So do you need to have the installer be ready to fill them with nitrogen when they're mounted, and if so, where do you go to adjust pressure? Obviously releasing pressure is straight forward enough, but do you keep a bottle of N2 in your trunk? Seems like a hassle and a half, but I'm curious.

Thanks!

 

First...the installer just did this, I did not request it. I asked the same question...hummm...keeping a bottle of nitrous around...No they just said fine to top off fill with regular air...should not lose pressure like regular and I can drop by there if I need to.

 

Statman: Please listen extremely closely when Chris Cervelli posts. He is technically very solid and one hell of a good race car driver. He was 100% correct and you are 100% incorrect.

1. Nitrogen is not an inert gas. The "inert gases" are helium, neon, argon, krypton, etc. from the final column of the periodic table.

2. You are confused as to what an inert gas means. An inert gas is highly unreactive. In other words, you have to do very strange things to them to get them to react with another material (very high heat, etc.), and inert gases don't want to do this.

3. All gases expand and contract with temperature. All! The benefit of Nitrogen is almost solely due to the fact that it is dry (free of moisture). The moisture does quite a bit of expansion on heating so your tire pressures will change more with normal moist air then when filled with Nitrogen.

4. Nitrogen is actually smaller than oxygen (although they are close) so there is practically no difference in diffusion and therefore leakage rates between tires filled with Nitrogen and tires filled with air. Again, the benefit is no moisture and much less pressure change as the tires come up to temps.

5. Finally, the performance difference between Cups and PS2's is not as large as most people would expect. The max g difference is at most 0.1 g's and in practical terms, they are worth maybe 1 second in a 1:30 second course. The biggest differences are in their dynamic characteristics (turn in is sharper, etc.), and their heat handling capability (you can push them harder and longer before they go off). On the negative side, you have to get them hot before they grip and the older they get, the harder they are to get up to temps. When they are cold, they have much less grip than the PS2's. And before you try to challenge me, I have the data to back up my claims.

 

Bling king... well I guess I had that coming to me...so sorry to respond to Chris in such a demeaning way. Anyway it would help if you read what I posted...I state "a relatively inert gas" (quoted from my chemistry book).

The information I posted was directly from other sources:

http://en.wikipedia.org/wiki/Nitrogen

so tell them they are 100% incorrect. BTW I'm a statistician and I don't believe in 100% anything.

This is a direct quote:

"Contrary to some claims that nitrogen will diffuse more rapidly through rubber tires than air (and oxygen), nitrogen molecules are less likely to escape from the inside of a tire compared to the traditional air mixture used. Air consists mostly of nitrogen and oxygen. Nitrogen molecules are larger than oxygen molecules and therefore, all else being equal, larger molecules diffuse through porous substances slower than smaller molecules.", but I suppose you are a PhD and would refute this?

Finally...did you read my posts? I'm not advocating Nitrogen and actually don't care about it so why are you attacking me?

As far as performance...all I can post is my experience...perhaps you know more than me about that as well? I could give a sh*t about times around the track...I don't track. But I can tell you taking the twisties around my neck of the woods is a lot and I mean a lot better with the MPSCs...COLD! So show me the data on my car with me driving on my roads... don't think you have any of that. Data is just data without context!

 

Quote:

Originally Posted by wross996TT

Bling king... well I guess I had that coming to me...so sorry to respond to Chris in such a demeaning way. Anyway it would help if you read what I posted...I state "a relatively inert gas" (quoted from my chemistry book).

I sadly anticipated a response something like this statman. Demonstrate character and admit you are wrong. I will only spend a little more time unequivocally demonstrating your errors.

1. You say nitrogen is a totally inert gas. It is not and you are 100% wrong.

2. You say it does not expand or contract with temperature. Again, you are 100% wrong. All gases expand and contract with temperature.

Let me show you how someone of character would have responded.

Sorry blink king, I am not a scientist and shouldn’t have stated what I did. My bad and thanks for setting me straight.

 

Sorry Bling King I am totally wrong and should be banished from your kingdom forever...please never let me in there again.

You anticipated it because of you created it with your "less than friendly" post. I really don't know what I did to set you off. Are you insecure?

