RCCrawler Forums

neillarson · 10-28-2010, 07:09 AM

I want to add one or the other, I can get the 43/13 rears or the 36/14 fronts, but I can't seem to find any info on what the standard gear set is.

Does anyone know or has anyone done this and can give me some recommendations?

Katan · 10-28-2010, 07:19 AM

13/38 (38/13 to you)

constantmotion · 10-28-2010, 07:20 AM

I believe 38/14 is stock. I run over in the front and under in the rear.

Katan · 10-28-2010, 07:47 AM

Quote:

Originally Posted by constantmotion

I believe 38/14 is stock.

check the manual

neillarson · 10-28-2010, 07:54 AM

I downloaded the parts list and checked, it lists "Axle Set", that's why I asked.

Stormin2u · 10-28-2010, 11:39 AM

Quote:

Originally Posted by constantmotion

I believe 38/14 is stock. I run over in the front and under in the rear.

Yup I like the under drive in the rear and stock HD up front, are you running 36/14 in the front constant?

cornel4web · 10-28-2010, 01:05 PM

I know i'm newbie, but what is the stuff you talking about?...different raports for the differentials?...what means that?

murky123 · 10-28-2010, 01:32 PM

by using differtent gear ratio in the front andback.
You can choose to make the front wheels spin a little faster than the rear wheels.
this will help the truck pull itself in a steep climb
it will even help turning the truck a little

Big Bill · 10-28-2010, 01:37 PM

I actually run the Overdrives up front, and it seems to work OK. I think with the ODs up front that it will keep the wheel speed up and give me the added front wheel speed. And as mentioned it does help with turning in some types of dirt.

neillarson · 10-28-2010, 01:40 PM

Crawlers with both diffs locked drive all 4 wheels at the same speed, so on a steep climb, the truck can pull a wheelie and roll over end to end. On a steep descent, the opposite can happen, roll over forward end for end. Here are some examples.

http://www.youtube.com/watch?v=prbSkB-kr8Q

The red truck could use overdrive in the front or/and underdrive in the rear to help keep the front end in contact. To be honest though, this is also a case of weight distribution because it is so damn tight in these things.

The yellow truck, if it had over/under drive, as it started the decent, the front wheels would have been turning at a faster speed than the rear which would effectively applied more breaking on the rear.

Oddly enough, I did not have these issues with my SCX10, but I am doing a complete rebuild and the weight is going up a lot so this becomes more of an issue.

Big Bill · 10-29-2010, 06:31 AM

I had both the OD and UD gear sets in my first AX-10 sportsman rig, and the gearing just seemed to fight each other. This was really noticeable when trying to use small amounts of throttle in tight gates. Finally pulled the UDs out of the rear and it worked alot better for me. Has anyone tried UDs in both axles??

neillarson · 10-29-2010, 07:08 AM

I would think using both would be overkill, I want to use one or the other, which ever set I can find. and using UD in both would be the same as using stock except a tick slower.

sally1800 · 10-29-2010, 08:03 AM

Quote:

Originally Posted by neillarson

I would think using both would be overkill, I want to use one or the other, which ever set I can find. and using UD in both would be the same as using stock except a tick slower.

Not only is it over kill, it is super rough on your transmission. I had both in my 1.9 Geo. It turns on a dime almost like using a dig. I really have found that using the over drive in front and the harden gears in the rear will get you where you need to be.

neillarson · 10-29-2010, 11:19 AM

Quote:

Originally Posted by saydee1800

Not only is it over kill, it is super rough on your transmission. I had both in my 1.9 Geo. It turns on a dime almost like using a dig. I really have found that using the over drive in front and the harden gears in the rear will get you where you need to be.

There is the answer I was looking for. Thanks, I owe you a hilux body.

cornel4web · 10-29-2010, 03:09 PM

as a newbie, I intend to buy the OD (36/14) from RPP...so, it will be helping me using this in front and stock in rear? Thanks

Cableman · 10-29-2010, 08:36 PM

3racing makes the stock gearing HD bevel gear set http://www.3racing-parts.com/shop/ax...-90006890.html

Beveled should be smoother with less play.

neillarson · 11-21-2010, 02:49 PM

I installed Underdrive gears in the rear Diff today. I also switched out the Novak 18.5 Havok for a Goat 3S 18.5. Running a 3S 1300 pack and I managed to get all of it over the front axel.

I was amazed at how well it climbs and no more flipping over..

tech712 · 03-04-2014, 11:21 AM

If you want smoother stronger gears you go with helical cut gears rather than beveled gears. Helical cut gears also reduce radial and or axial thrust depending on the application.

666 · 03-04-2014, 11:23 AM

Good search, bring out the dead.

johnnyh66 · 03-04-2014, 11:28 AM

lot's of od/ud reading going on today.

10-28-2010, 07:09 AM	#1
neillarson RCC Addict Join Date: May 2010 Location: The heart of the south Posts: 1,138	Overdrive or Underdrive I want to add one or the other, I can get the 43/13 rears or the 36/14 fronts, but I can't seem to find any info on what the standard gear set is. Does anyone know or has anyone done this and can give me some recommendations?

