looking for some details on Babolat RDC machine


Hall of Fame
Hopefully someone that owns/has access to Babolat RDC machine can help me here:
1) regarding measurement of the flex of the racket. On the RDC machine - what is the distance between the hook that presses the tip of the racket downward and the bar that supports the racket in the middle?
2) what is the distance between the bar and the clamp that holds the handle of the racket?
3) when the flex measurements is being done - is the pressure always the same and the RDC measures how far the racket flexed? Or is the machine flexing the racket a constant distance at the tip and it measures how much force is needed to do that? What is the force and/or flex distance that RDC uses?
4) when string-bed stiffness is measured - is the constant force applied and the flex of the string bed is measured? Or is the flex of the string-bed constant and the machine measures how much force is needed to cause that pre-set flex of the sring-bed? What is the force and/or flex distance that RDC uses when measuring stringbed stiffness? What is the size of that 'thingy' that presses the stringbed downward?

Tommy Haas

Hall of Fame
Are you attempting to replicate the flexibility test for those who don't have access to an RDC?

From what I can tell the fulcrum point is at the lower 1/4 portion of the hoop on a midplus sized frame.

The RDC measures flex at the hoop and when you test for flex with a strung racquet, the value will be higher because the strings stiffen the hoop.


Hall of Fame
Babolat reps did get in touch with me - so many thanks for that. Unfortunately they were not willing to provide the info I was looking for - which is a bit surprising as the data I'm looking for is easily available to anyone that has RDC machine (so it's not like it is a manufacturer secret or anything).

Anyway, if someone does own an RDC machine - could he eyeball the following for me:
  • when racket flex measurement is done - what is the bend of the tip of the racket? Like 1cm? 5cm? I'm looking for an approximation, I realize that perhaps the bend is different for different rackets.
  • when stringbed stiffness measurement is done - what is the flex of the stringbed? Like 1cm? 2cm? I'm looking for an approximation, I realize that perhaps the flex is different for different strings.


I don't own an RDC myself, but my stringer has one. I might be wrong, but from memory I would say about 3 cm when measuring flex and about 1-2 cm measuring stringbed.


New User
This is an approximation as I don't have the machine before me but it seems that the distance between the tulip and center bar which provides the fulcrum point is about 12 inches. That also seems to be the distance between the bar that secures the handle and the center bar or fulcrum point. This is just an estimation based upon a photo that I had taken with a 27 inch frame mounted on the machine. I haven't been that technical in my observations but it does seem that some frames will bend a bit more than others so I can only assume that the tulip has a set amount of force applied and the distance the rod upon which the tulip is mounted travels is used to determine the flex factor. I would assume that it would also apply to string bed deflection as it is the same unit measuring the resistance. The difference between the flex of one frame in comparison to another is slight and would seem hard to measure if it was soly dependent upon the amount of effort required to move it a certain distance. It seems that it would be easier to have a standard amount of energy applied and then measure the travel distance of the rod supporting the tulip and use it's travel distance as a means of determining a reading. Just my 2 cents worth as I am neither a mechanical engineer nor a Babtec technician.