An idea came to me while riding the other day that I believe has value. It’s regarding the steerer profile for the 32″ forks that we should be seeing soon. I’m looking for a shorter tapered section so that I can use head tube options below 85mm. I sent an email on it to a fork manufacturer. To make my descriptions clear, I included a drawing. It’s was a section view of the head area of a bike that I’m working on. The drawing below is very close to what I sent.
What makes the drawing you see now different from what I sent is the inclusion of the star nut. My model, until just now, didn’t have that. It made my skin crawl to send such an incomplete drawing. So much that I had to I fix it.
This small project forced me to take a deeper look at the star nuts that we use on bikes. I have a large collection in my stash that had been accumulated over the last 36 years years. Different times and places get preserved in small piles of parts. Nine different sizes. A few that allow cable through the steerer. Only one, though, is used in the current era. The 26.6mm that would be used in a modern suspension fork.
Here are the most common sizes as far as I can see:
- 1″ steel steerer – 23.7mm
- 1 1/8″ aluminum steerer – 26.6mm
- 1 1/8″ steel steerer – 27.8mm
- 1 1/2″ aluminum steerer – 36.5mm
Look a little deeper and we start having a lot of problems. Star nuts sizes are very poorly described in catalogs, if at all. It’s challenging for anyone to know what they have or what they may be ordering.
FSA/TH buries something in their catalogs…. this is as good as it gets.
Star nuts in cycling are also known as sunflower star nuts. They are mainly used for the ends of tube fabrications and electrical mounting. They can be round, oval, or rectangular. A few Chinese companies specialize in these types of components.
Dongguan TinFin Hardware and MeiDaXin (Huizhou Meida Xin Hardware Co., Ltd.) have catalogs that shows many of the sizes that would be common.
This information should provide others with a starting point for figuring out what they have in front of them.
If ANYONE has better information, drawings, or specifications regarding star fangled nuts that I can share here, please reach out and let’s talk. I’d like to provide the best information that I can.
While discussing this post with Adam Prosise, he talked about failing star nuts. For 99.99% of us riders, this isn’t an issue. A star nut should not be failing if the system is properly installed. Adam’s issue is that he is an elite rider that might be coming up short on gigantic gaps. This will overwhelm much of what typically holds the head assembly together. A star nut will tend to be where that shows up.
For Adam, a product like the Chris King PreLoader will be used. This eliminates a failure mode when the system is entirely overwhelmed.
I also believe the the devil in my point that “properly installed”. This means that the base of the stem and the frame must be properly faced. Many riders have stems installed so as to destroy their bike. Check that the stem is square and flat to the head axis. If it is not, like almost all forged stems, it must be faced.
