These new soft tyres are so soft that it is difficult to get them onto the wheels without stretching them way out of shape. No matter how hard I try, they still run unevenly. Some of that is due to the tyre itself but mostly it is just a question of trying to spread the tyre evenly. After several attempts, I gave up and decided to make a small tool to help me with the job…
A conical piece of aluminium was turned with the small end small enough to let the tyre slip fairly easily over it without much of a stretch. I ended up with a small diameter of 18.5mm but 15mm would have been better if I had a longer piece of aluminium to hand.
The large end is the same diameter as the wheel – 23mm for Decimus. A step cut in the end allows it to sit exactly inside the wheel rim.
The tyre can easily be pushed evenly up the cone and then slipped onto the wheel. Small, even movements of the tyre on the cone should ensure that the tyre ends up in place with minimum distortion.