mrgold35

Normal air is already about 78% nitrogen and 21% oxygen. I think the nitrogen service place can only give you 85%-90% pure nitrogen overall because there is always some left over air (oxygen) in the tires.

I’m also uncertain about the molecular size of nitrogen compared to oxygen. Nitrogen comes before oxygen on the periodic table and this makes it a smaller atom (7 protons/electrons for nitrogen compared to 8 protons/electrons for oxygen). Most Nitrogen and Oxygen found in nature are linked together to form N2 or O2 molecules. The nitrogen molecules will still have a small atom weight/mass/volume compared to an equal amount of molecules of oxygen. Maybe the tire air loss is coming from the 78% by volume nitrogen molecules because they are smaller compared to 21% by volume oxygen molecules? Adding more nitrogen might speed up air loss in your tires.

I think it is one of those cost vs benefit arguments and I’ve haven’t seen any real benefits to offset the costs.

DuckDodgers

No, just keep it where you are happy with performance (squealling vs. harsher ride, etc...).

The real limit on your tire is found on the sidewall...there will be a maximum inflation pressure on your tires (my stock tires show a max of 44 psi) molded into the sidewall. Look for the max weight in bigger letters, and the max pressure is right under it in smaller letters, usually in a lozenge shaped box.

If you put the tires at 35 all the time in VA, you're fine most of the year. Just check your tires at least once a month...and if you had a cold snap followed by a heat wave, check your tires and see if the press went up too much and let a little out if necessary.

Can I ask why 35 psi (I know all around to keep it simple...but put a sticker on your tire gauge maybe)? I like the stock values for stock tires because the car was set-up for them...of course, in the current litagatory environment, that generally means understeer (or push)...which is then increased by over stock pressure on the rear tires to get them to match the front pressure. Basically, you are potentially increasing your understeer with balanced pressures...

1Louder

Hello! Tire pressure will rise and fall 1 psi per 10 degrees (as a general rule). That's a big jump for 20 degrees. Now is that bad? Depends. I've run tires at the max sidewall pressure before for years. The ride will get rough, but that's about it. Going past the sidewall max is generally not a good idea. So, what you want to do is just stay on top of the pressure if you have large temperature swings like that. I run all four of mine at 35.

STL

Here is what I use:
http://store.summitracing.com/partde...5&autoview=sku
It's a nice gauge at a reasonable price.

TSeXy_Grl

thanks all for the input. why 35 psi? Well that's what my ex-boyfriend told me once and i've stuck to that. also, my bother and dad have always kept their car at 35 psi. so i guess i've grown on 35 psi. and plus va weather does fluctuate at times so being at 35 psi won't under inflate the tires when it's cole and won't over inflate the tires when it gets to hot.

right? make sense?

TSeXy_Grl

the reason for the huge jump is that i checked the tire pressure after driving it (returning from lunch). i know you shouldn't check it after driving on it but i just wanted to check.

so from checking at that point, it went from 35 psi to 39 psi.

the ride is fine. all the roads i drive in are pretty smooth.

Mokos23

i forgot to mention you know that air expands when heated right? that's why it went from 35 to 39 because as you drive your car the air expands in the tire making it go from 35 to 39 psi.

enzojr

Piggying back on what DuckDodgers said earlier, as long as the tire pressure doesn't exceed the maximum pressure as imprinted on the tire sidewall after you've been driving the car around on a hot day, you should be fine. Not sure what happens if it's over but I wouldn't want to risk a tire blowout.

DuckDodgers

Errrrrrrrrr........no (duck)

Actually, I like your reasoning (Keep It Simple Stupid or K.I.S.S. keeps a lot of people out of trouble)) except for the choice of 35 psi. You really need to tailor your chosen level of inflation to both the vehicle and tires. For instance, some tires are only safely inflated to about 35-40 psi (generally cheap tires not found on sportly vehicle).

What I would do is look at the recommened manufacturer psi and the tire's rated max pressure. Then you factor in load (if you carry a full vehicle, you need the tires more fully inflated! Tires load rating is based upon a maximum inflation pressure test), driving conditions (sand transit means lowering pressures), etc...(go to perhaps http://auto.howstuffworks.com/tire.htm or http://blogs.consumerreports.org/cars/tires/index.html to learn a little more about the numbers on tires...)

For the TSX, if I was going to go balanced, I'd go 32 psi all around.

OK, now for bonus points, who knows, without looking, what the maximum rated load (passengers and cargo) of a TSX?

385kg or 850 lbs!

If you want to have real fun, look at some other vehicles carrying capacity and be ready to be shocked...we routinely overload our vehciles!

ATsxMan8305

When I first bought my '07 TSX it had 37psi in all four tires, yet in the manual it states 32F/30R. Any ideas why they gave it to me with 37psi of pressure? Did anybody else experience the same thing? The ride actually feels okay (maybe a TAD stiff). I'm thinking 36F/34R in the future...

DuckDodgers

Cause the stealership prep department hired a moron who can't read a gauge and Acura's instructions?

The reality is that the people that check tire pressures in the stealerships are often very low wage and poorly trained. I've had tires inflated to sidewall max pressure because "that's what the tire says". The Service Manager almost had a heart attack when the poor high school age car washer/tire pressure checker said that to him in front of me...

ATsxMan8305

Maybe I should be happy I had 37psi instead of the max! You make a good point, though. I personally think 36F/34R is a good compromise, without sacrificing fuel economy :wink: