Filed under: Uncategorized | Tags: Bike Commuting, Costco, extender, fixing, flat, HowTo, inner tube, maintenance, Midtown, pressure, psi, pump, repair, schrader, Schwinn, tires, tube, valve, valve stem
If you’ve read my previous posts, then you probably realize that when I started commuting with my Schwinn Midtown I had some problems with flats on the rear tire. Based on recent comments from readers, it seems that many of you out there also have had flats on your Midtown, and you have struggled to repair those flats so that you can get back to your riding. With that in mind, I figured I would discuss some more of the things I’ve learned as I’ve worked on my Midtown, and what I’ve done to deal with my tire issues.
I’m not going to go into the details of actually fixing a flat tire because there are plenty of other places that will do a much better job of teaching you than I ever could. I would recommend that you check with your local bike shops and see if any of them offer a free bike maintenance clinic. I attended such a clinic at my local REI store, and it was a great help. You can also find plenty of great videos on YouTube that will give you some good advice.
When you are dealing with a flat tire, one of the first things you need to do is to figure out what caused the flat. Did you run over some kind of road hazard, like glass, or a thorn, or a piece of sharp metal? Did you have your tire pressure too low and hit a bump, like a curb, so that the inner tube got pinched against the rim, which caused a “pinch flat”? Or is your tire just flat and you have no idea what caused it?
In my case, the rear flats were not caused by a road hazard, and did not seem to be pinch flats, which are usually on the sides of the tube. In both cases the leak in my tubes was on the inside edge of the tube, where the tube is against the rim, a few inches from the valve stem. I am still not sure what caused those leaks, but I think it might have been similar to a pinch flat, but caused by the tube going against the spoke holes in the rim ,which was enough to rub a hole in the tube.
One of the next things to think about when dealing with flat tires is whether you can repair the inner tube, or if you need to replace the old tube with a new one. In my case, I tried to repair the tube twice, but the hole was in a spot where the rubber had a bump in it, and I also used the new press-on patches, instead of the old glue-on kind. As soon as I put the tire back on and pumped it up, I heard the sound of air leaking and realized my patch wasn’t holding. Argh!
So here is what I did to remedy my problems…
1) I replaced the rear tube with a heavy duty tube with Slime in it. I have read mixed reviews of Slime, and it seems like people either like it or hate it. I was pretty desperate to find a solution, so I tried it, and I have not had issues. I don’t know if it is the Slime, or the heavy duty tube, but I haven’t even had to add air to the tire at all since I replaced it a couple of weeks ago. If you don’t like Slime, then there are plenty of other tubes out there. Just be sure you get a 26 inch tube that’s about 2 inches in diameter and has a Schrader valve. The tires on the Midtown are 26×2.00 so a 26×1.75-2.25 Schrader valve tube will work just fine.
2) I made sure that all of the spoke holes on the rim were nice and smooth. There is a rubber strip, like a big rubber band, that goes around the rim, and sits between the metal rim and the inner tube. It is there to cover up the holes and protect the tube. I removed that strip, and then checked each of the spoke holes and cleaned them up with a file to make sure they were nice and smooth, then replaced the strip, and put everything back together. That took a bit of work, and I’m not sure if it made a difference, but as I said, I was desperate. Reader Jon Grinder, an experienced bike mechanic, also recommend replacing the rubber rim strip with rim tape which is thicker and tends to stay in place better than the rubber strip. I have not done this yet, but it sounds like a good idea, and I’ll probably do so at some point.
3) I make sure that my tires are at the proper pressure every single time I ride. The recommend pressure for the tires on the Midtown is 40-65 PSI. I actually fill my rear tire a bit more than that to make up for the extra weight that I have over the rear tire when I carry stuff on the rack. Do this at your own risk, since you are exceeding the rated pressure once you pass 65 PSI. The other important part of keeping the tires at the right pressure is to have a good pump with an accurate pressure gauge. I have an air compressor and it was easy and fast to fill my tires with it, but I found that I was having a hard time keeping the pressure consistent. I went to REI and got a Serfas floor pump and it was a great investment. Now I hook the pump up and check the pressure before I ride, topping the tires off if needed. It only takes an extra minute or two, and the peace of mind is worth it.
Extra Long Valve Stem
If you replace the original tubes on the Midtown, you will quickly realize that the stock tubes have an extra long valve stem. The picture on the left is the stock Midtown tube, and the picture on the right is a normal tube.
When you install the standard tube in the Midtown rim you will notice that the valve stem just barely sticks out of the hole in the rim. Again, the picture on top is the stock tube, and the picture on the bottom is a replacement tube.
Getting the shorter valve stem to go all the way through the rim is a bit of a challenge, and the best way I found to make it work was to pinch the SIDES of the tube and tire, which helps push the valve through the hole. My first instinct was to push directly behind the valve stem, but this was difficult, and didn’t accomplish much. Instead, squeezing the sides of the tube seems to extend the valve stem farther into the hole. Once you get the valve stem through the hole then you can put the cap on to hold it in place while you finish installing the tire, or better yet, put a valve extender on the valve stem.
Getting the pump to grab on to the short valve stem can be a challenge, especially when the tube is completely empty, so I picked up a set of valve stem extenders from a local auto parts store, and now filling the tube is easy again.
I did look around a bit to try to find tubes with a long valve stem, and I haven’t been able to find them anywhere. At this point, I don’t really consider it to be a problem, because I’m confident I can make a regular tube work.
It has been at least two weeks, and probably 75 miles of riding, since I took the actions described above, and I haven’t had any more issues with flat tires on my Schwinn Midtown. Hopefully this information will help those of you that have experienced similar challenges, and get you back on the road again.
22 Comments so far
Leave a comment