Conference noted::bicycle

     A good start is the stated tire pressure on the tire...
    
     The softer a tire the more rolling resistance and the possibility of
    snake bites...
    
     I always run 150-160 in a 125psq tire. I'm not into comfort,
    obviously.
    
     Tires are generally well underrated (for guys like me) by the
    manufacturer.
    
     Do not go below the recommended pressure...
    
         Chip

    well, Chip's talking on-road, you're talking off-road, that's
    two different animules.  I just saw an artical that described
    the effects of tp relative to traction.  Softer tires will
    improve your traction for mud and dirt, or so I've been told.
    
    I'm sure the off-road enthusiasts will give better answers.
    
    ed

    If you're curious how max pressure is established for a tire/tyre,
    I read an article in Bicycling that explained it for U.S. tires.
    
    It seems they inflate the tire untile it either bursts or blows
    off of the rim.  Whatever number they get is divided by two, and
    that is max pressure (after repeated trials).  Bicycling made
    that point in order to keep people from being squeamish about
    "over-inflating".  
    
    r�

    .2 is quite right, road tire pressure and off-road tire 
    pressure is very different.  For road riding, you get 
    less rolling resistance (drag) when you have higher tire 
    pressures.  And you get a less comfortable ride.  But that
    is fine for the road because you generally don't have to 
    worry about traction or foriegn objects.  [though over 
    pressurizing can be hazardous.  I have clincher/wire-on
    rims, and I used to overinflate my road tires.  But then
    I used to get many more pinch flats from hitting the 
    slightest bump or rock.  I believe that it is a function
    of the rims.  Now I inflate them just shy of maximum and
    I'm doing just fine.  Hadn't had a flat in a while]
    
    Off road is definitely a different matter.  You want/need
    traction and "float".  That's where the fat tires come in.
    They give you a wide contact patch and "float" you over 
    really soft ground.  So, the less tire pressure you have,
    the greater the contact patch => greater traction and float.
    [float = your tires don't dig/sink into the dirt/sand.  
    If you ride in loose sandy soil, your front wheel will seem 
    like it has a mind of it's own because it will dig into the
    surface]  A side bonus of low tire pressure is that it can
    help absorb alot of the bumps, like a shock absorber.  
    
    In your case (RE:.0) I would recommend getting tires that 
    have all the Knobbies connected down the center ridge of the
    tire.  This would lower your rolling resistance when you are
    commuting to work, as well as cut down on the droning noise 
    that knobbies make.  For commuting, pump up your tires as much 
    as you feel comfortable (probably manufacturer's max)  When you
    go off road, you can reduce your pressure to the manufacturer's 
    min and have alot of fun.  If you find that you are having too
    much fun and want to try more technical stuff,  you can 1) reduce
    your tire pressure some more ( about 30 lbs. ) 2) get wider
    tires, pump them up to 30 lbs. and swap tires every weekend, or 
    3) get another set of wheels with wider tires and low pressure
    and swap wheels for road and off road riding. :-)
    
    Have fun!
    
    -john
    
    ps Riding on trails is good.
       Riding on wet trails is bad.

    Reply to 2539.4
    
    John;
    
         You probaly should look at buying a different set of rims.  I used
    to use Matrix ISO rims and had quite a few pinch flats ( relatively
    speaking ).  I now use Mavic MA40 and Open CD4 rims with Continental
    Gran Prix clincher tires and have had one flat in 2 1/2 years ( I
    often hit small rocks that sit in the road, especially when I am tired
    ).  I consider my current setup to be almost bullet proof.
    
         I noticed that Chip gave some info on tire inflation, for the
    road I agree with his technique but not as much.  I inflate 10-15
    PSI above the recommended, I find that steering and conering response 
    is better.  It seem that R-squared offered the best advice on tire
    inflation for offroad riding, but if you ride your bike to work you
    may want to take a middle ground between what is best for offroad and
    what is best for pavement.
    
     AS 

    if you do inflate your tire over the manufacture's limit don't leave it
    in a closed car during the summer.  Pressure can build even higher and
    you'll be buying a new tube/tire.

    So on Mt bikes I would guess that the front tire should be inflated
    much more than the back. The front should float and the back should
    have tracsion.
    
    Alan

    I think .4 says that "float" comes from less inflation.
    
    ed

    
    Chip, how often do you puncture? I agree, that the manufacturer's
    recommended is too low, but I've never had the confidence to go over it
    by just as much as you. I ride 100psi Michelins which I will put
    110-115 psi in.
    
    I don't know anything about MTB pressures, but since this note title
    doesn't specify bike type, I'll stick in my road feelings. These
    pressures are dry roads only. As soon as it starts getting greasy from
    rain, you need to release some air to get more traction. Especially if
    you ride on the smooth tarmac like Germany's. I don't know of any great
    formula, just if it feels confident, it's OK.
    
    Also, if you're descending mountains, it can be worthwhile releasing
    pressure to get more grip on the corners. One pro used to always let
    his tyres down at the top of the French cols and I'm quite sure Merckx
    did it at least once.
    
    Finally, release your pressure whenever you store your bike. Even if
    it's just in the shed overnight. You never know when you're going to be
    wheeling out flats...
    
    Graham.

     Hi Graham... It's rare I get snake bites. Usually it's a tire gashing
    something I hit (after I've slipped into a coma toward the end of the
    ride).
    
     I was talking with a Continental Rep. at the local shop. He explained
    that they (like all mfg.'s in the States) significantly underrate the
    recommended pressure. By underrating, I do not mean the recommeded
    pressure, but the maximum "burst" pressure. 
    
     When I ran the Conti G/P they were rated at 155lbs. psi. I never ran
    them under 180. The representative told me they'd take 250lbs. easy.
    He pulled a chart out and showed me their test results on various
    tires. 
    
     Go for it!
    
         Chip

    Re: Conti underrating pressures
    
    Here in UK, I gathered that Conti are about the only mfrs. who don't
    underrate. I tend to run 23mm at 125psi, Michelins will rate them 110
    and Conti 125. I had my first puncture in about 2000k on Tuesday. I
    tend to hit a lot of bad road-repairs on my commute route but
    snake-bites have never been a porblem.

    
    On my MTB I usualy have 40. lbs on front and 35 lbs. rear. Although
    manufacturer recommended is  45 to 65 lbs. I find it smoother on
    bumps and better traction on loose gravel etc... 
    On easy rides or ones that involve some paved roads too I will go up
    by 5 to 10 lbs. 
    However if you have real good knobbies on your bike, you might want
    to consider another set of tires or wheels, to exchange for commute 
    to work. Knobbies wear out a lot faster on paved roads and are not
    that much fun either with all the noise they make. 
    
    Shaw

    
    
    Thanks, all, this is great stuff!  I do have the cross-trainer tires
    that are (relatively) smooth on the road, but also have some byte on
    the trails.  I inflated to 60 lbs before the trip to work today (it
    feels great!) and it wasn't at all uncomfortable.
    
       GJD