So it starts out a few days ago when I replaced my tubes in both my tires. I bought some Forte Lunar Lights from Performance and decided to try them out. Pulled my wheels, deflate them, and realize I don't have any tire levers (I haven't changed a tire in years). So I figure what the hell, I'll try it without and if I need them, I'll make a trip to the shop.

So everything goes well, deflate, pull the tires off the rims working them over the edge with my thumbs, seems easy. I swap tubes, get the tires put back on the rims, and go around the edges to make sure the tire is in. I pump them up to the 100psi recommendation, and put my wheels back on my bike. I hang it back up from the J hooks in my garage, and go back into the house.

A minute or two later I hear a "bang" like something fell and hit the ground. At first I thought it came from somewhere in the house, but then when I go to the garage and look at my bike, I see the tire is popped off the rim on one part, and obviously the tube blew. I figured I didn't seat it correctly, and the pressure blew the tire off. So I replace the tube with the spare Lunar Light I bought, and everything seems well. I was extra careful to check the bead after that.


So that was Thursday. I rode to school Friday, and Monday on the tires after that (7~8 miles each day) and the tires seemed to feel much much better than before. Not sure if the tubes could actually make a difference, but the wheels felt 100x better.

So then yesterday on my ride to and from school I start feeling something weird. When I brake to a stop, it feels like the headset is loose and wobbles just before I come to a start. I check the headset and it feels perfect. Then I think maybe there is something wrong with my brake track causing it, but I can't see anything wrong. Then it starts feeling like the spokes in my wheel are flexing when I stop, kind of rubber-band-esc. It only seems to happen when I brake to a stop.

So I get home, a little unerved, and hang my bike back up in the garage. I go into the house, sit down, an hear BANG! Go into the garage, and my front tire blew off the rim. It was the back tire before btw.





Does anyone have any ideas of what I could be doing wrong? This seems abnormal to say the least.


Also, Clif notes for the reading impaired:

Changed tubes for Forte Lunar Lights
Tire blew off rim while bike was in garage
Changed tire again
Worked for a few days, rode really well
Started feeling weird loose feeling when stoping
Tire blew off again while bike was in garage

A common cause of that is when your tube slips past the wire bead of the tire and forms a bubble. The wheel can be ridden on it like this, but it will eventually explode. Make sure the tube doesn't get between the tire and rim. Once the tire is mounted you can "roll" the tire away from the rim on both sides with your fingers to peak in between the rim and tire and make sure it isn't. That or your tire isn't seated correctly.

There might be something wrong with your garage. I'd check that out.

Yeah, I had an explosion while the bike was sitting in the apartment. Mine was due to overinflation, though.

I had that problem once when I inflated my tires outside in the winter, when I brought the bike inside the air expanded with the heat and exploded. It sounded like a gun shot and my ears rang for a few hours afterwards.

Either:
1. tire bead wasn't seated all the way around in the rim hooks or
2. tube wasn't inserted fully inside the tire

Hint:
1. pump the tube up a little to give it some shape before inserting in the tire
2. after mounting the tire, pump it up half way and inspect the bead, then pump up the rest of the way and inspect the bead again

Reading impaired over here so a quick analysis is in order: you messed up somewhere, or as as sd790 pointed out, there is something going on in that garage.

You probably have #2 on the above list, causing a pinch flat, but might also need to replace your rim tape. You can get big bangs and unseated tires that way, too. Don't ask me how I know that.

Inflate the tubes slightly before mounting so the tubes don't get pinched and caught. Use powder. Check the tires all the way around the rim so that the tube isn't outside the bead before inflating.

Definitely inflated the tubes partially to help get them into the tires, and I check the bead after I got the tire on, but perhaps I wasn't careful enough. I also didn't use powder, I will try this next time to make sure the tube doesn't get caught on anything.

Also, I'm using Ksyrium Elites so no rim tape on these.

I pump up the tube just enough for the bead to seat - probably less than 10 psi. Then I go around the rim and give the bead another push around both sides. I check to make sure that everything is seated properly. Only then do I inflate to the full pressure.

I had a flat with a lunar the 1st time I rode on it after zero flats in years. I'm not convinced they're worth their weight savings. They are much lighter than stock tubes, though.

I notice that the tire blew off right at the valve. Presta valve right? Do you use the nut to secure the valve to the rim? If so you may be doing that before the tire bead is seated. You need to push the tube into the rim when you seat the rim and I suggest not tightening it till you get pressure in the tube. If you tighten the valve nut first, it sucks up to the edge of the rim and displaces the tire. Personally ater I did exactly what you did, I stopped using those little nuts.

Spot on, especially if both tires blew at around the same spot (i.e., right near the valve).

I've found it helps me to use this process:

- insert the tube, mount the tire, check all the way around the tire bead on both sides.

- inflate the tube just a little bit and check AGAIN all the way around the tire bead on both sides.

- Be very sure and push the valve stem up into the tire so the fat part of the tube around the valve stem gets past the tire bead on both sides.

- Consider adding an extra step of inflating the tire to 40-50psi or so to seat the tire, then deflating and checking the tube along the tire bead again.

- Once you're sure it's not pinched anywhere (especially around the valve stem), pump it all the way up.

I think this is exactly what happened. I tightened down the valve nuts first and that's exactly where it blew.

Cheers guys, very helpful!