Mugen Internal Ratio
Hey guys, for those of you that have adapted a Serpent or Kyosho transmission to your cars. You will probably notice that these two brands (S and K) have their transmission set for a lower gear ratio, as low as 2.
A Mugen car has a ratio of 2.158 and as you will probably notice, you will run out of top speed in fairly average size tracks.
Two pulleys need to be changed in the internal ratio in order to bring it lower.
In my case, I changed it from 2.158 to 2.05.
What you need is:
-20T Brake Pulley
-19T Rear Side Pulley or 23T Front Side Pulley (These pulleys are the ones that run on the side belt, you need to change ONE not BOTH)
Here is a few options you have:
For the Brake 20T pulley
-Mugen MRX-4X pulley can be adapted no problem
-Team Titan or Zepping 20T Aluminum Pulley can also be used
-Xray NT1 has a 20T brake pulley, but you may need the NT1 brake adapter and possibly use a NT1 rear belt due to width. (Never tried this one myself)
For the Side Pulley
-MTX-3 Pulley set has the 23T and the 19T pulley
-3Racing makes an aluminum 23T pulley
Inconveniences with belt tensions
From 19T to 20T (Brake Pulley)
You can resolve this two ways:
-You can use a Kyosho Rear Belt which is 1 tooth longer
-Or you can get Serpent's Aluminum Eccentrics which allow the Diff to sit higher and forward in order to lower the tension. Other modifications to the Rear diff cover need to be done in order to have a smooth run. In my case, I only have one belt tension set which is having the eccentrics tab completely backwards.
From 18T to 19T (Side Pulley) (Option 1)
-Mugen Belt is really really long, longer than it should be in my opinion. So using a 19T side pulley presents no inconvenience to the belt as this can be adjusted using the Belt tensor.
From 24T to 23T (Side Pulley) (Option 2)
-This might present a problem, because it means the belt will be very loose. I have not tried this one myself yet, but if any problem arises, Kyosho's side belt is 1 tooth less than the Mugen Belt and will probably fit there.