Urgent help replacing a flat
 

OK this is really embarrassing but I really don't want to miss tomorrow mornings ride so help me out if I am doing something wrong. If nothing else, venting may help keeping me from going insane tonight...

So I got a flat (rear wheel) on my last ride. It was very close to home so I limper home and postpone it until today to change the flat.

Its getting late so I quickly change the flat. I put the wheel back on. I turn on the mini compressor to fill the tire up while I tidy up some mess in the garage. The tire blows up. It scares the bejeebus out of me. It scares the bejeebus out of my wife.

Well, what can you do? Maybe the tube got pinched while I was in a hurry. So I change the blown tube again. Veeeery careful to check that there's nothing protruding from the tire, that the tube is completely seated in the tire etc. I pump it up in stages: first up to 40 PSI So far so good. then to 115PSI (I usually ride at 120). So far so good. I pump up the front as well and I think may be I go for a quick spin around the driveway... And then BAAAM the back tube blows up again!!!

I've been swearing in 6 languages for half an hour but I still wanna ride tomorrow morning and I have only one more spare tube left.

What can I possibly be doing wrong? I am no Shelden Brown (RIP) but I've easily changed a dozen tires over the last year, often on the road with no such problem ever. Should I go to the LBS and rip him a new one that the tubes he sold me are defective?

HELP!!!

I have done the same exact thing with new wheels, new tires and new tubes.

You are pitching the tube.

Remove tire, Blow up tube with your mouth. Place tube inside tire.
Put one side of the tire on the rim. Put the remaining side on the rim.

Add about 20 lbs of air. Check both side of the tire for any out of roundness.
Finish airing the tire.
Install on bike.

Hand pumps are better than a compressor.
Good Luck.

Are the tubes blowing up in the same area?
If it's the same brand/model, might be a factory defect.
But more likely, you're pinching the tube.
Try putting some air in the tube before mounting,
if it gets really tight when you get to the last part;
let the air out. Watch for any bulging on the tire
while pumping. Good luck.

Do you have a spare tire? Try a new tire and tube and see what happens. If it happens again, maybe there is something sharp inside the rim, whether part of the rim itself or something foreign.

Its same brand, model, batch of tubes. both blew up close to but not exactly at the vent.

The second time around, I filled up the tube, then let the air out and only then went about putting it back on the wheel. Should I put it in the tire and on the wheel with more air? As you know it does make the process a bit unwieldy. Once back on I did fill it up to 40PSI spun it around : seemed fine. when I pumped it to 115 PSI spun it around again: I saw no protrusions/ pinches...

I am not trying to be defensive. its just I have only one more tube left and I'm not really sure how I can possibly be more careful than last time.

BTW guys many thanks for responding at that ungodly hour.

You may also have sliced your sidewall by limping home on your flat tire. The slice might be quite close to the rim, so try about 40-50psi and then examine verrrrry closely for the tube herniating through the sidewall anywhere on either side.

Also notice how the tube's built-up around the base of the valve... before you begin inflation, push the entire valve into the rim far enough to make sure that thick base is up in the tire casing, so it doesn't prevent the tire beads from seating under the hooked edges of the rim.

Bigger picture: I wouldn't want to go on a group ride with a tire that habitually blows off the rim. Might be best to get yourself a new tire if there's any uncertainty about this one.

I do have another tire (Serfas Seca) but I'd rather use the current (GP 4000). the sidewalls seemed not more damaged than before. With the delivery times of PBK it would be tragic if these blow ups somehow have damaged the tire too.

Anyway, I'm going to sleep now and tomorrow with a fresh mind will give it one last even more careful try.

If it blows up again, I'm going to the LBS.

Thanks again.

Did you damage the rim the first time around? (hope not!)

sounds exactly like a worn, or out of alignment rim strip. as you put pressure in the tube it presses against the sharp edges of the holes in the rim harder and harder, until you puncture. check the rim strips to make sure no hole edges are exposed, and that the strip itself is thick enough to prevent the sharp edges from protruding through. if in doubt go to a cloth rim strip like velox as opposed to a plastic one, those suck.

it could also be that whatever flatted your tire originally is still in there.

I tend to think something might have still been inside the tire, that is, if you didn't swipe your fingers a few times on the inside of the tire, itself. My second thought would be that, despite your careful examination, you pinched the tube.

As per the sliced sidewall, I suppose it's possible, but it would have to be one heck of a slice and you would have seen the tube pushing through to the outside world.

I hope you had a good ride this morning.

At the risk of asking a dumb question (but this is the 41), did you check to see where the failure seemed to occur and then match that to an area of the tire/rim?

My thought as well is something is still in the tire.

yeah, check the tire. take it off the rim and check carefully all the way around the inside for anything sharp.

I've had the same issue as well... Could be multiple things.

1) Always always check the inside of the tire for protrusions and debris. You can generally (but not always) feel them. A piece of wire, a piece of glass, a thorn, whatever. Make sure you're starting clean! :)
2) Always mount your tires the same way -- I always put the manufacturer logo in line with the valve stem. Compare the puncture location on the tube with the same location on the tire. What passed the feel test (step 1) may show up in a visual examination. Sometimes a piece of debris embedded in the tire won't rear it's ugly (and sharp) head unless under pressure.
3) Always partially inflate the new tube by mouth to give it some shape.
4) Always mount the tire/tube back on the rim by hand if possible, being careful not to pinch the tube.
5) Check for pinches all the way around before adding any air
6) Add ~30-40 PSI and check for pinches again
7) Fully inflate, listen for leaks, etc.

Sounds obsessive but I've had your problem before.

And, as you mentioned, sometimes you do get bad tubes. I've had a batch of bad ones and it drove me absolutely nuts. I ordered another set of tubes and suddenly the blowouts stopped.

Good luck! I hope you find the root cause.

I've had that happen once, and it turned out to be a problem with the rim strip not covering the spoke nipple properly.

Edit - although Phantoj may be right, I dont recall the tube going "bang". It let go with a pretty loud hiss though, scaring the crap out of both my dogs that were sleeping next to the bike (they both looked very sheepish afterwards).

wrong! "bang" means the tube got outside the tire casing somehow (probably was pinched between the bead and rim)...

Me too. It's frustrating because you're usually not in the habit of looking at the rim side of the tube. That little problem cost me 3 tubes until I finally figured it out.

wrong! See above -- blowouts occur when the tube escapes from the tire somehow.

Could be pinched tube or damaged tire (sidewall or bead) or damaged rim. Or simply too much pressure, LOL!!

Update:
Bought a new different model tube from LBS this morning (after the ride left of course) : same steps as before and no blow out this time.

It can't be a something in the tire even if somehow I missed it twice : it would hiss not blow up so that the whole hood can hear. I did look carefully the second and third time around at the rim tape and though I am not a specialist I saw no sharp edges etc. Besides why would it blow and not simply puncture/hiss?

It is either two pinches one after another (even though I was careful god damn it!) or bad batch (same operator but no blow out with the third tube I put today).

Bottom line: today is min 60 - max 73 degrees but I did not ride. I am bummed and and at work...

P.S the tears are not exactly at the same spot; both are on the rim side but a bit off center.

Pump up the tube to about 5 psi, check all around the wheel to make sure the bead is seated, and the tire isn't pinched. Finally, jam the valve stem back into the tire to make sure the tire bead at the stem gets below the tube. That's the area where the bead is most likely not to seat well. Pushing up the valve stem lets the bead get around the tube and seat properly.

This is a likely cause. If you don't push the valve down into the tire, the edge of the tube can be caught under the bead right at the valve. Then it eventually pushes the bead off, blows up like a balloon, and Bang!