Jeez, I sure hope these work like I hope they will.

The headset top cap has been my great white whale for decades. I’m not trying to kill it, just to wrestle it down to its proper size. I write about this from time to time and the problem is lessened with the advent of superbikes in triathlon. So if you own a bike that costs you $4000 or more, pretty good chance what I’m writing about today is not going to affect you. For tri.

But if you own anything other than a really expensive tri bike, or a road bike in any price range, we’re back to that top cap problem. “What problem?” you might ask. The problem of spending all that money for a bike and then having a chunk of its height taken up by technologies found on Walmart bikes (round, untechnical metallic things). If a bike almost fits you, but it’s just 10mm or 15mm too tall, you can flatten the stem, assuming it’s not already a stem with an extension parallel to the ground. You can buy a new stem that is pitched flatter.

Or you can get rid of that tall headset top cap and replace it with one that minimizes the height of round steel and aluminum stuff. Here’s the problem: I’ve been round and round with FSA and Cane Creek, who make most of these top caps on most bikes, and you can’t get any cheat sheet for what caps go on what bikes. For example, I have a Cervelo R3, I’d like to get 10mm lower, that would be perfect for me. I’ve already got a –17° stem on it, that is, a stem that’s parallel to the ground. It’s got no spacers to take out. But it’s got a 16mm headset top cap. I wish I could – alas – just lower than to 5mm or 6mm.

John Cobb to the rescue. John sits in on many of my fit workshops, lending advice to fitters here and there, and coming up with products that fill small niches. You want a 145mm crank? John’s the king of short cranks for tri bikes. You want wrist relief extensions for your aerobar? John’s always got those lying around.

As John listens to me drone on he routinely hears about the inability for both shops and end-users to lower the fronts of their bikes via the replacement of over-tall headset top caps. So, here’s what he came back from the Orient with after his last trip over.

These top caps are 5mm tall, which is about as low as you can make it if you’re putting a standard stem on the bike. Each cap will come with 4 shims allowing the cap to work with top bearings of different tapers. This means this top cap should work with most headsets made by either Cane Creek or FSA, by putting the appropriate shim between the top bearing and the top cap. You would, I assume, just set each shim on the top bearing and see if it fits on there square. Then the top cap. Then the cap for the steerer’s wedge mechanism.

Now, to be clear, the installation succession will probably go like this: the upper cartridge bearing sits on the bearing race machined into the frame’s head tube. On that will sit a compression ring. On that will sit the appropriate shim, and then the top cap. Then the wedge cap through the center of which you compress the entire front end with the wedge bolt.

Bear in mind we have a nomenclature issue, some people call what I’m calling a top cap just a “dust cover” and they refer to the piece that goes over it all the “top cap.” Fine, have it your way, then it’s the dust cover John Cobb is providing. The point is, it’s a whole bunch lower in height than a lot of the OE “dust covers” that are coming on a lot of bikes these days, and this little package John is providing will probably retail for about $20, more or less.

I’m a little fuzzy on the exact installation instructions, and the final cost, and its precise utility with all these various headsets, because I haven’t seen the product yet. Nor, obviously, used it. Nor checked with these headset makers to see what they think of this aftermarket part being used on their headsets.

But these headset companies have had their chances! I’ve been making a pest of myself for years with them, asking them, “Do you have a low-profile aftermarket headset top cap [or dust cover] to replace the high profile versions shipping OE on many of your customers’ bikes?” The answer: Depends on the headset. My follow-up: Okay, what headset goes OE on a [then I name a bike model]. Answer: You have to ask our OE salesman in China.

Foiled, I then go to the bike maker, and I ask that company’s road or tri product manager. Answer: You have to ask our assembler in China.

So, we have these two mysterious people in China who engage in a headset transaction, and nobody stateside really knows what they’re doing. These two mysterious fellows in China know the answer but I haven’t been able to crack that code. So, it’s John Cobb to the rescue.

And here’s my message to the bike world: If you don’t want a big COBB logo on all your bikes, all your frames, all your headsets, staring all your customers in the face every time they look down to grab their water bottles, then, make your own low-profile replaceable top cap!

These are scheduled to ship from Cobb Cycling sometime in mid- to late-January.