Losing tire pressure?

Discussion in 'General Harley Davidson Topic' started by DaveInPA, Jul 2, 2008.

  1. DaveInPA

    DaveInPA Frozen Account

    122
    0
    0
    Hey guys,

    I have a question on tire pressure. I have a new Sporster, and I've only really been able to ride once or twice a week due to weather and some other things.

    Anyway, it seems like every time I uncover the bike and check the tire pressure, both the front and rear have lost 2-3psi while sitting parked in my driveway. Is this normal, or do I have a problem?

    The manual says 30psi front, 36psi rear. How low can it be and still be safe? They read 27 front, 34 rear this morning and I rode to work without problems.

    Thanks
    Dave
     
  2. glider

    glider Veteran Member

    25,464
    108
    43
    Normally tires will loose a bit of pressure when they sit over time, a couple of pounds isn't a big thing but they should be checked on a regular basis to assure the proper pressure. Probably one of the most overlooked areas on the bikes. Remember they should always be checked when they are cold and not warmed up from riding.

    Try a bit of soapy water on the valve stem and see if they are leaking there.

    Two pounds or so isn't a safety issue but will shorten the life of the tire if ridden any length of time when low.
     
  3. rsneede

    rsneede Member

    22
    11
    0
    Two things: your pressure will be a bit lower if you check it on a cool morning than a hot afternoon, and if you have tube type tires some loss is normal, they're made from rubber after all, a natural product. Good that you're making checking pressures part of your riding routine, a lot of riders neglect this, sometimes to their great regret. Ever try to steer with a flat front tire?
     
  4. Dr. Dolittle

    Dr. Dolittle Experienced Member Staff Member Moderator Contributor

    6,397
    98
    18
    I have to agree - I'm trying real hard to check the tires and oil at least weekly. It's just so darned hard to take those extra 5 minutes when the sun is shining and the road is calling!
     
  5. DaveInPA

    DaveInPA Frozen Account

    122
    0
    0
    I check my tires before every ride. I have noticed a slight variation based on outside temperature. Thanks for the advice guys.
     
  6. DaveInPA

    DaveInPA Frozen Account

    122
    0
    0
    And can I get a nitrogen compressor for use here at home? I have a shop about 15 miles away that fills tires with nitrogen, but if I check my tires one morning and one is a little low, I don't have the luxury of putting more in here at home.
     
  7. Buzzy

    Buzzy Active Member

    125
    26
    0
    Gonna try hydrogen in the tires and rename Annabelle...... Hindenburg (oh the humanity). Bike needs to go on a diet anyway (cause I'm not about to).
     
  8. Sharky1948

    Sharky1948 Junior Member

    640
    28
    2
    I wouldn't sweat topping off nitrogen filled tires with a bit of air. Quick math.

    Starting: 36psi, 100% nitrogen
    Check: 34 psi, top off with air. (~79% N2, 21% O2)
    Ending: 2/36 * .79 + 34/36 * 1.0 = .9883

    In other words, you only have introduced 1.17% O2.

    In all likelihood, you would have more O2 than that in the tire anyhow since they are unlikely to be able to fully evacuate the tire of air prior to the N2 fill.

    For my money, you're better off just sticking with air, checking it regularly, and keeping it full. The tires will be replaced from wear long before they deteriorate from O2, and unless you're a pro racer, I doubt you'll be too bothered by pressure fluctuation from heat.

    JMO

    ps. You're welcomed to all my nitrogen you want!! It's a terrible gas in breathing mixtures for scuba diving.
     
    Last edited: Jul 6, 2008
  9. Dr. Dolittle

    Dr. Dolittle Experienced Member Staff Member Moderator Contributor

    6,397
    98
    18
    I'm going with Sharky on this one. If you check your pressures regularly and ride a normal amount, I can't see the cost benefit of doing nitrogen. You'll be replacing your tires from wear on the outside long before you'll see wear from the inside (oxygen damage.)
     
  10. glider

    glider Veteran Member

    25,464
    108
    43
    I think we should go back to solid rubber tires, that would eliminate all the problems.

    WOW, I'm on a roll here :small3d026: