I Learned My Lesson the Hard Way – Don’t Do What I Did!

Have you ever done a certain task so often that you figured you had it mastered and as a result started to get a bit lazy? I did recently and paid the price for it. This point was driven home to me last weekend at a bike race that I was completing in.  It was a modified cyclocross race where part of the circuit was on a paved road and the other part was on a gravel road. The previous week’s race was on the same course and I noticed that as I rode, my rear tire felt uneven.

I Have Changed Lots of Bike Tires

I couldn’t put my finger on what it was but it just felt as though I was hitting a bump during every revolution. I made a mental note to check my tire after the race once I was back in my shop. The race was quite muddy so I removed the wheel from my bike and then removed the tire from the rim (see the article How To Fix a Flat Bike Tire for a simple procedure on how to do this). With the tire and inner tube removed I checked the inside of my rim for any defects that I may had picked up during the race. I could find nothing wrong.

Nothing Found So Problem Solved Right?

I gave my rim a good wipe down and replaced the inner tube and tire back onto the rim (see my article on repairing an inner tube for a detailed description of this process).

Fast Forward to the Start of the Next Race

As soon as the next race started I knew that I had missed something when I had diagnosed the bumping action of my rear tire. I started to pedal and sure enough the bumping and bouncing was back. There was nothing I could do now but to just finish the race.

I did end up finishing the race but not after having to fix my flat rear tire after I had punctured. Luckily I always carry a spare tube and tire pump (read Where It All Began  for my reason) with me now whenever I ride. Just nearing the end of the first lap, I knew immediately that I was in trouble. I could feel the tire pressure in my rear wheel decreasing slowly but surely.

It Had To Happen On a Muddy Section

Do you think I could have flatted on a nice dry section of pavement? No, that would have made things too easy. I flatted on a muddy, greasy wet section of the circuit. I found the least muddiest spot I could find and got down to switching out my punctured inner tube for a new one. With the Job complete, I got back on the bike and pedalled in a desperate attempt to catch up to the back of the group.

The bumping feeling on my rear tire was still there. All I could think of was what is going on? I just kept pedalling and hoping that I would be able to at least finish the race. I did and when I got back home swore that I would find out what was going on.

After washing the tire and rim, I placed my bike into the bike stand to take a closer look. The first thing I did was to spin my rear wheel. Sure enough it looked totally uneven? I watched the rim and it was perfectly straight so it definitely had something to do with my tire. I grabbed a piece of chalk and spun the tire again. Each time it came to the spot that looked like it went out of alignment, I touched the tire quickly with the chalk.

This now left me with a chalk line on the tire to compare to the area that seemed to be in alignment.

There It Was!

I found the answer. Upon closer evaluation of the tire, I noticed that there was a small section that wasn’t “seating” itself on the rim.

If you look at a tire you will noticed that it has something called a bead (see picture below).

The purpose of this bead is to hook itself under the lip of the wheel rim (which then locks the tire into position). For some reason, the tire was having difficulties, seating itself (i.e. hooking the bead under the rim).  Most tires will self centre themselves on the rim so that both sides of the tire’s beads get hooked under the rim. I most likely “pinch flatted” during my race because of this off centred tire. This would have been a result of my tire having a bit of movement and while it moved it managed to snag a section of the inner tube and puncture it.

My tire wasn’t self centring and as a result, there was too much tire on one side of the rim and not enough on the other.

How Do You Fix This?

My solution for this problem was to remove most of the air from the inner tube and manually centre the tire on the rim with my hands. This took a bit of trial and error but my hard work paid off. I finally was able to pump my tire back up and have it spin perfectly. No more off centre, out of alignment spinning.

Yes I was happy with the result but angry at myself that I didn’t notice this before.

Next time you have to change an inner tube, give your tire a spin once the air has been pumped back in. If the tire looks lop-sided or out of alignment, then you probably have not seated the tire properly. Remove the air and manually adjust the tire on you rim. With a bit of practise, you will eventually have a perfectly centred tire.

Have any of you experienced what I just did? How did you go about diagnosing it? I’d love to hear your tales so leave me a comment.

Till then ride safe!

Robert Flaherty