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[SpartanGA]

A pet peeve of mine, curious on thoughts/opinions

I just picked up a 2011 335i m-sport. It has the 19" rims. very low profile Pirellis.

So the door label states tire pressures at 39 front, 46 rear. Quite high, but expected for this low profile.

What did the dealer have them at? 35 psi all around. and that was not a cold temp, but after driving.

I dont understand how they are not taught such a simple task especially given all the focus on BMW handling and the dangers of low tire pressure.

Thoughts?

[chromisdesigns]

I've had the opposite problem, the dealer refusing to set the pressure to what I want, stating they were "required" to set it to factory standards.

Just one more reason to go indy shop. As if there weren't dozens more as well.

[Alpineweiss e90]

At least your dealer didn't send you off with a broken TPMS valve stem after mounting winters.

The valve could easily have blown out and I could have had a blow out. The only reason why I knew was because the tire was losing air slowly.

Paul Miller FTL.

[CamelBiscuit]

Originally Posted by chromisdesigns

I've had the opposite problem, the dealer refusing to set the pressure to what I want, stating they were "required" to set it to factory standards.

Just one more reason to go indy shop. As if there weren't dozens more as well.

They are required to set it at factory standards. If they don't and you crash because of it not even Jesus can get them out of that law suit.

[BQTuning]

Do not go by the psi rating on the side of the door. Go by what the manufactures rating on those tire.

Just go to the manufactures website and find the recommended tire pressure. More than like lit about 10 psi less than whats on the door.

[BQTuning]

Originally Posted by HaveQuick

They are required to set it at factory standards. If they don't and you crash because of it not even Jesus can get them out of that law suit.

Vise versa with BMW. The reason I say this is when I got my car the tire pressure was 32 psi front and 35 psi rear.

Months later took the car in to replace my rear tires. Got the car back and noticed the handling of my car went to shit with a massive amount of oversteer and it was hell noisy.

I checked my tire pressure and it was 43 psi front and 46 psi rear based on what was written on the door. Bridgestone states on the tire do no inflated ABOVE 40 psi which contradicts BMW pressure settings . Their website confirms the same thing.

I lowered the pressure to Bridgstone rating 32 front and 35 rear. My car now handles like it originally did, no over steering , and road noise has dramatically decreased.

[Tom K.]

Originally Posted by BuraQ

Do not go by the psi rating on the side of the door. Go by what the manufactures rating on those tire.

Just go to the manufactures website and find the recommended tire pressure. More than like lit about 10 psi less than whats on the door.

I never heard of this one as recommended pressure varies for each car. The Bridgestone site states that:
"Vehicle manufacturers list recommended tire pressures for original vehicle tires in the owner's manual or on a placard on the end of the driver's side door or in the glove box."

http://www.bridgestonetire.com/SiteS...spx?q=pressure
http://www.tiresafety.com/maintenance.asp

And if you mean the pressure listed on the tire sidewall, that is the Maximum psi which should never be exceeded, and will likely result in a terrible ride and spooky handling.

Tom

[CamelBiscuit]

Originally Posted by BuraQ

Vise versa with BMW. The reason I say this is when I got my car the tire pressure was 32 psi front and 35 psi rear.

Months later took the car in to replace my rear tires. Got the car back and noticed the handling of my car went to shit with a massive amount of oversteer and it was hell noisy.

I checked my tire pressure and it was 43 psi front and 46 psi rear based on what was written on the door. Bridgestone states on the tire do no inflated ABOVE 40 psi which contradicts BMW pressure settings . Their website confirms the same thing.

I lowered the pressure to Bridgstone rating 32 front and 35 rear. My car now handles like it originally did, no over steering , and road noise has dramatically decreased.

Different size tires from stock?

[Tom K.]

Originally Posted by BuraQ

I checked my tire pressure and it was 43 psi front and 46 psi rear based on what was written on the door. Bridgestone states on the tire do no inflated ABOVE 40 psi which contradicts BMW pressure settings . Their website confirms the same thing.

.

According to TireRack, the maximum inflation pressure for the OEM Potenza on an E92 335is is 51 psi, not 40.

http://www.tirerack.com/tires/tires....utoModel=335is Coupe&autoModClar=

Tom

[SpartanGA]

Originally Posted by BuraQ

Do not go by the psi rating on the side of the door. Go by what the manufactures rating on those tire.

Just go to the manufactures website and find the recommended tire pressure. More than like lit about 10 psi less than whats on the door.

oh crap...here this is the problem.

First, (in another post) the maximum rating is NOT the recommended PSI.

Also, I worked at a major automaker OEM in developing the handling characteristics of a car. The automaker OEM sets that PSI based on testing with that tire/chassis/vehicle combo. Especially with an OEM tire, of which mine is, the OEM sets that PSI.

The max psi rating on the tire means NOTHING.

[Wires]

Originally Posted by smithsonga

oh crap...here this is the problem.

First, (in another post) the maximum rating is NOT the recommended PSI.

Also, I worked at a major automaker OEM in developing the handling characteristics of a car. The automaker OEM sets that PSI based on testing with that tire/chassis/vehicle combo. Especially with an OEM tire, of which mine is, the OEM sets that PSI.

The max psi rating on the tire means NOTHING.

+1. The driver door sticker should match the manual for the correct pressures. Just match the size/parameters for the installed tires to the sticker/book.

The max pressure is just a number the tire manufacturer specs as the maximum without failure. Probably never gets used in a car, occasionally useful say in a truck where you've loaded the crap out of it, and need to inflate the tires a bit more to deal with the loading issue.

[BQTuning]

Originally Posted by Tom K.

