Tire pressures- what's best?

[WoodlandHills]

My ex-extended test i3 was delivered to me tonight with 28 front and 35 rear tire pressures. I have the 20" rims, but page 170 of the manual shows the same pressures for all wheel and tire combinations of 35 front and 41 rear. I am going to give the recommended pressures a try tomorrow, but was wondering what others were using. I am assuming there will be an increase in NVH, but I hope it won't be too bad, I also hope the higher pressure will help protect the rims too.

 

[DAZ]

:shock: Coming from a Prius, most Prius owners run higher tire pressure to increase EV and fuel mileage. I run 40psi front and 42 rear in my Prius. I believe the i3 BEV calls for 33psi front and 40psi rear. I went with 40psi front and rear in my i3. Overall ride with the higher front tire pressure is still very comfortable. For me, it's all about better EV range.

 

[noakey]

:shock: Coming from a Prius, most Prius owners run higher tire pressure to increase EV and fuel mileage. I run 40psi front and 42 rear in my Prius. I believe the i3 BEV calls for 33psi front and 40psi rear. I went with 40psi front and rear in my i3. Overall ride with the higher front tire pressure is still very comfortable. For me, it's all about better EV range.

I always run the fully loaded pressures even though 90% of the time it's just moi in the car.

 

[Bunter]

I always run the fully loaded pressures even though 90% of the time it's just moi in the car.

Same here but I found that it really affected the cars handling so will drop them to base pressure when I get the chance.

Bill

 

[Boxbrownie]

I always run the fully loaded pressures even though 90% of the time it's just moi in the car.

Same here but I found that it really affected the cars handling so will drop them to base pressure when I get the chance.

Bill

Yes........recommended pressures are stated for a reason.

 

[jadnashuanh]

The i3 has several different tire packages, square 19", offset 19", and offset 20"...each one has a different recommended air pressure. Make sure you're looking at the proper table, and use that. There is a sticker on the door that shows the proper pressures, and that may be more up-to-date than the manual.

 

[WoodlandHills]

The i3 has several different tire packages, square 19", offset 19", and offset 20"...each one has a different recommended air pressure. Make sure you're looking at the proper table, and use that. There is a sticker on the door that shows the proper pressures, and that may be more up-to-date than the manual.

What does your door say? Mine repeats what the chart in the book says: 33+41. Where did you read that the various tire combos have different recommended pressures? The chart on page 170 seems hard to misinterpret.....

BTW, I drove 20 or so miles today with the higher pressures and the car felt fine. If anything it was a bit smoother as if the sidewall was properly supported and working to absorb shocks. I did hear that weird oscillating noise when cornering: I like it, it sounds like a phaser firing or something similar.

 

[noakey]

The i3 has several different tire packages, square 19", offset 19", and offset 20"...each one has a different recommended air pressure. Make sure you're looking at the proper table, and use that. There is a sticker on the door that shows the proper pressures, and that may be more up-to-date than the manual.

What does your door say? Mine repeats what the chart in the book says: 33+41. Where did you read that the various tire combos have different recommended pressures? The chart on page 170 seems hard to misinterpret.....

BTW, I drove 20 or so miles today with the higher pressures and the car felt fine. If anything it was a bit smoother as if the sidewall was properly supported and working to absorb shocks. I did hear that weird oscillating noise when cornering: I like it, it sounds like a phaser firing or something similar.

Hi.. I get that oscillating noise when cornering too...

 

[jadnashuanh]

The i3 has several different tire packages, square 19", offset 19", and offset 20"...each one has a different recommended air pressure. Make sure you're looking at the proper table, and use that. There is a sticker on the door that shows the proper pressures, and that may be more up-to-date than the manual.

What does your door say? Mine repeats what the chart in the book says: 33+41. Where did you read that the various tire combos have different recommended pressures? The chart on page 170 seems hard to misinterpret.....

My mistake...I never really looked at the other tables in the user's manual and assumed that if they were all recommending exactly the same pressures, that they'd only need to supply one chart rather than three. I know in my 535GT, there are like three pages of recommended tire pressures for the various tire/wheel combinations to include various loadings and different speed ratings (and they DO differ!), so I made the assumption (and you know what that means!).

But, in general, different tire sizes on the same car, usually require different pressures.

 

[Boatguy]

I saw this thread, and a post on wind sensitivity and wondered about my pressures. I had assumed that since the car was just delivered 7 weeks ago, and was in the shop just a month ago for the software upgrade to fix the AC, that the pressures were ok. Wow, was I wrong! Another demerit for my dealer's service.

