Results 1 to 12 of 12
  1. #1
    mtbr member
    Reputation:
    Join Date
    Mar 2013
    Posts
    4

    Never ending Pinch Flats, What did I miss?

    I'm around 6'4" and 240 pounds. I ride a stock Marin Hawk Hill '11 with WTB DX23 rims. I'm riding almost exclusively on asphalt until I get my fitness worked out and can run over a manhole cover without a pinch flat. I rode with the stock continental Mountain King 2.2's and got a pinch about every 5 Miles. I started at 30 Pounds and went up to 50 psi. Then I thought maybe the soft tires were hurting so I picked up some CST Chicopee's and still get a pinch every ride on asphalt. Today it happened on a bike path with no curbs, gutters, or bumps. I do tow a trailer with a 20 pound toddler, but it is exceptionally well balanced and doesn't put much weight on the bike. What am I doing wrong?

  2. #2
    No talent hack
    Reputation:
    Join Date
    Nov 2010
    Posts
    950
    It sounds like you may be set up for pinch flats when you install the tube into the tire. I weigh more than you are have never had a pinch flat running at 45psi on just about any tire I have had. If the tube is being pinched between the tire and rim, you will pinch flat every time. That is really the only reason I can think of to pinch flat at 50psi on a paved path.
    Fat guys need bikes too.

  3. #3
    mtbr member
    Reputation:
    Join Date
    Jul 2005
    Posts
    652
    It doesn't sound like a pinch flat. As said above, it sounds like a possible fault with the installation of the tube, or is there a problem with the rim? Is it the same wheel? Same point on the rim? I'm 10 lbs on you and have only had one pinch flat in all my time riding.

  4. #4
    mtbr member
    Reputation:
    Join Date
    Mar 2013
    Posts
    4
    Quote Originally Posted by TooTallUK View Post
    It doesn't sound like a pinch flat. As said above, it sounds like a possible fault with the installation of the tube, or is there a problem with the rim? Is it the same wheel? Same point on the rim? I'm 10 lbs on you and have only had one pinch flat in all my time riding.
    It seems to be the rear wheel only, but not in the same everytime. I thought about bad installation, but I will hold air for several miles, and then flatten very suddenly. It does seem to happen often with only one cut, not the two cut "snakebite" from when I can tell I hit something. I thought maybe when I lean into a turn hard I had the wrong size rim or something?

  5. #5
    No talent hack
    Reputation:
    Join Date
    Nov 2010
    Posts
    950
    That is not a pinch flat. There is something else going on. If you pinch flatted in a turn like you think, you would be on your ass real quick when the tire squirmed out from under you and rolled off the rim.
    Fat guys need bikes too.

  6. #6
    beater
    Reputation: evasive's Avatar
    Join Date
    Feb 2005
    Posts
    3,792

    Never ending Pinch Flats, What did I miss?

    Check your rim strip/tape, and make sure it hasn't bunched up into a ridge that is cutting your tubes. Sometimes the tire bead scoots the tape inward.
    "Back off, man. I'm a scientist." - Dr. Peter Venkman

    Riding in Helena? Everything you need to know, right here.

  7. #7
    mtbr member
    Reputation: GR1822's Avatar
    Join Date
    Jun 2009
    Posts
    2,147
    You are not pinch flatting. There is something wrong with your rim.

    Go tubeless. It will solve all of your problems

  8. #8
    mtbr member
    Reputation:
    Join Date
    Jul 2005
    Posts
    652
    OK - stop fixing the puncture and start looking for a cause.

    Does the rim have any imperfections, flat spots, sharp edges? Is the join from the rim manufacture still OK and hasn't deformed or got a gap / edges? Is the rim tape complete and sticking well to the rim?

    While you've got the tyre off and are inspecting the rim, closely examine the tyre. Does it have any cuts or abrasions or imperfections on the inside? Is the bead good all round the tyre? Have you ever put some talcum powder inside the tyre? This helps stop the tyre and tube binding.
    When you fit the tyre and inner tube, how are you doing it? Tyre bead off on one side, put a couple of pumps of air into the inner tube before fitting - it makes things a bit easier. Then put the valve in and locate the inner tube on the rim / inside the tyre, then pop the bead back on all the way around. Check the inner tube isn't trapped between teh bead and the rim and start to inflate.
    A top tip is to get about half pressure in, then stop pumping and grab the tyre with both hands together and work it back and forth on the rim a couple of times. Work your hands around the wheel doing this. It really makes sure the tyre is properly seated before you get back up to full pressure.