03-04-2014, 11:21 AM	#18
tech712 Pebble Pounder Join Date: Jul 2013 Location: BFE Posts: 177	Re: Overdrive or Underdrive If you want smoother stronger gears you go with helical cut gears rather than beveled gears. Helical cut gears also reduce radial and or axial thrust depending on the application. Last edited by tech712; 03-04-2014 at 11:24 AM.

03-04-2014, 11:23 AM	#19
666 MODERHATER™ Join Date: Nov 2005 Location: Colorado Posts: 10,939	Re: Overdrive or Underdrive Good search, bring out the dead.

03-04-2014, 11:28 AM	#20
johnnyh66 Scale Detail Engineering Join Date: Apr 2010 Location: Turtle Island Posts: 5,573	Re: Overdrive or Underdrive lot's of od/ud reading going on today.

10-28-2010, 07:19 AM	#2
Katan Rock Crawler Join Date: Jan 2007 Location: UK Posts: 829	13/38 (38/13 to you)

10-28-2010, 07:20 AM	#3
constantmotion On the lookout for Rocks Join Date: Mar 2006 Location: Monroe, Louisiana Posts: 3,711	I believe 38/14 is stock. I run over in the front and under in the rear.

10-28-2010, 07:54 AM	#5
neillarson RCC Addict Join Date: May 2010 Location: The heart of the south Posts: 1,138	I downloaded the parts list and checked, it lists "Axle Set", that's why I asked.

10-28-2010, 01:05 PM	#7
cornel4web Pebble Pounder Join Date: Jul 2007 Location: deva - romania Posts: 154	I know i'm newbie, but what is the stuff you talking about?...different raports for the differentials?...what means that?

10-28-2010, 01:32 PM	#8
murky123 Quarry Creeper Join Date: Jul 2010 Location: netherlands Posts: 348	by using differtent gear ratio in the front andback. You can choose to make the front wheels spin a little faster than the rear wheels. this will help the truck pull itself in a steep climb it will even help turning the truck a little

10-28-2010, 01:37 PM	#9
Big Bill Rock Crawler Join Date: Dec 2008 Location: Fortuna Calif. Posts: 997	I actually run the Overdrives up front, and it seems to work OK. I think with the ODs up front that it will keep the wheel speed up and give me the added front wheel speed. And as mentioned it does help with turning in some types of dirt.

10-28-2010, 01:40 PM	#10
neillarson RCC Addict Join Date: May 2010 Location: The heart of the south Posts: 1,138	Crawlers with both diffs locked drive all 4 wheels at the same speed, so on a steep climb, the truck can pull a wheelie and roll over end to end. On a steep descent, the opposite can happen, roll over forward end for end. Here are some examples. http://www.youtube.com/watch?v=prbSkB-kr8Q The red truck could use overdrive in the front or/and underdrive in the rear to help keep the front end in contact. To be honest though, this is also a case of weight distribution because it is so damn tight in these things. The yellow truck, if it had over/under drive, as it started the decent, the front wheels would have been turning at a faster speed than the rear which would effectively applied more breaking on the rear. Oddly enough, I did not have these issues with my SCX10, but I am doing a complete rebuild and the weight is going up a lot so this becomes more of an issue.

10-29-2010, 06:31 AM	#11
Big Bill Rock Crawler Join Date: Dec 2008 Location: Fortuna Calif. Posts: 997	I had both the OD and UD gear sets in my first AX-10 sportsman rig, and the gearing just seemed to fight each other. This was really noticeable when trying to use small amounts of throttle in tight gates. Finally pulled the UDs out of the rear and it worked alot better for me. Has anyone tried UDs in both axles??

10-29-2010, 07:08 AM	#12
neillarson RCC Addict Join Date: May 2010 Location: The heart of the south Posts: 1,138	I would think using both would be overkill, I want to use one or the other, which ever set I can find. and using UD in both would be the same as using stock except a tick slower.

10-29-2010, 03:09 PM	#15
cornel4web Pebble Pounder Join Date: Jul 2007 Location: deva - romania Posts: 154	as a newbie, I intend to buy the OD (36/14) from RPP...so, it will be helping me using this in front and stock in rear? Thanks

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10-29-2010, 08:36 PM	#16
Cableman Quarry Creeper Join Date: Jul 2009 Location: Long Island Posts: 347	3racing makes the stock gearing HD bevel gear set http://www.3racing-parts.com/shop/ax...-90006890.html Beveled should be smoother with less play.

11-21-2010, 02:49 PM	#17
neillarson RCC Addict Join Date: May 2010 Location: The heart of the south Posts: 1,138	I installed Underdrive gears in the rear Diff today. I also switched out the Novak 18.5 Havok for a Goat 3S 18.5. Running a 3S 1300 pack and I managed to get all of it over the front axel. I was amazed at how well it climbs and no more flipping over..

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