I did correct my "totally" in a later quote (I guess you couldn't read the whole post?) with relatively. All of the other info. is from other sources like the one I quoted and your sources are????

So what about the molecule size? Right again. Do you understand the concept of 100%? I think not. I mention the moisture content...must be wrong about that also...100%? huh?

So Dr. Bling King...what is your basic "character" let me guess...

 

Colorchange,

Can you post the G data comparison please, this sounds interesting.

Also, no need for the aggressiveness, do you guys have a history or something? This sounds ridiculous when seen from an outsider's POV..

Thanks

 

Jean, just having some fun.

Yes, I will dig up the data.

 

ColorChange,

Glad to hear that

Any luck with the data? I am interested by your findings. I have seen more than 1 second in lap times difference between Hoosier and MPSC, I would guess that street tires would be quite inferior when R compound get hot to optimum temps, and cannot (the street tires) pull more than 1.1 lateral Gs. Would you have any data showing that they can indeed?

Thanks

 

What size should I run on my factory wheels ??
please advise,
thanks,

Marty K.

 

Marty...235/40 & 315/30.

 

Jean:

Here is some typical data. You can see there is a slight max lat g limit benfit with the MPSC's, a little under 0.1 g typical. This is similar under threshold braking, a 0-0.1 long g advantage for the MPSC's. MPSC lat g's in dark blue, PS2's in cyan. Lap time 1:19.818 versus 1:20.672, and no, most of the difference in lap times is driver variability but when you look at enough data, you start to see how consistent the difference is in g's, and it's there, like I said, but pretty small ... like I said.



While it is difficult to create exacting test conditions, both tires were up to temp and had good thermal profiles (I have realtime IR tire temps), the conditions are fairly consistent and show that the difference between the PS2 and the MPSC is not very large, at least on my car. Other street tires blow, but the PS2's are outstanding street tires IMO.

I believe that the difference from PS2's to MPSC's is less than the difference from MPSC's to slicks, but this is just my opinion and I have no hard data on that.

 

Interesting data color change....it is the "scientific way" to measure and report on the difference in measurement metrics. These are the way we do things in the technical world of pressure gauges/calibrators/etc.

However even in my own small micro-cosm there are subjective factors or factors of climate etc. that can change outcomes or the suitability of responding to certain outcomes.....a couple of points:

1. Car & tire combo's that can corner above 1g are relatively rare. And although the TOTAL improvement at 0.1g SEEMS small as measured over the full scale the improvement at that higher level is actually substantial IMHO. Kind of like perhaps the difference between pole and the just next fastest car in a race.
2. No question that the street PS2 is a good tire (I run them now), but it is not as "good" on a track under the correct conditions. I ran MPSC's for about a year in combo track/street and my times were better on the MPSC's by varying amounts, but always better. Remember "good" is also subjective ultimately as the MPSC WILL aquaplane and the PS2 is RESISTANT to aquaplane. I have been able to get both to do this ;>).
3. As you say recreating the exact comparison data is difficult; different times on a: skid pad, long track, short track, hot day, cold day, etc. etc. Not to mention the driver.....there's not a doubt in my mind that there are plenty of guys who could get into a car with an inferior tire and still whip me although it pains to admit it!

Now my seat of the pants on the TRACK differences between the two tires is that the PS2's get really greasy feeling quickly and although they are consistent they lose grip over time while the MPSC's do not in a single session.

On the street the MPSC's will drag all kinds of small rocks, rodents, and detritus into the garage which must mean something is sticking to them.

So, there's more than just a single data set involved here!

 

Garey: We are in agreement I believe. The 0.1 g is the max I saw, to some even 0.05 g's would be a godsend. Yes, MPSC's are better ... I said so. Are they worlds better, not to most people, and I would argue, not to anyone on the street who is driving short of reckless.

 

Forgot to add (sorry); to ALL, never ever fill your tires from a gas station pump except in emergency. The do not keep dry air systems and you will load your tires with moisture! Most tire shops (I guess most anyway?) try to run a decent air system so that they do not load the compressed air with moisture.

I can tell you it is expensive and difficult to have "dry" compressed air! So, don't use the gas station air if possible.

P.S. Nitrogen is relatively chemically inert as it relates to other materials in contact with it, but it will in fact react to temperature changes depending upon its' relative purity.