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  1. #1
    Professional Crastinator
    Reputation: Fleas's Avatar
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    2 pinch flats in 2 weeks and I DON'T need tubeless - here's why

    Earlier this Summer it was wet. A lot. I was running my rigid Nimble 9 with just over 20 psi in my 29 x 2.2 tires. That worked perfectly fine.

    Then it started to dry out.

    Speeds started to pick up.

    My fitness was improving (at an embarrassingly slow rate). My speed started to pick up.

    I plowed a rocky creek crossing and pinched the rear tire.

    OK. 20 psi. High speeds. Rocky creek crossing. I was asking for it.

    2 weeks later. Now I'm running 23-24psi rear, 21-22 psi front.

    It's dry today. The trail was as fast as it's been all year and I was feeling my oats.

    I hammered the same creek crossing, but maybe, somehow, a little smoother.

    The next test was a big root cluster.

    Mind you, conditions are such that I'm going wayyy faster than earlier this year.

    I hit the first root - it is a good 3" high. The way I read the trail, I decided to just launch off that 3" root and clear the whole mess, which I did with envy-able grace and dexterity.
    ...but I heard that rear tube fail right on the launch. F***.

    So, what have I learned?

    I learned that I have to start thinking like a downhiller.
    I can't have tires squirming on the rims.
    I can't have rims denting every time I want to clear an obstacle by air.
    I need to run 25+psi or more. At that pressure - regardless of speed - it doesn't matter that there's a tube in the tire.
    If we had goathead thorns all over it would be a different story, I'm sure, but we don't.
    I will admit, when I'm riding slower (mud, snow, low fitness), the low pressure thing works perfectly fine. But as speeds increase, low pressure will not allow the tire to hold its shape and will not protect the rim. Plus, I change tires pretty regularly: Winter, wet Spring, dry Spring/Summer, Fall, and Pennsylvania/New York. So don't try to sell me anything.
    btw - I weigh 190# +/-.

    -F
    It's never easier - you just go faster.

  2. #2
    Sweat is just fat crying.
    Reputation: Finch Platte's Avatar
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    Huh?
    Mountain Biking Is Not A Crime stickers, free! (You pay postage. PM me for details.)

  3. #3
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    25 lbs seems a bit low.... But, that's just me.
    I was gonna stop by and see you, but the Jehovas witnesses came by. When they left I started drinking. Voicemail from Paul

  4. #4
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    Im 225lb on a Fuel EX 8 w/ tubes and I run 50 with zero issues.

  5. #5
    B.Ike
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    50 is way too high. try 30 and get back to us.

  6. #6
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    Put a mountain biker in a room with 2 bowling balls and we'll break one and lose the other - GelatiCruiser

  7. #7
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  8. #8
    Professional Crastinator
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    Yeah, I think that was 44oz. of Sierra Nevada Pale Ale talking...

    In short, I have increased my tire pressure.

    -F
    It's never easier - you just go faster.

  9. #9
    Ride Instigator
    Reputation: Ricko's Avatar
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    If you want to run that low of pressure...you need tubeless. I run UST at 28 psi, low 20's psi with tubes is just asking for pinch flats.

  10. #10
    The Original Suspect
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    The pressure you're running seems perfect for tubeless but I would say a bit low for tubes.

  11. #11
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    Quote Originally Posted by Fleas View Post
    Yeah, I think that was 44oz. of Sierra Nevada Pale Ale talking...

    In short, I have increased my tire pressure.

    -F
    Even shorter GOYFA and ride smooth

  12. #12
    Professional Crastinator
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    Quote Originally Posted by jeffscott View Post
    Even shorter GOYFA and ride smooth
    I had to look that one up. Not even a huh.

    Well, above a certain speed, smoothness is no longer possible. It's more about hitting "the gates" - those passages through the trail that offer the least resistance - ...and hanging on.
    Sometimes even the path of least resistance has a lot of resistance.

    -F
    It's never easier - you just go faster.

  13. #13
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    Quote Originally Posted by Fleas View Post
    I had to look that one up. Not even a huh.

    Well, above a certain speed, smoothness is no longer possible. It's more about hitting "the gates" - those passages through the trail that offer the least resistance - ...and hanging on.
    Sometimes even the path of least resistance has a lot of resistance.


    -F
    Get off Your FA

    Regardless of speed, terrain or difficulty one can always ride a little bit lighter.

  14. #14
    Anytime. Anywhere.
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    Why don't you want to go tubeless?
    I got some bad ideas in my head.

