Advertise on Bikeforums.net



User Tag List

Results 1 to 11 of 11
  1. #1
    Senior Member Ebbtide's Avatar
    Join Date
    May 2003
    Location
    Ohio's Cycling Capital, America's North Coast.
    Posts
    4,618
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Why do my tubes EXPLODE?

    I went through three tubes in 15 minutes

    I changed my worn tire for a new Conti. It is smooth and clean on the inside. My rim is clean and free of debris. Rim tape is in perfect condition. It is going on a 1982 27 inch clincher rim that appears to be "like new". Every time fill it up it explodes on the side opposite the valve stem. It blows the tire right off the rim

    I got the bike second hand and it held air in the previous tire w/o problem. It almost seems as if the tire is not hooking on the bead.

    It is a Japanese Bunchi Road bike.

    Any idea on what might be causing this?

  2. #2
    Senior Member nick burns's Avatar
    Join Date
    Oct 2004
    Location
    Absecon, NJ
    My Bikes
    Puch Luzern, Puch Mistral SLE, Bianchi Pista, Motobecane Grand Touring, Austro-Daimler Ultima, Legnano, Raleigh MountainTour, Cannondale SM600
    Posts
    2,941
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    The thing that pops into my mind first is maybe the tire's not seating at the valve stem location properly. When mounting the tire, make sure you push the valve into the tire a bit. That will allow the tire to get past the thicker part of the tube where the valve stem is and seat into the hook bead.

  3. #3
    Senior Member
    Join Date
    Jan 2005
    Posts
    211
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    What size are the original tires and what size are you installing?

    Many 27" tires have almost no ability to hook the rim. You have to line it up perfectly as you inflate it.

    One other problem could be with the rim. If it is damage it would casue the tire to hop off.

    Inflate to 30psi and use your hands or a vise to line the tire up to the rim, go up 10psi and do it again. Repeat untill you get to the desired pressure.

  4. #4
    Senior Member
    Join Date
    Jan 2005
    Posts
    211
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by nick burns
    The thing that pops into my mind first is maybe the tire's not seating at the valve stem location properly. When mounting the tire, make sure you push the valve into the tire a bit. That will allow the tire to get past the thicker part of the tube where the valve stem is and seat into the hook bead.
    His 27" tires and rims are probably flat sided, no hook.

  5. #5
    Senior Member Ebbtide's Avatar
    Join Date
    May 2003
    Location
    Ohio's Cycling Capital, America's North Coast.
    Posts
    4,618
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by r8ingbull
    What size are the original tires and what size are you installing?

    Many 27" tires have almost no ability to hook the rim. You have to line it up perfectly as you inflate it.

    One other problem could be with the rim. If it is damage it would casue the tire to hop off.

    Inflate to 30psi and use your hands or a vise to line the tire up to the rim, go up 10psi and do it again. Repeat untill you get to the desired pressure.

    27x1 1/4 for the same. I'll give that a try when I get home. I did seem to notice that the "hook" on these rims seem to be machined into the inside of the rim's sidewall, not rolled over/pressed like most rims I've used. This is also on the rear wheel, I have not problems with the front, but maybe got lucky?

    The rim does not appear dammaged.

    Thanks so far.

  6. #6
    Senior Member sydney's Avatar
    Join Date
    Jan 2004
    Posts
    9,428
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by r8ingbull

    Many 27" tires have almost no ability to hook the rim. You have to line it up perfectly as you inflate it.
    Wrong concept.Some 27" rims have no hook to retain the bead and are intended only for relatively low pressure.
    Last edited by sydney; 02-25-05 at 08:49 AM.

  7. #7
    Senior Member Ebbtide's Avatar
    Join Date
    May 2003
    Location
    Ohio's Cycling Capital, America's North Coast.
    Posts
    4,618
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by sydney
    Wrong concept.Some 27" rims have to hook to retain the bead and are intended only for relatively low pressure.
    I wonder if thats it? At 80 psi it holds, up to 110 it blows. The rims are just as narrow my other road bikes. I assumed they would handle the same pressures. Did early 80s technology only allow for lower psi in tires? If so, any problems running Conti 1000s at low psi?

    I will also add it takes about 3-4 minutes to explode after I fill it. Scared the hell out of me all three times too.
    Last edited by Ebbtide; 02-25-05 at 08:50 AM.

  8. #8
    Immoderator KrisPistofferson's Avatar
    Join Date
    Oct 2004
    Location
    POS Tennessee
    My Bikes
    Gary Fisher Simple City 8, Litespeed Obed
    Posts
    7,596
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I think perhaps the rims are manufactured for lower pressures, Most of the old school 27x1 1/4 tires I see have a max pressure rating of 90psi. I'm thinking maybe out and out "racers" back then were the ones using high pressure tires, if not "sew ups". But I might be a dumbass who's about to be flamed by a "retrogrouch"...
    Quote Originally Posted by Bikeforums
    Your rights end where another poster's feelings begin.

  9. #9
    Senior Member
    Join Date
    Jan 2005
    Posts
    211
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by sydney
    Wrong concept.Some 27" rims have no hook to retain the bead and are intended only for relatively low pressure.
    If you get the tire seated right you can run them at 90psi. Actually it sometimes take 90-100psi to get these in place just right. It seems that the pressure from the tube holds the tire in place with friction between the rim and tire, so the more pressure you get they tend to fit better.

    Does it pop off right away or does it sometimes take awhile?

    It seems that there is no true standard for 27" tires and rims, some tires have a small bead, some have no bead, and some 27" rims have what appears to be a regular bead. I've always been able to get the tires to work. Sometimes they take awhile. Every 27" tire have seen is an ISO 630, so they fit, just not right.

    Another thing, make sure the rim sidewall isn't bent or damaged. Make sure it's true also, that helps alot.

    When you get the tire to 30psi make sure the markings on the tire are sticking out from the rim evenly all the way around, inflate slowly and wear earplugs.

  10. #10
    Senior Member Ebbtide's Avatar
    Join Date
    May 2003
    Location
    Ohio's Cycling Capital, America's North Coast.
    Posts
    4,618
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    http://www.bikeforums.net/archive/index.php/t-52039

    I found this (^) thread, it answered my question. I'll try lower psi and walking the tire on.

    Thanks,

    Ebbtide

  11. #11
    Dog is my co-pilot 2manybikes's Avatar
    Join Date
    Jun 2003
    My Bikes
    2 many
    Posts
    13,629
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Most tires, probably a 27" tire, will say on the tire, Something like.......

    "max pressure 80 psi ~ 110 with hook bead rim".

    Meaning two maximum settings depending on if you have hook bead or not.

    I'm just using those numbers as an example I have no idea what your tires actually are. But if this bike does not have hook beads, and it seems like it does not, use the lower setting. Your are right you may have different maximum ratings.

    Also sometimes you may pinch a small part of the tube between the tire bead and the rim. This happens a lot. Before you inflate the tire to maximum pressure just put a few pounds in it and go around very carefully and move the side if the tire over a little and look for a small piece of tube pinched under the tire.

Posting Permissions

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