When people hear "drop," they might think of the drop curves thrown by Masaichi Kaneda or Nobuyuki Hoshino, but here at Circles, "drop" means the CHRIS KING DropSet series.
There was a time when the world of bicycle headsets was so overrun with proliferating standards that even bike shop staff gave up trying to keep track of them.
Among those, integrated headsets were particularly confusing.
The CHRIS KING DropSet series was the solution that cut sharply through that chaos.
First, please take a look at this list I've put together.
| Model | Upper Bearing OD | Upper Bearing Angle | Lower Bearing OD | Lower Bearing Angle | Notes |
| DropSet 1 | 41mm | 45°x45° | 52mm | 45°x45° | Discontinued |
| DropSet 2 | 42mm | 45°x45° | 52mm | 45°x45° | Differs from 5 by grip-lock |
| DropSet 3 | 41mm | 45°x45° | 52mm | 36°x45° | |
| DropSet 4 | 42mm | 45°x45° | 42mm | 45°x45° | |
| DropSet 5 | 42mm | 45°x45° | 52mm | 45°x45° | Differs from 2 by grip-lock |
| DropSet 6 | 41mm | 45°x45° | 41mm | 45°x45° |
I don't mean to brag, but I struggled because a concise chart like this didn't exist, so this chart alone is worth the read! (lol)
First off, what is an integrated headset?
Headsets usually have a place where the bearings sit, but in an integrated headset, the cup for the bearings is built directly into the frame, as seen in the photo.
The advantage of an integrated headset is that by building the bearing cups directly into the frame, you save weight by eliminating the need for separate, added-on cups.
The downside is that it requires a high level of machining precision on the frame, which is why this standard is often adopted by major manufacturers and for carbon fiber frames.
Now, let's explain the important parts of the integrated headset individually.
Regarding the outer diameter of each bearing.
In integrated headsets, the bearings sit bare inside the frame, and the size of that space is crucial.
For King, there are three types:
"41mm," "42mm," and "52mm."
However, you need to be careful with 41mm and 42mm; while a 1mm difference sounds straightforward, strictly speaking, it's a 0.8mm difference (41mm vs 41.8mm), which is almost impossible to distinguish with the naked eye.
Therefore, please be sure to verify the size on your frame when identifying which one you need.
Regarding bearing angles
Integrated headsets house the bearings directly, so the contact angle is vital.
That would be these angles:
45° × 45°
This is how it’s expressed, and with CHRIS KING, the first number represents the inner bearing angle, and the second is the frame contact angle.
These numbers are also very hard to distinguish by sight, so please check your frame specifications carefully.
By now, you should be able to make a rough identification, but the real issue is the difference between the DropSet 2 and 5.
Difference between DropSet 2 and 5
As you can see in the table, these two are numerically identical. So what is the difference? It comes down to the shape of the grip-lock, which you can see visually.
The grip-lock on the 2 has a skirt at the edge, common to other DropSets besides the 5.
The 5 has a dedicated grip-lock with no skirt at the edge.
The choice depends on the shape of your frame.
Everything other than the 5 is for frames where the bearing cup is shallow, with a depth of 2.8 – 3.0mm.
The 5 is for frames where the bearing cup is deep, with a depth of 6.85 – 7.05mm.
It can get confusing just reading about it, but looking at the photos makes it clear. Please check which one is compatible with your bike.
Now that you understand this, you should be able to determine which DropSet will work on your bike.
Since integrated headsets lack traditional bearing cups, their presence can sometimes be subtle, but as you would expect from CHRIS KING, they exhibit a quiet, solid quality even without the external cups.
Of course, in terms of performance, they offer the same stability of CHRIS KING bearings, contributing to smooth handling.
The headset connects the frame to the fork and handlebars, transmitting the rider's intentions to the bike.
You definitely want to use reliable parts for such a crucial component.