Never do this…to carbon handlebars

from Rookie’s keyboard,

Hello, friends

Today, I saw a cycling friend of mine try to do something that should never be done – he was about to cut carbon handlebars to length with a pipe cutter.

a basic pipe cutter

I stopped him. This is a very bad practice for many reasons. Where do I even start?

The first issue is the compression. Carbon isn’t a tough material when it comes to resisting clamping force a.k.a. compression. For that very reason, you have to be gentle when clamping a tool onto a carbon pipe. Ideally, you’ll use a torque wrench to avoid crushing the tube.

A pipe cutter has to squeeze the bar very hard to operate properly and produce a good cut. And I have never seen a torque reader on a pipe cutter. 

And without having that info, you can exert too much force on the bars and damage them. I do realize that this outcome is certainly not guaranteed, but why risk it, fellas?

The second problem is found within carbon’s very structure – it’s made of laminated fibers. 

Pipe cutters rely on a V-shaped blade that ruthlessly digs itself into the material. On aluminum bars, this doesn’t create any problems, but in the case of carbon, the cutter may delaminate some of the layers. The outcome is an ugly-looking cut with splinters. Just awful.

Badly cut carbon bars – notice the splinter/tear out

Doing it right

I am not one of those people who will tell you that your method doesn’t work without offering a solution. I got your back, bros. 

So, here’s how to cut those carbon bars the right way. 

The ideal tool for cutting carbon bars is a hacksaw with a blade that has at least 28 teeth per 1 inch(28TPI).

This is needed to get a nice, smooth cut. Ideally, you will also have a guide for the saw to ensure a straight cut, but it’s not the end of the world if you don’t have one.

a hacksaw guide

If you don’t own a hack saw guide, you can use two pipe clamps. DO NOT overtighten them (or the saw guide) to avoid damaging the bars.

Put masking tape on the spot. The tape adds support to the carbon fibers and reduces splintering. (It’s similar to using tape on a particle board when cutting it to avoid chipping.)

Put soapy water on the cut to stop the formation of carbon dust. 

You can technically use a vice, but I’d rather mount the bars on the bike and tighten the stem to the needed requirements. That way you avoid crushing the bars.

What about a dremel?

A sharp hacksaw blade will eat the bars like nothing, but if you insist on using a power tool, you can technically try a Dremel/rotary tool of any kind (Dremel is just the brand, not the name of the tool). This isn’t my preferred approach, but it’s been done. Use a diamond cutting wheel. 

A rotary tool operates with small-diameter discs, and it’s difficult if not impossible to produce a straight cut.

You can also use one of those 3″ cut-off tools or an angle grinder. 

Keep in mind that those tools rotate at high speeds and will build up carbon dust in the air within seconds. And that’s not ideal for anyone’s lungs. Get a face mask that offers protection against 3-5 micron particles (or simply use the hacksaw method).

Measure thrice before cutting…

A wise man once said, “Measure thrice, cut once.” It applies here too. Before cutting, make sure that the dimensions are correct. 

The total amount of reduced length has to be divided by 2 to figure out how much to remove from each side. 

If you have 800mm bars and want to get them to 720mm, you need to remove 80mm. This means that you have to cut approx. 40mm on each end.

In my case, I used a hacksaw to cut the bars of my friend for him. The blade wasn’t new, but it worked just fine. 

The most important part to remember is this – don’t over-compress carbon bars and do everything slowly and methodically. 


I have to go now, friends as the evening shift awaits me. It’s Friday, at least.

Until next time, 

– Rookie






Leave a Reply

Your email address will not be published. Required fields are marked *