LOVEMYBS

I'm a firm believer in inflating my tires with nitrogen instead of air. This morning I made the switch and WOW what a difference in ride quality. I inflated my OEM Pirelli's to 40 front and 35 rear (recommended 38/33 up to 155 mph). My ride home was a lot smoother and less jarring when compared to my ride in. I've noticed the difference with all my cars (SL55, wife's BMW X3 and former E55) but it was more evident in my CLKBS.

DFW01E55

I don't understand how that works.
Is nitrogen more compressible than air?

PSI should be psi whether measured in air or water ... right?

(Okay, so I'm a little weak at air and fluid dynamics!)

Edit: After a bit more thought, air and nitrogen are both gases, so psi should still yield the same "feeling" .... Am I missing something?

amdeutsch

http://www.engineeringtoolbox.com/ai...ion-d_212.html

Doubt it.

LZH

I doubt you are getting better ride quality with nitrogen....The only realy benefit is more consistent and lower pressures.

AMG Dictator

I hate to break it to you but your ride quality may have changed due to the change in pressure but not the Nitrogen.

You are wasting your money.

alexander stemer

To be generous of spirit, the OP could be correct if his "air-filled" tires had a great deal of moisture. Cold pressures could be the same with Air and Nitrogen, but heat could cause the water content in the Air tires to vaporize and increase pressure, and hence hurt ride.
Seems like the "end of trip" pressures would be measurably higher with Air, and it seems like it would take a heck of a lot of moisture to do this to the point you could easily feel it. AS

LOVEMYBS

I went in with 40/35 and came out the same. But the ride quality was better on the same roads.

LOVEMYBS

It was free but I would still make the change even if it wasn't.

LOVEMYBS

Agree, thanks. One of the benefits of nitrogen is constant pressure without expansion. Typical tire will expand up to seven psi when hot. Nitrogen remains the same. Tires inflated with air also lose 1.5 psi/month vs. 1.0 psi every three months with nitrogen. Refer to http://www.getnitrogen.org/why/index.php and http://www.getnitrogen.org/ to name just a few websites that will verify what I've posted.

Jim Brady

Last track day I filled the Pirelli Corsa's with N. There was some pressue build up about 3 psi over a 30 minute session compared to the usual 7-8 psi with air. Tire temps were also lower by about 8-10 degrees! So, I have to say based upon my experience there is some measurable difference. Whether this turns into lower lap times hasn't been confirmed.

MACHC5

Hey Jim,

How many sets of CORSA'a have you used already.?

Jim Brady

Is this a trick question? I'm on my third set of fronts as Willow eats the left ft. I could get another track day if I could flip the tires. I've got two sticker rears awaiting to be mounted shortly. I have 7200 miles. I replaced my pads twice, once with Porterfields (junk) and back to the stock pads which are holding up quite well.

For comparison, this is about the same tire consumption as a porsche turbo with MPSC except they go through the rears at a two to one rate.

I wish someone would mount a set of Hoosiers which would be worth at least 2 seconds a lap. Maybe 3 seconds with Nitrogen fill.

alexander stemer

Isn't "Air" 80% Nitrogen? Most of the rest is oxygen. The problem is moisture. AS

MACHC5

Maybe someone will...!

spr

Hey Jim Why not go with pagid yellows p/n pag-2938-rs19 (f) and Pag-8031-rs19 (r). I liked the compound on my 996 with stoptechs, my friend with a CGT said they were the same as his after the setup-. They require a bit more heat and squeel like a stuck pig if you don't abuse them regularly the mounting plates are d66 (f) and d47 (r). You can get whatever you want with that info as it's a standard-

Jim Brady

spr,
Nice find, thanks. The squeeling is dependant upon rotor composition and I've lived with Pagid Orange which are the most notorious. I'll give them a try next set.

spr

NP. I liked the yellows for this reason:

http://www.braketechnology.com/techinfo.html

Orange's are more like the 4-2-1 sport (blue) in many ways (friction). I had those before the yellows. I haven't used the orange's so cannot comment.

BTW the pricing is rediculous that's why I was saying go by backing plate from pagid or wherever and you'll prob get them for half the cost. I used to get them from racerswholesale sp? or something like that up north.

SickSpeedMonte

Yes, pressure is pressure.

But, (looking at the extreem example) if you were to fill a tire with 35 psi of water, it would be a much harsher ride than air because water is much closer to incompressible and the only compliance would be in the distortion of the tire to maintain a constant volume.

That being said, there isn't enough difference between nitrogen and air to feel a difference as a result of compressibility.

shuttie

Hi Jim,
I have the same problem with the front left, so I swapped the two fronts it didnt seem to have much effect, I have had two runs on the track like this ,the only problem is you cant drive in the wet. I am going to transfer them back the right way for the next run. I did it because I wore the left tyre when i was playing around with tyre pressures and wanted to get some benefit before replacing.I have replaced the front pads once with genuine parts and I think the original tyre choice by Benz will be my replacements.
The service guys advised me I would have to change the rotors at the next pad change also the rear pads.I will be interested to see the rotors as the handbrake is never used on my car on track days and rarely any other time.
Cheers

AMG Dictator

Handbrake?

The Black eats rotors if you are super aggressive with the brakes.

DFW01E55

The rotors seem pretty stout to me. I just changed front pads at 13k and the rotors were fine and my calipers are more gold than silver, so they've seen plenty of heat.

I can't find the hand brake though!

shuttie

Sorry have always called parking brakes hand brakes, If I had a
choice I would prefer the hand brake and not the footbrake system Benz use.The front pads were changed at the 3000km diff oil change, I would have got another run with them ,though better safe than sorry.

DFW01E55

I was talking about 13k miles, that's 21k km!
I agree about better safe than sorry.