Eighteen Bikes


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Sunday 17th July

Headtube options for 18Bikes Custom frames

As part of creating frames that would pass the EN test, we needed something a little more custom on the headtube side of things. Not finding what we needed from any of our suppliers, we machine our own!

An example of the polished headbadge on our eccentrically machined headtube

We start with aircraft grade 4130 chromoly tubing which is cut to length and faced on the lathe to ensure a square end. We start with a slightly oversized tube and machine it on the lathe to leave material where we need it and take it off where we don't. In order to leave some more material at the rear of the headtube, we eccentrically machine the headtube, removing material from the front. This also creates a lovely frame for the headbadge - click here for more details about headbadge options.

A few of tools we use including dummy axles, disc tab fixtures and our headtube machining fixture

The raw, faced tube is mounted in our custom fixture, to ensure the correct offset. We then turn this tube down on the lathe, leaving in-built reinforcement rings. Ace.

We've also been working on a tapered headtube option to allow new tapered forks to be fitted to a nice custom steel hardtail. These are machined from solid using a CNC lathe to our specification. It only adds around 60g to the frame weight. This headtube is designed to take the new 44mm lower standard to take a 1.5 fork lower but with a standard 1 1/8" top cup, it's a tapered tube but in skinny steel proportions! We've only got one rough sample so far, but once this is sorted we will be putting a longer travel frame through the EN test.

Our Tapered Headtube

We can also offer a machined headtube from Reynolds that will take a 44mm low stack headset top and bottom. It is machined from Reynolds 631 tubing, so matches with the rest of the frame nicely. This can either be used to keep the front end low or it can take a tapered fork but you don't get the look of a tapered headtube.

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