I own a 2005 Trek Pilot 2.1. I am looking at possibly replacing the headset and was wondering if the Chris King Inset headset would be compatible. My google skills have failed me and I was hoping someone here would be able to tell me if it is or is not. What I do know is that the headset the bike came with is internal and it is made by Cane Creek, and thats about all I know

Chris King doesn't do integrated headsets, as far as i know.

There are two types of "internal" headsets, semi-integrated and integrated. The former installs like a standard external headset using pressed-in cups. The difference is that they go into an over-sized headtube which allows the bearings to sit inside the frame. The latter uses built-in bearing races (either machined into the frame or a metal insert for a carbon frame) so the "headset" is really just a set of bearings. There are many different types of integrated headsets and they are interchangeable. It is this type of headset that Chris King cries about.

No they are not.

There are are at least a half dozen "integrated" headset standards and most of them are *not* interchangeable.

If you need to replace that headset it's simple. Pull it apart take the two bearings out, find out what size integrated they correspond to and buy the replacement. Here's a good page.

https://www.parktool.com/repair/readhowto.asp?id=68

Typo. Good catch.

A person in the club has a similar bike to me, I asked them about the headset. They said that the bearings sit in this metal ring, but they are loose apart from sitting in this ring. Apparently there were problems with the fork rattling inside the headtube. Upon inspection of the bearings by a mechanic, they were completely destroyed, the person said. The mechanic brought them out, and the ring the bearings rolled around in was broken in three pieces, and the bearings were just all over the place. From that description it sounds like its a fully integrated headset. I did check into chris king headsets further, and yes they make no integrated headset, and they say that the headtube would likely have to be re-machined to accept a non-integrated headset. I don't want my bearings to go out like this other's guy had happen to him, thats why I was thinking I could try another type headset, but didn't know what would be involved. Seems a hassle to convert.

Park makes cutting tools to recut the head tube so the same type of headset can be reinstalled. Unless the bike was ridden for a long time with ruined bearings, the frame should not be damaged so bad that it can't be salvaged.

The problem is most likely caused by Trek specing a cheap headset or failure to maintain the bike.

I've owned four frames with IS standard integrated headsets since 2004 and never had a problem. I do know how to keep them properly adjusted, but it's rare to need any readjustment. Although the IS standard uses slip-in bearings, my frames have removable bearing seats that can easily be replaced.

The guy I was talking to said he was not the first owner of the bike, so the previous owner of his bike could have failed to maintain the bike. He had new bearings installed (top and bottom), and there has been no issues with his bike since.
My bike has had no problems, yet. But if it was to start acting strange, I'd haul it into my LBS pronto to make sure something wasn't going to cause damage.
I was just worried that integrated headsets are cheap the point where I should think about replacing it with a non-integrated one

AFAIK, all forms of "integrated" headsets, both the true integrated design where the bearing seats are machined into the head tube and the "zero stack" type where shallow cups are pressed into flared ends of the headtube, use cartridge bearings. Therefore, the actual bearing balls roll against races that are part of the cartridge and should never really touch anything in the headtube.

So, if your friend had his headset "destroyed" I can only presume that one of the cartridges came apart through misadjustment, neglect or a manufacturing defect. He needs new bearing cartridges and the frame must be inspected to assure the bearing seats weren't damaged by the broken pieces.

Yeah it was inspected to make sure no damage occurred as a result of the broken cartridges. Those were replaced (look like rings with bearings in them) he said, although he didn't know the name of the part the mechanic showed him that was all broken up. All is good with his bike, although I have to wonder what the previous owner did to the bike to even get them into that kind of condition.
My own concern was that if these type of headsets are this janky, maybe I should replace mine with a non-integrated headset. However, I have no issues with the headset on my bike right now, and you guys have allayed my fears.

Utter nonsense.

Integrated are pretty much 99% of the mid/high end road bike market. You will hardly see a 09/10 OEM road bike without an integrated headset. Also it is not possible to replace an integrated headset with non integrated. That chris king blurb on integrated headsets just make them look like luddites.

I question their motives for producing such an "informatiom" pamphlet.

My initial impression of them being janky came from my fellow club member who started having shuddering in the entire front end during descents, and eventually the fork rattle around in the headtube due to his "headset" being literally in pieces, not what Chris King thinks. Their bias is clear on their website, but having known other people who have been happy with their CK headsets, it was a starting point to look at if I needed to replace the headset proactively (didn't know that re-machining the headtube would be required before i started looking into it).

I don't know what model headset and/or cartridge bearings Trek used as OEM but there are some very good Integrated/Zero stack headset bearing out there. Cane Creek, FSA Campy and others supply reliable bearings in a variety of configurations to match the bearing seats.
There is nothing inherently wrong with this type of headset. Their biggest weakness is the lack of standardization.

I am confuzed now.
I have a road bike with an FSA integrated headset, the sort with pressed in races that the bearings drop into. Hasn't given me trouble in fully 7 years of frequent, wet riding, through several nonviolent fork replacements.

How do conventional headsets like the CK ones work? Are the cups pressed into the frame, and then the bearing cartridges further pressed into those? CK is bashing integrated headsets on mountainbikes (judging by their brochures), and on a MTB the HS does get extra impact and stress, so I can sorta see their point. But then... how do theirs differ in installation?

You have a semi-integrated headset in that case. On a traditional threadless system the cups are pressed in and the bearings are slip fit, if cartridge or just directly loaded into it either in a cage or loose.

I believe the official term for a semi-integrated headset is "zero-stack".

Chris King's traditional press-in headsets, both threaded and threadless, are a bit different from others in that the bearing cartridges are sort-of "staked" into the cups and can't be removed or replaced. They can be cleaned in place by removing the seals, relubing the bearings and replacing the seals but when they are shot you have to replace the entire headset. It's good thing CK has a long warranty and uses exceptionally high quality bearings.