RCCrawler Forums

Kanine38 · 03-26-2010, 07:01 PM

Is the purpose of underdrive gears to be "pulled by the front as to not induce a back flip and keep the front wheels planted?

Phylodog · 03-26-2010, 07:07 PM

That was my understanding. I saw a small difference when I installed mine but not enough to make much of a difference. I'm waiting for a set of overdrive gears to put in the front now to see how that works.

2500hdon37s · 03-26-2010, 07:24 PM

that and to trun a little tighter

liverkiller1 · 03-26-2010, 07:50 PM

i heard it helps out with TT a little mine are on the way

DickyT · 03-26-2010, 07:54 PM

It certainly helps with torque twist, all of the other things mentions are additional benefits too.

Stormin2u · 03-26-2010, 08:18 PM

I have tried it both ways overdrive and underdrive and it works about the same either way tighter turns it keeps the rear tires slightly slower than the front and improves the front traction as far as TT it helps but won't eliminate it. I prefer the underdrive set up as it produces most wheel speed.

rockerrc · 03-26-2010, 08:31 PM

so underdrive in rear and overdrive in the front should be the best? or is it one or the other?

Phylodog · 03-26-2010, 08:32 PM

Quote:

Originally Posted by Stormin2u

I have tried it both ways overdrive and underdrive and it works about the same either way tighter turns it keeps the rear tires slightly slower than the front and improves the front traction as far as TT it helps but won't eliminate it. I prefer the underdrive set up as it produces most wheel speed.

Did you try overdrive up front and underdrive in the rear? I'm planning to give that a shot and see how it does.

RockGarden · 03-26-2010, 08:41 PM

was planning on doing mine as well would like to know wich setup has helped the most with tt thanks,,,

Stormin2u · 03-26-2010, 08:58 PM

Quote:

Originally Posted by rockerrc

so underdrive in rear and overdrive in the front should be the best? or is it one or the other?

Quote:

Originally Posted by Phylodog

Did you try overdrive up front and underdrive in the rear? I'm planning to give that a shot and see how it does.

Running both gear sets is to wide of a gear ratio gap IMO I run the stock Axial gear ratio up front.

Quote:

Originally Posted by RockGarden

was planning on doing mine as well would like to know wich setup has helped the most with tt thanks,,,

It's works good either way I've already explained my set up above it's a matter of personal preference.

RockGarden · 03-26-2010, 09:34 PM

Thanks for your repley... i try mine in rear see how i like it...

rockerrc · 03-26-2010, 09:45 PM

I'm tring the rear also thanks for the info

MikeyBike · 03-26-2010, 09:53 PM

I have 2 trucks, one Overdrive in the front and the other Underdrive in the rear. The underdriven truck is much faster now but both work great. I don't really see the benefit of putting both in your truck. One of the guys here has both sets in his truck but it holds nothing over mine. The overall outcome by putting one OR the other in is about the same.

Kanine38 · 03-27-2010, 06:57 AM

Quote:

Originally Posted by Stormin2u

Running both gear sets is to wide of a gear ratio gap IMO I run the stock Axial gear ratio up front.

It's works good either way I've already explained my set up above it's a matter of personal preference.

I would think that if both under and over are used the ratio gap may be a little counter productive as to put too much stress on the drivetrain and not allow enough traction. If the rear is always being pulled and the front is always pulling then neither really gets a real "bite" on the surface.

I could use some expertise here.

Drail · 03-27-2010, 07:29 AM

i run od up front and hd in the rear. i tried od/ud f/r and found it uber ruff on the tranz. GSRCC Drail

RockGarden · 03-27-2010, 07:34 AM

That might be a worry i have in the back of my head the trany... Has anyone running this setup ever ran into a trany problem?

irok · 03-27-2010, 07:46 AM

i started with the rears and i ran both in a heavy rig last year and it creates alot of stress and binds to much but i never broke the trany,it had alum.gears and H.D outputs so that may have helped

i pulled the rears i ended up just running the fronts,i like the faster front axle speed and it turns tighter then just the rears it seems

easleycrawler · 03-27-2010, 08:15 AM

I'm actually going here in a few minutes to see how the overdrive front and underdrive rear works. I will post my findings later today.

Stormin2u · 03-27-2010, 08:29 AM

Quote:

Originally Posted by Kanine38

I would think that if both under and over are used the ratio gap may be a little counter productive as to put too much stress on the drivetrain and not allow enough traction. If the rear is always being pulled and the front is always pulling then neither really gets a real "bite" on the surface.

I could use some expertise here.

Quote:

Originally Posted by Stormin2u

Running both gear sets is to wide of a gear ratio gap IMO I run the stock Axial gear ratio up front.

