59 replies to this topic

[FTodaro]

I just inherited a full nitrogen tank for filling tires. I have never used it before but understand that the advantages are that you start out your tires at a higher pressure because nitrogen does not expand as fast as air.

I would think that this would be an advantage because you could start out your session with more air pressure, which may get you up to speed faster.

Anyone use nitrogen, any pros or cons? Is it worth doing?

[Jim Drago]

Frank
Most compressed air has high moisture content and it varies. So it plays with the amount your race tires blow up when your tires are coming up to temperature. Nitrogen is obvious consistent and does not grow as much and is always constant.

[dstevens]

Some folks say they can dry compressed air enough so it doesn't vary but I've never tired it. Karting I always used nitrogen and found great consistency. To add to what Jim posted, the volume of moisture in compressed air not only makes inflation inconsistent but tire temps, depending on the how much water is in the air. The moisture is a byproduct of the heat generated compressing the air that then condenses in the system. Same reason you should drain your air compressor regularly.

IOW, if you are getting inconsistent readings across the contact patch with temps and inconsistent pressure readings and you know you are on a balanced and/or optimum set up, could be the compressed air. That said, I ran compressed air from my compressor and dryer/filter (Motorguard M60} the second season of stock car racing because I traded my big tank for MIG mix. I now have enough tanks for welding and Nitrogen so the SM will get nitrogen. I couldn't tell in the hobby stock but I was on old street tires from the used tire joint and there were other things wrong with the car. Kept having a problem with a loose nut behind the wheel, though I did finish 8th for the season in a 40 car class in a car that was less than optimal. I bet most SMers won't notice but the gang at the pointy end of the grid probably will. It is cheap to fill (compared to welding gasses). My last big 250 cuft bottle fill was 27 bucks, out the door. My last 100% argon was 80 bucks plus for a 150cuft and last 86/14 MIG mix150 cuft was just under 70 bucks. Nitrogen is pretty cheap.

Link to bottle size designations from where I get my gases.

http://www.airgas.co...d=7000000000234

[Glenn]

Royal PIA without much benifit. You have to COMPLETLY evacuate the air out of each tire before you put in the nitrogen. As was stated before its not the air expanding its the moisture in the air.

[Glenn]

Some folks say they can dry compressed air enough so it doesn't vary but I've never tired it.

I used SCUBA air for several seasons. less than .1% moisture. A 60cf alum tank lasted 2 week ends filling tires and running air tools.

[LarryKing]

Royal PIA without much benifit.

+1

[davew]

Nitrogen is great to travel with, just a big hi-pressure are tank. No compressor or elctricity needed.

Is it better for use in a tire. Maybe.

Air is 72% nitrogen, so what we are worried about is the other 28%. On a cold day in December, humidity is around 5%. Hot summer day in August it may be 90%. It is that variation in water content that gives the inconsistent readings. Even on a dry day, if the compressor is full of water, you end up with humid air.

Just like doing allignments, there are many methods, but consistency is the important part. If you can keep your humidity consistent from your compressor, you will always have the same amount of tire pressure increase for a given set of circumstances. Nitrogen is always the same humidity. Therefore consistant.

To properly use nitrogen, you must mount the tires with air (no sense wasting expensive nitrogen beading tires. Then purge all the air out, refill with nitrogen, purge that out. Then fill for use. As Glenn said PITA.

I carry nitrogen all the time in my semi. I do not normally fill tires with nitrogen.

Dave

[philstireservice]

At best you end up with 93% or so nitrogen in your tire. Also tire pressure will continue to grow/expand in a tire with nitrogen just like a tire with so called standard air. What happens though, as the tire reaches the higher operating temperatures when filled with nitrogen, the expansion slows and the tire pressure remains more constant. Like Dave said, the less moisture content is why nitrogen doesn't "grow" as rapidly when the higher tire temps/pressures are reached.

[FTodaro]

Any one want to buy a cheap tank of Nitrogen, Just kidding, I may give it a try, i have nothing to lose. Maybe this will be the equalizer between the weight and plate debate for my 99.

[Rob Gibson]

Definitely worth doing if you value consistency and predictability in tire pressures. If your goal is only to be within 2 psi of your target, don't bother. With air we could only predict within maybe 1-1.5 psi of the target. Our first weekend with nitrogen and we were predicting within .5 psi. And now after 5 or 6 races, we're disappointed if we're not within .25 psi. Of course this goes along with a stringent recording of tire pressure/temp data.

But don't NOT do it just because people say it's a PITA. A lot of things are a PITA in racing, but you do all these little things and they add up. Let's talk about a very basic PITA item in racing: changing cross weight. You have to jack up one side of the car, turn both spring perches (the correct way and the same amount), then jack up the other side of the car, turn those spring perches, then go to both the front sway bar, loosen lock nuts, turn the coupling nut (as long as you have a left and right hand threaded coupling nut), remove the bind in the sway bar link, tighten the lock nuts, then do the same for the rear sway bar. Oh yeah, and this is all after you've set up the scale stands to be perfectly level.

