- Jul 9, 2007
Does anyone have any positive or negative experiences to relate regarding the Tacx Cosmos? Also, any issues with using a Powertap while riding it?
can you explain how you did this or have pics. I would like to try thiscrakatoas said:Hi all,
The tacx Cosmos is a very good training tool to simulate or prepare during the winter a particular outdoor workout for the spring or the summer (I use it for 3 years now). You may purchase it, but take care about the temperature of the roll of the motorbrake, it may influence the behavior of the measurement and the friction effort.
After 1 hour training between 250W and 400W the roll temperature may create trouble. To prevent such problem I finaly decided to watercool the body of the motorbrake (like you can do it with your CPU of your computer). Now temperature is constant, measurements reliable, and efforts regular (the unit never trip), and the lifetime of your tacx training tyre will be much longer.
Of the water cooling set up, how it was done, explain.crakatoas said:Dear Mtnclimber1,
I am French and I am not sure to have understood your question. What do you mean by pics ? (for Moutains, for Temperatures, for Powers, in fact for what)?
crakatoas said:Dear Mtnclimber1,
You will find attached some pictures to better understand how it has been made.
pic 1 : The whole system
pic 2 : MotorBrake with the cooling pipe
pic 3 : Tank which contains the water at ambient temperature
pic 4 : 12V water pump + pipe (easy to find in a camping shop)
pic 5 : 12V Battery charger (easy to find in a car shop)
It is quite simple and quick to make it (I spent around 70 Euros)
To make it just roll up the pipe around the motor brake and use 2 screws of the motorbrake to fix it with metalic plates. Put the pipe on the pump and the pump in the tank with the water at ambient temperature. Connect the 12V wiring to the battery charger (be careful, don't invert + with -). When you put the power just move the pump into the water to expluse the air from the pump and it will works.
Before starting your workout, put the watercooling system on, then run your bike during 3 min with a slope at -5 (this will warm-up the motorbrake at the correct temperature the speed should be around 41 Km/h), and then calibrate the power (setup + calibrate menu).
Use always the same pressure for the tacx type (the best is 7,5 bar) and tune the screw below the motobrake to get a calibration value at -2.0 when calibration is completed (you likely have to do it several time for the first tuning to find the correct position of the motorbrake, after you don't need to touch it anymore).
Once done, you should be able to develop a constant power around 350W - 400W during 30 min without any over temperature. The best speed to avoid any unstability of the regulation and slippage of the type is higher than 20 Km/h.