Rim tape. The stuff that protects your inner tubes from the inside edges of the rim bed. Hardly the topic to make palms sweaty, but it's important to understand why it's there and more importantly how to fit it.
Traditional drilled rims, where access to the rear of the spoke nipples is through the rim bed, tend to have sharply defined edges to the spoke holes. Some rims are fitted with separate metal spoke eyelet reinforcements. The backs of these reinforcements also present thin metal edges, edges which can and will puncture inner tubes if not shielded with some sort of rim tape.
There are a few different types, traditional cloth, synthetic tape and looped band. Pick the one which best suits your rims, taste and pocket and follow these simple instructions.
Tools and material
This rim (shown without spokes for clarity) is being cleaned prior to being fitted with a rim tape. Notice the holes, which are drilled to hold the spoke nipples. The light metal rings around the holes is a thin brass flashing, the rear end of the eyelet reinforcement - with or without eyelet reinforcement, your drilled rims need rim tapes fitted to stop them puncturing inner tubes.
Take the joined loop and see that it is turned the right way, there is occasionally an inner and outer surface, but check anyway. When you're ready, line up the valve hole in the tape loop, with the actual valve hole in the rim.
While you're fitting the loop, it can, and will, slip around the rim as you manhandle it into position in the rim bed. We use a screwdriver shaft dropped through the lined up tape and rim valve hole to effectively lock them together while you're fitting the remainder of the loop.
As you work around the rim circumference, away from the valve hole keep a good level of tension on the tape. This will cause the side of the tape to curl up a fraction, narrowing the tape and making it easier for it to be seated in the rim bed.
When you get to the last section is can be very tricky to snap it over the rim wall with you fingers as they get in the way a bit. We use another screwdriver instead. When you get to the last six inches or so, slide the shaft of the screwdriver under the tape and use it to lever the last bit into position. After it snaps into the rim bed run the screwdriver right around the outer edge of the rim (as shown) to even out the tape tension around the rim. Remove the locking screwdriver from the valve hole and carefully withdraw the one you've just used to install and even out the tape.
Give the tape a visual inspection to ensure that it is fitted squarely into the rim bed and isn't creeping up the sidewalls - which is why buying the right width tape for your rims is important.
Fabric self adhesive rim tape
Traditionalists will love the fabric tape with self adhesive backing, it comes on a roll and in different widths. It's probably the easiest rim tape to fit.
As with the loop type, start by lining up the precut valve hole.
Again like the loop rim tape as you apply it you should try to maintain a good even tension. This will help seat the tape and ensure the tape sticks well to the rim bed.
The roll of tape will be a bit longer than the rim, so use a sharp pair of scissor to trim the excess off. I like to trim the two ends for fit flush up next to each other, rather than overlapping.
Tubeless conversion tape
Air tight tubeless tape like this fits in a similar way. It won't have the precut valve hole in it, which doesn't matter as you're going to make one yourself... Start at the valve hole and cover it as you move around the circumference.
The tubeless tape needs to fit tightly and evenly into the rim bed - after all it has to also provide an air tight seal.
You might want to add a second wrap of tubeless tape to build up the height of the rim, which in turn helps make the tyre fit more tightly and speeds up the process of the tyre bead 'finding' the inside edge fo the rim wall - to create a seal.
Trim off neatly.
Work around the fitted tubeless tape ensuring it is well stuck to the rim with no air pockets, ripples, folds or creases.
Locate the valve hole in the rim. Make a small hole in the tubeless tape with a sharp, pointy object -we've used a fine cross head screwdriver.
Other tape types
Of course, if you're not looking for a tubeless air tight finish and have a roll of bog standard self adhesive electrical tape, that will do at a push. Similarly, plastic and cloth 'gaffer' tape, when ripped lengthwise to the right width, will also get the job done... I'd avoid classic Sellotape and packing tapes, as neither are thick enough.