  15. #15
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    You're working with what you have like all of us and trying new things as necessary. I run tubes and low psi too. Not quite as rocky as PA. But here's some more ideas. 30mm inside rims can up your volume 24% or so. You will get better traction, sidewall support with less washout from fast rolling 2.2s. You can go 4-5psi less because of that volume. I'm 180+ and run 15 & 19 before I get rim hits. I use cheaper 26x2.1-2.5 tubes in 29x2.2s with no pinch flats this year or the last two seasons on 21mm rims.

  16. #16
    The White Jeff W
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    I ride my rigid bike tubeless around 20 psi front-25 psi rear. If I were using tubes I'd be changing 4 tubes every ride. Just sayin'
    No moss...

  17. #17
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    If I ran tubes in central Texas, I would have to walk more than ride, or fill my backpack with spare tubes instead of water.

  18. #18
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    There may be a lot of reasons to go tubeless but I agree with the OP that pinch flats aren't one of them. I run around 25# with tubes and if I went much lower I'd be destroying rims regularly, and tubeless wouldn't change that.

  19. #19
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    I've pinched at 40 psi, twice.

    The rule, as I've deduced it, is that the more pressure the less chance of a pinch flat, but there is no magic number where you can say you are safe from pinch flats. Carry spares.

  20. #20
    Professional Crastinator
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    Quote Originally Posted by jeffscott View Post
    Get off Your FA

    Regardless of speed, terrain or difficulty one can always ride a little bit lighter.
    True.
    You may understand then, that if you are bombing a smooth trail/fire road at ~25mph, staying smooth is easy - until the road is washed out from a flood - or, better yet, there is also a bulldozer parked on the side in preparation for the repair. Sure, you can try to be "smooth", but how smooth are you going to be at 25mph over all the rocks that were exposed when the dirt washed away, and there's a huge rut cutting diagonally across the road/trail. I suppose one can attempt to stop and walk over, OR, if one is so inclined, just hang on and point the bike in a logical direction - or do some sort of bunny hop across the rut, despite the presence of many rocks in the landing area. One can be as smooth as they want, but they will take some hits. If their tire pressure is too low, they may pinch flat or dent a rim. I've hit things hard enough to break an alloy spoke nipple on the front wheel - without flatting or crashing. It happens.

    I am running 28mm Velocity Blunt rims. They have been really good.
    Tires have been 2.1 Ignitors, 2.2 Tsali, 2.2 Pisgah, 2.3 Exi-Wolf, 2.4 Racing Ralph, 2.4 Ardent.
    It looks like pressure will be 23/25 F/R.

    Here's some slow riding.
    MTB Video: How many of you like slow, technical rocks like this?

    That vid links to others - there's actually an entire video of me riding "not smooth" at Vulture's Knob race course (it even says so in the vid!). You can also see how F my A is.

    -F
    It's never easier - you just go faster.

  21. #21
    Just a flesh wound
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    People still use tubes?
    My name is Chris and I ride a Prophet 650b with a Lefty.

  22. #22
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    Quote Originally Posted by Prophet Julio View Post
    People still use tubes?
    This.

    Tubes = obsolete.

    And yeah, 25 psi with tubes is WAY low. I weigh 175-180 I before I realized that tubes were obsolete I ran them 30 psi front and 35 rear. Then I realized there are zero advantages to tubes, so I shed some pounds, stopped fixing flats, and ran lower psi for more grip by switching to tubeless.

    :-P

  23. #23
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    I run tubes still but have a hard time understanding how I could run much lower psi. I get a couple rim hits at my current psi and if I dropped I'd be destroying rims. Are all you people who run ~ 20psi replacing rims every year? I go through about 2 tubes a year. 200# and run 26/32psi

    Honest question not just trying to stir the pot.

  24. #24
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    Quote Originally Posted by Prophet Julio View Post
    People still use tubes?
    Quote Originally Posted by pointerDixie214 View Post
    This.

    Tubes = obsolete.

    And yeah, 25 psi with tubes is WAY low. I weigh 175-180 I before I realized that tubes were obsolete I ran them 30 psi front and 35 rear. Then I realized there are zero advantages to tubes, so I shed some pounds, stopped fixing flats, and ran lower psi for more grip by switching to tubeless.

    :-P
    What these guys said. I guess I don't understand why you're so against tubeless.

  25. #25
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    20psi is dangerously low.
    .

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