This is a simple little part that I came up with for those people that ended up with a steerer tube slightly too short for whatever reason. Here it is.
There’s nothing too unique about the part itself but there is something kind of novel about the way it mounts to your currently too short steerer tube. The first thing that happens is I remove the regular star nut and install a BMX star nut a little deeper than the extender. Notice that the BMX star nut is meant for a larger bolt than a regular star nut.
I machine the extender with a step down profile so that I can press it into the steerer tube with Loctite retaining compound. The steerer tube end obviously has to be machined completely flat in order for this to work seamlessly.
So here comes the interesting part. The bolt that’s normally used in an old BMX top cap is hollow. It was meant for a cable to be run through the headtube for barspin purposes. Anyway a lot of those large hollow bolts are also threaded on the inside with the perfect thread for a convention mountain bike or road bike threadless top cap bolt. Here’s the extender pressed in with the hollow bolt cranked down to keep everything together.
So there you have it, a lightweight aluminum steerer tube extender that’s pressed in, Loctited, and bolted down. Now you can sprint your balls off or do sick drops without a worry.
50 bucks later, it looks completely stock like nothing happened.