I can't figure out how to select variable speed belt for our variable speed drive design with the following specifications of our BAJA vehicle: 1.) BHP= 10HP 2.) Max. Belt velocity = 35 m/sec 3.) Max. Engine RPM = 3700

We are designing this variable speed drive for our CVT. Any help regarding the description of selection process will be greatly appreciated.

Thanks in advance!

  • Have you considered that the max belt velocity and the engine speed will limit the size of the gear you can use?
    – Solar Mike
    May 7, 2020 at 9:24
  • Yes, that was considered and we will design the sheave according to our belt May 7, 2020 at 9:30

1 Answer 1


So, simple analysis is:

max belt speed <= engine speed * gear circumference

Throwing in the numbers and solving for the diameter at the maximum point:

Edit based on a unit error...

D = 35 / ((3700/60) * 3.14159)

which gives 0.18 metres ie 18cm.

That should enable you to work out what you want to use for a final drive ratio..

  • I think you forgot to convert rpm from minutes to seconds to write D in mm May 7, 2020 at 9:53
  • @VaibhavDixit converting minutes to seconds matches the units of rpm to velocity, it won't change the metres...
    – Solar Mike
    May 7, 2020 at 10:04
  • I wanted to say, you had to convert mins to seconds so that you can obtain units of D in SI units and I just found out your edited answer. I want to ask you how can I select the belt from the catalogue of belts of variable speed drive belts with these specifications May 7, 2020 at 10:08
  • 1
    @VaibhavDixit about the only thing left for you to define is the length of the belt - distance between centres and pulley sizes should give you that or you can use a piece of string to measure it. also remember tensioning. And the width of the belt based on the power...
    – Solar Mike
    May 7, 2020 at 10:14
  • Thanks for the help Solar Mike, but I need the procedure which can help me select the variable speed belt specifications from the standard catalogue May 7, 2020 at 18:02

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