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  1. #1
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    Road bike tyre pressure

    Hi everyone,

    Seems I wrote a long and detailed post and it somehow didn't get posted, so here I go again. I've just had my first flat on my road bike, a slow leak. I am currently around 212lb and give the tubes maximam rated pressure, which is 120psi.

    So I went to replace the tube whcih was easy enough. The trouble was when I pumped it up to 120 it blew out. I tried it again with another tube and got the same result and it felt like I might go deaf. The third tube I tried I only pumped it up to 100psi because I was getting a bit squeamish.

    So, what is a good pressure to run road tyres at? Could I possibly just had some bad luck with tubes?

    PS - There is a thread of tyre pressure in the sticky, but it concerns more MTB tyres and tubes.

    Thanks
    I want to live.

  2. #2
    Galveston County Texas 10 Wheels's Avatar
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    The tubes that blew out were pinched in between the tire and the rim.
    Most of us have done that.
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  3. #3
    Triathlon in my future??? flip18436572's Avatar
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    I run mine at 120. I think you probably had the tube between the rim and the tire. I have run them at 130 and never had a tube blow out while pumping it up. Either that or you have a bad bunch of tubes.
    2007 Jamis Ventura Comp
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  4. #4
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    Like 10Wheels said, probably a pinch between the tube and the rim. What happens is the tube is not inside the tire correctly, part of it is pinched between the tire and the rim.

    When you put the tube on, put a little bit of air in it so it has the basic tube shape it will have inside the tire. If it is too hard to mount, you put too much air in. Let a little out. After you get it mounted, put just a little more air in it and then squeeze the tire together and look between the bead of the tire and the rim and make sure you can't see any of the tube. I go all the way around the rim, checking to see if the tube is pinched anywhere. Then inflate.

    I run my rear tire at 120, front at about 100 and I weigh more than you do. That is on 25's. You should be able to run 120, but you may not need to. What size tire are you running?

  5. #5
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    hI,
    Be sure tire didn't get damaged at the bead, I had a rather expensive tire that ripped the kevlar bead cord after a blow out and every time I aired it up to around 120, the tire would slip alittle at the bead and it would blow out at the rim..
    Anoter trick is to inflate the tube alittle where it stays in tire and then mount one side of the the rim, this prevents the tube from being folded over as the bead is mounted. Try to only use your fingers when you set the bead thats why I use talc it help it slip on easier.,tire tools can cut tubes our pinch them when mounting.
    Some people also use a little talc on the tube makes it slippery helps seat the bead., or windex so it will slide around in the tire as it inflates.
    I usally only go up to 90 psi let all the air out of the tire completly and check for tube at our near the rim it should not be visable. Always inflate off the bike if you can that way the rim seats evenly. I saw all these idea's on the Bike repair forum by the late Sheldon Brown I try and read every time I can about mechanically problems and quick fixes..
    Some of the Vittoria folding tires are rated to 150 PSI perfect for us clydes. They cost more but seem to wear very well, I bought mine on the Bike Island free shippin.
    Doug
    http://sheldonbrown.com/flats.html


    tire I like and I weigh 230 I keep the front at 110 psi the rear at 135 psi they roll very fast seem almost fluid contact with the road.
    TR3417: Vittoria Diamante Pro 700x23c Black
    Last edited by djnzlab1; 01-22-10 at 09:08 AM.

  6. #6
    Banned. Mr. Beanz's Avatar
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    Quote Originally Posted by MrClyde View Post

    When you put the tube on, put a little bit of air in it so it has the basic tube shape it will have inside the tire. If it is too hard to mount, you put too much air in. Let a little out. After you get it mounted, put just a little more air in it and then squeeze the tire together and look between the bead of the tire and the rim and make sure you can't see any of the tube. I go all the way around the rim, checking to see if the tube is pinched anywhere. Then inflate.
    This!....I use enough air to make sure th tube has a chance to seat inside the tire. Then I use both thumbs on one side to push the tire aside looking for teh balck rubber of the tube taht may be pinched. This is very improtant. I've seen too many riders just install the tire and go with the same results you are having. DANGEROUS!

    Another thing I do at this time, is push the valve stem up into the tire so that it pops into place. Seems to be one of the trouble spots so it's actually the first thing I do.

    I've run 120 for 12 years while riding at weights of 220-245 lbs with no problems.

    BTW, you can tell if a tire is not properly mounted by spinning it and watching the line of the tire bead as it spins. If it is not consistent, there's a problem, not seated properly.

  7. #7
    Banned. Mr. Beanz's Avatar
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    Avoiding the pinched tube 101

    Place air in tire, push sidewalls wit both thumbs to enure proper seating or tire bead onto rim. Also make sure rimstrip/tape hasn'tmoved to side exposing spokes and that the tube is not pinched.


    Grab hol dof valve stem (pic 1) then push into rim (pic 2) to relieve any binding or pinched rubber surrounding teh valvestem



    Final check
    Spin wheel to verify that the tire bead is seated on the rim properly. Tire bead should be consistent. Notice the line of the bead I highlited. While tire is spinning, it should be uniform. If thre is a bump in the line, something is wrong which means the tire is not seated properly.

  8. #8
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    I agree with pinch flats and FWIW I ride 110 on front 120 on back.
    Best thing about cycling is when I'm at work I'm thinking of cycling, when I'm cycling I'm thinking about cycling.

  9. #9
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    This is a pretty good way to determine what tire pressure to run...

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