woodcraft

A: The tire beads are pushed in making a space for the tube to bulge out and burst.

B: The tire beads are pushed in, allowing the tube to bulge; the tire reseats, tearing holes in the tube.

C: The tire beads are pushed in, over-stretching a small section of tube, which tears.

D: ?

Bill Kapaun

E.
The rim smashes down against the tire tread area, cutting the tube which is sandwiched between the rim & tire.

Homebrew01

That would be a "sandwich" flat

A pinch flat is:

The rim smashes down against the tire tread area, cutting the tube which is pinched between the rim & tire.

Looigi

D: A sharp edge or object pushes the tread of the tire toward the edge of the rim (black) causing the tube (red) and sidewall of the tire (blue) to bulge outward. The bulge progresses outward as the tread gets closer to the rim, the tube gets squeezed between the portion of the sidewall against the rim of the wheel and the portion of the tread/sidewall against the object. With enough force the pinch cuts the tube. More force and the sidewall may also get cut.

FBinNY 

As the name implies, it's an issue of the tube getting pinched the same way the same way that crazy uncle does to your cheek.

Two common causes.

During installation, the tube is pinched between the tire lever or other tool and the rim. The force of levering drives the point through both layers of the pinched fold.

While riding, a sharp corner such as a cub or the far lip of a pothole, compresses the tire back on itself all the way to the rim. The tube inside is caught in the fold, and cut through.

BTW- generally pinch flats show up as double cuts like this /\ a short distance apart since they happen when the tube is folded. Based on the appearance, they're sometimes referred to as snake bites.

Leebo

Run tubeless to avoid, or just use an air guage.

JTGraphics

Fix the cause and eliminate the problem!.
Under inflated tire for the given tire size and riders weight.
This is assuming its installed correctly in the first place and tube is not between tire bead and rim bead.

fietsbob

in short, Tube is caught between a Rock and a Hard place..

woodcraft

Thanks.

I thought the 'snake bites' were on either side of the rim.

So is there sometimes a double snake bite?

FBinNY 

Snake bite is a term that came into vogue long relatively recently, probably with the advent of mtn biking, though it might have been in use in some areas much longer. Here, we always just called them pinch flats. The characteristic "bite" happens on one side and the two tooth marks are very close to each other. Of course, it's possible to crush both sides of the tire against both sides of the rim on the same impact, so you'd get two snake bites at the same time.

I sort of did that with my new car the night I drove it home from the dealership. It was raining and about a mile from home I dropped both left wheels into a rain filled crater at about 35mph. I knew it wasn't good, stopped looked, heard the hissing, and raced home and into the driveway. Next day, 2 dented rims, one dented on both sides, and 2 destroyed tires, (3 snake bites"). That was my introduction to 60 ratio tires.

noglider 

In my mind, it's more like when one boxer hits another in the cheek, and the skin is pinched between the cheekbone and the glove. The high pressure causes the skin to tear.

woodcraft

Are sidewall cuts attributed to glass, etc. sometimes from pinch flatting?


When a tire is improperly installed, leaving some tube between the bead and the rim, which soon flats,

Is that also called a pinch flat?


FBinNY- Bummer, but good that those weren't carbon fiber rims- or the internet would still be reverberating.

FBinNY 

Don't get caught up in semantics. Regardless of what you call it, you can usually make a judgement call about cause based on the location and appearance of the damage. IMO, there are pinch flats, cuts, punctures and sidewall cuts in the tire. Causes can be impacts, poor installation, something in the rim or rim tape, or any number of road hazards, from pot holes to glass and nails.

The car was a nice story of good dealer service. I phoned them , told them what happened, and asked for a "bad break" deal. I also asked how long it would take to get new rims and tires, and while he was at it could I get a deal on 2 spare rims for snows. Twenty minutes he calls, shoots me a great price for 4 wheels off a car, with tires mounted, and the salesman dropped them off on his way home that evening. We changed the two wheels in my driveway and went out fro some beers.

Homebrew01

In some municipalities you can make a repair claim against the local government for poorly maintained roads (unless they have posted "road maintenance" warning signs absolving them of responsibility on that road)

FBinNY 

I'm a graduate of the old school, and take my lumps when I get them. Always have, and probably always will. Stuff happens, it's not always somebody's fault.

BTW- around here the towns are actually pretty good at repairing road hazards including serious potholes when they're reported.