Yup

James003 · 03-27-2010, 08:43 AM

the only benefit from both overdrive in front and underdrive in rear is for turning in my opinion. i've seen a rig perform with it on and it's almost like dig.

but I think it's too much, he also had a hard time with reversing. I have the under drive in the rear and I love it. I think it's all you need

03-26-2010, 07:01 PM	#1
Kanine38 Quarry Creeper Join Date: Jan 2010 Location: Gill, Taxachusetts Posts: 390	Underdrive in the rear differential Is the purpose of underdrive gears to be "pulled by the front as to not induce a back flip and keep the front wheels planted?

03-26-2010, 07:07 PM	#2
Phylodog Quarry Creeper Join Date: Oct 2009 Location: Indianapolis, IN Posts: 298	That was my understanding. I saw a small difference when I installed mine but not enough to make much of a difference. I'm waiting for a set of overdrive gears to put in the front now to see how that works.

03-26-2010, 07:24 PM	#3
2500hdon37s I wanna be Dave Join Date: Mar 2009 Location: sittin in the sky Posts: 4,630	that and to trun a little tighter

03-26-2010, 07:50 PM	#4
liverkiller1 Rock Crawler Join Date: Dec 2009 Location: Lynnwood Posts: 569	i heard it helps out with TT a little mine are on the way

03-26-2010, 07:54 PM	#5
DickyT I wanna be Dave Join Date: Oct 2007 Location: Scumrise, Flooriduh Posts: 5,181	It certainly helps with torque twist, all of the other things mentions are additional benefits too.

03-26-2010, 08:18 PM	#6
Stormin2u I wanna be Dave Join Date: May 2007 Location: Taylors Falls just hanging with the MNRCRC crew. Posts: 7,843	I have tried it both ways overdrive and underdrive and it works about the same either way tighter turns it keeps the rear tires slightly slower than the front and improves the front traction as far as TT it helps but won't eliminate it. I prefer the underdrive set up as it produces most wheel speed.

03-26-2010, 08:31 PM	#7
rockerrc Rock Crawler Join Date: May 2009 Location: Idaho Falls, ID. Posts: 539	so underdrive in rear and overdrive in the front should be the best? or is it one or the other?

03-26-2010, 08:41 PM	#9
RockGarden Pebble Pounder Join Date: Jan 2010 Location: Murrieta Posts: 130	was planning on doing mine as well would like to know wich setup has helped the most with tt thanks,,,

03-26-2010, 09:34 PM	#11
RockGarden Pebble Pounder Join Date: Jan 2010 Location: Murrieta Posts: 130	Thanks for your repley... i try mine in rear see how i like it...

03-26-2010, 09:45 PM	#12
rockerrc Rock Crawler Join Date: May 2009 Location: Idaho Falls, ID. Posts: 539	I'm tring the rear also thanks for the info

03-26-2010, 09:53 PM	#13
MikeyBike Quarry Creeper Join Date: May 2008 Location: Grande Prairie, Alberta, Canada Posts: 294	I have 2 trucks, one Overdrive in the front and the other Underdrive in the rear. The underdriven truck is much faster now but both work great. I don't really see the benefit of putting both in your truck. One of the guys here has both sets in his truck but it holds nothing over mine. The overall outcome by putting one OR the other in is about the same.

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03-27-2010, 07:29 AM	#15
Drail N.E.R.C.C Uncle Blinky Join Date: Dec 2008 Location: RUKDNME... Posts: 976	i run od up front and hd in the rear. i tried od/ud f/r and found it uber ruff on the tranz. GSRCC Drail

03-27-2010, 07:34 AM	#16
RockGarden Pebble Pounder Join Date: Jan 2010 Location: Murrieta Posts: 130	That might be a worry i have in the back of my head the trany... Has anyone running this setup ever ran into a trany problem?

03-27-2010, 07:46 AM	#17
irok Rock Crawler Join Date: Aug 2008 Location: B.C.Canada Posts: 608	i started with the rears and i ran both in a heavy rig last year and it creates alot of stress and binds to much but i never broke the trany,it had alum.gears and H.D outputs so that may have helped i pulled the rears i ended up just running the fronts,i like the faster front axle speed and it turns tighter then just the rears it seems

03-27-2010, 08:15 AM	#18
easleycrawler Rock Crawler Join Date: Jan 2010 Location: SOUTH CRAWLINA Posts: 947	I'm actually going here in a few minutes to see how the overdrive front and underdrive rear works. I will post my findings later today.

03-27-2010, 08:43 AM	#20
James003 Rock Crawler Join Date: Jan 2010 Location: Arvada Posts: 783	the only benefit from both overdrive in front and underdrive in rear is for turning in my opinion. i've seen a rig perform with it on and it's almost like dig. but I think it's too much, he also had a hard time with reversing. I have the under drive in the rear and I love it. I think it's all you need

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