Which Headset Do I Need?

Here at Mountain Bikes Direct, we're commonly asked, “What headset do I need to fit my…..”

Well, here it is, the ultimate headset guide!

Rather than confuse you a heap of standards that are now obsolete, we're going to stick to the ones that are current and common.

You can see our range of complete headsets here.

Or our range of headset parts and bearings here.

Anatomy Of A Headset

Different Styles Of Headsets

EC - External Cup. The Headset bearing sits outside or external to the frame.

IS – Integrated or Drop Fit. There is no cups in this headset, the bearings drop straight into the frame. Effectively the cup is built in to the frame

ZS – Zero Stack / Semi Integrated / Internal

Types Of Steerer Tubes

There is 2 major and 2 much less common types of fork steerer tubes.

The two more common ones are:

• Tapered 1 ?^th to 1.5”. (1.125” to 1.5”) - This is by far the most common type. It tapers from 28.6mm where your stem clamps out to 39.8mm where the crown race sits. This set up is basically the same weight as a straight steerer while also boosting stiffness and strength. This is by far the most common on high quality bikes.
• 1 ?^th (1.125”) – This is becoming outdated now, but is essentially a straight steerer tube that measures 28.6mm except for the where the crown race is installed that is 30.0mm This is considered as being an older standard with almost everything now running Tapered.

The two less common are:

• 1.5 Inch (onepointfive) – This is discontinued now, but is a straight steerer that is 38.1mm where the stem bolts on and 39.8 at the crown race.
• Overdrive 2 or OD2 – This is a Giant specific size that tapers from 1 ¼ to 1.5 Inch. Giant used this on some of their mountain bikes for between 2012 and 2014. It is still used on Giant road bikes.

Which Headset Will Fit?

If you can't find the exact details of your frames head tube online, then you're going to have to do some measuring!

1. If there is already a headset in your bike, you're going to have to remove the cups (if it is a ZS or EC headset)
2. Now measure the internal diameter of the upper head tube and write this down.
3. Now measure the internal diameter of the lower head tube and write this down.
4. Measure the external diameter of your steerer tube where the stem clamps on to it and write this down.
5. Measure the external diameter of your steerer tube where the crown race sits and write this down.

S.H.I.S.

The wonderful people at Cane Creek came up with S.H.I.S. (Standard Headset Identification System). This system offers a standard way of describing a headset. After taking a few measurements of your frame and fork, you can look at the string of letters and numbers and know for sure if the headset will fit you frame

An example of a S.H.I.S Headset description is:

ZS44/28.6 | EC49/40

Let's break this down. The first half of the description refers to the upper half of the headset. ( ZS44/28.6)

• ZS – Zero Stack
• 44 – 44mm Internal Diameter of the top of the headtube on the frame.
• 28.6 – 28.6mm is the size of the steerer tube where the stem will clamp on

The second half of the description refers to the lower half of the headset. (EC49/40)

• EC – External Cup
• 49 – 49mm is the internal diameter of the headtube at the bottom.
• 40 – 40mm is the diameter of the fork steerer tube where the crown race will sit.

So, this headset has got a zero stack top cup, with an external bottom cup and it is to suit a tapered steerer.

Common Headset Sizes

Upper Headset (Based On A 28.6mm Steerer Diameter At Stem Clamp)

Lower Headset

* The headset cups and bearings are the same for 1 ?^th forks and 1.5" forks. It's just the crown race that changes.