That to me is a PITA. And how much time are you gaining based on that? But if you want the car to be better you do it. Same goes for Nitrogen, only it's a lot simpler, it can be done at home/shop at your leisure, and then you're done.

[FTodaro]

Thanks Rob, I was thinking that I can over fill the tires a little at home before going to the track. I can fill my spare air tank with Nitrogen to bring to the track. I assume I should not have to make dramatic changes at the track and will have the air tank to do it if I need to. So its certainly doable.

With my 205/50/15 tires with regular air I would see on average (this is average) about 6 to 8 lb increase from cold to hot pressures, what range of change have you seen using the nitrogen?

[Glenn]

Definitely worth doing if you value consistency and predictability in tire pressures. If your goal is only to be within 2 psi of your target, don't bother. With air we could only predict within maybe 1-1.5 psi of the target. Our first weekend with nitrogen and we were predicting within .5 psi. And now after 5 or 6 races, we're disappointed if we're not within .25 psi. Of course this goes along with a stringent recording of tire pressure/temp data.

But don't NOT do it just because people say it's a PITA. A lot of things are a PITA in racing, but you do all these little things and they add up. Let's talk about a very basic PITA item in racing: changing cross weight. You have to jack up one side of the car, turn both spring perches (the correct way and the same amount), then jack up the other side of the car, turn those spring perches, then go to both the front sway bar, loosen lock nuts, turn the coupling nut (as long as you have a left and right hand threaded coupling nut), remove the bind in the sway bar link, tighten the lock nuts, then do the same for the rear sway bar. Oh yeah, and this is all after you've set up the scale stands to be perfectly level.

That to me is a PITA. And how much time are you gaining based on that? But if you want the car to be better you do it. Same goes for Nitrogen, only it's a lot simpler, it can be done at home/shop at your leisure, and then you're done.

Are you trying to tell me you can tell the difference in tire pressures of .25#? Driver ability/skill/consistancy affects changes far more unpredictibility than using AIR. I set 20 cars in the mourning to the same pressure and after the first session I sample EVERY tire. What do ya thing that spread is?

[davew]

What do ya thing that spread is?

8 psi

[Bench Racer]

What do ya thing that spread is?

At first I thought the "thing" was a DC thing, but Now I'll guess it's also a Beloit thing.

I wish my driver had the ability to feel .25 psi difference.

[38bfast]

I don't think anyone should use nitrogen in their tires. It is so much easier just to used compressed air. I will still use it and enjoy the competitive advantage all to my self.

[Jim Drago]

A lot of things are a PITA in racing, but you do all these little things and they add up. Let's talk about a very basic PITA item in racing: changing cross weight.

+1

[dstevens]

Royal PIA without much benifit. You have to COMPLETLY evacuate the air out of each tire before you put in the nitrogen. As was stated before its not the air expanding its the moisture in the air.

You have to mount them with nitrogen and make sure what you clean your wheels or tires with doesn't take away any of the benefit. That's where using a purge valve is handy though not allowed in SM. As said before, it's all those little pain in the ass things that add up to win races and championships. Most of us ain't gonna notice.

[FTodaro]

You have to mount them with nitrogen and make sure what you clean your wheels or tires with doesn't take away any of the benefit. That's where using a purge valve is handy though not allowed in SM. As said before, it's all those little pain in the ass things that add up to win races and championships. Most of us ain't gonna notice.

Since I have not done this yet, my plan on the purge was, I have the TR motorsports rims from Tire Rack, It has two air valves in it i was going to connect the inlet to one and open the other side and hopefully displace the air with Nitrogen. Does that sound plausible?

[Bench Racer]

Since I have not done this yet, my plan on the purge was, I have the TR motorsports rims from Tire Rack, It has two air valves in it i was going to connect the inlet to one and open the other side and hopefully displace the air with Nitrogen. Does that sound plausible?

Frank, a more common option is a little metal T shaped dealy bob that you screw onto the normal valve stem after you take the valve core out. The T shaped dealy bob has valve core end, normal air in end & air exit end. Using normal compressor air a vacum is created to suck air out of tire. More commonly called blocking the tire. The tire sides are actually sucked into the rim. Remove the T shaped dealy bob, insert valve core, fill with nitrogen. I guess the dealy bob would be called a blocking tool.

[philstireservice]

Frank, a more common option is a little metal T shaped dealy bob that you screw onto the normal valve stem after you take the valve core out. The T shaped dealy bob has valve core end, normal air in end & air exit end. Using normal compressor air a vacum is created to suck air out of tire. More commonly called blocking the tire. The tire sides are actually sucked into the rim. Remove the T shaped dealy bob, insert valve core, fill with nitrogen. I guess the dealy bob would be called a blocking tool.

You can get said "dealy bob" from Myers Tire Supply.