SX internal ratio changers

[stegger]

The internal transmission ratio's (2.4, 2.6, or 2.8:1) are changed i know by changing 34/22, 33/23 and 32/24 but which is which ? And do you only change them to get the desired ratio ?

[AmiSMB]

As far as the manual goes I thing you will find that the overall ratios are as follows:-

34/22 = 2.78
33/23 (std) = 2.58
32/24 = 2.4

In Si Moss setup sheets it talks of a 36t idler but I cannot see that in the parts list and am unsure of the size of the other gear that would go with it.

[AmiSMB]

Click here for a gear ratio chart spreadsheet in Excel format for the CAT SX.

[MattW]

As you've said, there are 3 different pairs of gears, which give you 3 differnet ratios. I have been using the kit std one for a while to be honest.

[AmiSMB]

I ran my car on Friday indoors and ran the std pulleys and spur gear with a 21T pinion which gives an overall ratio of 10.21 and this was on a 5.5 Team Orion motor and LRP Spere TC ESC and felt that it had a very high top speed but felt that it was a bit gutless in the infield. When I have looked at the ratios I noticed that on my X-5 I used to use 16/108 which gave me an overall ratio of 11.81 so I may try getting closer to this so I expect an 18t pinion is nearest on the standard setup.

[stegger]

Good stuff, cheers boys.

[gps3300]

What's the advantage of being able to change the internal ratio?

[Adam Bailey]

In a nutshell you can fine tune your car for optimized brushed and brushless ratio's.

Especially stock brushless!

Originally Posted by gps3300

What's the advantage of being able to change the internal ratio?