Constant Flats

soundz

soundz

The Hat
Team MTBNJ Halter's
My fixie has developed some kind of issue with the tube in the rear tire constantly developing a gash. It's not like a regular flat in that the puncture in the tube is not a small hole, but more like 1/2" to 1" slit in the tube.

It's a 700c wheel and I have a 700x23c tire on it. It's a shraeder valve wheel. After I pump it up to about 100psi, the tube "explodes" (more like I hear a "poof" sound) sometimes within 5 minutes, sometimes 1 hour, sometimes the next day, sometimes when I'm moving it, sometimes when I'm riding it.

Here some stuff I've tried to remedy the problem w/ no success:

1) new rim tape
2) different tire
3) vacuum the inside of the rim
4) try 90 psi instead of 100 psi
5) presta tube with presta saver

I'm not sure if the tire size I'm using is right for the wheel. There's no markings on the wheel. Could this be caused by using a wrong size tire? How do you measure the rim for the correct tire size? I've gone through about 5 tubes already.
 
ebineezer said:
is there anything on the inside of the rim that might be puncturing the tube?
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I looked but couldn't find anything. Plus the puncture is in a different location all the time.

EDIT: I should also add that the puncture is sometimes on the tire side and sometimes on the rim side.
 
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I'd start with the obvious. Right size tubes ? Proper pressure for the tire and tube combo? Try a different floor pump, maybe your gauge if off. Try less pressure and go for a roll through the neighborhood. That the tube is splitting in a different place each time is bizarre. Is it a hard rim to seat the tire on, try a different tire may be an issue of pinching the tube between the rim and tire bead.
 
ryderX said:
I'd start with the obvious. Right size tubes ? Proper pressure for the tire and tube combo? Try a different floor pump, maybe your gauge if off. Try less pressure and go for a roll through the neighborhood. That the tube is splitting in a different place each time is bizarre. Is it a hard rim to seat the tire on, try a different tire may be an issue of pinching the tube between the rim and tire bead.
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One thing that's always seemed funny to me is that the 700x23c tire seems to fit kind of loose on the rim. I can take it off the rim with my hands with no effort at all. When I get home, I'm gonna try taking some measurements: http://www.sheldonbrown.com/tire_sizing.html

Also, I remembered that when I tried a different tire on it, it was a 700x20c. It seemed to fit a bit tighter .. I probably didn't have to use levers, but did anyway. Problem is I used a 700x23/28 tube on it cause I didn't realize at the time that it was a 700x20 tire.

Will post more info when I have it.
 
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Took some measurements and photos. Rim interior is about 15-16mm on the bigger gap .. 8-9mm on the inner, smaller gap. Photo:

tube.20090816.002.JPG


According to Shelden Brown, a 15mm rim should be able to take 23-32mm width tire, so my 700x23 tire should have been fine. Well, that tire is no more anyway, the last time I got the flat (Sat), the tube exploded resulting in tire failure:

tube.20090816.001.JPG


Gonna go pick up a new, cheap'ish 700x23c tire and hopefully I'll have better luck with that.
 
I'm used to 26er tires and havent had a problem ever with them. 700c tires are a PITA. I've had so many problems with loose fitting tires and flats.

Pump it up to like 20psi and then push the bead into the rim all the way around, make sure it's even. Unlike a 26er tire you have to make sure 700c tires are equal all the way around, or else when you pump it up the bead will blow out with a BOOM. Pump it up, push the bead it, pump it more and push the bead in make sure its equal all around. Keep doing it till its pumped all the way.
 
I washed out the inside of the rim with some water and put a cheap 700x25 tire on it. It seems all OK so far. Someone suggested to me that maybe shards of glass made it in to the tire/rim, so maybe that was it.
 
I am having an issue with constant flats myself. Its a brand new bike. We have repaired the front and rear tubes a few times. Come to find out there was a few thorns stuck in my tires. Has anyone else had this problem? What do you recomend to stop this from happening? My buddy and I were either thinking getting new tires or the tape for inside the tires.
 
You will pick up thorns its just something that happens. You should check your tire every time you change out a flat tube to make sure there is nothing like a thorn poking through.

The only real "fix" is going tubeless 😀
 
Ez-E said:
I am having an issue with constant flats myself. Its a brand new bike. We have repaired the front and rear tubes a few times. Come to find out there was a few thorns stuck in my tires. Has anyone else had this problem? What do you recomend to stop this from happening? My buddy and I were either thinking getting new tires or the tape for inside the tires.
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We typically do not have issues with thorns in our area. There are some out there but they only occasionally cause flat tires. Other parts of the country have different vegitation where thorns are nasty.

If the object that caused the flat remains in the tire, you should expect to get another flat pretty quickly. With every flat, you should inspect the tire casing in search of the cause. Carefully run your gloved hand along the inside of the tire feeling for a snag. 9 out of ten times you will find nothing. You will be thankful the one time you do.
 
I found most of the thorns, used a towel to run the inside when were it could catch you can find them. It just seems that every time I go for a ride i have flat.
 
Ez-E said:
It just seems that every time I go for a ride i have flat.
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Ride somewhere else!

I notice you are in Hamilton. Are you riding at Mercer CP? There is some plant that drop golf ball sized balls with thorns all over it. That could be your problem. If that is the case, it may be time to run a sealant in your tubes or go tubless with sealant.
 
Yes, I ride there and been riding Allaire, looks like Ill just have to go tubeless, it is just a PIA every time I try go riding the tires are flat, and with the nights getting shorter don't want to waste time changing tubes out.
 
Ez-E said:
Yes, I ride there and been riding Allaire, looks like Ill just have to go tubeless, it is just a PIA every time I try go riding the tires are flat, and with the nights getting shorter don't want to waste time changing tubes out.
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I used to have the exact same issue and I rode MCP a lot. I went tubeless ~ 2weeks ago and it seems to be working out OK. I have not been into the overgrown areas in MCP but I Can guarantee you I have run over a number of thorns, etc and no issues so far. I really suggest you look into this as an option. Like you said a major PITA to interrupt every ride to change a flat. Good luck.
 
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