure. If it's ever above 35, I reduce pressure. I do that on all of my cars, regardless of the recommendation and get good results. But if I ever see uneven tire wear, I'll modify my pressures accordingly. I just feel like BMW has high recommendations in the rear for some reason, and I'd prefer less pressure for a wider tire patch. Especially because I rarely if ever have a car full of people and a full trunk that would need more pressure in the rear. So it all depends on your use and conditions.

[johnung]

Originally Posted by kern417

It's all a part of maintenance. For example, I park in the same spot at work every day. So every day the tires on the right of the car have more pressure than the left. Why? Because the sun has been beating on them all afternoon, while my tires on the left have been in the shade. So don't expect it to be perfect. Just monitor your tire wear, keep up with tire rotations, and everything will wear evenly.

I keep my tire pressures at 32-33 all around. If it's ever below
30, I add pressure. If it's ever above 35, I reduce pressure. I do that on all of my cars, regardless of the recommendation and get good results. But if I ever see uneven tire wear, I'll modify my pressures accordingly. I just feel like BMW has high recommendations in the rear for some reason, and I'd prefer less pressure for a wider tire patch. Especially because I rarely if ever have a car full of people and a full trunk that would need more pressure in the rear. So it all depends on your use and conditions.

Curious how you do tire rotations since I've read so many different opinions. Are you talking front to back every so many miles with a square setup?

Also I just read someone say not to store summer tires in the cold. I don't have any inside space available. Tried to talk my wife into tossing out the boxspring and holding up the mattress with a tire at each corner. Can't believe the look I got! She married a car guy. What did she expect?

[kern417]

Originally Posted by johnung

Curious how you do tire rotations since I've read so many different opinions. Are you talking front to back every so many miles with a square setup?

Also I just read someone say not to store summer tires in the cold. I don't have any inside space available. Tried to talk my wife into tossing out the boxspring and holding up the mattress with a tire at each corner. Can't believe the look I got! She married a car guy. What did she expect?

I do rotations side to side because my tires are staggered and asymmetrical. If they are directional and staggered, then you can't rotate them. But if they are square and asymmetrical, then you can rotate side to side and front to back. I do every 5k miles, or at least every oil change.

Not all summer tires have issues in the cold. I have rcomp track tires that can't see temps below 40*, so I store them inside. But my regular continental summer tires stay in the garage. It just depends. Most street tires won't have an issue.

[luckstr]

Originally Posted by Gen13 F36

I run 36 and 38 on my 19" with indy 500

How do you like the tires? I have a 2017 440i convertible and am getting new tires next week, DEFINITELY NOT RUN FLATS. Choice is the Indyhawk 500's or General. Thanks

[thejeremyman9]

Originally Posted by luckstr

How do you like the tires? I have a 2017 440i convertible and am getting new tires next week, DEFINITELY NOT RUN FLATS. Choice is the Indyhawk 500's or General. Thanks

Get some michelin PS4S. I just got mine installed a week ago and autocrossed on them yesterday. They are generally regarded as the best for a reason. Great tires. I have used their predecessor (MPSS) on other cars with the same result.

[johnung]

Originally Posted by thejeremyman9

Get some michelin PS4S. I just got mine installed a week ago and autocrossed on them yesterday. They are generally regarded as the best for a reason. Great tires. I have used their predecessor (MPSS) on other cars with the same result.

Definitely agree! MPS4S are the best! I'm enjoying the winter Michelin X-ICE and had a great experience driving them in a recent 20 degree snow/ice storm. But I can't wait for it to warm up in a couple months so that the 245/40-18 MPS4S can go back on.