I checked this morning and they were totally wonky. Fronts were high, rears were low and left right were off by 4-5psi! I set them to the factory settings (33/41) and what a difference!

The car now tracks much better on the freeway and rides noticeably more comfortably. Driving on the freeway today in a significant amount of wind the car held the road much better. The steering is much more calm and less twitchy. I've typically run higher pressures for better handling in my other cars, but the factory settings really make the i3 drive much better.

 

[tiburonh]

I saw this thread, and a post on wind sensitivity and wondered about my pressures. I had assumed that since the car was just delivered 7 weeks ago, and was in the shop just a month ago for the software upgrade to fix the AC, that the pressures were ok. Wow, was I wrong! Another demerit for my dealer's service.

I checked this morning and they were totally wonky. Fronts were high, rears were low and left right were off by 4-5psi! I set them to the factory settings (33/41) and what a difference!

The car now tracks much better on the freeway and rides noticeably more comfortably. Driving on the freeway today in a significant amount of wind the car held the road much better. The steering is much more calm and less twitchy. I've typically run higher pressures for better handling in my other cars, but the factory settings really make the i3 drive much better.

Ditto! I got mine from the same dealer as "Boatguy". Assumed tire pressures were correct, as never got a message from the TPMS system saying there were not. But when I checked them manually a couple weeks ago, I found the rears were pretty much correct, but the fronts had been set to 43 PSI.
When I took the fronts down to the recommended 33PSI, lo and behold all the twitchiness I had been experiencing in the steering and the instability in high winds disappeared.

 

[jadnashuanh]

Once you have the tire pressures where they are supposed to be, you need to run the reset routine on them. The alert doesn't trigger for too high, only too low, but it uses the current value when you reset them as the reference. It does not actually know what it should be, the computer stores that value during the reset procedure, assuming you know what it should be. It's quick and easy.

 

[user 1096]

CAUTION: my onboard TPM is off by about 2.8# at each wheel. I double check my pressures with a BMW electronic gauge and a brass-head real gauge and set fronts for 35 or whatever and rears for 43.

When the car was delivered they were ALL at about 45 (shipping/chain-down) pressures and I thought for sure they were those horrid thump-flats. Nope, they just needed adjustment and what a relief.

I reported the faulty readings to the dealer and they said to check them after software update; I did and they are still wrong. But at least I KNOW they are correct though reported incorrectly.

 

[jadnashuanh]

WHen I put my OEM winter tire set on, 3 of the 4 read the tire pressures about the same as my gauge...one was a couple of pounds low. So, it appears, that isn't uncommon...annoying, but not uncommon. Use a good gauge, then, note what you have for future reference.

 

[noakey]

WHen I put my OEM winter tire set on, 3 of the 4 read the tire pressures about the same as my gauge...one was a couple of pounds low. So, it appears, that isn't uncommon...annoying, but not uncommon. Use a good gauge, then, note what you have for future reference.

Same here.. One of mine reads 2lbs low, but for me it's a reference... so long as it stats 2lbs low all is good.

 

[moezilla]

I get the " weird oscillating noise when cornering" but also when slowing down going straight

I had another i3 last week that did not have anything like that.

It almost sounds like a bad wheel bearing

It definitely sounds like something is wrong

Wondering if anyone can clarify what might be going on.
Taking it to any of the BMW dealers will not help, as they don't understand the car yet. I need to be able to talk directly to the engineering team at BMW

 

[alohart]

Some with 20" wheels/tires experience an odd "whoop-whoop" noise, but I've never read of 19" wheels/tires making this noise. If your i3 has 20" wheels and the other i3 had 19" wheels, your experience sounds common.

 

[moezilla]

Some with 20" wheels/tires experience an odd "whoop-whoop" noise, but I've never read of 19" wheels/tires making this noise. If your i3 has 20" wheels and the other i3 had 19" wheels, your experience sounds common.

thank you very much!
you are correct- I had 19" an no whoop whoop
and now 20 and whoop whoop

thinking of finding a way to go back to 19 as the 60 series tires has a much less harsh ride on the horrific roads in Marin County (just north of the Golden gate Bridge)

 

[ACDCBMW]

After driving my i3 for over 20k miles, i would suggest using the recommended tire pressure. Any higher or lower will change the wear pattern on your tire and cause uneven wear.

 

[jadnashuanh]

Only if you were regularly running the thing at full gross max weight might it help raising the tire pressure much of any.