As for during
"How can I minimize the chance of getting a puncture while driving through glass?"
Coast and distribute your weight evenly.
Don't brake - it will grind the glass in.
If you think you can clear it then hop it - be sure you can clear it with both tires.
And a hop - not a bunny hop - a bunny hop is for height not distance.
There is lot you can do before and after.
Nature of a glass flat
To avoid a glass flat it is important to understand the nature of a glass flat.
Rarely get a glass flat in one pass.
Glass is very different than a nail, tack, or screw. Glass is brittle.
Two type of glass:
- Big chunks
- Little shards that you can't easily see
Not often you will get sliced open by a big chunk as the sharp edge has to be up and since glass is brittle you often break it. But like the base of coke bottle with some 1/4 points sticking up. Tires loses pretty much every time. At least those are easier see - steer clear.
A long narrow sliver of glass does not have the structural integrity to puncture a tire in one pass - glass will fracture. A sliver of glass is rarely standing upright.
The are 4 stages to a glass shard flat:
- The glass penetrates the rubber surface.
There is minimum or threshold force per area for the glass (or any sharp object) to penetrate the surface.
- Work into the rubber. This takes many revolutions.
- Work through the belt.
First the glass has to make it to the belt. If the tire is thicker than the belt then the glass will not make it to the belt.
Kevlar and other fibers resists cuts.
But these fibers cannot stop abrasion. If you leave the glass on the belt long enough it will work through.
- Work though the tube.
Tube is designed to hold air. Tube does not resist puncture, cut, or abrasion.
I have pulled glass out tires at least 20 times. Only twice out of a flat tire. From inspection that glass had been in the flat tires a while. A glass flat rarely happens in two seconds or two minutes. A glass flat can take days.
As for before - Lots you can do
- Puncture resistant tire
- Fatter lower pressure tire
Puncture resistant tires
- Harder rubber to resist penetration.
I personally don't like harder rubber.
It is a harsher ride and not as much grip.
- Thicker rubber.
Some puncture resistant tires tires even have a spacing foam.
- Puncture / cut resistant belt.
This is where you get the best bang per weight
Before you go out and buy THE most puncture resistant tire consider it comes at a cost.
They are hard and heavy.
Fatter lower pressure tire
I know people say higher pressure is better for puncture resistance but I disagree.
Let me be clear.
I am not suggesting you run A tire at a lower pressure.
Run a tire that has a lower design pressure.
A fatter tire has a lower design pressure.
If you weigh 180 lbs or more then run your 25mm at the max (e.g. 110 psi).
I am suggesting if you run 35mm that has a maximum pressure of 80 psi then it will have better puncture resistance.
For rolling resistance, grip, pinch, and other factors run the tire at the design pressure.
There is a threshold force for the glass to enter the tire.
A larger tire has less PSI and a bigger footprint.
For the same weight 50 PSI will have twice the footprint size as 100 psi.
Larger tire makes contact with more pavement around glass such.
So a larger tire avoids penetration from a range of glass that would have penetrated the smaller harder tire.
Even if the large tire makes contact with more glass it is more points of contact.
The force is spread out over more points of contact.
A person can lie on a bed of nails but not stand on it.
If you had to walk through a bed of glass would you spread your foot to spread the load or would you walk on your heels to minimize the pieces of glass?
If a fatter tire more puncture resistant
Slime is not much good for glass. Glass tends to have larger cuts.
The best thing you can do to prevent a glass flat is to remove glass.
First two seconds, two minutes, or two days.
If you leave glass in a any tire longer enough it will puncture the tube.
On the road can use key or a knife to gently pry it out.
At home I use hemostats.
Don't go out and buy the most puncture resistant tires without evaluating the trade offs.
I have a pair and I don't like the ride, grip, or roll.
And they are going to last a long time.
You have not had a flat yet.
Consider a tire that is a mix of ride, grip, roll, and protection.
A Marathon Plus weighs almost twice as much as a Gator Hardshell.
And inspect your tires on a regular basis.
If you can go 28mm or 32mm then do so.
Not just for the reduced pressure but you also have a lot more options in flat resistant tires.