Sunday, November 30, 2014

POP! Hard lessons of a rear tire blowout

My back tire blew out, POP!, on the bike trail, and I immediately knew why. I’d put thousands of miles on it. And I recently had to ride three miles for help with it rubbing its sidewall against the rear fork. A rear spoke broke while I rode out in the middle of nowhere, making the wheel oblong.
No doubt, the rubbed side of the tire was weakened. But I figured it had plenty more miles in it. Well, yes and no. With a new wheel set, I rode on it for a few hundred miles more. And then, the tube forced through a small hole near the bead of the tire and blew up.
It was then that I began a journey of re-learning that, A) I had a 23 mm wide tire that is a very tight fit on the rim, and B) that my tire changing skills were pretty much flawed, as in Not So Hot.
I managed to wedge one side of the tire off and pull out the exploded tube. I knew it was best to leave one side of the tire in the rim, to cut down on the time of replacing the tube and wrangling the tire back inside the rim. I inflated the new tube to work it over the rim, then used my plastic lever to help get the last bit of tire bead over the rim. Which, because of the very tight fit of the narrow tire, took some gnashing and busted knuckles. When I tried to inflate it with my hand pump, the tube wouldn’t take air.
Ugh! I’ve had this happen before. Just not good, I wanna get back on the trail. So what’s with the damn faulty tube? (You probably know where this is going. Hint: it wasn’t a bad tube. Initially, at least)
So I use the tire lever to take off one side of the tire and pull out the offending tube. I then realize I don’t have the right air cartridge for the trigger unit I have. I have unthreaded kind and it takes threaded. Oh man, another fail! A rider happens by and asks if I need anything.
By the way, all during my repair stop, many riders offered help, and even a park ranger stopped on the road above the trail and asked if I needed a ride, and did I have a phone? That was awesome. I thanked them all and said I was good. Ha Ha!
So this latest rider asked, and I said, “ Do you happen to have a threaded air cartridge?” And he said he did. He stopped and gave me one. I told him my first tube didn’t take air.
“I hate it when that happens,” he said.
I thanked him and then managed to get my second spare tube – I aways carry two, so that was good -- aligned on the rim and work the released tire bead back into place.
Again, I used the plastic lever to get the last bit of tight fitting tire over the rim, grunting like a pig snorting for scraps. I popped the cartridge into the trigger valve and the tire filled up immediately as I hear the tube crackle a bit. Alright, I’m feeling I’m almost road ready! I lean the wheel against my upside down bike to gather the effed up tubes and, suddenly, POP! The tube exploded through the tire sidewall again!
Now I’m thinking, OK, I’m toast, no more tubes. Gotta think about getting a ride home.
Another rider comes by and asks me if I need anything.
“I’m outta tubes,” I said, feeling very stupid as I look at the pile of three useless tubes on the ground.
The guy lays down his bike and fishes out a spare tube. I think he noticed I looked a little defeated.
“Here, he said, motioning for the wheel. “Let me give it a try.”
I handed him the wheel and he used his levers to wedge the tire out of one side. He pulled out the bad tube as I had done. He inflated the new tube to give it shape as I had done, and aligned it in the wheel gutter. He got the tire onto the rim, and I don’t even remember if he used his tire levers to get the last part over. He suggested using the hand pump to get enough air in to ride on, since he said the bead was damaged. The tube took air, and held, and we mounted the wheel on the bike and I was good to go. Richard was his name, and if you read this Richard, thanks a whole lot, bro.
I rode slowly the 16 or so miles home without a problem. The next day, I decided to replace the back tire with a new one.

Tire change, Part II
I set up in the back yard and pulled off the old tire, then began to work with the brand new folded tire, a 23mm Continental Grand Prix Four Season, a great tire that will perform well for mucho miles. This tire will last so long, that if and when it flats, you may have forgotten the right way to change out a tube. Yes, I pretty much did!
But being brand new and 23mm wide, the fit over the rim was extremely tight. After another titan struggle, again, using the tire lever, I finally managed to pop it over the rim. I found some areas where the tube was bunched between the rim and the tire bead and stuffed them them back under the tire with the lever. Again, this is a no-no.
So I started to pump up the tire, and, guess what? The tube wouldn’t take any air! Leak. AGAIN? This is NUTS, I thought. WTF? (This only a conservative description of my reaction. Imagine a primal scream that may have prompted calls to the police)
So I pulled out the leaky tube and put in another one. I got the tire fitted into the rim all the way except the last four inches. And after repeated fails, I couldn’t make any progress in attempts to pop it entirely over the rim and into place. At that point, my hands were raw and hammered, nicked, cramps were starting to set in. So, I told myself, hey, face the music, bro. You don’t know how to do this right. You need expertise here.
It was time to head over to the bike shop.
I asked the guy there to show me what I was doing wrong. The first thing to realize, he said, is that the 23mm wide new tire is going to be very hard for anybody to fit over the rim. It is a very snug fit. He said a 25 mm might be a better choice for less challenging future tube changes. OK, noted.
Anyhow, I knew the first two things. Take only half the tire off, and fill the new tube with enough air to give it shape.
Next, you push the tube under the tire and fit it into the wheel gutter. OK, I think I had been shoving it up under the undone part of the tire. Wrong.
Then, he said, you start tucking the free side of the tire into the rim, pinching it in the middle as you go, and letting air out of the tube a little as you go. OK, here’s the new info: The pinching and air letting helps to bring the tube and tire to the center of the gutter as you tuck in the free side of the tire. That is key to freeing up room to get the last few inches of the tire tucked in, which is where I hit the wall.
I asked him about using the lever to tuck in the tire bead. Uh, never do that, he said. Here’s the second bit of info that is obvious when I look back at all the “bad” tubes I’d installed that wouldn’t take air. Using the lever to tuck in the tire bead puts the tube in danger of being punctured. Don’t do it. Use your hands all the way.
Now, that seems obvious. But I didn’t think it was possible without using the levers. Hands only? Damn.
Using your hands on the last part of the tire bead, where you stretch the tight fitting tire over the rim is a truly tough task.
But, the guy said, if you just keep pinching the middle of the tire to keep it centered, then twist the last part of the tire, it’ll pop into place. He showed me, and he, a guy who can change a bike tire in his sleep, had to work the hell out of that last section of tire with his hands. But he did it in a minute or less. OK, no punctured tube, new tire on, good to go.
Now I just hope I remember all these little tricks the next time I have a flat. Just as a way to keep the primal screams at bay.

Til next time, remember to strap on a helmet every time you get on the bike. Then, keep the rubber side down, ride safely and have a blast.

-- Mark Eric Larson

No comments:

Post a Comment