How hard can it be to get a clincher tyre off its rim? Very, if most road cyclists are to be believed; the prospect of getting the tyre off in the event of a flat or for replacement seems to trouble many of us and can indeed be a bit of a task.

It can also be easy – too easy – if either the tyre is to big or the rim too small. The former is less likely because of the way tyre beads are fitted but extruded aluminium rims are cut to length, allowing some room for error, and it doesn’t have to be much; the permissible tolerance for rim dimensions according to the European Tyre and Rim Technical Organisation is +-0.5mm on bead seat diameter and the same on the height of both flanges before they are added together, which means that the diameter difference between the biggest and smallest permissible rims is… er…

Anyway, since a tyre has to fit any permissible rim, it has to have a bead with large enough circumference – nominally 1955mm – to fit over the largest which means that, if fitted to the smallest permissible rim, the tyre would be likely to blow off during inflation unless perfectly centred.

Of course, this takes no note of the depth of the rim well. A deeper well will allow the bead to fall closer to the wheel centre on one side and therefore afford more slack on the other, making tyre fitment easier.

So, even a correctly-sized rim will make for an easy-fitting tyre if the well is deep. Why is this a bad thing? ‘Cos a clincher tyre that is easy to fit will come off as easily in the event of a flat, which is potentially bad news if it happens while riding.

I was once informed by a Banesto mechanic that Miguel Indurain preferred a clincher on his front wheel for mountain Grand Tour stages since, as a heavy rider and fast descender, he put a lot of heat into his front rim when braking and did not care for the possibility of melting tubular tyre cement. To obviate the possibility of the clincher coming off in case of a puncture, the mechanic would fit extra rim tapes to build up the rim well diameter, to the point that getting the tyre on required tyre levers…

So, when I recently tried fitting tyres and found them a bit too easy fitting for my liking, I removed the rim tapes supplied, fitted a supplementary tape to each  rim and refitted the originals.

The result: both tyres significantly tighter to fit although they did not come close to needing tyre levers. Worth it? Personally I don’t like a slack-fitting tyre for reasons touched on above, so yes. Although I would not go quite as far as “Miguelon’s” mechanic.