Cycling Tips

Bicycle Tyre and Tube Repair.

Common Causes of Punctures in Bike Tyres

1) Conventional; puncture caused by glass, wire etc. (Remedy; = tyre liners, thorn proof tubes, better quality tyre)

2) Explosion; caused by possible split in the tyre, over inflated tyre, incorrectly fitted tyre and tube, wheel slammed into a gutter or pot hole etc. (Remedy; = refit or replace tyre and tube correctly, purchase tyre gauge, revise riding habits.)

3) Puncture inside of tube, caused by sharp edges or fillings in rim or rim tape. (Remedy; = clean and file any protrusions. Note; some rim tapes on the market actually cause punctures.)

4) Split or leaking valve, caused by under inflated tyre. (Remedy; = keep inflated to correct pressure, under inflated tubes can cause the valve to separate from the tube. As you brake the wheel stops moving but the tyre continues to move taking the tube with it and causing the valve to split from the rim)

Tools Required

1) Plastic tyre levers

2) Hand or track pump

3) Pen or pencil

4) Valve tool (for car valves)

Proceedure

Firstly remove all air from tube, pressing the inner part of the valve in does this. While pressing on the valve squeeze the tyre down to ensure as much air has escaped as possible.
Note high-pressure valves have a small brass head, to release air from these tubes unscrew the brass head first, then press down.

Once the tyre is deflated as much as possible make a small mark on the sidewall of the tyre at the point the valve comes through the rim, we will explain why later.

Now with your tyre lever go to the opposite side of the rim from the valve and insert the tyre lever under the bead of the tyre, be careful not to catch the tube with the tyre lever as you do this.

Pull the tyre lever down to the rim in order to get that part of the tyre over the top of the rim, then slide the tyre lever along the side of the rim to remove that side of the tyre.
Note; if your tyre is quite a tight fit then place two tyre levers in approximately 2 inches apart and pull both tyre levers down together. Always use tyre levers as little as possible and never use steel tyre levers, screwdrivers, spoons etc. If your tube isn't already punctured then using these may cause them to puncture.

Now that you have the first part of the tyre removed carefully move the tube over that side of the rim, then again working at the opposite side of the valve pull the rest of the tyre off the rim.
You can use a tyre lever if the tyre is too tight to remove by hand.

If your tube has been going flat, you will need to find the cause of the problem.

Remove the tube from the tyre taking notice of which way the tube came out of the tyre, you can mark the valve on the same side as you marked the tyre earlier if you need to.

Inflate the tube and listen for any escaping air, if you only have a small hole you will need to over inflate the tube and then submerge the tube in water to locate the hole.
If you cannot locate the leak in the tube then submerge the valve in water and watch carefully for any small bubbles forming, if this is the case then tighten or replace valve.
(Note many new tubes purchased have loose valves, it's a good idea to check these when buying a new tube.)

If the hole has been found then mark the hole with your pen (it's your choice to replace or repair the tube however if the hole is large or split, on a join or near the valve, then we recommend you replace the tube), if the tube has been punctured on the top side of the tube then you probably have a normal puncture. If the puncture is on the inside of the tube then the puncture was probably caused by the rim.

Now using the mark you made on the tyre you can trace the problem point to either the tyre or rim.
Check the inside and outside of the tyre for any foreign objects and remove.
Don't worry if you don't find anything because most objects that cause punctures don't stay with the tyre.
It's now a good idea to check the rest of the tyre for any pieces of glass or metal. Remove anything you find. They may not have caused this puncture but may cause the next one.
Also check the bead of the tyre for any exposed bead wire; if this is the case then replace the tyre.

When the cause of the puncture has been located and the inside and outside of the tyre has been thoroughly checked then continue on to the next section.
If your puncture was on the inside of the tube and not caused by the tyre then you need to inspect the rim and rim tape. Look for any sharp edges or metal filings, quite often there will be brass filings from the nipples, going back to when the wheel was originally built.
These are rarely cleaned out by the manufacturer or your local bike shop, clean out all filings from both the rim and rim tape and file down any sharp edges you may find.

To put everything back together is basically a reverse of the above steps.

First place a small amount of air in your tube, just enough to give the tube it's shape, this will reduce the chances of the tube getting twisted or creasing inside the tyre reducing the chance of explosion.

Place the tube inside the tyre and place the valve through the opening of the rim, fit the first half of the tyre over the rim then carefully move the tube over the rim.
You should now have everything back together with just one side of the tyre remaining.

It is critical that the next step is done properly.

Going back to the valve push the valve up into the rim without pushing it all the way through, and at the same time seat that area of the tyre.
If this is not done properly then the area of the valve that is joined to the tube can get caught under the tyre, which will cause the tube to explode.

When the first area of the tyre is seated properly in the rim then continue to seat the rest of the tyre constantly checking that no part of the tube is caught under the tyre. Try to finish opposite the valve, if the last section of the tyre is hard to get on by hand then try stretching the tyre, or if you absolutely have to, then very carefully use a tyre lever to help you.

Now the last stage is just pumping the tyre up.

First make sure the valve is coming straight through the valve and not on an angle. Pump the tyre up to about half recommended pressure, deflate and pump up to half pressure again.
The recommended tyre pressure will be written somewhere on the side of the tyre.

Check both tyre beads are seated in both sides of the rim, if the tyre is riding high or low at any particular point then deflate tube slightly and reseat that area of the tyre.

When tyre is sitting correctly on the rim then inflate to normal recommended pressure. Now spin the wheel to see if the tyre line is sitting true with the wheel.

DONE