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RE: Mystery Solved! How to select the proper gearing f... - 5/24/2005 6:55 PM   
monsterpede360



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Status: offline 		Ok what will i use to push maxx tires and with a huge lift kit and going threw mud and climbing hills and what type of engine would i use i am running i titan brushless right now with stock tires is that enough to push maxx tires with the traxxas stampede stock gears in it???

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RE: Mystery Solved! How to select the proper gearing f... - 5/24/2005 9:52 PM   
SkrapIron



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Status: offline 		I think that the Mini's are undgergeared, simply because of the size of the motor. They are far too small to move the trucks by themselves, and rely heavily on the gear reduction to produce sufficient torque. My Trinity IB Spyder is much like your Losi Mini-T. It's stock gear ratio is -1.755. That's running the stock 17t pinion. I must say, MAN that thing gets hot! I actually stepped down to a 14t pinion, and the motor runs much cooler.

So, when gearing a 1/18 or a 1/24 scale, it looks like a final ratio of -3.0 is a good setup. I had no experience with the 1/18 scale before April, so they were never considered when I wrote the article. The calculator does work BEST for 1/10 scale vehicles and most motors.

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RE: Mystery Solved! How to select the proper gearing f... - 5/24/2005 10:03 PM   
SkrapIron



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quote:

ORIGINAL: monsterpede360

Ok what will i use to push maxx tires and with a huge lift kit and going threw mud and climbing hills and what type of engine would i use i am running i titan brushless right now with stock tires is that enough to push maxx tires with the traxxas stampede stock gears in it???


If I deciphered your question correctly, you should be running an HVMaxx brushless, or a Feigao 9l, or a Lehner Basic XL 3100.

With those Monster Maxx Tires, you should gear your Pede, are you ready? 96/15. It won't be fast, but it's going to have stump pulling torque.

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RE: Mystery Solved! How to select the proper gearing f... - 5/25/2005 2:41 AM   
monsterpede360



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Status: offline 		hey man thanks i dontwant any speed i just want torque. To be able to drive inthe sand water and mud and trails and hills.

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RE: Mystery Solved! How to select the proper gearing f... - 5/25/2005 6:51 PM   
jaejw1


 

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Status: offline 		well i tried it out at the track,, eventhough my topend went away i was able to maintain a straighter line than before... and jumping wasnt crazy as before also,,, didnt get to test thing all the way but i noticed the motor nor the esc was hot as before,,


next will be to test it at the track..

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RE: Mystery Solved! How to select the proper gearing fo... - 5/27/2005 3:41 PM   
rickou812


 

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Status: offline 		What would the reccomended gearing be for an Evader ST with pro-line gladiater tires running the Novak SS5800 brushless.
I tried to make heads and tales of the thread before asking but there is a lot of conflicting info...
Thanks in advance

P.S. Uses include back yard bashing with occasional races on loose dirt track and occasional drag races against nitro cars.
Thanks again

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RE: Mystery Solved! How to select the proper gearing fo... - 5/27/2005 11:28 PM   
RC God


 

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Status: offline 		any gear you want.if you gear it low it will be quick off the line provided you have traction but it wont have the top speed you can obtain with a higer gear.just experiment with gear changing.

smaller pinion=low
larger spur=low

smaller spur=high
larger pinion=high

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RE: Mystery Solved! How to select the proper gearing fo... - 5/28/2005 1:55 AM   
S.A.E.W.O.T.



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Status: offline 		if u go 2 hight tho, u'll start 2 (overgear) witch is bad 4 motors and can wreak electroincs VERY FAST!

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RE: Mystery Solved! How to select the proper gearing fo... - 5/28/2005 2:06 AM   
rickou812


 

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Status: offline 		cool, what would you reccomend as a goog starting point?
What would you guestimate as an obtainable top speed with this motor package?

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RE: Mystery Solved! How to select the proper gearing fo... - 5/28/2005 2:25 AM   
S.A.E.W.O.T.



