Bicycle Flat Tires, Blow Outs and Slow Leaks

Hello and Welcome, Reoccurring flat tires and slow leaks can be baffling. It is not always obvious what the cause is. This post will talk about some not so typical causes of flat tires and slow leaks.

This clogged Schrader valve caused a slow but persistent loss of air pressure. This leak was found by inflating the inner tube and working it around slowly under water.

Above: This is an uncommon cause for a bicycle flat tire. Jagged edges caused by welds that were not ground down during manufacturing. Or sharp edges caused by not grinding down a weld enough during manufacturing. To smooth out this weld I ground it down using my 4 inch Makita angle grinder. I was lucky enough to be at Powers Schwinn one day many years ago when the latter was found to be the cause of a reoccurring flat on a new Schwinn bicycle. This is not a problem you are likely to have with higher end wheels.

Above: The incorrect tire size is a fairly easy cause to spot. If at the correct pressure the tire blows off the rim causing the inner tube to bulge out the side and rupture. That is a pretty good indicator that your tire and rim are not a match. I have been told by one of my suppliers that a 26 x 1.75 is not the same as a 26 x 1 & 3/4 I have never challenged this info and have no plans to in the future. Also some older Schwinn models require a special type tire like the S-7 . So read your tires care fully before ordering. And if you have any doubt call the supplier and ask for the tech person. (that is what he or she is there for)

Above: Incorrect or non matching ISO numbers are usually the cause of the type of tire blow-off described above. This is the ISO info for the same tire shown above. I mention ISO numbers a lot because it is a pretty common problem with beginners. As it was for me when I first got into the bicycle repair and restoration thing. The ISO numbers indicate the inside diameter of the tire.

Above: The incorrect valve stem type can also cause problems. This rim has a large hole for a Schrader type valve stem. If you were to use a inner tube with a Presta valve without some sort of adapter the tube can easily blow out at high pressure and rupture.

Above: Improper use of tools. Only one of the tools shown above,(Spoon type bicycle tire lever) is designed for removing bicycle tires. If you are going to use something other than the correct tool to remove tires, you better make damn sure it has only smooth rounded edges.(unlike the slotted screwdriver shown above)

About the only "other tool" I have seen used successfully to pry bicycle tires tires off rims was the handle of an old set of pliers. And that was on cruiser style tires. I doubt a pliers handle would work well on high pressure road or racing tires. I was about about 10 or 11 years old when I tried to pry off a tire off using a slotted screwdriver. Of course I punctured the tube and then had two holes to patch. Bill at the old Sinclair gas station (in my hometown) showed me how to use the pliers handle. Now days most pliers have rubber coated handles. And they do not necessarily have smooth edges under the rubber or plastic grips. So your best bet by far is to use a proper bicycle tire lever. Shown above Park Tool tire levers from a "Park Tool" bicycle tire repair kit.

Above: If your tire pressure goes all the way down when your bike has been stored long term. For The Love Of God don`t roll the bike around like that! Either bring your pump to the bike or carry your bike (or tire) to the pump. Next to the screwdriver thing "pinching the tube" might be the most preventable way to get a flat tire. And you will want to pump it up too about 20 psi, then release the air and refill this will help prevent the inner-tube from kinking.

Above: You can also puncture the tube while mounting the tire. I prefer to mount my tires by hand. If you have to use a tire pry bar, keep it to an absolute minimum. Also using a larger tube than you need is going to make it more likely that you will get the tube stuck (pinched) between the rim and the tire bead while mounting. In other words if my tire is 20 x 1.25 I will purchase a tube that is maxed out at 1.25 (if possible) It would read something like "fits 20 x 1.0 to 20 x 1.25 . In my opinion the fatter the tube the more likely it is to get in the way. I also prefer to have just enough air in the tube to hold it's shape while inserting it into the tire. If need be I can release the pressure when mounting the tire. As always...To help avoid your inner tube from kinking inside the tire inflate it to around 20 lbs psi. Then release the air and then refill the tire to desired pressure.

Above: The first thing I check if I have a slow leak is the Schrader valve. This Schrader valve tool is made for removing and installing Schrader valves. The tool has a hollow tube end with notches that fit over the top of the valve. The core of the valve is replaceable, the threading is typical clockwise to tighten and counter clockwise to loosen or remove. Or if you prefer "rightly tightly" / "lefty loosey". Obviously you do not want to apply a lot of torque when checking for tightness. If it does not turn clockwise with minimal pressure it is threaded in all the way.

Above: A Presta valve core is removed or tightened basically the same way. It does however require a different tool. The Park Tool VC-1 tool will work on both Presta and Schrader valves. I will not talk about typical punctures as we all know a nail or piece of glass (or metal) will puncture a tire. I will suggest that you check into puncture resistant tubes if you ride in an urban area with lots of glass and other debris. Also you might want to look into puncture resistant bicycle tires. Some tires have a Kevlar layer to help prevent punctures. There are also puncture guard strips that can be placed inside the tire to help prevent flats. And there are self sealing inner tubes available. I personally do not use any liquid sealer in my inner-tubes, but that is just my preference.

Above: Soon I will soon be reviewing my first truly rechargeable bicycle headlamp. And reviewing the Diamondback 29er now that I have had it a while. I regret I have not done any bicycle restoration work lately. We are currently having our kitchen and dining area remodeled. Which also includes a guest bathroom and laundry closet. Right after this project began, we started the process of repairing our septic system. I have also been cleaning up the mess that having a new well drilled created. Once the inside work is finished I should be able to jump back into the bicycle restoration work.

Above: A pic from a recent ride along the north end of White lake. I have made it a point to get out and ride more lately. Riding is a great way to to get rid of the stress that comes along with having multiple home remodeling and repair projects going simultaneously.

Above: The road home from Alderman Lake. Photo taken on another recent bicycle ride. Until next time, Please Ride Safely and Remember to Always...RESCUE, RESTORE & RECYCLE

Cheers, Hugh

A Special THANK YOU to those of you have been checking out Hugh's Online Bike Shop. The link to Hugh's Online Bike Shop is located on this page in the right column near the top, just below the followers / members. You probably noticed that I am now adding word links to components, tools and supplies ect. ect. that I mention in my blog posts. Like the Store these links are powered by amazon.com . I am doing this to make it more convenient to purchase things that interest you on the blog. Also if you are new to bicycle work, and you are not sure what I am talking about? You can click on the word link just to see some examples of what I am referring to. I look at this as a positive change and I hope you do too.

Thanks, Hugh