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Old 08-26-2008, 03:22 PM   #1
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Default Motor Placement Pros/Cons?

I have a AX10, stock setup for now.

Wanted to know what the pros and cons are for motor placement? Seen some pictures on this site of the motor on drivers side and passenger side.

Does this make a difference which side it's on?

What's would be best for a comp rig? any advice would be cool?

Thanks -RCHuffer
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Old 08-26-2008, 03:37 PM   #2
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I know on mine i put the back of the motor facing the front of the truck, thinking i was putting more weight to the front of the crawler.
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Old 08-26-2008, 06:45 PM   #3
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Most times the motor would be on the drivers side and front of the vehicle for good weight distribution.

However, a lot of us have it on the passenger side because we need the side opposite the spur for room to place our dig units. To compensate for the weight distribution we mount the transmission slightly forward on the skid plate. That's why a lot of the after market skid plates come pre-drilled with a forward bias for mounting the trans.
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Old 08-27-2008, 09:09 AM   #4
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If you mount the motor and trans so that the motor endbell is facing the rear you'll get rid of the forward motion torque twist. You have to reverse the power leads on the motor though. Reversing the power leads to the motor will have no effect on power since lathe motors have "0" degree timing.

It worked great for me. It eliminated my front wheel lift when climbing. Now the rear wheel lifts, but who drives backwards?
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Old 08-27-2008, 11:52 AM   #5
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Quote:
Originally Posted by cyclone-charlie View Post
If you mount the motor and trans so that the motor endbell is facing the rear you'll get rid of the forward motion torque twist. You have to reverse the power leads on the motor though. Reversing the power leads to the motor will have no effect on power since lathe motors have "0" degree timing.

It worked great for me. It eliminated my front wheel lift when climbing. Now the rear wheel lifts, but who drives backwards?
I don't think the placement of your motor had anything to do with your torque twist, unless you're driving a rock racer and always punch it off the start. It must have been something else that you did. In the end your transmission's outdrives have to rotate in the same direction to make the vehicle move forward or back, despite the orientation of your motor. That's why we have to reverse the power leads when the endbell is facing the rear.

Oh... I've seen people place in comps after having to drive backwards through a gate. If you want to be competitive, keep in mind that driving backwards and accepting a 1 point penalty is better than continuing forward and hitting that gate.
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Old 08-27-2008, 06:04 PM   #6
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Originally Posted by crazy_kanaka View Post
I don't think the placement of your motor had anything to do with your torque twist, unless you're driving a rock racer and always punch it off the start. It must have been something else that you did. In the end your transmission's outdrives have to rotate in the same direction to make the vehicle move forward or back, despite the orientation of your motor. That's why we have to reverse the power leads when the endbell is facing the rear.

Oh... I've seen people place in comps after having to drive backwards through a gate. If you want to be competitive, keep in mind that driving backwards and accepting a 1 point penalty is better than continuing forward and hitting that gate.

Try it! It works! The motor in turn is running the opposite direction with the trans installed backwards. The torque twist will only effect going backwards this way.

I didn't think it would work either till I was out with this guy who had done it. With the stock orientation mine would lift the right front wheel when making a sharp right turn. Now, running backwards it lifts the left rear wheel when turning sharp to the left. Now when doing vertical climbs it doesn't lift the front wheels causing backover flips.

I think you'll find that most people that run VF digs have their trans reversed. They are the ones that complain the least about torque twist.
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Old 08-27-2008, 06:32 PM   #7
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Quote:
Originally Posted by cyclone-charlie View Post
I think you'll find that most people that run VF digs have their trans reversed. They are the ones that complain the least about torque twist.
Everyone that runs a VF dig have their trans reversed, and it has nothing to do with fewer complaints about torque twist. Most people that run any type of dig, have the experience to know that you need to lower your center of gravity, set their suspension up properly with stronger springs in the right areas or run droop, to reduce the effects of torque twist. Torque twist is the result of the drive shaft's rotational force acting against the axle. With your motor in the front or rear, the rotation of the drive shaft has to be the same to make you vehicle move forward or reverse.

I have two axial trucks one with dig and the motor facing back and one without with the motor facing forward. I haven't ever noticed a difference in tt because of it; however, I have noticed that proper suspension setup and having a lowered center of gravity can play the major factors in minimizing torque twist.

