| Author | Message | ||
     Electraglider_1997 |
Decided to check the air pressure on the tires and was surprised to see they both were way down. My Harley tires hold air and never seem to need topping off. The ULY manual states 36# front and 38# rear. Both were down at least 10#. Yes I have checked them before, just not this year until today. Maybe that is why my gas mileage sucks. We shall see. | ||
| Roadrailer |
It's always a good idea to check your tire pressure before each ride. Outside air temps can have a significant effect on the small volume of air in motorcycle tires. | ||
| Sparky |
Rule of thumb(s): Besides the mandatory Pre-flight checkout (lights, dangling parts, etc.), check bike including air and oil at each fillup. Running low on air can be expensive if you have polished PM's and hit pavement edges on the freeway. Don't ask...  | ||
| Freyke |
Has anyone here tried filling with nitrogen yet? I hear it's all the rage now days. Apparently, it takes way longer to leak out as the nitrogen molocule is larger than an air molocule. http://www.straightdope.com/columns/070216.html | ||
| Strokizator |
That article has at least one error. Oxygen, being a diatomic molecule, is "fatter" than a nitrogen molecule (learned that in 1968). Even so, each molecule is so small it doesn't matter what size they are. An inline dryer or water separator on your compressor is about all you need. | ||
| Littlefield |
There's no such thing as an 'air' molecule. Air is about 3/4 nitrogen, 19% oxygen, and little bits of lots of other things. It's hard to imagine how pure nitrogen would be much different than air. | ||
| Atoms |
Pure nitrogen would be different than air in that it probably costs a LOT more.  | ||
| Roadrailer |
...and you wouldn't be able to find it out on the road. I'm not sure why anyone would spend the money for pure nitrogen when good old-fashioned air is free. | ||
| Florida_lime |
It's 'free' in my garage, but it is rare (around here anyways) to find free air at a gas station. Nothing like putting your 50 cents into the machine, only to find out none of it comes out the airchuck.  | ||
| Flynuly |
I have been servicing nitrogen in aircraft tires for the last 25 years. I wouldn't waste your time or money putting it in motorcycle tires, just can't imagine you would notice the difference. my .02 cents. | ||
| Ftd |
"That article has at least one error. Oxygen, being a diatomic molecule, is "fatter" than a nitrogen molecule (learned that in 1968)." Whoa!!! Nitrogen and oxygen are both diatomic and their diameters are 0.31 nanometers and 0.29 nm respectively. So nitrogen molecules have 7% larger diameters even though N2 has a molecular mass of 28 vs 32 for O2. The reasons to run pure nitrogen are the molecule size difference and more important the dryness of the N2. A small amount of water coverts to a large volume of gas at the elevated temps in a fully warmed up tire and this really screws up your pressure readings. At least this is true for racers who adjust tire pressures at tenths of a pound increments. For street use I believe it totally unnecessary. Frank (Message edited by ftd on April 19, 2007) | ||
| Windrider |
The great thing about running N2 in tires is that it also helps the flux capacitor charge up 32% faster. It allows you to run faster, weigh less, improves your sex appeal and makes the fan on a Uly sound like a sweet violin symphony.....  | ||
| Roadrailer |
It's 'free' in my garage, but it is rare (around here anyways) to find free air at a gas station. Nothing like putting your 50 cents into the machine, only to find out none of it comes out the airchuck.  Walmart. $10. Plugs right into the 12v outlet. Never having to look for air again: priceless. | ||
| Florida_lime |
Roadrailer said: Walmart. $10. Plugs right into the 12v outlet. Never having to look for air again: priceless. I do have a portable compressor in addition to the 5HP in the garage, I just don't carry it in every vehicle I own.  | ||
| Freyke |
WALMART! The evil empire! I have a 19 Gal. compressor in my garage - free air, real cheap. For folks that don't have a compressor it might be a better deal to go with N2 if it does not leak out as fast as air. | ||
| Roadrailer |
I do have a portable compressor in addition to the 5HP in the garage, I just don't carry it in every vehicle I own. So how do you refill the tire if you have to plug a flat on the road? | ||
