Gearing Down for 3S

[Rekreant]

What gearing are you guys running on the 3 gear transmission for 3s? I always hear gear down volt up, so whats the standard for high torque low temps?

[Jboucher]

Im using an 11T pinion on my Bomber. Stock spur (64T) for my 550 21T.

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[svt923]

The more gear reduction, the better for everything.

The answer on what pinion to run depends on what motor you are running and how fast you want the truck to be on the top end.

If you are talking about a RTR, the stock gearing is a good mix of reduction and reasonable wheel speed on 3S.

[Rekreant]

Originally Posted by svt923

The more gear reduction, the better for everything.

The answer on what pinion to run depends on what motor you are running and how fast you want the truck to be on the top end.

If you are talking about a RTR, the stock gearing is a good mix of reduction and reasonable wheel speed on 3S.

I have the honcho RTR, and I run the Trailmaster Sport 27t.

[jokersinsanity]

You can buy actual gear reduction units the motor pinion goes right in them but then they go to a transfer case

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[svt923]

Originally Posted by Rekreant

I have the honcho RTR, and I run the Trailmaster Sport 27t.

So are you currently running 2S or 3S? Are you happy with the current top end speed or do you want to make it faster or slower?

The Honcho has a pretty good gear ratio out of the box so heat and lack of torque really aren't a concern compared to the old SCX10 RTRs.

[2mtech]

I stayed with stock gearing, or more specifically, didn't change gearing on any rig when I changed over from 2S to 3S a couple years ago, and didn't detect any significant changes in heating.

[Rekreant]

Originally Posted by svt923

So are you currently running 2S or 3S? Are you happy with the current top end speed or do you want to make it faster or slower?

The Honcho has a pretty good gear ratio out of the box so heat and lack of torque really aren't a concern compared to the old SCX10 RTRs.

I run 2s SMC batts for now, but am looking at getting a nice sized 3s for my crawler. Its fast enough for me as it is now.

[svt923]

Then a 10T pinion on 3S would be about the same top end as the stock Honcho gearing on 2S.

[Rekreant]

Originally Posted by svt923

Then a 10T pinion on 3S would be about the same top end as the stock Honcho gearing on 2S.

ok cool. Thanks for the help!

[Rekreant]

I was looking into gearing down because I ended up somehow stripping my front diff bevel gear, the cast one. I have SSD replacements on the way, but since I am moving to 3s eventually wanted to fully understand it.

Can anyone explain to me why / what the benefit is to under / over driving front/rear?

[NitroDarwin]

The benefit of over driven front/ under driven rear is tighter turn radius and better climbing ability. As the rig turns the front tires travel a longer path but tires spin a same rate thus the rear tires push the rig. With od/ud gears on climbs the front tires are spinning faster thus helping pulling rig over the obstacle better

[nosser]

On my 10.2 I run 3s with 12t with a Traxxas 21t. And I have an overdrive on the front.


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[Rekreant]

So Im a little confused still on overdriving. Wouldnt the force pulling the rear tires put a lot of strain on the rear diff since its moving slower?

[Ninomaniac]

In super grippy situations, yes. The stress is distributed, not only the rear diff. The front diff is pulling!

But think about it: whenever the truck is not going straight on a level surface, that's already happening! Turning and climbing places loads on the driveline that aren't there when driving in a straight line. Which you rarely do on a crawler anyway. So a bit of over/under won't add much strain but will improve the rig's capabilities quite a bit.

[Hal]

OD/UD is great for climbiing, turning, and descending. In climbing it alows the fronts to pull you up with the rear just kind of following along. This helps it not want to "wheelie" and go over backwards as much on steep terain. With no variation the rear tries to push the truck up and lifts the front tires. Steering is better because it has the rear wheels spinning slower so they act like an anchor or pivot point. Descending is better because the rear will act like a brake because they are not turning as fast. It will not have as much of a tendancy to do endos down a hill. I would recomend doing both to get the most benefit. Just UD on rear if only doing one. The tire / driveline wear on our small light rigs is minimal. There is just not enough traction or weight to worry. Think........ a 1:1 rig weighs 5000 lbs, most of our rigs are 1/10 scale, 1/10 of this is 500 lbs. Does your rig even come close to this? If it is 10 lbs I might start to worry but at 10 lbs you probably have beefed eveything up already anyway. On our MOA rigs, going up down or turning we quite often lock up the rear wheels with no harm to our drivelines. I know we have seperate trannies for front and rear but I see no harm done to the tires, axles, or ujoints. We may get a bit more wear on the tires but I dont realy notice it. Doing tire stagger would be very expensive to experiment with. 1 set of tires $30.00, 1 set foams $15.00, 1 set wheels $50.00 and you would probably need multiple sets or at least a way to shave them down to change dia. I paid $23.00 for a set of gears. I am not saying it wont work but it could get pricey. With all that said I prefer personally to do both if possible. If it makes some obsticles easier PRICELESS.

[Jboucher]

MY EYES!
Paragraphs please...

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[Helmy Ihsan]

Originally Posted by Hal

OD/UD is great for climbiing, turning, and descending. In climbing it alows the fronts to pull you up with the rear just kind of following along. This helps it not want to "wheelie" and go over backwards as much on steep terain. With no variation the rear tries to push the truck up and lifts the front tires. Steering is better because it has the rear wheels spinning slower so they act like an anchor or pivot point. Descending is better because the rear will act like a brake because they are not turning as fast. It will not have as much of a tendancy to do endos down a hill. I would recomend doing both to get the most benefit. Just UD on rear if only doing one. The tire / driveline wear on our small light rigs is minimal. There is just not enough traction or weight to worry. Think........ a 1:1 rig weighs 5000 lbs, most of our rigs are 1/10 scale, 1/10 of this is 500 lbs. Does your rig even come close to this? If it is 10 lbs I might start to worry but at 10 lbs you probably have beefed eveything up already anyway. On our MOA rigs, going up down or turning we quite often lock up the rear wheels with no harm to our drivelines. I know we have seperate trannies for front and rear but I see no harm done to the tires, axles, or ujoints. We may get a bit more wear on the tires but I dont realy notice it. Doing tire stagger would be very expensive to experiment with. 1 set of tires $30.00, 1 set foams $15.00, 1 set wheels $50.00 and you would probably need multiple sets or at least a way to shave them down to change dia. I paid $23.00 for a set of gears. I am not saying it wont work but it could get pricey. With all that said I prefer personally to do both if possible. If it makes some obsticles easier PRICELESS.

No, if weight of a real car is 5000 lbs, then 1/10 scale weight would be 5 lbs, because we count the volume, the height is divide by 10, wide is divide by 10 and height divide by 10, thus the volume is divide by 1000 and also weight