Page 1 of 2 1 2 LastLast
Results 1 to 15 of 76

Thread: What's the problem with tire pressure?

Hybrid View

  1. #1
    Registered User WalterK75's Avatar
    Join Date
    Feb 2009
    Location
    Mississauga, Ontario
    Posts
    556

    What's the problem with tire pressure?

    I see repeated tire pressure threads and I'm not sure why. Since the manufacturer gives the recommended pressures in the owner's manual I don't understand why there should be any need to discuss it.
    Walter

    All government, of course, is against liberty.
    H. L. Mencken

  2. #2
    Registered User
    Join Date
    Nov 2007
    Location
    Joplin, MO
    Posts
    953
    Quote Originally Posted by WalterK75 View Post
    I see repeated tire pressure threads and I'm not sure why. Since the manufacturer gives the recommended pressures in the owner's manual I don't understand why there should be any need to discuss it.
    different brands of tires prefer different pressures.

    different styles of riding prefer different pressures

    It is all about learning the bike, and your preferences.

    Sharing your preferences helps other people learn.

    Simple

    Rod

  3. #3
    Small road corner junkie pffog's Avatar
    Join Date
    Apr 2006
    Location
    WNY, Further fron NYC, than 6 entire states!
    Posts
    2,093
    Because some BMW riders seem to be OCD when it comes to proper inflation. There was a post asking if they needed to adjust pressures when they rode up and down mountain passes!
    2010 F800GS Full Ohlins package, '04 R1100S Replika
    '01 F650GS Wife's bike
    Maritime Alps and Vosges 2012
    Tuscany and Central Italy 2010

  4. #4
    Proud Veteran SteveAikens's Avatar
    Join Date
    Mar 2003
    Location
    Clovis, NM
    Posts
    942
    Simple answer is, BMW publishes their recommended pressure averages for their bikes - not their customers, the loads they carry, the differences in one tire manufacturers optimal pressure for the design of their tire - again with an average load.

    I ride an R12RT. The total permitted weight of this bike is 1091 lbs.

    With me on it, and ready to ride long distance or in a rally, that bike weights 940 lbs. That's the actual weight taken by the NM MTV on August 18th. Before Aerostitch, helmet and boots, I weigh 160 lbs.

    Here's some food for thought. How much do you weigh? How much does your passenger weigh? - both ready to ride? What about gear in your bags you travel with normally?

    How does BMW know whether it's me on my bike - at 940 lbs. actual weight - or my buddy that weighs over 320 lbs. before Aerostitch, helmet, boots - with a passenger?

    I recently had a discussion with the service manager at my local shop while I was changing front tires. I gave him my tire pressure gauge and told him to have the tech set the front tire pressure at 40 psi, using my gauge. Knowing me pretty well, he related a recent tire seminar he attended in Las Vegas with a few tire manufacturers [forget who he said sponsored it]. He told me that every tire manufacture rep told the group the same thing. For highway riding, the best performance and mileage is almost always going to come from tires inflated to the maximum pressure on the sidewall. Every rep also agreed the difference of one lb. can make a significant difference in how long the tire lasts - again, under highway conditions.

    I have a calibrated gauge. I've been running 40/40 and 40/42. I've now bumped that to 42/42 and even in the mountains [just came home for a rally in MT that was mostly mountains] the only thing I "think" I notice is the front attacks frost heaves and the like more aggressively - less of a "thud" - more of a "Bump!" I think much harsher.

    I'm watching wear pretty close - not because I much care about how fast I can scrub tread off, but rather if the extra couple lbs. of air are going to make a difference. In regards to the ride, I don't notice much yet. However, my new Ohlins shocks go on the bike Saturday. That's going to be a whole new story.
    Nom de Plume:
    Steve Aikens, Clovis, NM
    BMW MOA #6218
    IBA# 442

  5. #5
    Small road corner junkie pffog's Avatar
    Join Date
    Apr 2006
    Location
    WNY, Further fron NYC, than 6 entire states!
    Posts
    2,093
    Quote Originally Posted by SteveAikens View Post
    ....................... However, my new Ohlins shocks go on the bike Saturday. That's going to be a whole new story.
    And a good story, suspension is the best $$$ you can spend on a vehicle
    2010 F800GS Full Ohlins package, '04 R1100S Replika
    '01 F650GS Wife's bike
    Maritime Alps and Vosges 2012
    Tuscany and Central Italy 2010