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Status: offline 		u could gear it 22/88.... 22t pinion 88 tooth spur...u'll get about 37 mph on 6 cells

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RE: Mystery Solved! How to select the proper gearing fo... - 5/28/2005 2:33 AM   
rickou812


 

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Status: offline 		thanks

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RE: Mystery Solved! How to select the proper gearing fo... - 5/29/2005 8:29 PM   
jaejw1


 

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Status: offline 		used the the calculator to figure out my gearing for my xcellerator,,, but wht i didnt take into account is that if you are using more than 6 cells you must gear it down,, better to have more torque and save electronics than have top speed and burn everything up,,,

with 7 cells my esc went into failsafe,,, i did make some improvements to my motor,,, heavier tension on positive spering brush,, ,, but even with a 90/18...(chnaged from 90/20) things were still great,,, still very fast...


the gearing does work though,, cant wait to try the masher 2000 on the indoor track...

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RE: Mystery Solved! How to select the proper gearing fo... - 6/4/2005 6:31 PM   
thunderw0lf



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Status: offline 		Using this calculator, to keep the same tire/gearing ratio I have with the Masher 2ks, when I put the road hawgs on my pede, I need to go to 30/75 gearing to keep about the same speeds I get with the mashers.

And no I'm not overgeared, if anything the 8s in my pede is actually under geared from what Mike over at RC-Monster tells me with the motor temps I see.

Does anyone know of a spur gear that size or even smaller that would fit? The pinion I'd need with the 84 tooth spur I have on it now wouldn't fit.

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RE: Mystery Solved! How to select the proper gearing ... - 6/10/2005 3:37 PM   
aintskeered


 

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RE: Mystery Solved! How to select the proper gearing ... - 6/10/2005 11:06 PM   
Poohblah


 

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Status: offline 		This thing is a piece of junk. It says I should be at 24/87 when the best gearing for my truck & motor is 18/90. Also it does not account for motor turns or cell count.

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RE: Mystery Solved! How to select the proper gearing fo... - 6/11/2005 4:18 PM   
SkrapIron



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quote:

ORIGINAL: thunderw0lf

Using this calculator, to keep the same tire/gearing ratio I have with the Masher 2ks, when I put the road hawgs on my pede, I need to go to 30/75 gearing to keep about the same speeds I get with the mashers.

And no I'm not overgeared, if anything the 8s in my pede is actually under geared from what Mike over at RC-Monster tells me with the motor temps I see.

Does anyone know of a spur gear that size or even smaller that would fit? The pinion I'd need with the 84 tooth spur I have on it now wouldn't fit.


I think you have missed something here. If you are assuming a 75/30 spur to pinion, and multiplying that by your Pede's transmission, ( 2.72:1), that gives you a final drive ratio of 6.8:1. Pro-Line Speed hawgs Have an overall diameter of 3.5", or a roll out of 10.9955".

It doesn't matter what you call it, that's overgeared. By a factor of nearly 1.61 times! Running even a brushless motor, with that kind of gearing disparity will cause a thermal shutdown in a hurry.

Your tire/gearing ratio is a fluid number. Not a fixed value. It changes with every change that you make in your tire, and more importantly it's roll out. The correct gearing for your Pede, with the Speed Hawgs, is 84/21 ( for top speed )or 87/22 ( for faster acceleration, more torque). That will allow you the best performance, but enough room to add a 7 cell pack if you want even more speed, without causing thermal issues with your Pede.

quote:

ORIGINAL: Poohblah

This thing is a piece of junk. It says I should be at 24/87 when the best gearing for my truck & motor is 18/90. Also it does not account for motor turns or cell count.


