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What tire pressure should I have?

13K views 18 replies 9 participants last post by  4evrwyntr 
#1 ·
recommended is 33 front and 36 rear

i have 17x8.5 w/ 235/40

spirited driving
 
#6 ·
mmclaren said:
my pirelli's on a 17/225/45 have a max psi of 51 i usually run 45 check on ur tyres and have it to suit ur driving

wow u have a 45 inch rim huh??? and your profile, is HUGE also.
 
#9 ·
Strange... you have a 92-95, right? OBDI? Those don't have the staggered wheels? I wonder if that makes a difference...

I could have sworn mine said 30-35 front 35-40 rear.
If you're going to drive "Spirited" you want to underinflate by around 4 psi. But that's ... well... like REALLY spirited (unless things have changed?!?). Also, you don't want to underinflate too much ... I dunno. I just wouldn't. It would make me feel uncomfortable on something with a large sidewall to underinflate so much (stress on the weak part of the tire) - but you're in something with real low profile, so I wouldn't worry too much. Unless you're riding Kumhos or something.

I'll shut up now.
 
#11 ·
If you look at your tire and where the tread begins there are little dots all the way around. After you take corners fast you get those wear marks, if those wear marks begin where the dots are you are fine, if not you have to adjust the air presure. I had my tires 235-40-17 at something like 30 psi on a track day, but they got warm on the track so Id say they were at around 32 psi (the presure goes up in heat and comes down in cold right, correct me if Im wrong) but my wear marks were just around the dots.

-Serge
 
#17 ·
Interesting. Ah. I see. Those are "maximum" psi's... Not "recommended." Understanding comes slowly sometimes.

Running the PZero Nero M&S's...

And I'm keeping them at 35 and 40, respectively.

You might want to check those numbers though, mm, I mean, even if the tire can withstand up to 51 psi, 45 + 6 from the heat + excessive load = blown tire...
 
#18 ·
do NOT go off max pressure when determining what to run on your car. go with manufacturer specs.. running high pressure can be a bad thing, worse then too low if its too too high. the bead can loose its sitting , vs low tire pressure can cut grooves into the sidewalls of the tire causing a blow out.

go off what is recommended by the manufacturer(car... bmw).. not max psi of the tire

i just had a fight about this with one of my service advisors the other day when a customer came back to bitch at me and my department for not setting his tires to the max psi because that is what the customer wanted. i wouldnt do it. i ordered my techs not to do it. the customer isnt always right when it comes to safety and running at max psi can upset the suspension of the vehicle(feels floaty, bouncy, etc)..

fine line between too low, too high, and just right. in this case, the door jam is your friend.

as one of my professors at college used to say "if you check nothing else, check three things on your car every time you fill your car with gas. 1: tire pressure. 2: tire pressure. 3: tire pressure"
 
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