slllygrl10

What would be the ideal PSI if im running 19's? There are so many potholes where I live so would it be better to have over 36? or stay with my F 32 and R 36??

irish8

32 psi. If you run higher you will kill your tires. IMO.

- Irish

EZZY

best to check with the tyre guy.
it has to be more than 32psi.
remember, you are running tyres with less profile

e

crossbow

Lower load rating = more psi. Contact the tire manufacturer and give them the wheel/tire setup, weight of car, and the stock wheel/tire sizing. Some 6 owners with 19's have to run as high as 40-45 psi to maintain the same load rating. (Which is why its good to shop around and get "reinforced" tires when upsizing)

flatso

sillygirl makes me moist when she posts questions like this

slllygrl10

I dont know if I should laugh or is that sarcasicm

flatso

please laugh

bean438

Wouldnt you just stick with the pressure stated on the door regardless of tire size?
Plus or minus sizeing leaves you with the same rolling diameter more or less so wouldn't the internal volume be the same?
I would stick with what the door says, and add the extra 4 psi or so for winter tires. Can't remember off hand what the exact pressure was for winter.

crossbow

Bean,

When you change the tire profiling, you move away from stock specs. Different psi's are then required to maintain the same load ratings. Door Jam PSI's are only for stock 225/45/18's...anything else "may" require different psi to maintain similar load ratings.

Here's a repost from toyo. (Everything below this line is from a toyo rep...the quotes are the questions)

__________________________________________________ ___________
PLEASE NOTE: THE FOLLOWING INFORMATION WAS OBTAINED FROM TOYO'S ELECTRONIC FITMENT GUIDE. IT MAY BE POSSIBLE TO RUN LOWER PRESSURES THAN STATED BELOW, HOWEVER, PLEASE EXERCISE CAUTION AS IT IS GENERALLY PREFERABLE TO RUN A LITTLE HIGHER PRESSURE THAN TO RUN UNDERINFLATED. IF YOU HAVE SPECIFIC QUESTIONS REGARDING YOUR VEHICLE, PLEASE PM ME. THANKS!

I haven't seen any threads on this, so if I'm repeating info already discussed, I apologize, but it's information worth repeating anyway. I want to bring to everyone's attention the importance of correct air pressure, especially in plus applications (meaning if you have 18 or 19 inch wheels).

When you go to a larger rim diameter, you are making the air chamber smaller, thus requiring additional air in the tire to carry the same load. For example, if your Mazda 6 came with the P215/50R17 tires, your minimum air pressure stated on the door placard is 32 psi. Same is true with the 16 inch tires.

Now, let's say you've upgraded to 235/40R18s. Hopefully, you're using a reinforced construction tire like the Toyo Proxes 4 (load index 95). You'll now need to have at least 33 psi to maintain the same load. Not bad, not a big difference.

But let's say 235s are too wide for you because your wheel offset makes that size rub, so you're using 225/40R18s. If you're using a reinforced size (load index 92), you'll now have to run 38 psi to maintain the same load! Many owners continue to run the original 32 psi and wonder why their tires wear out quickly. Running low air pressure creates heat which accelerates wear on the tire.

If you do not have tires with a load index of at least 91, your tires may not properly carry the load of your car!

Perhaps you've got 19s on your beloved 6. Hopefully, you've got at least a 235/35R19 91V (reinforced). You'll have to run 39 psi to maintain the same load as the oe tire at 32 psi!

Even if you've simply gone to a wider tire on the oe wheels, you need to make sure you've got the right air pressure. A 225/45R17 (94 load index) requires a minimum of 35 psi.

If you've gone to anything smaller than the above listed sizes (like 215/40R18 or 225/35R19) you should probably inflate your tires to the max air pressure listed on the sidewall. Chances are, though, you have a tire that won't carry the load of your vehicle properly.

Also, check your air pressure at least once a month as air will seep out at the rate of 1 psi per month. Your air pressure will also change with the ambient air temperature. For every 10 degrees of ambient air change, your tires will lose/gain 1 psi. If the last time you checked your air was in June and the average temperature was 80 degrees and now its October and now its 60 degrees, you've lost 6 psi of air (4 months + 20 degrees ambient air change)! Make sure you check the air when the tires are cold. Do yourself a favor and get a quality gauge. Thanks for looking!

When you go to a lower profile tire, you change the shape of the air chamber. In the case of going from 17 to 18, you are also making it smaller. Therefore, you generally have to squeeze a lot more air in there to carry the same load. I was quoting information from Toyo's Fitment Guide and I hate to contradict that information as it is researched quite thoroughly. In checking load and inflation tables, it would appear that you may be able to run lower air pressures than I originally stated. For example:

Size--Load Rating--Load @ 32 psi

P205/60R16--91--1224
P215/50R17--93--1146
235/40R18--95--1224

However, I would tend to err on the side of caution and run a little higher than oe. Uneven wear would likely appear only on grossly overinflated tires, but my original point was to remind everyone the importance of maintaining proper air pressure.

Yes to all of those. You don't want to overload the tires as the heat buildup could cause catostrophic tire failure (worst case, depending on how overloaded the tire is). Heat will also cause the tire to wear quickly. You want the tire to be able to meet or exceed the highest stated GAWR (Gross Axle Weight Rating). I have a 6i 5-door. The front axles have a GAWR of 2370 lbs. This is the most amount of weight that the springs/shocks can handle. You can find the max load rating on the sidewall of the tire. The oe Michelins can carry 1433 lbs. @ 41 psi. Typically, we reduce the load rating by 10% as a safety margin. That gives you 1289 per tire x 2 = 2578 lbs per axle, which exceeds the GAWR of 2370. I run the 225/45R17 94W Proxes 4s which max out at 1477 lbs @ 50 psi.

I don't know what the 6 cylinder models state on the door placard. Perhaps someone could pm me. As you can guess, there are tires that are smaller than the oe tire that meet or exceed the GAWR, but then we strongly recommend that you do not go smaller than 2% of the original overall diameter to avoid negative effects to ABS and engine management systems, speedo, odo, etc.
__________________________________________________ ____
Back to me...

Original posting...
http://forum.mazda6club.com/index.ph...pic=23786&st=0

You can pm him with exact questions, but he'll only answer if you own toyos . You can contact your individual tire manufacturers for specific ratings and recommendations on pressures for non stock tire sizing.

epitrochoid

and where is the cool java calculator so I don't have to think so hard? :D

bean438

SO, what would be the required pressure of a 225/50/17? That is my winter size. Stock pressure is 32 psi. I inflated to 36 psi because the manual staes to add an additional 4 psi for winter tires. I did not recalculate pressure for the smaller size.

petra

this information is great! Thanks for reposting
cheers