Nitrogen

[zukitek]

My sentiments exactly Brad.Dont throw away perfectly good tire money on something you are going to PSSSSS away anyway.If you have a street only car...with a tire pressure monitoring system ,nitrogen is the way to go .Nitrogen tire filling was brought to the public for this purpose .3 days last week we had a differance of 30+degrees bwtween morning and afternoon.This is enough to trip tire pressure lights if the pressures are on or close to the low or high threshold.

Thank you Ford and Firestone for the Explorer.....now we are federally mandated to have tire pressure monitoring systems.

RR

[claym]

I am making things too difficult. On my wife's car with TPMS, if the light comes on (after it turns cold), I check the pressures with an air gauge. If one or more is low, I put air in them. When the light goes out, I drive the car. Costs about 5 min of time every few months in the winter. So if I go spend $100, then I can avoid spending that 5 min (unless the light comes on, and then I can spend about an hours worth of gas and time, as well as cost of nitrogen) every few months in the winter?

Or if there is an actual gas leak (not air leak), I can find nitrogen at the tire repair shop for $s (or take it home and plug it for $5 and 10min of time).

I need to rethink this......

[DAB21]

I prefer hydrogen myself- reduces unsprung weight and improves handling

[Demon_ni2]

lol, my 2 cents - (little off topic)
nitrogen, is also ideal for a daily driven car, for people thats dont know, or arent smart enough to check there tire pressure.. nitrogen molecule is larger (but lighter)and can not fit through the small pours in tires like oxygen can..(pressure wont go up much with street us, and you wont lose tire pressure over time)
(testinmate, my dads viper has been sitting for 2 years, driven maybe 10 miles amonth, and i hasnt touched, the tires are still at 30psi. i just checked them) if they were just oxygen they would have dropped atleas 12-20 psi already (about 1 psi a month)

but im to lazy to use nitrogen, gas station air is good enough for me, its 100x easier to use when you change your air pressure alot like me.

[revvhappy]

You have a push drop a pound in the front. Still pushing add two to the rear.

My dream is to someday be a good enough driver to tell the difference between 1psi changes. I can't even imagine the driving consistency it would take to remove all of the other variables. I have much to learn.

[TouringBubble]

Peter, I bet you can feel the difference, you just don't think about it. I mainly feel the difference (and adjust) in the rear and just watch rollover in the front.

[Welacey]

I prefer hydrogen myself- reduces unsprung weight and improves handling

I like helium even better. We call it the Mazeppelin Miata.

[Jedi1]

Peter, it's honestly all about seat time. I would be willing to bet that if I changed the pressures on your car from run to run you would be able to feel the difference, even if I didn't tell you what I changed. Have you tried to play around with pressures at all or are you setting them and forgetting them? Just curious.

[revvhappy]

I've been on so many different tires lately that I'm still learning about pressures. After 100 runs on my Azenis, I finally figured out the correct numbers. Then they were dead and I got some used Kumho and Hoosier r-comps and started experimenting again. Now I have the new Hankooks, and I'm zeroing in on the correct balance. Each type and brand of tire has been so different in compound, carcass design and stiffness, and optimal temp range that it gets confusing. Add to that my relative lack of seat time, and I just find something close and keep the tires there each day. I figure that the 'pushes' and lack of rotation are more due to my driving than the tire pressures - I never get through a section the same way twice.

I'll be looking for every opportunity to get more seat time next year

[Jedi1]

After awhile you get to know what tire has a decent sidewall and how the tire reacts to temperature and it all just sort of falls into place to be honest. Like I said, seat time and it will sort. Always remember, when in doubt ASK! Everyone has their own opinion when it comes to just about everything in racing, but more often than not if you find someone that has been doing this for awhile they will at least get you soemwhere near the zone you need to be in with regard to pressure and you can dial from there. Shoe polish can be your best friend when it comes to figuring out where you need to be as well. If you have the sidewalls marked and it's rubbing off the sidewall then it's pretty obvious you need more air. lol. After that get a pyrometer. Seeing 20 degree differences between the inner/outer and middle of the tire can tell you a whole lot about where you need to go.

[EWaugh]

t get a pyrometer. Seeing 20 degree differences between the inner/outer and middle of the tire can tell you a whole lot about where you need to go.

I think you're only the second person to mention measuring tire temps!

[Jedi1]

You want to know where you are with the correct pressure for all conditions, this is part of the tools you can use to get it right. I can't believe more folks don't use this? $59 bucks at radio shack gets you a little hand held battery powered unit that was 2ish degrees off from one that a friend paid several hundred for. This will at least let you know if you are over or underinflated. Combine that with the shoe polish on the sidewalls and a notebook and pretty soon you will know exactly where you need to be with pressures for all occasions.

[revvhappy]

Thanks for the information, Sean. My first problem is that I go "cheap" when I buy tires, rather than getting the same brand/size. I liked the used Hoosiers, but can't justify paying $900 for a set versus the $400 I paid for the new Hankooks. I understand and use the 'indirect sidewall' method of pressure in the front tires (how far down the sidewall the tire scuffs). I go as low as I think I need to in the rear to get the back rotating. I'll bet that I'm within 2-3 psi of 'pretty darn close', but if 1psi make a difference, I'd better rethink that strategy.

I'm interested to know more about the pyrometer readings. Given that we get to run Zero camber, and we really stress the outside edges of our tires compared to the inner tread, what's the validity of measuring temps across the tread.

[revvhappy]

Thanks for the information, Sean. My first problem is that I go "cheap" when I buy tires, rather than getting the same brand/size. I liked the used Hoosiers, but can't justify paying $900 for a set versus the $400 I paid for the new Hankooks. I understand and use the 'indirect sidewall' method of pressure in the front tires (how far down the sidewall the tire scuffs). I go as low as I think I need to in the rear to get the back rotating. I'll bet that I'm within 2-3 psi of 'pretty darn close', but if 1psi make a difference, I'd better rethink that strategy.

I'm interested to know more about the pyrometer readings. Given that we get to run Zero camber, and we really stress the outside edges of our tires compared to the inner tread, what's the validity of measuring temps across the tread.

[zukitek]

And how do you go about replacing the air with nitrogen - assuming only one valve stem? Fill, empty, fill, empty...... how many times do you gotta do that? Yea once for 78% but what if you want close to 100%. Do they check the amount of Nitrogen afterwards?

If I were doing it I would drill another hole in the wheel for another valve stem,assuming most stock wheels dont possess them.The only thing I cant answer is when and how do you know when it is 100% nitrogen.Wouldnt one need a gas identifier?I dont know...I have never filled a tire with Nitrogen ,I have only heard about the concept and its benefits of more consistent pressures and less pressure gain /loss.I would never be caught giving anybody 100 bucks for it .