Replacement headset for Cannondale Trail SL

I have a Cannondale Trail SL Single speed (2013) and the headset has died. It died because I was impatient during a fork upgrade and mangled it, but that's beside the point.

The good news is that it's easy to replace the headset and you even have some choices on manufacturer as well.

Firstly, if you are coming to replace your headset in your Cannondale Trail SL, then you'll need to verify the dimensions of your head tube and seek a suitable replacement.

Dimensions of the Cannondale Trail SL head tube

There's a lot of information out there on the web about the different sized Cannondale head tube diameters. This was mostly from the old world of the Headshox and the early Lefty's. Now, most of the Cannondales, including the very latest Lefty's, use a standard 1.5 steerer tube.

You'll find that the diameter of the head tube is 49.6mm for both the top and the bottom. If you have a frame other than the Trail SL, then I can't be sure it won't be the same measurements, but a good bike shop should be able to remove the headset and confirm the diameter.

Replacing like for like

If you are using a Trail SL frame with a 1.5 straight steerer tube fork, then it's 99% likely that you are using the Cannondale KP191 headset. That's their standard go-to headset.

If you're using a tapered fork, then you're probably using a combination of the Cannondale KP191 for the lower cup and bearing and a Cannondale HD232 for the top. Cannondale don't offer just a tapered option.

Both of these are readily available and priced reasonably too.

However, now that you know the size, you can choose other non-Cannondale brands to satiate the brand-lover in you.

What type of headset is it?

There are three types of headset, IS (Integrated System), EC (External Cup) and ZS (Zero Stack).

• Integrated headsets have the bearing cups pre-built into the head tube. You simply drop the bearings in and you're away (This isn't the Cannondale Trail SL).
• External cup headsets are pressed into the frame (commonly also known as press-fit headsets) and the bearings sit outside of the frame.
• Zero stack headsets are the half-way house. They are pressed into the frame and the bearing is generally within the frame too.

They are accompanied by four numbers.

• The first number is the internal diameter of the top of the head tube
• The second number the external diameter of the stem clamp area
• The third, the internal diameter of the bottom of the head tube
• The fourth the external diameter of the fork crown race

Put together, and using the Cannondale Trail SL headset with a 1.5 straight fork as an example, the headset designation would be:

• ZS49/30 EC49/40

Simple, right?

Chris King and Cane Creek headsets for a Cannondale Trail SL 1.5' head tube

Chris King

If, like me, you want a 'King' headset on your bike, then you'll need to choose either one of these headsets depending on the fork you have:

• 1.5 straight fork - 1.5 NoThreadSet
  designation: EC49/40 EC49/40
• 1.5 to 1 1/8 Tapered fork - Chris King InSet 5
  designation: ZS49/30, EC49/40
• 1 1/8 straight fork - choose either, the Chris King InSet 4 or the 1.5 NoThreadSet Devolution
  designation: ZS49/30, EC49/30 for the InSet 4 or EC49/30, EC49/30 for the 1.5 devolution

Cane Creek

Whilst probably the better headset and they have a great following, Cane Creek headsets are simply just not as lust-worthy. Still, if function over form is your preference, then go for the 40 series. Handily, they also include the designation / sizing in the name of the product:

• 1.5 straight fork - 40.EC49
• 1.5 to 1 1/8 Tapered fork - Tapered ZS49 | EC49/40
• 1 1/8 straight fork - Tapered Conversion ZS49 | EC49/30

I personally went for the Chris King and ordered a InSet 5 to go on my trail and to match up with my tapered Reba. Fitting took minutes and it's fantastic. Couldn't be happier.

Hope this helps someone. Do ask any questions about the Cannondale Trail SL, Chris King headsets or headsets in general below.