overdrive & underdrive gears... Why?

[thomas]

i run overdrive and underdrive like calvin was sayin and i love it! it does steep stuff WAY better.

[alexchen86]

Also since the gears are spiral cut and heavy duty they are a lot smoother and will provide much smoother wheel motion. Not to mention save a bit of energy from your packs I guess.

Since I don't plan on running dig on shafties having OD in the front is awesome when you are on loose rock or dirt you can keep goose tapping it so the rig hops almost like a front dig lol.

[irok22s]

I run over and under in my axles, I wouldn't run it any other way. The benefits by far out weigh the negatives. Actually unless you are going in reverse up a steep climb I personally do not think there is a negative affect from running both.

I have also tested this set up with a little more speed involved. I decided to put a 10 turn race motor into my comp rig with a 22t pinion gear. I ran 2 2500mah packs through it, total of about 35min straight full throttle run time. Both ring and pinion gears held up fine. Diffs were not even warm to the touch. Nothing made any strange noises. Now well over 25 comp packs later still going strong no issues at all.

I would recommend over/under or either combination of the 2 for any axial axle based rig. The advantage over/under provides on steep climbs, and the reduction of torque twist (if you were not able to remove it with link geometry) is well worth the price. The addition of both gear sets makes the front go approximately 1 full revolution extra when the rear turns 8. So when the rear tires turn 8 times the front turns 9 times.

With the correct link geometry to reduce torque twist and add forward bite setup before installing over/under gears. The difference is simply amazing. Torque twist in a forward direction does not exist in a noticeable amount IMO. Reverse is a different story tho, a climb in a reverse direction definitely lifts a tire. Forward traction with the front tires spinning slightly faster than the rear helps in every situation I have come across so far IMO.

[hitekredneck]

Does anyone have any experience with how well a vanquish dig will hold up with overdrive or underdrive?

[winnerone23]

The dig is unaffected by the gears. The VP hurtz dig is top notch an can take a ton of abuse.. IMO

[Bananaclip]

Originally Posted by winnerone23

The dig is unaffected by the gears. The VP hurtz dig is top notch an can take a ton of abuse.. IMO

X2 and either way you go ie. over in the front or under in the rear will be a clear advantage. I personally I would stay away from running a combination of both.

[johnnyh66]

I run both in 2 of my rigs with great results.

[HARDKNOCKZ]

Originally Posted by Bananaclip

X2 and either way you go ie. over in the front or under in the rear will be a clear advantage. I personally I would stay away from running a combination of both.

Why is that? I run over/under in my 2.2 Shaftsmen & the results are nothing but good.

As far as running em with the Hurtz...I never have but cant imagine it'd hurt anything.

J.D.

[C*H*U*D]

I really like both at the same time. If I could go slightly higher in the front I would.

[chris.martell]

I agree guy I ran mine with just the over drive and I noticed a difference in climbing vertical and it steered a little better and then I added the under drive and it made a very noticeable difference in the steering and climbing and in all around performance. This is hands down a must do mod both under and over

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[Jus]

I've run both sets at once in a scaler and even driving for miles out on the trails I did not see any real down side. The only thing I did notice was that the back side of the rear tire treads were worn a little from being dragged down the trail.

[wings_of_fire]

I was not aware of this concept and it sounds good. It would be fun to have a gearbox that could do it on the go. ..

The number of channels on the pistol radios should be increased...
I wonder if the scaler guys use the stick type radios with all those many functions on their rigs.

[chris.martell]

Originally Posted by wings_of_fire

I was not aware of this concept and it sounds good. It would be fun to have a gearbox that could do it on the go. ..

The number of channels on the pistol radios should be increased...
I wonder if the scaler guys use the stick type radios with all those many functions on their rigs.

You dont need any more channels on your radio. The overdrive and underdrive gears replace you stock bevel gears in the diff.

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[wings_of_fire]

Originally Posted by chris.martell

You dont need any more channels on your radio. The overdrive and underdrive gears replace you stock bevel gears in the diff.

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I understand the concept. I meant, if there was a servo actuated gearbox that would convert it to overdrive and 1:1 ratio drive while running the crawler. That would be cool and would also require more channels on the radio. If radios have more channels, then it opens up a lot of possibilities.

I am also working on my own radio.. Its based on the 434Mhz Transceiver.Its not as good as the professional radios, but can do wonders through serial communication at the cost of speed.

[chris.martell]

So what you really want is a 2 speed transfer case? Pretty awesome idea. Are you building a transmitter from hobbyking website? I noticed they have lots of parts for this.

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[wings_of_fire]

Originally Posted by chris.martell

So what you really want is a 2 speed transfer case? Pretty awesome idea. Are you building a transmitter from hobbyking website? I noticed they have lots of parts for this.

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Yes, a variable speed transfer case that will control the ratio of each axle.
Not from hobby king. These transceivers are easily available in any local electronics shop.

I always like a crawler to be loaded with technological stuff all activated at the press of a button. I always feel, the 2 and 3 channel radios are way to less on channels for a scaler. No doubt they are good for comp.

[chris.martell]

Originally Posted by wings_of_fire

Yes, a variable speed transfer case that will control the ratio of each axle.
Not from hobby king. These transceivers are easily available in any local electronics shop.

I always like a crawler to be loaded with technological stuff all activated at the press of a button. I always feel, the 2 and 3 channel radios are way to less on channels for a scaler. No doubt they are good for comp.

Spectrum Dx6i:thumbup: I'd never fly a heli without one. Tried driving my comp rig with it at first and could never get it programed just right. I did however like the fact of being able to adjust throttle curves to my driving style! Ultimately my issue was the old goat2s esc I was running.

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[wings_of_fire]

Originally Posted by chris.martell

Spectrum Dx6i:thumbup: I'd never fly a heli without one. Tried driving my comp rig with it at first and could never get it programed just right. I did however like the fact of being able to adjust throttle curves to my driving style! Ultimately my issue was the old goat2s esc I was running.

Did you try it with a newer esc?

Are you still using the Dx6i for crawler? I like stick radios for surface rc I feel I am more in control with them.

[chris.martell]

No I got a pistol radio I sold all my heli stuff before I upgraded the esc

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