a Few questions as i wait for my monster

hello all first question for 5mm motor shaft does everyone shave a flat spot into it?


i have
3.3 revo conversion

RCM motor mount

medusa 36-60-2000kv motor

5s1p zippy-h 5000mah batt

talon tires 5.75"
does all this info look correct i remember looking at an 18 tooth pinion before and only getting 40-45mph which seems to be the best target speed and now i get 50-55 which is prob over geared correct?

did i make any mistakes?


Differential Ratio: 2.8461538461538463
Transmission Ratio: 2.111111111111111
Other Ratio: 1
Spur Tooth Count: 38
Pinion Tooth Count: 18
Total Voltage: 18.5
Motor KV: 2000
Tire Diameter (inches): 5.75
Tire Ballooning (inches): .4
Motor Current Draw: 0
Motor coil Ω: 0.006
Spur/Pinion Ratio: 2.11 : 1
Total Ratio: 12.68471 : 1
Tire Circumference (inches): 20.58 inches (522.67 mm)
Total Motor Speed: 37000 RPM
Vehicle Speed: 56.84 mph (91.3 km/h)
Estimated Adjusted Speed: 52 mph (84 km/h) - 8% loss
Effective KV Value: 2000
KT constant: 0.68 oz-in/A


thank you as always
jeff

[bruce750i]

I grind a small flat spot only as wide as grub screw. Throw it in a sandwich baggie and poke the shaft thru the bag then grab your dermal tool(or go by one) with a fine grinding stone and go to town. or you can use a file but that would blow.

good idea with the sandwich bag i didn't think about shrapnel getting in the motor, and of course i have a dremel, everyone should have one

[DRIFT_BUGGY]

I just used a dremel to do mine

[Takedown]

Originally Posted by DRIFT_BUGGY

I just used a dremel to do mine

Yep same here.

just curious if this seems to check out for what i have
3.3 revo conversion
RCM motor mount
medusa 36-60-2000kv motor
5s1p zippy-h 5000mah batt
talon tires 5.75"

Differential Ratio: 2.8461538461538463
Transmission Ratio: 2.111111111111111
Other Ratio: 1
Spur Tooth Count: 38
Pinion Tooth Count: 18
Total Voltage: 18.5
Motor KV: 2000
Tire Diameter (inches): 5.75
Tire Ballooning (inches): .4
Motor Current Draw: 0
Motor coil Ω: 0.006
Spur/Pinion Ratio: 2.11 : 1
Total Ratio: 12.68471 : 1
Tire Circumference (inches): 20.58 inches (522.67 mm)
Total Motor Speed: 37000 RPM
Vehicle Speed: 56.84 mph (91.3 km/h)
Estimated Adjusted Speed: 52 mph (84 km/h) - 8% loss
Effective KV Value: 2000
KT constant: 0.68 oz-in/A

does all this info look correct i remember looking at an 18 tooth pinion before and only getting 40-45mph which seems to be the best target speed and now i get 50-55 which is prob over geared correct?



peace
j

[magman]

When you did your earlier calcs., did you enter 4s instead of 5s?

Originally Posted by e-rev project

just curious if this seems to check out for what i have
3.3 revo conversion
RCM motor mount
medusa 36-60-2000kv motor
5s1p zippy-h 5000mah batt
talon tires 5.75"

Differential Ratio: 2.8461538461538463
Transmission Ratio: 2.111111111111111
Other Ratio: 1
Spur Tooth Count: 38
Pinion Tooth Count: 18
Total Voltage: 18.5
Motor KV: 2000
Tire Diameter (inches): 5.75
Tire Ballooning (inches): .4
Motor Current Draw: 0
Motor coil Ω: 0.006
Spur/Pinion Ratio: 2.11 : 1
Total Ratio: 12.68471 : 1
Tire Circumference (inches): 20.58 inches (522.67 mm)
Total Motor Speed: 37000 RPM
Vehicle Speed: 56.84 mph (91.3 km/h)
Estimated Adjusted Speed: 52 mph (84 km/h) - 8% loss
Effective KV Value: 2000
KT constant: 0.68 oz-in/A

does all this info look correct i remember looking at an 18 tooth pinion before and only getting 40-45mph which seems to be the best target speed and now i get 50-55 which is prob over geared correct?



peace
j

I have a similar setup in my conversion the same pinion/spur but I have the wide ratio gears in the tranny first gear removed. and locked in 2nd gear, FOC...you will soon see the Talon tires suck I now go between Crimefighter LPR and Badlands on Maximizer Beadlocks...it all depends on what I am doing...and my setup is good for mid 50s @ WOT... the rest of my setup is in my sig

the Medusa 60 can might get hot in a Revo though ...

[Larrydino]

you have a 38t spur gear?...are you sure about that....

Originally Posted by Larrydino

you have a 38t spur gear?...are you sure about that....

the 3.3 revos come stock with a 40 tooth so 38 is a slight change

i did not know that 40 tooth was stock (bought the truck on ebay), and yes it came to me with a 38t. i can easily buy another gear. would that still be over geared? i looked briefly on the traxxas site and did not find anything bigger than 40t, is there another option. i already have the 18 tooth pinion and was looking for a cheapskate way to lower the speed. i should have double checked Brian g speed calc

i did not know that 40 tooth was stock (bought the truck on ebay), and yes it came to me with a 38t. i can easily buy another gear. would that still be over geared? i looked briefly on the traxxas site and did not find anything bigger than 40t, is there another option? i already have the 18 tooth pinion and was looking for a cheapskate way to lower the speed. i should have double checked Brian g's speed calc

Originally Posted by e-rev project

i did not know that 40 tooth was stock (bought the truck on ebay), and yes it came to me with a 38t. i can easily buy another gear. would that still be over geared? i looked briefly on the traxxas site and did not find anything bigger than 40t, is there another option? i already have the 18 tooth pinion and was looking for a cheapskate way to lower the speed. i should have double checked Brian g's speed calc

you could go to a smaller pinion( I believe a 14 tooth is stock with the 3.3) or a 4s lipo if you want lower speed

revo's came stock with a 38 not a 40.