Kinda stupid question about tire pressure

jetblk328i · 12-01-2007, 11:36 AM

So i have seen my gas mileage drop right now so i went to test the tire pressure in both my cars. i tested my lexus RX 300 first and the tire pressure is a bit low, heres question #1:i have never had nitrogen in my tires before but in my Lexus that is the case, so does that mean i have to go find a place to pump in nitrogen? or will any old gas station with Air work?

also my 328i with brand new runflats replaced by the dealer looks low...they replaced it because i was complaining about the road noise and such. They replaced my EL42s with continental runflats. However it seems to me that they put less air in them, right now they are about 26 for each tire. heres question #2: BMW uses normal air right? Also do i have to reset the TPMS? Do i even have TPMS? my car is 07 328i but it was a pretty early build.

thanks!!!!

jetblk328i · 12-01-2007, 11:45 AM

by the way, im using the stupid little pen like thing to test, those arent teh most acurate are they?

DrGP · 12-01-2007, 03:45 PM

You do realize that air is about 80% nitrogen. Yes you can put air in the Lexus. The benefit of nitrogen is that it is not supposed to leak out as quickly as air. Some benefit but not a big one IMHO.

26psi in your 328 sounds low to me but check the specs on the door to see what BMW recommends. Since you have not seen a tire pressure warning light, I will assume that you are less than 8 psi from where the TPMS was set. I would reset the TPMS just to be sure it is set at a reasonable tire pressure.

jetblk328i · 12-02-2007, 12:27 AM

hmm thanks, im trying to find out if my car actually has TPMS any idea how? or do all e90/1/2/3 have it?

DrGP · 12-02-2007, 10:41 AM

Quote:

Originally Posted by jetblk328i

hmm thanks, im trying to find out if my car actually has TPMS any idea how? or do all e90/1/2/3 have it?

No, TPMS was added to the E90 in March 07 production. Look at your tire valve stem. If it is not metal there is no tpms system. BUT, if not, there is different type of tire pressure monitor that does not use the same sensors. I would suggest you consult your owners manual.

12-01-2007, 11:36 AM	#1
jetblk328i Colonel 324 Rep 2,458 Posts Drives: X3 M40i Join Date: Mar 2007 Location: Central PA iTrader: (1)	Kinda stupid question about tire pressure So i have seen my gas mileage drop right now so i went to test the tire pressure in both my cars. i tested my lexus RX 300 first and the tire pressure is a bit low, heres question #1:i have never had nitrogen in my tires before but in my Lexus that is the case, so does that mean i have to go find a place to pump in nitrogen? or will any old gas station with Air work? also my 328i with brand new runflats replaced by the dealer looks low...they replaced it because i was complaining about the road noise and such. They replaced my EL42s with continental runflats. However it seems to me that they put less air in them, right now they are about 26 for each tire. heres question #2: BMW uses normal air right? Also do i have to reset the TPMS? Do i even have TPMS? my car is 07 328i but it was a pretty early build. thanks!!!!
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12-01-2007, 03:45 PM	#3
DrGP Lieutenant Colonel 141 Rep 1,914 Posts Drives: Sapphire 335i coupe Join Date: Oct 2006 Location: SE, PA iTrader: (0)	You do realize that air is about 80% nitrogen. Yes you can put air in the Lexus. The benefit of nitrogen is that it is not supposed to leak out as quickly as air. Some benefit but not a big one IMHO. 26psi in your 328 sounds low to me but check the specs on the door to see what BMW recommends. Since you have not seen a tire pressure warning light, I will assume that you are less than 8 psi from where the TPMS was set. I would reset the TPMS just to be sure it is set at a reasonable tire pressure.
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12-02-2007, 12:27 AM	#4
jetblk328i Colonel 324 Rep 2,458 Posts Drives: X3 M40i Join Date: Mar 2007 Location: Central PA iTrader: (1)	hmm thanks, im trying to find out if my car actually has TPMS any idea how? or do all e90/1/2/3 have it?
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12-01-2007, 11:45 AM	#2
jetblk328i Colonel 324 Rep 2,458 Posts Drives: X3 M40i Join Date: Mar 2007 Location: Central PA iTrader: (1)	by the way, im using the stupid little pen like thing to test, those arent teh most acurate are they?
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