Creaky CSU Solution
7/27/2025
This topic is related to the origins of Blue Liquid Labs. I’m talking about solving creaky CSU’s. I thought I’d post about this here because if I don’t, this topic might fall victim to historical revisionism. It would be very easy for a company with more resources and a nicer website to claim that their people were actually the ones to figure all this out, so it’s best that I at least give an origin story and put it on record, since this is now history. Mind you it’s a very very tiny portion of history we’re talking about here, but it’s still history nonetheless. Luckily at any point, anybody can use the wayback machine to cross reference what’s been written on the internet with real dates, just in case there are any doubts. And it’s entirely possible that conversations about this might have happened in R and D departments and behind other closed doors. Even more possible is that somebody might have spelled this all out somewhere on the Japanese, Russian or German internet, but I can’t read any of those languages. At least on the English internet, back then at no point did I find even so much as a suggested diagnosis to the problem, let alone a real solution. So now I’ll tell the story of how my diagnosis and solution came about.
It all started with my 2002 Rockshox Psylo SL. After only a year of riding, it began to creak horribly. The internet was still in its early period so there was no good information about this type of thing. Bike shops were still the main source of information and at the time, the people working there preferred to pretend like creaking issues didn’t exist. You were essentially a crazy person if you started pondering aloud about what this mysterious creaking might be linked to. It was almost as bad as if you came in and started contemplating where bigfoot might live. Getting help was hopeless.
Many years went by and I heard through the grapevine that a respected mechanic in my city was using Loctite retaining compound on headset cups. That was very relevant at the time because 1-1/8 head tubes were getting ovalized. I almost couldn’t believe that some loctite could actually hold and stabilize something subject to that much force. Years before, I had heard about people putting headset cups into ovalized headtubes with red loctite as a homebrew type of solution. Now the year was 2008 and I was riding a 2003 Norco Sasquatch with a Marzocchi Z1. Sure enough by that point, the headtube became ovalized. I could feel a well defined knock during braking as the lower headset cup moved rearward inside the head tube. I tried the old loctite trick and it worked. I couldn’t believe it. All the forces coming in through that long fork were effectively being held by the Loctite.
In 2010, I was working at a bike shop that had a hydraulic press and a mini lathe. By that point I was educated about the fretting corrosion seen in other industrial settings, such as the type you’d see on a shaft that had a bearing sitting on it or what you’d see in a machine taper that hadn’t been removed in a long time. I began to wonder if maybe the same thing could be happening inside the press fits of the CSU. By then the internet had matured somewhat and there was now a widespread acknowledgement of the existence of CSU creaks. But at least in the English internet, you could google until you were blue in the face and you’d see nothing written about a solution. My plan was to combine the lessons I learned from using loctite on my Norco Sasquatch with what I knew about fretting corrosion. I made some tooling to press apart my old Rockshox Psylo CSU, cleaned out the corrosion inside and added some loctite retaining compound. Sure enough it worked.
More years went by and there was still nothing written on the internet about how fretting corrosion applies to mountain bike fork CSU’s. Even worse, by that time there began to emerge various suggestions at solutions, all of which missed the mark in one way or another. I heard recommendations to clean out headsets, I read memos about increasing the torque on the top caps, I heard recommendations to drip wicking grade loctite into the CSU without taking it apart, and I also heard a call to increase the press fit interferences of the CSU. While there isn’t anything horribly wrong with any of those things, none of them could reliably produce a situation where a customer handed you a creaky CSU and you handed them back the same CSU in silent form. I knew that pressing the CSU apart, cleaning out the corrosion and loctiting the CSU could reliably produce a situation that made customers happy.
Finally in 2014, I decided to make my own website that was going to spell the whole thing out. It took years to get noticed but once enough people read that article on my website, the connection between fretting corrosion and mountain bike fork CSU’s became something closer to common knowledge. Maybe not exactly common, but among the technical people out there, these concepts and connections became understood. Since then I’ve been able to provide many shops around the world with the tooling necessary to replicate my results. My article and later on my video gave many other shops the courage to develop their own tooling and methodology to fix the problem in their own communities. As far as I’m able to tell, it all started with me publicly pointing out the culprit and the solution back in 2014. This is the article I wrote on my website back then, with the original timestamp of June 21st, 2014. You can click it and make it bigger if you want to read through it.
