# Tjet Gear ratios



## Boosted-Z71 (Nov 26, 2007)

OK I am lazy, before I calculate it all out does anyone here already have the numbers for the final drive ratios for T-jet, AFX & Super II chassis configurations using all the gear combinations?

Needing the info for a dyno setup.

Thanks

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## alpink (Aug 22, 2010)

all the Aurora pancakes have a 15 tooth crown gear except the Super II which is 19. original pinion gears were 9, 12, 14 there are 10 tooth after market pinions and maybe more. sorry I don't have the ratios, but I am sure someone else does. Merry Christmas and a safe Happy New Year


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## Boosted-Z71 (Nov 26, 2007)

Ok, I would like someone else to check these and see if they are right, but here are the magic gear ratio numbers, for a T-Jet, this does not include tire size. 

Will have similar numbers for AFX, Magna-T & Super II later

T-Jet

Pinion - Idler - Cluster - top - Drive Pinion - Crown - Ratio to Axle - Final Drive Ratio
14 ---- 24 --------- 24 ---------- 9 -------- 15 ------- 0.35 ---------- 2.86 
14 ---- 24	--------- 24 --------- 12 -------- 15 ------- 0.47 ---------- 2.14
14 ---- 24	--------- 24 --------- 14 -------- 15 ------- 0.54 ---------- 1.84

AFX 

14 ---- 24 --------- 24 --------- 14 -------- 15 ------- 0.54 ---------- 1.84

Supper II

14 ---- 24 --------- 24 --------- 14 -------- 19 ------- 0.43 ---------- 2.33



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## LDThomas (Nov 30, 1999)

Those numbers work for me.


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## LDThomas (Nov 30, 1999)

Those numbers work for me.


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## rholmesr (Oct 8, 2010)

Boosted:
Your ratios are correct. Also the AFX, Super-II and Mag Tractions all use the same gearing combo as the tuffones so same 1.84 final ratio.


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## alpink (Aug 22, 2010)

Super IIs came with 19 tooth crown gears.


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## Ogre (Jan 31, 2007)

Maybe someone will find this usefull. It has helped me but I'm not the best at math. :hat:


http://virtualgarage.net/Automobilia/Miniatures/SlotCars/Tips/ModelMath.jhtml


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## Hornet (Dec 1, 2005)

I get 2.85 / 2.13/ 1.83 on my calculator Jeff
But it's probably more in reading the decimal point.

Went back and double checked,you're right,i didn't go far enough back on the decimals,oops,lol




Hey you should post a picture of the dyno read-out spread sheet.
That's a wicked dyno you've got now:thumbsup:

You guys gotta see what Jeff's dyno does now,a real world 1:1 chassis dyno is basically what he's built himself.
Rick


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## Boosted-Z71 (Nov 26, 2007)

Will do Rick, I will post the image tonight when I get home.

Thanks for checking my math

Boosted


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## Hornet (Dec 1, 2005)

If you guys haven't seen a dyno printout using Simple Dyno,it'll amaze you the info it gives out.
Jeff sent me a print-out off his updated dyno,and it floored me at the amount of info it'll spit out:thumbsup:

Figure i might have to wave a whole bunch of cash in his face,and tell him how good looking he is,as i want a duplicate of his dyno now,lol:thumbsup:

Rick


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## fordcowboy (Dec 27, 1999)

Ok would 1.84 be low gear. A tall tire makes the gear even lower. ??? Right or wrong?? fcb


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## LDThomas (Nov 30, 1999)

1.84 is high gear.


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## Hornet (Dec 1, 2005)

Actually in the world of rear gears Wendel,the 1.84 is a tall or high ratio,and the 2.85 ratio is a low or deep/steep ratio.
Rear gear ratio's are backwards to most things if you're trying to figure out if they're low or high gear ratio's.
And yes a taller tire will make the tall 1.84 ratio even taller.:thumbsup:

Oops:Larry got it covered while i was one finger typing
Rick


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## fordcowboy (Dec 27, 1999)

Well thanks two both of you guys. fcb


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## Boosted-Z71 (Nov 26, 2007)

Think of the tire example like this, any car if you put a shorter tire on it will have more power / and quicker acceleration, a taller tire will get you more top end speed, slower acceleration, but of course tire width / rotating mass plays a huge part in this as well, but I am not going there. 

Boosted


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## Boosted-Z71 (Nov 26, 2007)

Here is an example of the Data you get from the SimpleDyno Software, This is all done with the headphone / coil setup. I will try to take some more screen shots of actually taking the data later, Right now the truck is stuck in the driveway, going to get the tractor, get it out then plow. I Love snow

Boosted


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## rholmesr (Oct 8, 2010)

Oops. I forgot about that super II 19T gear.


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## Hornet (Dec 1, 2005)

LOL,about time you got some snow:wave:
Not good the trucks stuck though.
Rick


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## Boosted-Z71 (Nov 26, 2007)

Yeah just got in now, Its in the garage, no damage and the driveway is plowed.

Hey I posted the graph in your new dyno thread as well 

Boosted


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