What I would like to advise is: If you don't have a dig unit that requires the transmition to be reversed, then keep the motor in the forward position to gain the advantages of proper weight distribution.
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Old 08-28-2008, 08:13 AM   #8
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Quote:
Originally Posted by crazy_kanaka View Post
Everyone that runs a VF dig have their trans reversed, and it has nothing to do with fewer complaints about torque twist. Most people that run any type of dig, have the experience to know that you need to lower your center of gravity, set their suspension up properly with stronger springs in the right areas or run droop, to reduce the effects of torque twist. Torque twist is the result of the drive shaft's rotational force acting against the axle. With your motor in the front or rear, the rotation of the drive shaft has to be the same to make you vehicle move forward or reverse.

I have two axial trucks one with dig and the motor facing back and one without with the motor facing forward. I haven't ever noticed a difference in tt because of it; however, I have noticed that proper suspension setup and having a lowered center of gravity can play the major factors in minimizing torque twist.

What I would like to advise is: If you don't have a dig unit that requires the transmition to be reversed, then keep the motor in the forward position to gain the advantages of proper weight distribution.
You're really stuck on this axle rotation aren't you?

Think about it? The axles given "have" to rotate one certain way, the motor doesn't. By reversing the trans the motor has to run backwards, therefore, instead of adding to the TT caused by the axles that have to rotate that one certain way, the motor now helps to compensate for the TT created by the axle rotation by forcing the right front wheel down instead of up under heavy load.

The reason I tried it was because that when I went to different shocks with softer springs, the TT was amplified. After turning the trans around 90% of the TT was eliminated. Another advantage that I found was, I don't need to have as much weight in the front wheels making the Axial lighter.

Since you say you have 2 trucks, both set up differently, take them out and see which one lifts the right front wheel under hard right turn. I think you'll find out no matter how your suspension is set up, it will still do it.
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Old 08-28-2008, 08:30 AM   #9
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it doesnt matter what way the Motor spins ... the Tranny has to spin the same direction to go forward. dumping the motor around and wiring it backwards does 1 thing, more weight on the RF wheel aiding in (hopefully) less TT.

CK said it exactly ....... ''proper suspension setup''


you noticed a big gain in TT because you 'changed' your suspension ....... maybe it was a change 'you' prefered but your rig didnt. now you have to find that happy medium. imo you found a bandaid for your suspension change.
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Old 08-28-2008, 11:38 AM   #10
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it doesnt matter what way the Motor spins ... the Tranny has to spin the same direction to go forward. dumping the motor around and wiring it backwards does 1 thing, more weight on the RF wheel aiding in (hopefully) less TT.

CK said it exactly ....... ''proper suspension setup''


you noticed a big gain in TT because you 'changed' your suspension ....... maybe it was a change 'you' prefered but your rig didnt. now you have to find that happy medium. imo you found a bandaid for your suspension change.
I guess people running VF digs are installing a lot of bandaids then!
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Old 08-28-2008, 11:47 AM   #11
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Originally Posted by cyclone-charlie View Post
I guess people running VF digs are installing a lot of bandaids then!
I give up with you . If you think that motor placement, front or back of trans, is what solves your TT then good for you .

Oh... FYI...as far as I know... there are now 3 different digs that bolt on to the axial trans that force the reversal of the transmission, one still in pre-order. So it's not just people running VF digs. Also a lot of people chose to mount their trans backwards to afford them more room for their homemade digs.

I remember the old phrase "Never argue with an idiot. They drag you down to their level, then beat you with experience."

Last edited by crazy_kanaka; 08-28-2008 at 11:51 AM.
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Old 08-28-2008, 01:10 PM   #12
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Quote:
Originally Posted by crazy_kanaka View Post
I give up with you . If you think that motor placement, front or back of trans, is what solves your TT then good for you .

Oh... FYI...as far as I know... there are now 3 different digs that bolt on to the axial trans that force the reversal of the transmission, one still in pre-order. So it's not just people running VF digs. Also a lot of people chose to mount their trans backwards to afford them more room for their homemade digs.

I remember the old phrase "Never argue with an idiot. They drag you down to their level, then beat you with experience."
Who made you the almighty of the crawlers?

Different things work for different applications!

My set-up allows me more vertical climbs!
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Old 08-28-2008, 01:54 PM   #13
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The motor side of the tranny weighs more than the output side of the transmission. If you reverse the tranny the motor is on the side of the chassis that wants to lift up. More weight on that side is less lift. I dont know if it actually works out like that in the real world but it works in theory.
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