  6. #6
    Proud Veteran SteveAikens's Avatar
    Join Date
    Mar 2003
    Location
    Clovis, NM
    Posts
    942
    Quote Originally Posted by pffog View Post
    And a good story, suspension is the best $$$ you can spend on a vehicle
    I agree. I just wish I didn't have to spend so damn much of it....
    Nom de Plume:
    Steve Aikens, Clovis, NM
    BMW MOA #6218
    IBA# 442

  7. #7
    Small road corner junkie pffog's Avatar
    Join Date
    Apr 2006
    Location
    WNY, Further fron NYC, than 6 entire states!
    Posts
    2,093
    Quote Originally Posted by SteveAikens View Post
    I agree. I just wish I didn't have to spend so damn much of it....
    You only rent good suspension, as it will:

    A. will increase the resale value of the bike
    B. before you sell/trade you refit the OEM and sell the shocks to the next enlightened rider.

    Eeither was you should recoup 2/3 - 3/4 of the investment.
    2010 F800GS Full Ohlins package, '04 R1100S Replika
    '01 F650GS Wife's bike
    Maritime Alps and Vosges 2012
    Tuscany and Central Italy 2010

  8. #8
    No longer a member here
    Join Date
    Apr 2006
    Posts
    1,432
    Quote Originally Posted by WalterK75 View Post
    Since the manufacturer gives the recommended pressures in the owner's manual I don't understand why there should be any need to discuss it.
    The manufacturer recommends oil changes at certain intervals
    The manufacturer recommends brake fluid changes at certain intervals
    The manufacturer recommends a certain octane rating for the fuel
    The manufacturer recommends a specific oil weight
    The manufacturer recommends a certain total maximum weight for the bike incl passengers and all luggage

    ...and we all do what we think is the best choice and what works for us.

  9. #9
    Registered User chewbacca's Avatar
    Join Date
    Feb 2013
    Posts
    144
    Quote Originally Posted by EMSimon View Post
    The manufacturer recommends oil changes at certain intervals
    The manufacturer recommends brake fluid changes at certain intervals
    The manufacturer recommends a certain octane rating for the fuel
    The manufacturer recommends a specific oil weight
    The manufacturer recommends a certain total maximum weight for the bike incl passengers and all luggage

    ...and we all do what we think is the best choice and what works for us.
    Not sure about that "and we all do what we think is the best choice and what works for us." That is IMO what we should do. We "should be" smart enough to adjust settings for the conditions. I'll swear a whole bunch of BMW riders tend to need info from Bavaria to light their bike up in the morning.
    Old But Not Dead
    Semper Fi

  10. #10
    Benchwrenching PGlaves's Avatar
    Join Date
    Oct 2003
    Location
    "Big Bend" TX
    Posts
    8,654
    BMW generally gets it about right at the time they publish the recommendations. This is true of the latest models too. But tire technology has changed substantially over the past 25 years. What BMW got right for a specific Airhead in 1972 or 1995, and what BMW got right for a classic K bike in 1985 or 1995 may well no longer be right today. That depends on what tires are fitted today.

    As noted by several posts above, what works for me with 150 pounds of luggage in the desert southwest in August may well not be the best pressures for somebody else in Minnesota or New England in October. Tire temperature (along with pavement temperature) are key determinants of traction, and tire operating temperature is directly related to both ambient temperature and tire pressure.

    So the one size fits all recommendations by BMW are a good place to start. If published in the past few years they won't be way-off but also may well not be optimal for a specific rider, bike, and environment.

    So, as David Hough would explain it in his new book "The Good Rider", the good rider would actually think about this stuff, and would learn how to know if the tire pressure is optimal, good enough, or not.