I never heard of this one as recommended pressure varies for each car. The Bridgestone site states that:
"Vehicle manufacturers list recommended tire pressures for original vehicle tires in the owner's manual or on a placard on the end of the driver's side door or in the glove box."

http://www.bridgestonetire.com/SiteS...spx?q=pressure
http://www.tiresafety.com/maintenance.asp


And if you mean the pressure listed on the tire sidewall, that is the Maximum psi which should never be exceeded, and will likely result in a terrible ride and spooky handling.

Tom

On the end of the driver side it has:

Cold Weather:

39 Front, 45 Rear

Up to 100 mph:

42 front, 49 rear

On the Bridgestone site for the my tires it states recommended tire pressure:

32 PSI front
35 PSI Rear

http://www.bridgestonetire.com/Vehic...0Inch%20Option)


Writen on the rear and front walls of the tires it states cleary do no exceed more than 40 PSI

Originally Posted by HaveQuick

Different size tires from stock?

The 335is comes standard with 18" michelin tires. The 19" M-sport is optional, which I have, comes with Bridgestone Potenza

Originally Posted by Tom K.

According to TireRack, the maximum inflation pressure for the OEM Potenza on an E92 335is is 51 psi, not 40.

http://www.tirerack.com/tires/tires....utoModel=335is Coupe&autoModClar=

Tom

Whats written on side wall says do not exceed more than 40 PSI

The final results is the recommended tires pressure by Birdgeston performs better, safer, and quieter. If I followed the BMW's dyslexia PSI rating it will be the death of me.

[Tom K.]

[quote=BuraQ;11326461]
On the Bridgestone site for the my tires it states recommended tire pressure: 32 PSI front/35 PSI Rear

http://www.bridgestonetire.com/Vehic...0Inch%20Option)
[quote]


That site URL states 32F, "FF" rear pressure. Which leads me to believe the 32 may also be a typo. And the disclaimer states that this is not Bridgestone's recommendation but that of a "third party source". It also suggests "consulting the vehicle owner's manual".


[quote=BuraQ;11326461]
Writen on the rear and front walls of the tires it states cleary do no exceed more than 40 PSI

Whats written on side wall says do not exceed more than 40 PSI
[quote]


Not sure what the "rear and front walls" are, but the Potenza RE050A RFT which comes on your car has always had a max inflation of 51 psi.

And Bridgestone's web site does not list the maximum pressure among then tire specs:
http://www.bridgestonetire.com/produ...50A_RFT/MOE/II

As you apparently have a very unusual tire, perhaps you could post a photo of the sidewall where it states the maximum pressure is only 40psi!

Tom

[BQTuning]

^^^^ Not a typo , even Michelin website states the same thing when referencing the manufactures pressure ratings

http://www.michelinman.com/team-mich...Handling/tires

They said its noted on Vehicles Placard...

I checked the manual and it has the same tire pressure rating as posted above that is on the driver's side.

I will take a pic of the writing on the tire and post it tomorrow

BTW...on the Brdgestone site there is link for Front & Rear to see their tire pressure per tire size that auto changes when you click on it

[fun2drive]

It really doesn't matter what any manufacturer states or BMW states if you want your tires to be set for the best wear it takes some experimentation. I do think BMW does compromise and comes pretty close.
The best way to do this is to chalk your tires someplace in a parking lot that is not full so you can drive the car straight for a good distance. Chalking means perpendicular to the direction of travel. Drive the car straight ahead. Stop get out and see the wear marks. In the middle pressure too high, outer edges pressure too low. You get the drift.
Adjust until you have even wear.
This is how it is done in racing to know the baseline. From there you can adjust the pressure for either under or over steer if that is desired...

[kacki]

Not a frequent poster on this site but I get Buraq's point. I too have the E93 335IS and the car's placard says 39/46 (F/R), which is what I've been using since Day One. But the Bridgestone website clearly says 32/35. This is a lot of difference.

I will try the chalking method but if anyone else can weigh in on this apparent discrepancy it would be useful for quite a few people.

[Kolyan2k]

tire manufacture recommendations is minimum pressure, BMW recommended pressure is what's recommended for the car, sidewall pressure is maximum COLD pressure for the tire

[Fraggy]

I don't know how anyone could drive with 46 PSI in the rear and have the fillings stay in their mouth lol

[John 070]

Originally Posted by smithsonga

oh crap...here this is the problem.

First, (in another post) the maximum rating is NOT the recommended PSI.

Also, I worked at a major automaker OEM in developing the handling characteristics of a car. The automaker OEM sets that PSI based on testing with that tire/chassis/vehicle combo. Especially with an OEM tire, of which mine is, the OEM sets that PSI.

The max psi rating on the tire means NOTHING.

This is what I was always lead to believe, go by the mfg, not the sidewall. I've always done 35/32.

I think we live in a society that wants to super-size everything. If the mfg. says 35, that must mean 51.

[obert]

If the tires size is different then stock then the pressure will vary on what you put in them

[John 070]

Originally Posted by Fraggy

I don't know how anyone could drive with 46 PSI in the rear and have the fillings stay in their mouth lol

I was on a business trip in DC and took my Nissan. I though oh s***, that tire looks low (I know looks are deceiving but it looked low). So I found some free air after driving around 2 hours or so (not paying $1 for air). I filled it, said nah, better fill it some more to be safe. Got home and checked it with my gauge, 55 lbs.! LOL Lucky it didn't pop on the B-W Pky.....that's what happens when you eyeball instead of using a gauge

[John 070]

Actually, if you want to talk about pet peeves, how about TSBs telling techs to hand torque wheel nuts, yet, you know they used the impact wrench and cranked it up to 150 lbs. ft. or so? This isn't an SUV with a 6-132 rim!