Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 06-12-02, 06:55 PM   #1
Dirtgrinder
Dances with Rocks
Thread Starter
 
Dirtgrinder's Avatar
 
Join Date: Apr 2001
Location: Jefferson City, MO
Bikes:
Posts: 1,441
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Tire/tube question

Trying to reach a conclusion on my blowout.
The tire is a 700c x35. The tube in it was 28x1. What I'm wondering is if the tube being so big blew the tire off of the rim. That's exactly what I think happened. I just aired the tire up to 80psi. (tire is 85 max.) Then I took off and it blew. Tire is fine. Tire was also over the edge of the rim after it blew. The split in the tube was 15" long. Am I right? What do you think? I'm going to check the rear tomorrow and see what tube is in it.
__________________
If everything seems under control, you're just not going fast enough...

To become a registered member of BikeForums Click Here
Dirtgrinder is offline   Reply With Quote
Old 06-12-02, 07:10 PM   #2
ljbike
Senior Member
 
Join Date: Jul 2000
Bikes:
Posts: 1,049
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Continental marks their 700 tubes as 28". A !" tube is actually 22mm. I don't think it's a question of the tube being too big, but I really don't have any other ideas either.

Whenever this has happened to me, it was because I didn't have the tire seated properly on the rim. But, from what you have said, you've eliminated that possibility.

Let's hope there are some wiser members who will comment.
__________________
ljbike
ljbike is offline   Reply With Quote
Old 06-12-02, 08:23 PM   #3
John E
feros ferio
 
John E's Avatar
 
Join Date: Jul 2000
Location: www.ci.encinitas.ca.us
Bikes: 1959 Capo; 1980 Peugeot PKN-10; 1981 Bianchi; 1988 Schwinn KOM-10;
Posts: 17,050
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 65 Post(s)
Today's Contis require a hook-bead rim. If the inside sidewalls of your rim are smooth, the tyres will tend to blow off the rim.
__________________
"Early to bed, early to rise. Work like hell, and advertise." -- George Stahlman
Capo [dschaw'-poe]: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger, S/N 42624
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1981 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069
John E is offline   Reply With Quote
Old 06-12-02, 08:59 PM   #4
Dirtgrinder
Dances with Rocks
Thread Starter
 
Dirtgrinder's Avatar
 
Join Date: Apr 2001
Location: Jefferson City, MO
Bikes:
Posts: 1,441
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
This was a Kenda Kwik cyclocross tire if that helps any.
__________________
If everything seems under control, you're just not going fast enough...

To become a registered member of BikeForums Click Here
Dirtgrinder is offline   Reply With Quote
Old 06-14-02, 05:45 AM   #5
D*Alex
Banned
 
Join Date: Aug 2001
Location: upstate New York
Bikes:
Posts: 1,688
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Using a too-small tube is a common practice with many slip-shod bike mechanics. This way, they only need to keep a few sizes on hand, and the skinny tube is easier to mount than a larger one is.
A 1" tube is made for a 25mm (roughly) tyre, wheras your tyre was about 35mm. That means the tube was stretched preety d@mn thin at full inflation. You may also have a slighly rough inner edge on your rim. This might not be a problem when using a proper sized tube, but when your tube is already stretched out like a balloon, well, it's gonna blow to kingdom come!
Another problem with using a too-small tube-when you get a puncture, then patch the puncture hole, your patch will often blow off while inflating inside the tyre! Always use the proper size tube.
__________________
Je vais à vélo, donc je suis!
D*Alex is offline   Reply With Quote
Old 06-14-02, 10:57 PM   #6
pat5319
Senior Member
 
pat5319's Avatar
 
Join Date: Sep 2000
Location: Spokane WA
Bikes: Seven Axiom Ti, Trek 620, Masi cylocross (steel). Masi Souleville 8spd, Fat Chance Mtn (steel), Scwinn Triple Bar cruiser, Mazi Speciale Fix/single, Scwinn Typhonn
Posts: 1,141
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Hmm, Interesting THEORY about a 25mm tube getting blown up enough in a 35 mm tire, (10mm difference), to make it so thin it's going to rupture. I've never seen it proven in nearly 30 years of riding and racing, including over eight years working in some VERY respected shops. It's also interesting that mechanics who've provided neutral support in several Olympic Trials or who've been assigned to work the "Giro" for their team have actually recommend using a smaller tube than tire to save weight, to make installation quicker and easier and less likely to have seating problems because of the reduced bulk to deal with.
I've used smaller tubes in my tires for DECADES with only POSITIVE results, imagine that!!! (I've used same sized tubes as well and PREFER to use the "skinny ones"). Of course there are limits, but, ( I believe), they're a bit more than 10 mm.

A tire "blowing off" of a rim is almost always the result of poor seating, usually when an edge of the tube is caught under the rim or when the rim isn't seated evenly around the rim. Also the "hook bead" problem mentioned above is definitly a cause as well.

I guess we all have different experiences and opinions and need to check the credibilty of our sources of infomation- I KNOW I'm not omniscient.

Ride with an open mind
Pat

Last edited by pat5319; 06-16-02 at 02:42 AM.
pat5319 is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 04:26 AM.