MP3-Owner

Everyone who owns an MP3 might want to check your tire pressures. I checked mine today and they were way off. The Tire says 50(max) and mine were at 32(front) and 30(rear). This will cause bad gas mileage because of the friction. I adjusted mine to 42(front) and 40(rear). Just thought you guys might want to check. This can be for anyone really, read the side of the tire for max psi.

douggie

So what is the recommened tire pressures for a P5? I checked mine this monring and it's only 25psi!! (well it was a cold night last nite). I tried to look at the stickers at the side of the door frame, but it doesn't say anything.

JJB

I am pretty sure that the manual stated that it was 32psi front and back.

updated: I went out to check these to make sure the info I gave was correct. In my P5 there is no pressure listed on the door, but it is in the back of the manual where tire sizes are listed. For the 2.0L engine car with 195/50-16 tires the recommended pressure is 32psi front and back.

Exp_Ops

The recommended tire pressure is posted on inside of the driver's door. I'm pretty sure the spec says 32 psi front and 30 psi rear. Although I'm not at my car, I'm pretty sure that is correct. I assume the 50psi is max, so you should be safe anywhere within the spec, but Mazda's recommendation is 32/30.


Regards,
Exp_Ops
MP3#1479

douggie

Thanks. i found that sticker. now my tire pressures are back to 33/31 PSI. Just was weird that the pressure was so low for a new car like mine (i've had it for only 3 weeks). Maybe the dealer didn't check.

MP3-Owner

The 50psi is the max for my 17in. Rims...Your P5 rims are 16in. So your max tire pressures will be higher than my 17in tires(the smaller the tire the higher the psi). In the future you can look on the side of the tire as well to see the max psi.
Now that your pressures are back to normal you should notice a little bit of an increase in your mpg.

MP3-Owner

The 50 psi is max for my 17in. Rim...The P5 rims are 16in. So they will have a higher max psi. Look on the side of the tire for your max psi.

douggie

Nope, the P5 rims are 16inch and we have dunlop SP5000s. It says 51 PSI max on the sidewall.

Anyway, is higher pressure better to prevent bent wheels while running over potholes (unforseen ones, of course )?

MP3-Owner

Wow...16in.er's? That is cool. I didn't know they were 16's. Hmm...as for the higher pressure I would say yes but I would still keep it about 5psi below the max.

douggie

Yeah, our P5 rims are nice, but the MP3 rims are way more beautiful!

Anyway, I'll try to push up my tire pressures to 38-40 PSI and see how it handles.

douggie

Thanks for the clarification, PseudoRealityX.

Do you have the answer to my other question?

Is higher pressure better to prevent bent wheels while running over potholes (unforseen ones, of course )?

MP3-Owner

I didn't mean the smaller the tire the lower the pressure. You can look next to where I said that and in parentheses it says what I meant to say. Sorry for the confusion, I know that the smaller the tire the higher the psi. Take a ten speed bicycle for example: that little thing has like a 70psi(max) rating. And you are right about the tread wear as well. I am sorry for any mis-information

rodslinger

The 10 speed bike also has a much smaller ground contact patch. For a smaller tire, such as the 10 speed bike, you NEED a higher pressure to support it. Look at it this way...

A 10 speed bike has approximately 2 sq/in on surface area touching the road on each tire. Multiply that by the 70psi rating over two tires gives you about 280lbs of support. Enough with a little extra to support the bike and rider.

A typical car like ours may have about 25 in/sq surafce area touching the road. Inflated to 32psi on all 4 tires gives you about 3200lbs. support for car, people and all it's junk. The manufacturers adjust these pressure needs to compensate for the vehicle weight, tire size, weight distribution, handling and comfort needs. This is something else to consider when you go to a bigger or smaller size tire or placing a heavy stereo in the rear. The maximum PSI rating on the tire is just that. The maximum amount of air you should put in the tire regardless of what kind of car or wheel it is on. Just remember too that adding pressure to the tire will usually reduce your contact patch area but too little causes excessive heat buildup and eventual tire destruction. Think about all the Exploders with underinflated tires.... Hope this helps.

douggie

Thanks for all the information

one more question, should we maintain the same tire pressures for all different seasons? In the winter, tires tend to be less inflated because cold air is more dense and the tires don't heat up as much. Should I still inflate it back to 32 PSI as suggested?

What about in light snow conditions? is it better to have less inflated tires to have more contact or the other way is better?

JJB

One of the things folks also need to remember is that the recommended tire pressure is for a cold tire, not one that has been driven for a while. This means that you should check your pressure when you get out to your car, figure out how much you need to add, drive to where you are going to get air, remeasure, add the determined ammount to the new measurement and that is your tire pressure goal.

At least this is what I was tought to do... I'm sure someone will yell if there is a flaw in my logic.