Before you trim any bar work out if it’s the right thing to do. Consider long ride comfort, possible fitting of bar ends or other bar furniture and remember that wider, shoulder width bars are more comfortable and offer more control.
Before you move to make any cuts try adjusting your grips and controls by the amount that you want to remove. Ride for a few more weeks to see if the new narrower stance is really the one you’re after.
Don’t risk a crude ‘by-eye’ trim. Use a tape measure, a ruler or even a piece of string with a knot in it to ensure that you’re removing the same amount from each end of the bar. Wonky won’t do.
When you’ve got the amount to be trimmed nailed, mark the cutting point with masking tape. Make neat parallel wraps with only the cutting mark exposed as a visual guide. You can use the end of a lock-on step grip to give you a square cut.
Roll cut alloy
If you’re using a roll cutter retract the blade, then slide the bar though the tool. Locate the blade edge onto the cut marks and lightly snug the blade down. Begin rolling the tool around the bar. Increase the blade pressure gradually and the bar will cut.
Carbon bars require the cut marks to be covered again with some masking tape. This stops the ends of the carbon from splintering. Use a new hacksaw blade with a fine pitch and remember that blade speed makes a neater cut.
File the ends
When you have achieved your cut, you need to finish the ends of the bar neatly, not only for looks, but for safety reasons too. Sharp alloy burrs or carbon splinters are very painful. Use a fine file to remove the rough edges.
Fit a set of plastic bar plugs. They don’t weigh anything and stop your bar from filling up with mud every time you drop the bike. You might have to shave the fins a bit with a sharp blade to make them fit some bars.