| Cavi |
If you talk to the shops that sell sportbikes (not a Harley dealer), they will tell you why they use the nitrogen. It is not because it leaks out slower, it is because it is lighter, they will tell you it will reduce unsprung weight. Personally, I would not waste money, with the weight of the Uly, saving a few ounces in air or nitrogen weight will not make much of a difference. | ||
| Tootal |
The use of nitrogen is for racing. Air has moisture as mentioned above and in racing your tires get a lot hotter than on the street. The moisture in air can cause a lot of problems in maintaining a constant pressure. Nitrogen is dry and consistent so your pressures stay consistent. This is important on a racetrack, not on the street. Don't waste your money. All tires leak air slowly especially thin wall light weight sticky sport tires. Just check them every couple of weeks. | ||
| Ftd |
" (Message edited by ftd on April 20, 2007) (Message edited by ftd on April 20, 2007) | ||
| Galloper |
I fill mine with helium... adds 25hp to the rearwheel  | ||
| L_je |
There is no meaningful difference in the PV=mRT relationship for Nitrogen vs Standard Air. Nitrogen for consumer applications is a scam. Unless you are running 250 psig, or routinely operate in a temperature environment that goes from 200F down to -65F on a daily basis, or think your bursting tire is going to feed the flames of a pit crew fire.... you just don't need N2. Moisture is what you want to avoid. If your compressor can operate at pressures >= 3 times your tire pressure, you will not have moisture-related pressure issues. At higher pressures the moisture condenses out, and when the air moves into your tire, what little moisture remains will no longer pose a condensation threat. But, you will need a compressor with a tank or resevoir, the tag-along 12V compressor I keep under my seat will not go through the proper psychrometic cycle to dry out the air, but that compressor is for emergency uses only. Again, do you inflate your tires to 250 psig? Do your tires go through a -65 to 200F cycle every time you go for a ride? Are you a fire hazard? If you answered no to these questions, then you do not need N2. The 78% N2, 19% O2, 2% H2O stuff that you breathe will suffice. If you live along the Gulf Coast of the US, or Diego Garcia, or on the Iranian side of the Persian Gulf, and still have some reservations about air... Pressurize your air compressor, and let it sit overnight before using it to fill up your tires; this will allow for the compressed air to cool, and further condense/remove the moisture. Just say no to N2. Come on, "inert"?, how much fun is that? | ||
| Ft_bstrd |
My tires don't stay on long enough to lose any air.  | ||
| Florida_lime |
Roadrailer said: So how do you refill the tire if you have to plug a flat on the road? The VAN has this thing called a spare tire | ||
| Old_mil |
Actually, the latest rage among racers is to fill tires with Hydrogen. As a lighter than air gas, it actually reduces the weight of the bike, increases gas mileage, and gives you a higher top end speed... Just don't crash. [Note: don't try this at home. It's a joke.] | ||
| L_je |
I wish they were only doing silly things like filling tires with Hydrogen. Instead, some manufacturers do silly, and expensive things like... ...the carbon fiber front fender on my wife's Duc. What a stupid way to save weight. It's flimsy; it doesn't seem very durable; after 1200 miles, the carbon fiber is already starting to fray. ...how 'bout getting rid of one of those superflous brake rotors up front, if they really want to lighten the unsprung weight, aye? Somebody here needs to do a track day with both air and Helium. After the Helium lap, suck some out of the tire, and leave me a voicemail to let me know if your lap times differed!  | ||
| Blake |
 Good one!  ...how 'bout getting rid of one of those superflous brake rotors up front, if they really want to lighten the unsprung weight, aye?  For sure a very valid and novel idea. It's apparently a tough thing to do while maintaining the requisite floating rotor and race worthy stopping power. Sure would be cool if someone could figure out a way to do that on a production motorcycle. ![: ]](http://www.badweatherbikers.com/buell/clipart/proud.gif) |
