I’m curious as to what the general opinion/advise is regarding whether one should apply grease to the splines when refitting the crank arms to their unicycle hubs. From an anti-seize perspective I guess it makes sense but not sure it if has an negative effects like allowing movement to develop.
I’ve applied grease on my mountain bike crank splines many times but thought i’d check on here to see if there is any other view. I notice the splines on my nimbus are aluminium whether that makes any difference.
I tend to grease them a bit for corrosion resistance - with the correct spacers and a well torqued crank bolt it should be pretty impossible to develop any unwanted movement. If I had any around, I’d probably use anti-seize (since that stuff is designed for exactly that job), but I don’t think it really matters.
Each time I change cranks I wipe clean the splines and the inner part of the replacement cranks before adding a small amount of grease to them. I’ve always understood it to be good practise but I may be wrong.
Should I grease the spindle when installing the cranks?
This will depend on how the crankset manufacturer designed their crank. We have found that grease helps to ensure the cranks contact the stops on the spindle, thus reducing the possibility of the crank loosening while riding. Further, the use of grease helps to eliminate noise that sometimes exists in interfaces. The drawback of using grease on almost any interface is that it reduces the friction present between the mating surfaces, thus reducing the amount of load transfer through friction. Please refer to the instructions from your crankset manufacturer regarding the use of grease on the interface.
Everything I’ve seen indicates that the manufacturer recommends greasing.
With cotterless grease is essential to pull the cranks in as much as possible. I haven’t needed to remove my isis cranks yet but a ParkTool video says to use grease to prevent corrosion at the interface.
Not sure if it is true or not, but I apply grease to my Isis threads as I change cranks frequently on my gravel 29. People say doing this wears out the interface slightly each time, so I figure less friction means less wear and a longer life.
So I agree that grease should be used between most mating surfaces on assembly, if for nothing else to insulate between two dissimilar metal components to reduce galvanic scavenging effect. I use several different crank and axle materials so it may help.
Anti-seize is mad specifically for what you are talking about. I would never use grease on anything I’m trying to tighten down to keep in place. Grease is used to lubricate and help reduce friction on moving parts. I just received a new Nimbus unicycle and there was red grease on the crank arm pedal threads. It’s only going to help loosen them up quicker.
When you say expert, are you referring to the 12 year old factory worker that assembled the unicycle in Taiwan?
OP asked for thoughts and opinions and thats what I offered.
I worked for several years as a mechanic specializing in suspended scaffolding motors. They are very complex machines and peoples lives depend on them as they are dangling hundreds of feet in the air off the side of a building. I had extensive training in that field. What field of mechanics were you trained in?
Obviously no lives will be lost due to some grease on a unicycle spindle but that doesn’t mean that grease is the RIGHT product for the job.
Grease on pedal threads: Is a way of improving the interface with the crank. Here is the section from Sheldon brown covering this exact subject:
Note! The precession effect doesn’t substitute for screwing your pedals in good and tight. It is very important to do so. The threads (like almost all threads on a bicycle) should be lubricated with grease, or at least with oil.
Grease vs. Anti-Seize For Pedal Threads: Both grease and anti-seize compounds will work for pedal installation. Of the 2, I would recommend using grease as it acts as both an anti-seize agent and lubrication so reduces friction during installation. This is also the recommendation of the cycle industry with pedal installation.
Howard Zinn’s Zinn & The Art Of Mountain Bike Maintenance, which I consider an authoritative bike repair guide, says the following about crank installation:
With square-taper spindles, clean off all grease from both parts. Grease may allow the soft aluminium crank to slide too far onto the steel or titanium spindle and could deform the square hole in the crank. Apply grease to an ISIS or Shimano Octalink splined spindle.
Shimano’s factory applies grease to Hollowtech crank interfaces, so I suppose the same applies to Q-Axle cranks.