Fitting Bars to Quill Stems

Fitting bars to modern two or four bolt stems with removable face plates is easy. Avoiding scratches with older single-bolt style stems takes a little more care, especially when fitting drops or constant diameter bars. These have no raised middle section so half the length of the bar has to fit through the clamp.

Our bars are made to exact sizes but many stems are nominally sized - a 26.0mm stem might actually have a clamp measuring anything from 25.8mm to 26.4mm, similar variations exist with other sized stems meaning that even though you have purchased the correctly sized bar it may seem either a tight or easier fit when installing.

The most popular older stems are often Cinelli as here. The two illustrated are the XA and 1A. Other single bolt stems work in exactly the same way. Most of these stems have quite fine tolerances ensuring a good fit in use but also requiring patience in fitting the bar and care with tools to avoid damaging the stem.

First step is to ensure there are no burrs or sharp edges to the clamp area of the stem. Remove with a fine rounded file if necessary and finish off with fine grade abrasive paper or wet and dry. The aim is to have a smooth edge so the bar does not get gouged when fitting.

To avoid scratching your shiny new bar we need to very slightly (and gently) open up the clamping area. With constant diameter bars (and if you have somone to help) it may be easier to fit the stem to the bike securely and flip the bike upside down onto a soft surface with a friend holding it steady. Make sure the clamp bolt and any spacer is removed.

With the XA use a large wide flat screwdriver or similar and wrap some card or flexible plastic around the blade. Have the bar ready and simultaneously lever very gently to open the slot a tiny bit and slide the bar in to the centre. It should glide in with no drag or scratching.

With the design of some models of the Cinelli 1A with a 'V' shaped 'split' to the clamp it is sometimes easier to use the method below. Find a suitable smooth round metal tool (the shaft of a screwdriver, the smooth part of a drill bit etc) of the right size. You want it to just fit into the initial opening.

As before, holding the bar ready push the tool down into the slot while sliding the bar in. If the clamp starts to 'bite', stop, push the tool down again and as the bar loosens slide it home.

Sure all the above takes a little more time and isn't necessary for an old commuter or hack bike but if you are installing a brand new bar it's worth taking the time. This advice applies to drops and bullhorns too but only the centre section has to fit through the stem. Because of the shape of these bars the bike will need to be the normal way up too. Wrap a little brown paper inside the clamp or around the bar while going round the curves and use the above 'clamp opening' procedure to avoid a deep scratch right through the engraved centre section of your shiny Nittos' or NOS Giro D'Italias.