    Sorry that is a bit long-winded and might be teaching you to suck eggs in places, but I'm just trying to cover everything it might be in one post.

  9. #9
    mtbr member
    Reputation:
    Join Date
    Mar 2013
    Posts
    4
    Quote Originally Posted by TooTallUK View Post
    OK - stop fixing the puncture and start looking for a cause.

    Does the rim have any imperfections, flat spots, sharp edges? Is the join from the rim manufacture still OK and hasn't deformed or got a gap / edges? Is the rim tape complete and sticking well to the rim?

    While you've got the tyre off and are inspecting the rim, closely examine the tyre. Does it have any cuts or abrasions or imperfections on the inside? Is the bead good all round the tyre? Have you ever put some talcum powder inside the tyre? This helps stop the tyre and tube binding.
    When you fit the tyre and inner tube, how are you doing it? Tyre bead off on one side, put a couple of pumps of air into the inner tube before fitting - it makes things a bit easier. Then put the valve in and locate the inner tube on the rim / inside the tyre, then pop the bead back on all the way around. Check the inner tube isn't trapped between teh bead and the rim and start to inflate.
    A top tip is to get about half pressure in, then stop pumping and grab the tyre with both hands together and work it back and forth on the rim a couple of times. Work your hands around the wheel doing this. It really makes sure the tyre is properly seated before you get back up to full pressure.

    Sorry that is a bit long-winded and might be teaching you to suck eggs in places, but I'm just trying to cover everything it might be in one post.
    The only thing I haven't been messing with is Talc. The tire goes on without any irons. I can just work it around by hand. I put enough air in the tube for it to hold it's shape, but not expand, and then I work the tire onto the rim. (I'm only removing one side of the tire.) I can't tell if there is a problem with the rim, because it seems to have 2 sets of 4 holes drilled on a few places that are outside of the rim tape, but they appear to be factory. I didn't think they were the problem since they holes are in different places. Always on the wheel side, and have the "slit" shape as opposed to a thorn hole shape. I'll give the talc a shot for the next go along with the second tire massage.
    Thanks all for the replies. This is driving me a little mad.

  10. #10
    mtbr member
    Reputation:
    Join Date
    Oct 2007
    Posts
    28
    Replace the plastic rim tape with cloth rim tape. The plastic can split in the middle over a spoke hole, the split is opened up by the tube under pressure.

    or go tubeless !

  11. #11
    mtbr member
    Reputation:
    Join Date
    Jun 2013
    Posts
    118
    I agree with trying tubeless. I have not tried tubeless but I have never gotten a pinch flat. It seems like the conversion is pretty simple depending what wheels you have. That is a real pain having to fix it constantly.

  12. #12
    mtbr member
    Reputation: Bigb2000's Avatar
    Join Date
    May 2013
    Posts
    279
    My thoughts are that something sharp is stuck into the tire and poking a hole, or a spoke nipple is at fault. Next time you change it, feel inside the tire all the way around to feel for something sharp. It also helps to inflate the tube a little, around 5psi before mounting. If using a cheap tube, maybe switch to a better one. Flats suck and you seem to be blessed with them.

Similar Threads

  1. Tubeless, and still too many pinch flats...
    By JulianPeeters in forum 29er Bikes
    Replies: 31
    Last Post: 06-05-2014, 10:47 PM
  2. Pinch Flats?
    By fooldall1 in forum Beginner's Corner
    Replies: 8
    Last Post: 07-09-2013, 09:26 AM
  3. Trails with relentless goatheads, non-ending flats, what do you use?
    By ascarlarkinyar in forum Bikepacking and Bike Expedition
    Replies: 21
    Last Post: 12-11-2012, 12:29 PM
  4. Pinch flats
    By The Grimmer in forum All Mountain
    Replies: 28
    Last Post: 05-01-2011, 03:43 PM
  5. Pinch flats
    By biopacebob1 in forum 29er Bikes
    Replies: 20
    Last Post: 04-22-2011, 12:00 PM

Posting Permissions

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