Now, I know you missed a value somewhere when you came up with that ratio. First of all, that ratio is dependent on the overall roll-out of the tire on your truck now ( how much distance it covers when it turn one full revolution ). If you are claiming that 90/18 is the best Spur/pinion for your truck, I can deduce that you are running Pro-Line Dirt hawgs, or Dirt Works, ir a similarly sized tire ( approx 4" diameter). Your calculated answer of 87/24 would be intended for 3.0" dia buggy tires. I doubt that's what you are running on your truck.

As to your other two points: 1. The cell count is irrelevant for this exercise. One, because most chassis cannot handle more than 7 cells without modification. And Two, The addition of 1 cell will generate at most 5000 additional RPM from the motor. If the vehicle is properly geared to begin with, the additional voltage, and RPM will add some heat, but not adversely affect the vehicle.
2. We tackled the 'Hot Mod Motor' issue a while back. The conclusion is, if you are running a 27t-19t motor, gear to the high side of the ratio anything from 0 to 1.0. If you are running a Mid Mod motor 17t-13t gear it as closely as possible to a 0 ratio. If you are running a Hot mod motor 12t and lower, gear the vehicle at 0 to -2.0 depending on the motor.

Remeber, that this calculator is intended to help novices select a sound starting point for gearing their vehicle. It is not intended as a be-all and end-all for all applications. For what it's intended, it works very well, and has been proven over and over.

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RE: Mystery Solved! How to select the proper gearing fo... - 6/11/2005 4:37 PM   
SkrapIron



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quote:

ORIGINAL: jaejw1

used the the calculator to figure out my gearing for my xcellerator,,, but wht i didnt take into account is that if you are using more than 6 cells you must gear it down,, better to have more torque and save electronics than have top speed and burn everything up,,,

with 7 cells my esc went into failsafe,,, i did make some improvements to my motor,,, heavier tension on positive spering brush,, ,, but even with a 90/18...(chnaged from 90/20) things were still great,,, still very fast...


the gearing does work though,, cant wait to try the masher 2000 on the indoor track...


90/20 gearing, with masher 2k's is overgeared to begin with. Badly overgeared. By a factor of 1.31 times. It's no wonder that your ESC went into fail safe.

Depending on your motor, you should gear your truck at no higher than 90/17, especially running 7 cells. Your 90/18 ratio works, but is putting alot of strain on the motor, and building ALOT of unnecessary heat!

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RE: Mystery Solved! How to select the proper gearing fo... - 6/12/2005 2:59 AM   
thunderw0lf



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quote:

ORIGINAL: SkrapIron



I think you have missed something here. If you are assuming a 75/30 spur to pinion, and multiplying that by your Pede's transmission, ( 2.72:1), that gives you a final drive ratio of 6.8:1. Pro-Line Speed hawgs Have an overall diameter of 3.5", or a roll out of 10.9955".

It doesn't matter what you call it, that's overgeared. By a factor of nearly 1.61 times! Running even a brushless motor, with that kind of gearing disparity will cause a thermal shutdown in a hurry.

Your tire/gearing ratio is a fluid number. Not a fixed value. It changes with every change that you make in your tire, and more importantly it's roll out. The correct gearing for your Pede, with the Speed Hawgs, is 84/21 ( for top speed )or 87/22 ( for faster acceleration, more torque). That will allow you the best performance, but enough room to add a 7 cell pack if you want even more speed, without causing thermal issues with your Pede.




With the current setup I have, 21/84 gearing with Masher 2000s, after running a full 7 cell GP 3300 pack the ESC is under 120 and the motor is about 145. No thermal shutdown problems at all, and it's actually got almost too much torque as it is. Same setup on 6 cells I get 1/2 throttle wheelies or tire spinning torque on loose stuff. Mike says keep the motor under 180 and you won't have any problems so I've got plenty of room to spare.


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RE: Mystery Solved! How to select the proper gearing fo... - 6/12/2005 3:47 AM   
S.A.E.W.O.T.



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Status: offline 		WOW! my motors get nuts HOT! if i run anything over a 15t pinion when i run mashers....lol!