    As an added note to the OP, BMW makes recommendations for a bike with no regard whether the rider is in Ontario or Arizona. In those two cases I suspect the compromise recommended pressure is not quite right.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
    http://www.bigbend.net/users/glaves

  11. #11
    No longer a member here
    Join Date
    Apr 2006
    Posts
    1,432
    Quote Originally Posted by chewbacca View Post
    . I'll swear a whole bunch of BMW riders tend to need info from Bavaria to light their bike up in the morning.
    Careful with that! BMW motorcycles are made in Berlin. Part of Prussia.

  12. #12
    rangerreece rangerreece's Avatar
    Join Date
    Aug 2008
    Location
    Enterprise, AL
    Posts
    169

    Pic

    Quote Originally Posted by EMSimon View Post
    The manufacturer recommends oil changes at certain intervals
    The manufacturer recommends brake fluid changes at certain intervals
    The manufacturer recommends a certain octane rating for the fuel
    The manufacturer recommends a specific oil weight
    The manufacturer recommends a certain total maximum weight for the bike incl passengers and all luggage

    ...and we all do what we think is the best choice and what works for us.
    In aviation we have an acronym, PIC, Pilot in Command, emphasis on the word Command. It is implied that command means you will comply with the operators manual implicitly, however, with caveat, adedum, the regulation states that we can deviate from "normal" procedures in the event of an emergency. Now, what relevance does this have with the current conversation; like flying, riding is implicitly dangerous. Will the manufacure be on the bike when something goes wrong? No, you will. This gives you full authority to deviate from recommendations as the PIC sees fit. I take into consideration as a PIC of my motorcycle, all credible information, owners manuals, BMW master technicians, maintenance manuals, and experienced riders with a history of credible information, like Paul Glaves and others. The purist who follow the operators manuals and maintenance manuals implicitly will do well, but deviations are necessary, especially with tires and oil due largely to the changing technology on expendable items. Even some OEM parts change over time but are recommended as replacement parts for bikes that didn't include them as original stock; recalls come to mind. Like I tell my students, if ATC makes a mistake, your dead, if you make a mistake, your dead, this fact puts you the PIC in charge.
    2005 R1200RT
    BMWMOA # 143779
    "Positive Habit Transfer is no substitute for Situational Awareness."

  13. #13
    innate need to improve
    Join Date
    Sep 2008
    Location
    Lehigh Co., PA.
    Posts
    72
    A wise old tire Guru once told me that the proper tire pressure is always changing with weight, temp, driving style ect. His recommendation is to start with the recommended tire pressure checked cold. Ride and when you stop immediately check the tire pressure. The optimal pressure change will be 1-2lbs. If more you are under inflated, less you are over inflated.

    Having the tire pressure monitor on the bike makes this very simple. I have michelin PR 2 on my 08 RT and I have found that my optimal pressure using this technique is 38 front and 42 rear.
    Keith
    08 R1200 RT

  14. #14
    Enjoy The Ride saddleman's Avatar
    Join Date
    Apr 2009
    Location
    Huntersville N.C.
    Posts
    314
    Quote Originally Posted by dockeithdc View Post
    A wise old tire Guru once told me that the proper tire pressure is always changing with weight, temp, driving style ect. His recommendation is to start with the recommended tire pressure checked cold. Ride and when you stop immediately check the tire pressure. The optimal pressure change will be 1-2lbs. If more you are under inflated, less you are over inflated.

    Having the tire pressure monitor on the bike makes this very simple. I have michelin PR 2 on my 08 RT and I have found that my optimal pressure using this technique is 38 front and 42 rear.
    I just changed a set of PR2 tires on a 2012 RT that had just over 15,000 miles on them with 37 psi on the front & 42 psi on the rear & they could have gone another 1000 miles before they were at the wear bars.
    Dave
    2004 Black LT
    2000 Canyon Red LT
    The Only Vehicles I Own

  15. #15
    It is what it is. Bud's Avatar
    Join Date
    Feb 2006
    Location
    Long gone
    Posts
    6,493
    Sidewall tire pressure is the maximum per the tire mfg.

    It is not always the recommended or optimum tire pressure.

    Paul and others have it right. It pays to listen to the voices of experience.

    Your mileage WILL vary.
    I used to post here, but now I don't.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •