Hunter machines

[ekimv65]

Originally Posted by hayaku

you can build your own rig to vacuum out the air and then refill with nitrogen.... its on my list of things to do, but since i have access to a pro race shop, it makes me lazy to build my own rigs... simple hoses and connectors, tire chuck, valves and a vacuum (harbor freight has one for under $15 for air powered vacuum or you can use a motorized one for about $150) - so you can build your own for about 50-200 bucks depending on how fancy you want to get...

but firstly... filling nitrogen isn't going to mean a thing unless they vacuum the tire down and then fill it.. otherwise you still have ALOT of mixed air in there. (my race tires do not see a 12+ psi increase from cold to hot - yoko slicks or hoohoos )

prior to running R888's and ambient, i ran constantly 8 to 12. Now I have 3 to 4.

[JCL]

Originally Posted by ekimv65

Because air has a mix of gases, as your tire warms up it expand-es increasing your tire pressure. When you use nitrogen, your tire wears better because N also displaces moisture much better than air, keeps better displacement, keeps your tire pressure more consistent.

I run it in all my cars, most important on my race car. Pre-N I would start out at 22PSI and after 3 to 5 hot laps my PSI would be around 34 to 35. Very few times would it be consistent from tire to tire.

All race organisations use N because they can tune the car with more consistent results.

It really works well!

But the predominant gas in air is nitrogen. That is why air expands at essentially the same rate as nitrogen. If you are seeing large pressure differences between cold and hot, it is because you have moisture in the air, and not just because it is air.

Race teams use nitrogen so they can set hot pressures, tuning after each few laps. Nitrogen fills will be more consistent between hot and cold, because nitrogen is dry. Dry air has the same effect. However, since the tire pressure spec for your X5 is a cold pressure, the hot pressure is pretty much irrelevant for the street.

I agree with FSETH that simply replacing the air in the tires with nitrogen will make no difference in handling, unless the tires had the wrong pressure before the change, or unless the tires were changed at the same time.

[jadatis]

found this topic searching for tire-pressure and registered to react.
Been busy with calculating it with use of the same equation that the European tyre- and car- manufacturers also use.
Made spreadsheets for it and in the beginning one originally made to see what the temperature does to the pressure.
pressurecalculationwithtemp.xls - Windows Live

So I want to make something clear about it.
Every gas gives the same pressure at the same temperature.
Even if you put helium in it . Or Carbondioxide ( also a place to store it)
Only there Nitrogenium needs more energy to get the same temperature.
The diferences in temperature with Oxigenium will be marginal

[X5 Meister]

Or just follow the BMW SIB that says it's bullshit.

[chefwong]

DO NOT GO TO EMILS

The owner is a HACK. I usually drive 1.5 hrs to my tuning guy for anything tire related - even a simple plug/patch. I found Emils on tire rack and since it was only a 7 minute drive, I went there. Before work proceeded, he swore up and down he would be able to handle my wheel with no issues. I walked into the bay after waiting for a while.....and there was 2 guys with tire levers MANHANDELING my wheel setup. I asked them to immediately stop whatever they were doing.

EMILS f'ed up my $2000 HRE wheel setup. They were so rough they even took out 3/4 to 1" off the bead of my tire. The tire was only had 300 miles on them. I was not fully compensated for either the repair of the wheel (in which they gouged both the lip and spokes) and paid me pennies to buy a replacement $300 tire.


It's not the machines that count guys. Well, to a degree it helps...
It's the technician that is working on it...

[zigzag]

Sorry to hear that. My experience was good with them. Who's your tuning guy.

[Engz]

I will be visiting your shop this week Vince. See you soon!

[Vsmvince]

Nice. Happy to help you

[ekimv65]

Originally Posted by X5 Meister

Or just follow the BMW SIB that says it's bullshit.

I don't know that I would call it bullshit, If it maintains better tire PSI, that helps life of the tire and, I would assume fuel mileage. I use this as my logic... If a tire is over or under inflated you change the geometry of the contact patch. If that is not making contact properly, you are crossing the patch creating more heat and wear. Think about a tire crossing the road with a bit of toe in, the tire is crossing at a slight angle, wearing the tire unevenly.

Just a thought.

[JCL]

BMW never called it BS, they are above such language. What they did say was that it wasn't recommended, but that neither is it prohibited.

I agree that the main point is to keep tires properly inflated; one of the challenges with nitrogen fills is that people then mistakenly assume they don't need to check their tire pressures any longer.

Copy of SIB attached (I had this one on my computer, I am not sure if there is a more recent one)