Figuring out final gear ratio??

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Adam Smith

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I am trying to figure out my gear ratios. I have 44/18 (spur/bell) which by my calculations should be a 2.44 ratio. Now, I have the Robinson gears in the forward only trans which are 43T 1st gear and 39T 2nd gear(top shaft gear ratios are standard 13/17). But I am not sure where that puts me for a final gear ratio.
Another thing, what is a stock spur/bell on the new 3.3 TMAXX? online manual says 54/22, owners manual says 53/22, but then shows that 58/22 is the stock configuration in the gear ratios chart?? Kinda confusing. :\ I also have 7" claw tires which have a full 2" more runout than a standard TMAXX 6.3" tires have, thereby numerically reducing the drive ratio more. Anyone have any helpful ideas? Thanks
 
holy crap u r way to involved with that lol
 
If the new, bigger tires dog the engine and temps rise, then I would go to a smaller clutch bell or bigger spur(depending on how much room there is). That's about as deep as my feeble mind gets on gear ratios.
 
The truck has a .26 Picco on it so there is no bog. To be honest, it just has waaay too much top end. That much speed serves me no purpose as i dont have a football field to drive it on. I am trying to find out how far off i am of stock gearing. I have a 17 spur which would gear it down, but i dont really wanna be on the roof all the time either (slipper is already loose). The extra height of the tires makes a huge difference in the top end of the truck. guess i could just put the little ones back on...lol.
 
I am trying to figure out my gear ratios. I have 44/18 (spur/bell) which by my calculations should be a 2.44 ratio. Now, I have the Robinson gears in the forward only trans which are 43T 1st gear and 39T 2nd gear(top shaft gear ratios are standard 13/17). But I am not sure where that puts me for a final gear ratio.
Another thing, what is a stock spur/bell on the new 3.3 TMAXX? online manual says 54/22, owners manual says 53/22, but then shows that 58/22 is the stock configuration in the gear ratios chart?? Kinda confusing. :\ I also have 7" claw tires which have a full 2" more runout than a standard TMAXX 6.3" tires have, thereby numerically reducing the drive ratio more. Anyone have any helpful ideas? Thanks

Try this site..

http://www.rccaraction.com/ME2/Site...F6F27&SiteID=8398E64EA9C04E05B95200E5A3C25B85
 
I know these figures are somewhere within the threads of this site because I know that I personally have figured it out before. Just like you figured out your spur/CB ratio, you need to do the same for every gear mesh within the drivetrain. Then you multiply those numbers. Keep in mind 1st gear and 2nd gear will be seperate figures. These are all of your gear meshes...
  • 18 CB / 44 spur
  • 13 top shaft / 43 1st gear (17 top shaft / 39 2nd gear)
  • You also have another gear mesh within the trans which is your primary gear and your output gear. I'm not sure of the tooth numbers off the top of my head
  • Then there is your differential ratio
Just as you figured your 2.44, you do that for the other three meshes as well. Then simply multiply them. Just make sure when you are doing your division that you are dividing the proper way, that divide the later (further from engine)gear by the prior gear (closer to engine).
Spur/clutch bell
1st or 2nd gear/respective top shaft gear
output gear/primary gear
ring gear/pinion gear
 
Last edited:
I know these figures are somewhere within the threads of this site because I know that I personally have figured it out before. Just like you figured out your spur/CB ratio, you need to do the same for every gear mesh within the drivetrain. Then you multiply those numbers. Keep in mind 1st gear and 2nd gear will be seperate figures. These are all of your gear meshes...
  • 18 CB / 44 spur
  • 13 top shaft / 43 1st gear (17 top shaft / 39 2nd gear)
  • You also have another gear mesh within the trans which is your primary gear and your output gear. I'm not sure of the tooth numbers off the top of my head
  • Then there is your differential ratio
Just as you figured your 2.44, you do that for the other three meshes as well. Then simply multiply them. Just make sure when you are doing your division that you are dividing the proper way, that divide the later (further from engine)gear by the prior gear (closer to engine).
Spur/clutch bell
top shaft gear/1st or 2nd gear
output gear/primary gear
ring gear/pinion gear

It was the trans gears that were throwing me for a loop, thanks for the info!!!:)
 
couldn't you just rotate the 1st drive 1 rotation and count how many turns the final drive does, may have to engage your clutches some how though but you will get a rough idea
 
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