Interesting TIRE/Nitrogen/Air info from Daytona
02-05-2009, 08:29 AM
#1
Race Director
Thread Starter
Interesting TIRE/Nitrogen/Air info from Daytona
About 3 hrs into the 24hr race, they had a neat story about tire pressures. According to one of the DP teams, their tires were going from 22psi cold to 37psi hot. Hoosier was mounting with dry'd air, and I can only assume the teams were running nitrogen also.
A quick bit of (possibly bad) math means that IF the air/gas in the tires was truly dry, their tire temps were approaching 430 degrees F. Since this is impossible, it simply shows that even the dryest air still has enough moisture in it to wreak havok on tire pressures.
The story was about a particular car that ran best at 27psi, BUT in order to get that pressure, they had to start the pressure so low that it damaged the tires before they got up to temp.
Seems like they should consider speed bleeders!
A quick bit of (possibly bad) math means that IF the air/gas in the tires was truly dry, their tire temps were approaching 430 degrees F. Since this is impossible, it simply shows that even the dryest air still has enough moisture in it to wreak havok on tire pressures.
The story was about a particular car that ran best at 27psi, BUT in order to get that pressure, they had to start the pressure so low that it damaged the tires before they got up to temp.
Seems like they should consider speed bleeders!
Last edited by davidfarmer; 02-05-2009 at 08:34 AM.
02-05-2009, 08:42 AM
#2
Race Director
We went to the event and had a blast!! Garage passes are the way to go!!!
for what its worth It was our understanding that Pirelli was using "Dry Air" which had a +/- 1% moisture content and their tech's didnt feel there was a need to run nitrogen. However, I did notice when I watched the replay I recorded last weekend the commentator noted alot of teams were purging the "dry air" when they got their rims and tires back and filling with Nitrogen.
IIRC it was the #2 Gentleman Jack car that was setup for lower tire pressures (27) and I think they mentined to them Pirelli recommend they run no lower than 33 which caused some handling conditions.. Its amazing all the variables these teams have to deal with!!
The weather was great.. the sounds, smells and energy was WONDERFUL!!!
for what its worth It was our understanding that Pirelli was using "Dry Air" which had a +/- 1% moisture content and their tech's didnt feel there was a need to run nitrogen. However, I did notice when I watched the replay I recorded last weekend the commentator noted alot of teams were purging the "dry air" when they got their rims and tires back and filling with Nitrogen.
IIRC it was the #2 Gentleman Jack car that was setup for lower tire pressures (27) and I think they mentined to them Pirelli recommend they run no lower than 33 which caused some handling conditions.. Its amazing all the variables these teams have to deal with!!
The weather was great.. the sounds, smells and energy was WONDERFUL!!!
02-05-2009, 04:09 PM
#4
Race Director
Thread Starter
I've never seen a sanctioning body outlaw them, but I've not looks very carefully. I think many teams simply don't trust them.
Even with Nitrogen, you still get moisture in the tires, and that was really the point of my post. Even with the best of circumstances, you can't eliminate or even really reduce pressure growth very much.
I'd really like to get some of the Co2/Freon mixture Ferrari is running to see if it makes a difference in the real world. I don't know about you guys, but my tire shops WET-mount all of my tires, and I think if I insisted they dry-mount them (ie no soapy water), they'd run me off!
Even with Nitrogen, you still get moisture in the tires, and that was really the point of my post. Even with the best of circumstances, you can't eliminate or even really reduce pressure growth very much.
I'd really like to get some of the Co2/Freon mixture Ferrari is running to see if it makes a difference in the real world. I don't know about you guys, but my tire shops WET-mount all of my tires, and I think if I insisted they dry-mount them (ie no soapy water), they'd run me off!
02-05-2009, 05:59 PM
#6
Race Director
Thread Starter
I run Nitrogen in my Yukon tires.....as Onstar sends me a damn email (and warning light on my dash) if the tire pressures varry at all.....Of course that never happens towing my 10,000lb trailer!
Nitrogen is cheap, nearly free, so I run it often, I just want everyone to have REALISTIC expectations. I personally have a large tank of Nitrogen.....I can fill about 1000tires, or 1000 brake bleeds (pressure bleeds) for what a tire shop charges for one tire-fill!
Nitrogen is cheap, nearly free, so I run it often, I just want everyone to have REALISTIC expectations. I personally have a large tank of Nitrogen.....I can fill about 1000tires, or 1000 brake bleeds (pressure bleeds) for what a tire shop charges for one tire-fill!
02-05-2009, 06:26 PM
#7
Burning Brakes
Many new car dealerships are now 'offering' Lifetime Nitrogen Fill as a $69.00 add-on to their prices!! They've even devoted service bays to the stuff...
