Mountain bike tyre at road bike pressure Summary: A tyre that is 2.00 inches, or more, in thickness, that is designed to have a maximum allowed pressure or 7 or 8 bars, or 100-120 PSI -&gt; does such a thing exist?
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I've been obsessed for years about combining road bikes and mountain bikes into a single ideal bicycle.
I know about the options that already exist as compromises between road bikes and mountain bikes: hybrid bicycles (flat bar bicycles with tyres of intermediate thickness) and gravel bikes (road bikes that can go offroad as long as the terrain is not too technical).
But none of those options are good enough for me. I have imagined my own solutions.
It would take too much time to write all the details of the design that I have thought about here right now. I might write the entire design on this forum, but not right at this moment. For the time being there is one particular component that I think is the most crucial that I wish to ask about: tyres.
My design is not about compromise but about changing between &quot;modes&quot;: a mtb mode and a road mode. The important detail is that I want a bicycle that is very good in those modes, not a compromise. So as an MTB I want to be a very good MTB. There's a lot of properties and components that affect the quality of a mountain bike, but for now, I'm focusing on tyres, so the more versatile the MTB the thicker the tyres are.
A thicker tyre is also slower on the road, especially if run at the low pressure that off-road-ing demands. So to create this swiss-knife of a bicycle, I have thought about this: a 2.00 or 2.20 or 2.30 inch tyre that I would use at 7-8 bars (100-120 PSI) on the road and 1-2 bars in the forest (15-30 psi). Good idea in theory, but does such a tyre even EXIST? That is my question.
Alternative related questions:
Can a MTB tyre be modified to resist 7-8 bars of pressure?
Can a tyre less than 2.00 inches (such as a gravel bike tyre for example) be made o be puncture resistant and not slide of the rim at small presure of 1-2 bars?
2.00 or 2.20 or 2.30 inch tyre that I would use at 7-8 bars (100-120 PSI)

Does such a tire exist?
No.
A little math...
The surface area of a torus is 4 x pi^2 x R  x r, where R is the large radius of the wheel and r is the radius of the tire here.
Let's put a 2.00 tire on a 29er rim...
4 x pi^2
  x 15&quot; (approx radius of wheel at center of tire cross section)
  x  1&quot; (radius of tire's surface)

= 592 in^2

Assume the tire surface area is only about 2/3 of that, or about 400 square inches.  (It's probably more...)
Pump that tire up to 100 psi and each of those 400 square inches of tire surface has 100 pounds of pressure pushing on it.
That's a total of 40,000 pounds of force trying to push that tire off the rim.
Even if the tire can hold, the bead of the tire will be pushing HARD against the rim, trying to tear it apart.
40,000 pounds of force for a 2.00 tire at 100 psi.  Pump a 2.40 up to 120 PSI and it's more like 50,000 pounds of force.
There's a reason why tires have maximum pressure ratings, and larger tires have lower maximum rated pressures, and it's not because higher pressure starts to increase rolling resistance.
It's because high pressures in a large tire are downright dangerous.