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RE: Mystery Solved! How to select the proper gearing ... - 6/15/2005 4:14 AM   
stampede101


 

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Status: offline 		I have a pede...and it said i should go to a 17 tooth pinion and a 88 tooth spur...and it will be real close (but a bit below) to zero.


And since ima noob at rc....i have a chamelon motor thats 19 turn in it right now....will any pinion gear or spur gear fit? or only traxxas brand meant for only stampede...because id like to get a set or steel robinson gears for it...

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RE: Mystery Solved! How to select the proper gearing ... - 6/15/2005 1:44 PM   
SkrapIron



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Status: offline 		Yes,

Any 48p pinion gear will fit your Stampede. I personally like Robinson Racing gears.

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RE: Mystery Solved! How to select the proper gearing ... - 6/15/2005 6:37 PM   
stampede101


 

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Status: offline 		kool...so ill go ahead and order the right gears from robinsons....YAY

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RE: Mystery Solved! How to select the proper gearing ... - 6/27/2005 4:42 AM   
jdeez1


 

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Status: offline 		I am trying to use a Novak HV-Maxx motor with my E-maxx
I want to use two 7 cell packs Novak recomends 70/12 or 76/13 spur/pinion with this setup so your "Final Gear Ratio" is no lower thatn 28.6 : 1

I cannot find the "Transmission Ratio" for second gear for this truck

The other problem is I have Supermaxx 7.5 diffs Supermaxx says "These do lower your overall gear ratio, you will need to gear your truck up.
Maxx R&P ratio is 2.85:1
7.5 R&P ratio is 3.31:1"

So now I am very confused, and don't want to damage my Novak
Anyone have and Idea how to figure out the transmission ratio so I can change it for the new diffs?

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RE: Mystery Solved! How to select the proper gearing ... - 6/27/2005 2:56 PM   
SkrapIron



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Status: offline 		Your E-Maxx came stock with a 66t spur and an 18t pinion gear. It had a final drive ratio of 28.9:1 in first gear, and a final drive ratio of 17.9:1 in second gear. By dividing your spur by the pinion, (3.667) then dividing your Final drive ratio, by your spur/pinion ratio, you end up with your transmission ratio.

First gear transmission ratio is 7.882:1, second gear transmission ratio is 4.882:1.

Using the Novak Guidelines, you are best served by gearing your HV-Maxx at 76/13 with the 7 cell batteries. This gives you a final drive ratio of 46.0:1 in first gear, and 28.6:1 in second gear.

If you use the Supermaxx Diffs, you will have to raise your final drive ratio as well. The recommended Spur/pinion for that setup is 76/12. Novak also recommends strengthening your drive line with steel idler gears, and an aluminum drive shaft, to minimize breakage due to the excessive torque produced by the motor.

By the way. I just ran some quick numbers on that motor. Geared correctly ( 76/12 ) with stock tires and 2, 7 cell packs, you can realistically expect 35-38mph out of your E-Maxx. But your run time will be reduced to around 5-8 minutes....... That's a high price to pay if you ask me.

Good Luck!

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RE: Mystery Solved! How to select the proper gearing ... - 6/28/2005 7:35 PM   
jdeez1


 

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Status: offline 		I found this info and did the math"
I've got UE diffs, 14 cells, and the strobe slipper and sprong
A little Razer math:
1st - 2.77:1
2nd - 1.72:1
UE Spyder 6 Diff - 3.31:1

1st (including diffs) - 9.17:1
2nd (including diffs) - 5.69:1

You multiply those by the spur/pinion ratio to find the final drive ratio.

If the above info is correct I found a 76 spur 15 pinion would yield a 28.829 : 1 final gear ratio...is this correct (keeping in mind i am using the Supermaxx diffs)?

If it is, this pinion, (15) would be the largest While using the 76 spur. Correct?? Then I could only gear it with smaller pinions?



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