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Can someone here with Ultima & Turbo Ultima parts or experience provide me the following details? If you knew the stock gear ratio(s), that would be great too.

-Final pinion gear #teeth
-Counter gear #teeth
-Differential gear #teeth

Thanks, much appreciated!

Ok, this is from my horrible memory. I think the final pinion has 19 teeth and the diff gear has 58. All .8 module. I don't remember the number of teeth for the counter gear. The spur gear has 44 teeth though.

Stock Ultima gears:

Final pinion=19t
Counter gear=28t
Diff gear=37
Center gear=41t

HA! I was in the ballpark...mostly.

Mark, I don't get why you need to ask: they are identical to your optima gears.

Isn’t there a formula that you can use when you calculate the gear ratio?

ofcourse:
internal ratio = (diff/inner gear)x(outer gear/cluster gear)
final ratio = internal ratio x (spur/pinion)

Mr. ED wrote:ofcourse:
internal ratio = (diff/inner gear)x(outer gear/cluster gear)
final ratio = internal ratio x (spur/pinion)

Thanks Mr. ED! Sins Optima and Ulima have the same gearbox layout as the Scorpion. And I need to calculate the Scorpion gear ratio so I don’t over gear and kill my brand new 2X17 motor at our indoor vintage meet.

Coelacanth wrote:Can someone here with Ultima & Turbo Ultima parts or experience provide me the following details? If you knew the stock gear ratio(s), that would be great too.

-Final pinion gear #teeth
-Counter gear #teeth
-Differential gear #teeth

Thanks, much appreciated!

3.0 is the gear ratio for the Ultima and Optima

3.03 actually
www.rc10talk.com/viewtopic.php?f=40&t=17667&p=172084
this topic has a list with others also