Carbon Bars and Posts. Worth It, If You Do This.

Carbon bars and posts are a real upgrade, if you install them right

A carbon seatpost or handlebar can make a bike lighter and change how the road feels through your hands and saddle, and that benefit is real. What usually gets left out is the other half: carbon asks more of you at install time and after a crash. If you treat it right it holds up well, but if you treat it like aluminum it can let you down.

This post covers what carbon actually gives you, what it costs you, and how to tell if it is the right call for your bike.

What you get

Less weight

The weight gap is real, though often smaller than people expect. Zipp lists its carbon Service Course SL seatpost at 233 grams in a 400 mm length. Its aluminum Service Course post is 251 grams, even in a shorter 350 mm length. On a bar, Easton lists the carbon EC70 AX at 290 grams in a 42 cm width. Nobody will feel a few dozen grams on a flat road, but you will feel it carrying the bike up the stairs, and it adds up across a build.

A different feel on rough roads

Carbon can be laid up to flex in some directions and stay stiff in others, which is where the comfort claim comes from. Zipp says the fiber in its Service Course SL seatpost is "tuned for ride comfort." On a long day over chip seal, a post with a little designed give means your body takes less of the road.

How much you notice depends on your frame, your tires and your tire pressure, all of which matter more than the post. We would fix tire pressure before we bought a seatpost for comfort.

Shapes metal cannot easily make

Because carbon is laid up in a mold, a bar can be flattened on top for your palms, flared for gravel, or shaped to hide cables. The EC70 AX, for one, carries a 16 degree flare, according to Easton. Plenty of riders also buy carbon because it looks great, and that is a fine reason too.

A carbon bar or seatpost is a real upgrade, but only if it is installed properly.That means a torque wrench and friction paste every time, not a guess and a dab of grease.

What it asks of you

The care carbon needs matters more than the weight it saves, and it comes down to the five things below.

Before you buy

Five things carbon needs from you

1. A torque wrench, used every timeYou do not need a special one, just one that covers the low range carbon clamps use. ENVE lists 5.5 Nm for the saddle clamp bolts on its carbon seatpost, and Zipp lists 6 to 7 Nm at the seat collar unless the frame maker says lower. Too much torque can crush carbon, and too little lets it slip.
2. Friction paste, not greaseZipp's seatpost manual says to apply friction paste to the seat tube and post, and not to use grease. Paste adds grip so the clamp can hold at a lower torque.
3. An inspection after any crashSRAM, which owns Zipp, tells riders to inspect bars, stems and posts after any crash and to stop using any part that shows cracks, dents, deformation, discoloration, deep scratches or creaking.
4. No repairsSRAM is just as clear here: do not try to repair these parts. If you are unsure, have a dealer look at it. A bent aluminum bar is easy to spot, but damaged carbon may only show itself as a creak or a small mark.
5. A replacement scheduleSRAM also says to replace handlebars, stems and seatposts periodically, and that how often and how hard you ride, plus rider weight, changes how long they last.

Does carbon wear out?

You will hear people say carbon does not fatigue, and our old version of this post said it too. That is not right, and the manufacturers do not say it either.

SRAM's safety instructions for its bars, stems and seatposts, Zipp carbon included, tell you to inspect for "signs of damage or fatigue" and to replace parts that show them, which is not what a company says if it thinks carbon lasts forever.

What is true is that carbon does not rust, and a well made carbon part treated well can last a long time. "Long time" and "forever" are different things, and the difference is what the crash check and the replacement schedule are for.

The real downsides

One tip before you shop

Zipp uses the Service Course name for two different seatposts: the Service Course SL is carbon, and the plain Service Course is forged aluminum. We carry both, and the names are close enough that it is worth double checking which one you are looking at. The aluminum one is a great post, but it is not the carbon upgrade.

Is carbon right for you?

Our take is that if you are building a bike you plan to keep, you ride a lot of rough pavement or gravel, and you will use a torque wrench, carbon is a worthwhile upgrade. If you crash a lot, your bike gets tossed in the back of a truck, or you would rather never think about torque, a good aluminum bar and post will serve you well and cost less.

Either way, install it right. If you are doing it yourself, a preset torque driver or a small click torque wrench and a tube of carbon paste cover most cockpit and seatpost jobs. Check that your driver's settings match the numbers your parts call for.

The weight is real, and modest. You save a few dozen grams per part, and more across a whole build.

The feel is real, and secondary. Tires and tire pressure come first.

The install is the part that decides whether it was worth it.

Want help picking one?

Buy the torque wrench first, and then the shiny part.