Uncle_Bens

I just got my new rims and tires and checked the air pressures and I think they were a little high so I just wanted to see what everyone else is running? I am running 205/40/17 and the tires say a max of 44lbs of air. A couple were actually over 44lbs so I dropped the front down to 35 and the rear to 30 and I seems to have made a world of difference in ride and performance.

so what is everyone else running?

bB2NER

It depends on size and profile. The stockers like 32 psi. Bigger wheels (16's - 19's) need to be a bit higher to guard against pothole damage. Like 35 psi or so IMO.

Tomas

Toyota says 29 PSI in the owner's manual, service manuals, and the sticker on your "B" pillar.

That's what I run on mine (15s).

https://www.scionlife.com/forums/vie...422693#1422693

Tom

Uncle_Bens

From everyone I have talked to it seems like 32-35 is a pretty good range with 17's

bB2NER

That 29 psi is like for a cushy soft ride. 32psi will give better MPG and still ride good. If I ran 29 in my 17's I think a rim would crack on potholes. I'll stick with 32 -35 psi.

MattyRattyPoo

38psi for me. But then again im running 225/35/18 on a 9.5 inch wide wheel so I gotta keep the air pressure up with the super stretch.

Max

29-30 on stock tires.

tn_05_camo_xb

I am running 33psi in my 215/35/18s. That is what my tire guy said to run. I wouldn't run the max pressure because that is for maximum load capacity, and I don't think the xB is anywhere near the max load of any tire.

8BALL

I am running 35psi in my 215/35/18s. Since you are running a 40 profile I'd run 32-35psi. That should give you a decent ride and guard against pothole damage.

Prototype_xB

40lbs in my nankang NS-II's (215/35-18)

HeathenBrewing

32 psi in the 15" stockers, all 4 tires.

ProshopXB

Im running just abit high 38 lbs on 17's.

superjeer

30 psi on three and 10psi on right rear. freaking leaks :@!!!

mike51392

44psi all around rides a lil harsh but thats how i like it and the firmer the tire the less friction the more mpg's i check my tire pressure every 2 weeks

Chrno

Front: hankook 15's 195 55 15 36psi
Rear : Toyo proxie W tread 18's 215 35 18 44psi

works wonders on my box with Df210s'

slickyricky102

34

mattxb

Tell me if this is right. To much air preasure will cause excessive tread wear in the middle of your tire. To little preasure and the outsides of your tire will wear faster.
If that statement is true, how do you know what psi to run when your tire says max psi 44, and then everyone and their mother tells you to run something different?
I have maintained 35 psi in my 205/40/17's. When I changed out my last set of tires, the tread wear on the outsides of the tire was rediculous. I am just looking to prevent uneven tread wear no matter how it rides.

HeathenBrewing

Sounds like you answered your own question.

In my opinion, Scion offers up a pressure that is too low. Remember what happened with the Ford expeditions (or whatever model it was). Less pressure is more dangerous than higher pressure. I have already noticed an increase in milage from going up to 32psi from 29. Now im up to 34psi and lovin it!

When I had my wheels installed, they put the pressure @ 44 and the ride was too rough for my taste.

Tomas

Treadwear patterns are also the result of driving style and tire position on the vehicle.

Aggressive driving puts a lot more wear on the outside edge of the tires, especially the front tires.

Front tires, because of the steering inputs tend to 'roll-under' more than rears and wear more on the outside edges than the rears do, even with gentle driving, which is why tires are rotated.

These effects are exaggerated if the pressures are too low for one's driving style.

So, the more aggressive one's driving style, the more pressure required for even tire wear, which also improves cut-in and ability to handle rapid and excessive control inputs (but worsens ride).

The pressure indicated on the "B" pillar tag is for "normal" driving, not spirited. The pressure indicated on the sidewall is the maximum safe cold pressure for the tires, beyond which one can damage the carcass. Somewhere between the two is the best pressure for your particular driving style, offset, tire size, vehicle load, and road conditions.

Oh! Harder tires do handle better, BUT are also much easier to damage with road debris, potholes, and such. With softer tires it is much easier to 'break the bead' and lose air when driving very aggressively.

Running a rim width that is out of the design range of the tire size also makes a tire more prone to damage - too narrow and the tire can 'roll under', to wide and the bead does not seat properly. Rims wider than those the tire is designed for will also increase edge wear. (I see a lot of folks running rims waaaay too wide for their chosen tire size...)

An aggessive or spirited driver will fare better increasing tire pressures (within reason) over the recommended pressures from the vehicle manufacturer for "normal" driving.

It's really a lot more than just being black, round, full of air, and fitting in the wheelwell...

onemat

Yep, I went to 29 PSI and it runs just fine. The dealer had set them at 32. It is a little softer feeling in the corners, but I got used to it. I like to get a lot out of my tires.
Matt