One salesmen at a local Chevy joint actually told me that he loves the FEEL of his car with nitrogen in the tires. They don't have a clue what nitrogen actually does for tires.
One salesmen at a local Chevy joint actually told me that he loves the FEEL of his car with nitrogen in the tires. They don't have a clue what nitrogen actually does for tires.
02-05-2009, 06:56 PM
#8
Le Mans Master
I use a mixture of 78% nitrogen, 21% oxygen and 1% of trace other gases.
02-05-2009, 07:21 PM
#11
Le Mans Master
02-05-2009, 07:44 PM
#12
Race Director
Thread Starter
Jodys' got bags and bags of hot air!
I use nitrogen for brake bleeding........occasionally using it in tires is a side benefit of keeping a large commercial tank of it.
I use nitrogen for brake bleeding........occasionally using it in tires is a side benefit of keeping a large commercial tank of it.
02-05-2009, 08:43 PM
#13
02-05-2009, 10:41 PM
#14
CF Senior Member
Member Since: Feb 2006
Location: Tucson Arizona
Posts: 23,313
Likes: 0
Received 19 Likes
on
18 Posts
Maybe that's why I've never use nitrogen. You're right, I asked my buddies at Discount Tire about not wet-mounting my tires once and they kinda made faces. My friend and racing mentor always brings his tank of nitrogen to the track. Knowing how technical this guy gets, I'm just surprised he's not using Co2/Freon. 
02-06-2009, 12:16 AM
#15
Drifting
There were multiple Rolex teams that I worked with that (back in the Hoosier days) would dump the "dry" air out as soon as they got back to the transporter, charge with nitrogen, dump the nitrogen, and charge a second time, trying to purge more of the remaining air out.
One thing to keep in mind with the dry nitrogen as opposed to air or dry air is that these cars, depending on setup and driver, can be sensitive to 1 psi changes. If you use straight air, the pressure gain will be very different at Miller than at Daytona, just from moisture content. With limited practice time before qualifying and the race, you can't be spending a ton of time playing with trying to figure out what the pressure gain is this weekend. They know if the ambient is X and the track temp is Y, they can expect Z pressure gain. Z +/- 2 psi is no good. Call nitrogen a waste if you want, but if the guy filling the tires forgets to purge the drier on the air line, you've gained nothing. I've seen the difference between charging with air on a dry day at Watkins Glen and the next morning when it was sopping wet and foggy, and it wasted a lot of track time chasing setup and tire pressures at the same time.
One thing to keep in mind with the dry nitrogen as opposed to air or dry air is that these cars, depending on setup and driver, can be sensitive to 1 psi changes. If you use straight air, the pressure gain will be very different at Miller than at Daytona, just from moisture content. With limited practice time before qualifying and the race, you can't be spending a ton of time playing with trying to figure out what the pressure gain is this weekend. They know if the ambient is X and the track temp is Y, they can expect Z pressure gain. Z +/- 2 psi is no good. Call nitrogen a waste if you want, but if the guy filling the tires forgets to purge the drier on the air line, you've gained nothing. I've seen the difference between charging with air on a dry day at Watkins Glen and the next morning when it was sopping wet and foggy, and it wasted a lot of track time chasing setup and tire pressures at the same time.
02-06-2009, 02:23 PM
#16
Race Director
Thread Starter
I always drained and refilled my pro tires with Nitrogen, and it helped a psi or two. I think there is a misconception that it can DRASTICALLY change tire pressures, increase mileage, decrease wear, blah blah blah.....the usual aftermarket sales crap.
02-06-2009, 03:25 PM
#17
Melting Slicks
Member Since: Sep 2006
Location: San Mateo CA
Posts: 2,173
Likes: 0
Received 0 Likes
on
0 Posts
02-06-2009, 05:49 PM
#19
Instructor
Shipped next day air? 
A bit off topic. I thought I heard that the Nitrogen molecules are larger and this keeps air in the tires longer (22% longer right?).
Probably heard that at one of the $9.95 nitrogen fill places.
I could see nitrogen being of value to serious/pro racers looking for an edge but not in a streetcar.
A bit off topic. I thought I heard that the Nitrogen molecules are larger and this keeps air in the tires longer (22% longer right?).
Probably heard that at one of the $9.95 nitrogen fill places.
I could see nitrogen being of value to serious/pro racers looking for an edge but not in a streetcar.
02-06-2009, 07:32 PM
#20
There was a great discussion on using nitrogen in tires a few years ago on eng-tips.com. Very in depth, chemical analysis, etc., and for the most part, it was decided that there is no benefit to using it on the street.