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-   -   underdrive underdrive is it all that (http://www.rccrawler.com/forum/general-crawlers/586807-underdrive-underdrive-all.html)

ferp420 07-07-2017 08:21 AM

underdrive underdrive is it all that
 
I tryed the over drive underdrive set ups on my wraith ive tryed a few different set ups the best for me has been underdrives front and rear it worked great but i lost my rear gear set and i had the over drives laying around so i installed them up front and with nothing else changed i cant make any of the big climbs any more its like 2 tires wont get traction probably because the tires are spinning at differant speeds im woundering if this realy is the shiznik and i have my set up wrong or is this just a bad set up for a crawler the only time i herd of this in the 1:1 world is with subaru they used it to increse the handling on the dirt but they quickly did away with that set up my crawler rig is running bigger tires up front so basicly a overdrive underdrive set up and it works great so what am i missing what dose everyone else do for the over under mods and how is your rig set up
Thanks

I have new matching gears to install just woundering what everyone elses ideas are about this

Vagos2 07-11-2017 01:07 PM

Re: underdrive underdrive is it all that
 
You probably liked the ud/ud set up more cause it kind of "tames" the rig. If you are running big tyres and od/od gears they add up to excessive wheel speed (and torque twist I guess) so you ought to be less trigger happy or resort to other means like a smaller motor gear or a bigger spur gear if you want to keep the od ones. I run deepwoods cr tyres and they are rather huge for 2.2 so I had to fix several things to make it work ok...

strap624 07-11-2017 01:14 PM

Re: underdrive underdrive is it all that
 
The advantage I see is running more teeth on the ring gear equates to less torque twist, meaning on a steep climb, you are less likely to start lifting that front tire. Of course you lose top end, but you gain control and torque. When I had my wraith, it definitely helped stop that torque twist and allowed me to climb steeper grades.

ferp420 07-11-2017 01:47 PM

Re: underdrive underdrive is it all that
 
On my wraith I like the underdrive gears front and rear my new ones are installed and ready for axial fest

Hardcoretam 07-12-2017 04:25 AM

Re: underdrive underdrive is it all that
 
Quote:

Originally Posted by ferp420 (Post 5726613)
On my wraith I like the underdrive gears front and rear my new ones are installed and ready for axial fest

Is it not just easier to fit a bigger spur or smaller pinion? I thought fitting UD in front and back was the same as gearing down at the spur / pinion

Ninomaniac 07-12-2017 06:12 AM

Re: underdrive underdrive is it all that
 
Final drive ratio may be the same, but it also seems to have an effect on torque twist.

I just received my 11/38 gears for the rear, I wonder if it will help with turning and climbing compared to stock 13/38 I'm keeping in the font. Or is it too small of a difference to change handling.

Teng 07-27-2017 12:24 AM

Re: underdrive underdrive is it all that
 
I have heard many of my senior crawler fans said that the UD front and rear are the best in gear mesh. For durability sake, I think I would try this setups next time on my Wraith :ror:

FrancoSFL 10-09-2017 11:24 PM

Re: underdrive underdrive is it all that
 
I religiously ran over/under on my truck before I swapped to scx10.2 axles. It works awesome if set up right, more weight on front/softer foams definitely helps. Although running the same gear ratio feels more solid in a way, I could pull crazy lines with the overdrive

Ninomaniac 10-11-2017 05:56 AM

Re: underdrive underdrive is it all that
 
I did a couple of runs with underdrive on the rear of my Wraith and it would have made me jump with joy if I wasn't overweight and tired all the time!
"thumbsup"
Better turning circle, front axle more likely to stay on the ground when things get steep so steering when climbing is now a real thing, and I can still swing the rear around on loose stuff with a blip of the throttle. It did reduce speed overall a bit, so I switched back to 12/56 (3s 27T) for general fooling around.

Locked Up 10-11-2017 07:47 AM

Re: underdrive underdrive is it all that
 
OD/UD is great for making a tight turning radius and "should be" beneficial on hill climbs.
This can depend on your vehicle setup and certainly is impacted by foams and tire type/diameter.

On a climb the front should pull harder, which will start to put a hair of bind on the tires forcing them to grip.
If your tires aren't sticky (or hard foams) then you will lack the grip though.
If your tires are too big then the ratio might be too much.


So, if OD/UD is causing you to lose grip, you might be happier with a set of standard HD gears up front and UD in the rear.
That way you still get a little help with turning radius and climbing, but the ratio isn't so much to cause you to lose grip.

"thumbsup"

mewalsh100 10-15-2017 12:36 PM

Re: underdrive underdrive is it all that
 
I'm running underdrive in the rear of my Wraith. In conjunction with the Vanquish VVDs up front, turning radius is vastly improved! I also like how the front "pulls" over things now.

smc-93 10-24-2022 06:16 PM

Re: underdrive underdrive is it all that
 
Quote:

Originally Posted by mewalsh100 (Post 5757410)
I'm running underdrive in the rear of my Wraith. In conjunction with the Vanquish VVDs up front, turning radius is vastly improved! I also like how the front "pulls" over things now.

I'm running the same thing, for the same reason on my Bomber.

"Open" front diff with 20m "oil" and a standard ratio hardened gear. Hardened UD locked rear.

I didn't lose much on the performance side and the turning radius was vastly improved.

Sent from my LM-V600 using Tapatalk

lonleycreeper 10-24-2022 06:21 PM

Re: underdrive underdrive is it all that
 
Quote:

Originally Posted by smc-93 (Post 6125089)
I'm running the same thing, for the same reason on my Bomber.

"Open" front diff with 20m "oil" and a standard ratio hardened gear. Hardened UD locked rear.

I didn't lose much on the performance side and the turning radius was vastly improved.

Sent from my LM-V600 using Tapatalk

You do realize this was a nasty Necro post from The boi... Now calling himself Tiffany.

ferp420 10-24-2022 06:25 PM

Re: underdrive underdrive is it all that
 
Quote:

Originally Posted by smc-93 (Post 6125089)
I'm running the same thing, for the same reason on my Bomber.

"Open" front diff with 20m "oil" and a standard ratio hardened gear. Hardened UD locked rear.

I didn't lose much on the performance side and the turning radius was vastly improved.

Sent from my LM-V600 using Tapatalk

thats how my raptor yeti is set up but its not a crawler and the underdrive keeps it going in a straight line



my e10 has heavy overdrive i dont think i like it i might have to go back to the stock rear axle

the ar44 might be to much underdrive im still playin with it
i dont really like it but there must be a reason everyone is so for it i just havent figured it out

it dose make turning alot better but i dont comp so it dosent matter that much for me

smc-93 10-24-2022 06:58 PM

Re: underdrive underdrive is it all that
 
Quote:

Originally Posted by lonleycreeper (Post 6125093)
You do realize this was a nasty Necro post from The boi... Now calling himself Tiffany.

I didn't realize that. I do now. Thanks for the heads up.

It still popped up in my feed as new, after just blocking Tiffany. I didn't look at the date on the last post

Sent from my LM-V600 using Tapatalk


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