What type/grade of oil is used in a fluid turbo trainer?

I've got an old fluid turbo trainer that I've had to replace the bearings of. In doing so I've spilt some of oil in the fluid chamber. Does anyone know what grade of oil/lubricant I can use as the replacement fluid? Whatever it is it is very viscous. Ta, K


  • masjer
    masjer Posts: 2,613
    Some use silicone oil, eg Kurt kinetic. Others use hydraulic oil at around 46 iso -so quite low viscosity.
    Silicone oil has an advantage of maintaining a more constant viscosity when it heats up, but the bearings don't last as long running in silicone oil. Hydraulic oil is used in machines where the bearings run in the oil. eg Cycle-ops.
    You can buy silicone oil or hydraulic fluid on Ebay in small quantities. The amount of oil you use changes the resistance -so you might have to experiment. I used 100cc in a Cycle-ops and it runs well.
  • KJB69
    KJB69 Posts: 2
    Thanks @masjer for your advice here. Really appreciated.

    I thought I would have to fill the with hydraulic fluid chamber? Does having a half-empty chamber create more noise?

    The oil in the chamber is viscous compared to car engine oil. Is it possible as I've replaced bearings that have ceased, that the oil has also deteriorated over time? I reckon the trainer is around 10-15yrs old?

    Thanks again.
  • masjer
    masjer Posts: 2,613
    Yup, the oil could have certainly degraded over that amount of time. If the oil has become dark/brown in colour and not clear-ish that would indicate it could do with changing. On a cycle-ops trainer ,the chamber isn't filled to the top.