1. The most important thing about buying a new bike is to make sure it fits. The only way you'll know if the bike is right for you is to size up the bike and make sure that the bike's geometry matches your body's geometry. Ask questions and do some research.
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  1. #1
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    How hard are your tires?

    Hey all I don't know if this should be in the wheels forum instead, but as I'm a beginner I'll put it here to start.

    Yesterday I went for a short ride on some trials and I looked down and my front tire looked a little low, so I pumped it up a bit with my hand pump, but it doesn't have a pressure gauge on it. So I just pumped till it felt full and finished the ride.

    When I got back and checked some of these forums, most people were saying pressure should be between 30-40 psi in general. So today I stopped by my LBS and got a gauge that works on presta valves and started refilling the air while checking the pressure. The gauge definetely showed the increase from zero till 30 psi, then no matter how much I pump air in, the gauge won't go any higher. I was worried about over inflating my tires for a couple of reasons.

    So heres the question. Are your tires rock hard or does it sound like my gauge is broken? If your tires are that hard, should it be so difficult to get that last 5 or 6 psi? Is there a way to check the calibration at home on the gauge? I might just take the bike and the gauge back to the store and make sure everything is kosher.

    FYI, the gauge is a Meiser Pressure Valve with push button release model number pr160bx if that helps at all.Shown here on the top. http://www.ghmeiser.com/bicycle.htm

    Any thoughts/suggestions are much appreciated.

  2. #2
    i also unicycle
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    tires should definitely not be rock hard. 35 or psi is a good starting point. sounds like your gauge is borked. i'd recommend a decent floor pump, $25 and up and your LBS.
    mtbr says you should know: i work in a bike shop.
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  3. #3
    bi-winning
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    my tires are not rock hard
    When under pressure, your level of performance will sink to your level of preparation.


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  4. #4
    Double-metric mtb man
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    I'm a Clydesdale (over 200 lb rider, I run a little higher pressure as a result) and when my bike is sitting there without me on it, the tires are firm, but not hard like rock.
    As if four times wasn't enough-> Psycho Mike's 2013 Ride to Conquer Cancer Page

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  5. #5
    local trails rider
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    When I put my weight on my bike I can see that the tyres have some give but not so much that I see wrinkles in the side walls.

  6. #6
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    Thanks everyone, I'll be bringing the gauge back today.

  7. #7
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    It depends. If you have reasons to worry about snake bite(inner tube being torn as result of hard hit), you'd better pump more. I often go fast over rocky terrain, so I fill about 50-52 PSI rear and a bit less front. It is quite firm to touch. The rider's weight is to be considered as well - of course, heavier rider - higher pressure.

  8. #8
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    I'm 160 and I run my tires at ~30-35.

    Start at maybe 35 and go down by 5 PSI until you get pinch flats and then go back up 5 from there.

    You're looking to get the tires soft for good grip on the loose stuff but hard enough to be reliable.

    Also if you're on a more grippy surface you can go up in pressure to drop rolling resistance.

  9. #9
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    The problem may actually be your hand pump. I bought one and it will only give me about 28-30 psi, no matter how hard/fast/long I pump. Most of the cheaper hand pumps are designed to only go that high, basicly to get some air in the tire and get you back home, or at least finish the ride. Floor pumps will take you higher in the psi range, as will some of the more expensive hand pumps.

  10. #10
    All Mountain Rider
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    Quote Originally Posted by FLOutlander
    The problem may actually be your hand pump. I bought one and it will only give me about 28-30 psi, no matter how hard/fast/long I pump. Most of the cheaper hand pumps are designed to only go that high, basicly to get some air in the tire and get you back home, or at least finish the ride. Floor pumps will take you higher in the psi range, as will some of the more expensive hand pumps.
    I agree it might be your pump. Is it one of the "Minny bike pumps" the ones that easily fit in your bag. Basically one that is less that a foot long? They just are not long enough to pump beyond 30 PSI. if you want to pump more than that your are going to need a bigger pump.

    You can either get a floor pump or one that fits on your frame but it has to be bigger.
    The one i have is just shy of 2 feet long and barely fits in the triangle of my bike. However it has a Maximum pressure of a 110 psi. Lol it actually is meant for road bikes but hey it works well for Mountain bikes. only takes 2-3 minuets to pump a tire from flat to 40-60 PSI. Wish i remembered what brand it was and all but the label has been worn off a few years ago But this one is close . I have the Large one

    Also I highly suggest you buy a few Presta-shrader (how ever they spelled) valve adapters. great for using gas station pumps and everything. i know here they $0.10-25 a peace.

    good luck.
    Donít matter how many mm of travel, If your a 26 or 29. or if its SRAM or Shimano

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  11. #11
    Flying Goat
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    i run mine at 22psi... never had a pinch flat ever...

  12. #12
    tete de la course
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    I used to use one of those crankbrothers handpumps and switched to a regular footpump because I find it a lot easier. Pressure is maintained at 30-35psi.
    Hey man nice one!

