Tire pressure

Discussion in 'The Garage' started by eatdrinkadam, Apr 12, 2012.

  1. eatdrinkadam

    eatdrinkadam Adventurer

    Jul 8, 2008

    I put some new Heidenau K60's on my BMW 1200 GSA recently, and from what I understand, tire pressure fluctuates with temperature.

    The front tire moves between 37-33 psi (higher when being ridden, lesser when kept in the cold garage)
    The back tire moves between 39-32 psi (same as above)

    average temp here is 65 degrees F.

    I have reason to believe my back tire has a slow leak, due to a small tear I put into it, trying to get the tire on myself. (i ended up taking it to a shop and have it machined) The shop said the tear was a concern, but they put the tire on and checked for leaks, and said it should be ok.

    Since the tire pressure fluctuates so much, its hard to tell if the tire is losing pressure.

    Is there better way to test for super slow leaks? (Dunking it might not reveal anything if the leak is so minor)
  2. buickid

    buickid Lets ride!

    Jul 19, 2011
    Oahu, HI
    You should always check tire pressure cold. That means before you ride, and at least 2 hours after riding. Don't quote me on the 2 hours, thats a completely non-scientific guess.
  3. gsweave

    gsweave Yinz, blinkers are on, JACKWAD!

    Apr 2, 2005
    The Paris of Appalachia
    Your looking for roughly a 10% increase in psi

    cold to hot. street ridden. http://www.msgroup.org/Tip.aspx?Num=009

    Or you could just boost em to 2-5 psi below max pressure as labeled on sidewall of tire, like most touring GSers
  4. CycleDoc59

    CycleDoc59 Wrench Rider

    May 24, 2006
    East Virginia
    About 5# from cold to hot is expected. Ride hard is hot weather and it will rise even more.
    Replace the air w/nitrogen for much less change...
  5. MisterPX

    MisterPX Been here awhile

    Aug 29, 2011
    SE WI
    Run them at the 36 listed on the sidewall (Heid. recommened that pressure for a Tiger 800, figure your GS is a wee bit heavier) . After a good ride, stick them to see what psi you're at.
  6. fritzcoinc

    fritzcoinc Enjoying my last V8

    Apr 30, 2008
    Hockley, Tx
    I am confussed by your question. You are correct the air expands and contracts with temp. changes and thus the pressure changes.
    Are you expereincing pressure change or a steady decrease?
    To look for a very slow leak ( I just had one ) emerse the entire tire/wheel in water and take a seat near by.
    Mine turned our to be an ever so slow leak at the stem valve ( a BB sized bubble every two minuets or so ).
    The stem valve tightness would be a good thing to check first. Just screw in a new one and check for problem to go away.