>I have been steady riding more miles in the last weeks now that the weather has broken (roughly 100
>miles a week), commuting to and from school and around Chicago running errands. I have gone through
>two on the rear wheel. I have been installing brand-new tubes each time. After the first flat, I
>also noticed that shifting is completely off, though I am not sure it's related.
>
>Tire pressure is usually 80 psi front and rear. I ride 99% of the time on the road or paved bike
>path. Could I be installing it incorrectly?
>
>Thanks, in advance, for any advice.
3 flats in 3 weeks is a bit abnormal but certainly possible. 3 flats in one ride, that happens.....
It is not possible to tell if you are installing the tubes correctly without knowing how you
are doing it.
However the fact that you ask this question implies that you do not know the cause of each of those
flats. After removing the tube, the next step in repairing a flat is to find the cause of the flat.
This is a critical step because unless you know, it is likely that you will get another one.
Flats really fall into three classes:
1. Foreign object damage, glass, nails, staples, clipped cable ends carelessly left on the garage
floor, thorns etc. These will invariably remain in the tire, often hidden and unless you find
the problem, it will come back to get you.
2. Pinch flats: also called snake bites, these are caused by hitting something in the road, a pot
hole or curb, that flattens the tire against the rim, pinching the tube. Normally one can feel
that solid hit and know that a flat is likely.
Pinch flats are normally two small slices maybe a quarter of an inch long and separated by a bit,
they look like a "snake bite."
You did not indicate what size tires you are running, 80 psi might well be sufficient but if you are
running 700Cx 23 or 25's then this is certainly not enough. Keeping your tires pumped and avoiding
pot holes and other obstacles are the ways to avoid pinch flats.
3. Assembly problems, wheel/tire problems. One can always pinch the tube under tire when installing
the new tube. After installing the tire, it is best to pump the tire up slightly and then push
the tire away from the rim and look carefully to see if the tube is caught under the bead of the
tire. This will eventually cause a blowout.
It is also particularly easy to pinch or cut the tube if one is using tire tools to reinstall the
tire. the tube gets caught under the tool and cut. For that reason, many cyclists avoid using tire
tools to reinstall a tire. With proper technique, making sure that the tire beads are in the center
of the rim, all tires can be mounted without the use of tools. It may take some practice and some
hand strength but it can be done.
Another cause of a flat tire is rim tape that does not adequately cover the spoke hole in the rim.
If the tape is too narrow or has shifted, this will cause a flat, it is normally indicated by the
fact that the hole is on the inside of the tube rather than the outside but sometimes tubes are
twisted so it is difficult to tell. A similar problem is a broke spoke which stabs the tube.
A bad tire, one that has a cut in it, possibly from poorly adjusted brakes will allow the tube to
escape the tire and blow out. This should be obvious from the pop when the tire blows out and the
fact that if a new tube is installed, it will soon blowout.
So, I think i have hit on the major causes of flats, I might have missed some.
In order to avoid flats, the important things are to keep your tires inflated, keep a careful eye on
the road, avoid debris and problems in the road and to make sure that when you do get a flat, you
understand what caused it and take care of it prior to reinstalling the tire
Flats are always an issue with cycling but the problems with flats can be help to a minimum if one
is careful and attentive.
jon isaacs
