The past 2 months, I spend no less than 2 hours everyday to study on the viscosity of lubes and greases. I went around searching for the differences of grease performance, via Material Safety Data Sheet (MSDS). MSDS states the properties and the hazard of the particular material. But those data are often overlooked. In my work place, MSDS is the very thing for us to check. Click MSDS for more data. So what am I looking at to make my bike go faster? First we need to clearly understand the purpose of lubrication.
Picture I found from the internet.
My bike runs on a Mavic Ksyrium Elite, one of the bomb proof wheelset in the market. The bearings are all steel bearing. I want to make it roll smoother so I bought some tools from the internet and performed the overhaul by myself. I removed the bearing seal and flushed out the old grease, replace with my new homemade grease.
Hybrid ceramic bearing, the inner and outer race is made of steel while the balls inside is ceramic.
Full ceramic bearing.Theoretically fastest in the market.
Lubrication intends to provide full film lubrication, cooling, water and dirt repellent properties, corrosion prevention, reduce friction caused by surface contact and also dissipate heat. Bike bearing rolls less than 300rpm (human powered), it is so much slower than a table fan! But the grease provided in the market has a high viscosity than what we really need. For example, heavy duty greases are too thick (high viscosity) to be used and it ends up defeating the purpose of making the bearing smooth, the high viscosity cause the bearing to get "sticky". However, if the lubrication used is too thin, let say the Singer Mineral Oil, it wouldn't hold for long and most likely will leak through the bearing seals. Cut the story short, we want something in between a thick grease and the singer mineral oil. The correct viscosity will allow better penetration for lubrication and dissipate heat.
Cyclists and Ironman Triathletes spend long hours on the road exposed to heat radiated by the sun. The bearing rolls also generate heat. In my opinion, it can be only less than 60C. So the grease/lube used for bike bearings must remain the same viscosity properties within the required temperature range. For Malaysian weather, sub zero and above 45C is almost impossible. As the temperature goes higher, the viscosity drops. Check viscosity index for more details.
So what is the right mix? After the lengthy write up, I actually could not get the right mix for all the greases I bought. I bought Finish Line Ceramic Grease, Finish Line Ceramic Lube, Premium Dura Ace Grease, a few chinese lubes and many more. I made my own mix, went against all the advice in bike servicing.
Old grease removed, make room for new fresh grease.
New homemade diluted grease. =p
One time bike servicing, I used 3 types of grease. Some grease have better water repellent properties but lack friction reduction, so I use it in headsets and non rolling parts. The thinner and smoother ones I use for rolling parts.
I got everything assembled and perform a run down check. Put the chain at the big chainring and make one full spin.Take the time taken for the back wheel to achieve complete halt. Before I perform the servicing, I scored 44 seconds. After new grease pumped in, the run down time was 2 minutes 30 seconds. That shows how much of possible improvement with just a thorough servicing. I do not deny that ceramic bearings are so much faster. However, the feeling of eager to squeeze every tiny bit of improvement drives me to study more about bike maintenance and save some money for other commitments. When I have the money, I might get those wheels upgraded.