  13. #13
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    Didn't even think of that

    Quote Originally Posted by FLOutlander
    The problem may actually be your hand pump. I bought one and it will only give me about 28-30 psi, no matter how hard/fast/long I pump. Most of the cheaper hand pumps are designed to only go that high, basicly to get some air in the tire and get you back home, or at least finish the ride. Floor pumps will take you higher in the psi range, as will some of the more expensive hand pumps.
    Excellent point. I only have one of the small Topeak hand pumps that fits in my camelback. When its "closed" its only about 7" long. Never occured to me the pump itself couldn't handle the higher pressure. Make a lot of sense, since I took the gauge back to the store and they checked it against a couple of other bikes and it read those fine. They had floor pumps with gauges for $25 or $30. Looks like another trip to the LBS this weekend.

  14. #14
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    You may try to get a telescopic pump with lockout. It is designed to inflate to higher pressure, if the travel is locked out partly.
    I usually wrap a bit of teflon sealing band around the valves and adapter (my valves are presta) to reduce air leak during pumping. Not sure if it really works, but certainly does no harm.

  15. #15
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    almost always 40-45 psi, except on the road bike 90-100 psi.

    I had previous troubles with pinch flats and generally prefer the lower rolling resistance that the higher pressure allows.

  16. #16
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    Quote Originally Posted by mrpercussive
    i run mine at 22psi... never had a pinch flat ever...
    Are you serious even after those 5 foot drops and staircases?
    Maybe for xc...

  17. #17
    Flying Goat
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    Quote Originally Posted by taikuodo
    Are you serious even after those 5 foot drops and staircases?
    Maybe for xc...
    yes i'm serious... 22lbs... even with what i'm riding. Never had a pinch flat ever. If i was doing XC, i'd put in more air...

  18. #18
    local trails rider
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    Quote Originally Posted by mrpercussive
    yes i'm serious... 22lbs... even with what i'm riding. Never had a pinch flat ever. If i was doing XC, i'd put in more air...
    What tyres do you have and what is your weight?
    Any rocks out there threatening you with snake bite/pinches?

  19. #19
    Flying Goat
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    Quote Originally Posted by perttime
    What tyres do you have and what is your weight?
    Any rocks out there threatening you with snake bite/pinches?
    Maxxis Minions 2.5 Wire Bead... Running Kenda 1.2mm wall tubes. I'm 125lbs geared and i ride DH/FR. Rocks i ride are pretty threathening... and even when i miss a tranny from a gap i'm fine... I run them at 22psi for all round riding... But go lower depending on course conditions. Sometimes as low as 18psi... Like at CHDH in Livermore...






  20. #20
    local trails rider
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    Quote Originally Posted by mrpercussive
    Maxxis Minions 2.5 Wire Bead... Running Kenda 1.2mm wall tubes. I'm 125lbs geared and i ride DH/FR. Rocks i ride are pretty threathening... and even when i miss a tranny from a gap i'm fine... I run them at 22psi for all round riding... But go lower depending on course conditions. Sometimes as low as 18psi... Like at CHDH in Livermore...
    I am sure the fat tough tyres and tubes, and low rider weight, make a bit of a difference...

    With skinny XC tyres and 100lbs more rider weight the pressure would need to be something totally different.

  21. #21
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    Well, I'm not too sure actually but my pressure does vary from terrain to terrain. The faster I go, the harder the tire will be. Rough trails with sharp rocks and protruding roots that are fast will require higher tire pressure than smoother, softer and even steeper trails.

    Just a few weeks ago, on a fast mostly straight 8 mile trail, tire pressure was closer to 33+ psi but on the race couse a week later which had more turns and some off camber sections with rocks (not sharp), and over a mile of tractor tracks to ride through, I HAD to drop tire pressure to under <27psi because I was bouncing all over the place. ( I'm 155 lbs and ride a hardtail.)

  22. #22
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    Quote Originally Posted by mrpercussive
    Maxxis Minions 2.5 Wire Bead... Running Kenda 1.2mm wall tubes. I'm 125lbs geared and i ride DH/FR. Rocks i ride are pretty threathening... and even when i miss a tranny from a gap i'm fine... I run them at 22psi for all round riding... But go lower depending on course conditions. Sometimes as low as 18psi... Like at CHDH in Livermore...

    its your tires. On my downhill tires i run about 15-17 pounds of air and in my XC tires i run 30-35 pounds. And my downhill tires fill firmer than my XC tires with only 17 pounds of air in them. they are just a wire bead and thicker tire all together almost like a motor cycle tire.

    I hardly ever get pinch flats on my XC tires at 30 pounds but when i would run them lower I would spin the tube and pull the valve stem out. Now that sucks becuase you can't even patch the tube. But like someone said start at like 35 and work your way down. You will notice a big difference in traction as you get lower but keep an eye out for your valve stem moving and big rocks as you can pinch a tube.

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