Advertise on Bikeforums.net



User Tag List

Results 1 to 10 of 10
  1. #1
    J B
    J B is offline
    Just Ride
    Join Date
    Jul 2006
    Posts
    54
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Tire Blow Outs!!! (Question about Tire Size & Rim Size)

    Hope someone can help,
    After replacing tires and the tubes on an old 10 speed with 27" wheels. I had two blow outs in three days. I am convinced that when I put air in the tires the tubes are actually lifting the tires off the rim slowly and when it lifts enough the tube comes out and BANG!!!.

    One went BANG while I was eating dinner last night.

    The guy at the LBS when selling me the tires showed me two tires one was smaller and lighter and the other was larger and much cheaper. I went with lighter and smaller. I asked him how much air should I put in them. He said just put in what it says on the tire.

    Tire: Cyclepro Discovery 27" x 1 1/8. 105 lb.

    Tube: Cyclepro on the tube box:
    700X28-35C
    27x1/8 - 1 1/4

    Rim: ARAYA 27 X 1 1/4 W/O HP. Japan

    Last night I put just 85 lb's in and this morning I can see a white line starting to show just below the gumwall. With time this white line gets bigger. I am convinced that the tube is actually lifting the tire off the rim even at 85lb's

    I asked the guy if it was OK to use tires that say 27"x 1 1/8 when the rim says 27"x 1 1/4 and he said it was fine.

    I have attached a picture of the blow out. Both tubes went the same way.


    Any thoughts about this?

    Thanks for your help,
    J B
    Attached Images Attached Images

  2. #2
    Senior Member Old_Fart's Avatar
    Join Date
    Mar 2006
    Location
    In a cardboard box by Alki beach.
    Posts
    347
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Most likely it is a problem with the tire's manufacturing tolerances, but there are a couple things to look at before trying a different brand of tire from a different shop.

    Before mounting the tire make sure the rim tape or strip is centered in the rim and not riding up the side of the rim. If it is off center it could be keeping the tire bead from fully seating.

    When you put the tube under the tire, put in just enough air for the tube to take shape. This will help keep a fold in the tube from lodging under the edge of the bead and keeping the bead from seating.

    When you pump up the tire, start out with about 30 psi., maybe even a bit less. Take the wheel and go around both sides of the tire rolling the tire away from you a bit and checking the bead to make sure it is sitting evenly in the groove on the rim and making sure that there is nothing like the rim strip or the tube keeping the tire from sitting in the groove. Also if the bead is sitting too low in the rim on one side it will be sitting too high on the other side and can blow out.

    Having said all this, my guess is that the tire is just poorly manufactured and is slightly too large in diameter to sit properly in the rim groove. There are still good quality 27" tire to be had but most LBSs don't stock more than one or two choices.

  3. #3
    You need a new bike supcom's Avatar
    Join Date
    Aug 2002
    Posts
    5,434
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Almost certainly your problem is that you are using high pressure tires on an old smooth bead rim. You need a new style rim with a ridge on the inside of the sidewalls to prevent the tire bead from slipping off. Either that, or reduce your pressure until you stop blowing tubes.

    When your bike was built, the tires were not designed for high pressures and so it wasn't a problem.

  4. #4
    The Improbable Bulk Little Darwin's Avatar
    Join Date
    Jul 2005
    Location
    Wilkes-Barre, PA
    My Bikes
    Many
    Posts
    7,381
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    +1

    http://www.sheldonbrown.com/harris/tires/630.html

    Generally, the "rule of thumb" for traditional 630 mm (27 inch) tires is that they should be inflated to 70-75 psi. This shouldn't be a problem with any tire, despite whatever disclaimer the manufacturer puts on the sidewall. However, if you're restricted to this pressure range, you probably shouldn't be running tires narrower than 1 1/8, or preferably 1 1/4, unless you're a very lightweight rider.
    Slow Ride Cyclists of NEPA

    People do not seem to realize that their opinion of the world is also a confession of character.
    - Ralph Waldo Emerson

  5. #5
    J B
    J B is offline
    Just Ride
    Join Date
    Jul 2006
    Posts
    54
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by supcom
    Almost certainly your problem is that you are using high pressure tires on an old smooth bead rim. You need a new style rim with a ridge on the inside of the sidewalls to prevent the tire bead from slipping off. Either that, or reduce your pressure until you stop blowing tubes.

    When your bike was built, the tires were not designed for high pressures and so it wasn't a problem.

    Yes you are correct! These rims are smooth bead rims. They are in perfect condition and I would like to keep them on this bike. Do you think if I lower the pressure around 75lbs the bike will provide the same kind of ride it was capable of when it was new? I don't mind lowering the tire pressure if I don't have to give up original performance. Or would you recommend get the same kind of tires the bike came with (if possible). The original tires are so bad the only thing I can read on it is "High Racer"

    Thanks for all the responses,
    J B

  6. #6
    J B
    J B is offline
    Just Ride
    Join Date
    Jul 2006
    Posts
    54
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Wanted to update all of you. Having a hard time reading my old tires but it looks like the recommended tire pressure was 90lbs. I think 90lbs could be to much to ask for the new tires on these rims.

    Any other thoughts,
    J B

  7. #7
    The Improbable Bulk Little Darwin's Avatar
    Join Date
    Jul 2005
    Location
    Wilkes-Barre, PA
    My Bikes
    Many
    Posts
    7,381
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    I believe if you go to the page I linked to on Sheldon's site, he says you are likely to be OK with new tires as long as you don't inflate to over 70-75 pounds. Even though the tires say they must be used with hooked rims, this is likely the case because of the higher pressure rating.

    I think because of the lower pressure I would go with 27 x 1 1/4 at 70 psi... instead of anything narrower. This should be big enough and high enough pressure to avoid pinch flats. and should ride as well as the bike did originally.

    Good luck!
    Slow Ride Cyclists of NEPA

    People do not seem to realize that their opinion of the world is also a confession of character.
    - Ralph Waldo Emerson

  8. #8
    J B
    J B is offline
    Just Ride
    Join Date
    Jul 2006
    Posts
    54
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Little Darwin,
    Yes I did check out that page and I do agree with you. I would have liked 27 x 1 1/4 but LBS dude says 27 x 1 1/8 would be fine. I do disagree with him. Had these tires for about a week. For some reason I don't think he would be happy with me returning them. Although, I did bring rim /w old tire in for him to look at. At his request.

    Are there any vintage tires available for these old bikes these days? Can anyone recommend a good one?

    Thanks again,
    J B

  9. #9
    You need a new bike supcom's Avatar
    Join Date
    Aug 2002
    Posts
    5,434
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    The width of the tire is probably not the issue. However, you might check harriscyclery.com for narrower 27" tires.

    Even though the rims may be in great condition, if they are steel and you plan to ride the bike much, you would be well advised to replace the rims with aluminum. You will get much better braking performance in wet conditions. If you don't wish to have the wheels rebuilt, you might check Harris Cyclery for a set of new 27 inch wheels with freewheel rear hub.

  10. #10
    J B
    J B is offline
    Just Ride
    Join Date
    Jul 2006
    Posts
    54
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Supcom,
    They are aluminum and they are in like new condition. Replacing them at this point is not an option.

    Thanks for your response,
    J B

Posting Permissions

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