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I have a Schwalbe Marathon Plus 700x25 tyre which is very difficult to mount on my rim. The rubber has almost no flexibility. The wire make the tyre directly goes either outside the rim, or inside the edges of the walls of the rim. I can mount it though, but with damages to the edges of the tyre:
and with one or two broken levers:
How to mount these tyres without damaging the beads of the tyre and without too much strength?
The classical trick is to move the beads of the tyre into the well of the rim down to the center of the valley, so that the apparent tyre diameter become larger than the rim diameter. Then the tyre can be pressed with both hands towards the point where the lever can be finally used to insert the bead into the rim.
However, this is almost impossible with Marathon Plus tyres, which have a very strong wire and a inflexible rubber: when one spot is moved into the well of the bead, others go off, so that the diameter is never increased sufficiently.
To solve this issue, I tied several knots around the tyre with strings, so that the tyre is pressed into the rim.
However, with a classical knot, it would not be possible to press the rubber sufficiently so that the tyre would fit into the well of the rim, because these Marathon tyres have very little flexibility. To I used a Tarbuck knot, which makes it easy to get the sufficient pressure. One knot every 3 or 4 spokes allows to get a constant pressure.
It is then quite easy to push both sides of the tyre towards the point where the remaining work can be done with the levers, but without excess force.
With stubborn tires I have found that using two or even three levers can work. Put on the tire as much as you can by hand and insert both levers at as far apart as you can. Hold one lever stationary. Push a little bit of the bead with the other lever into the rim then let it go and slide it a bit towards the stationary lever. Push a bit more on, repeat, working your way towards the stationary lever. You may have to let off the stationary lever as you get closer. Don't try to just pop it on, you'll snap the lever.
There are several tools especially designed to help solve the stubborn tire mount problem. The one that I've used is the Kool Tool Tire bead jack. Youtube Video describing how to use it.
With the newer Tubeless ready road tires having much tighter clearances, I have used my Tire Jack more in the last year than in the previous 15 years I've owned it.
The Crank Brothers Speedier Tire lever also works very well for mounting tires, much better than any other tire lever I've tried.
