twobnvd

My Feedback: (1)

OK I had a differential go out. I read an article how to turn it into a posi diff. So I have done this n one of my trucks. I havent rean it yet because I am waiting to put a few parts back on it. Does anyone know the good and the bad about doing this? I have a couple good diffs just wanted to try it to see what it would do as far as wheeling and traction.. Anyone? Thanks in advance

dakamat

What's a posi diff???

twobnvd

My Feedback: (1)

When you take a differintial and you lock it so both tires spin in the same dirrection and are locked that way.

twomanytoys

posi diff will put alot more stress on other drivetrain components. It will also make steering harder. You wont be able to make tight turns because the outer wheel cant turn at a different speed than the inner tire. On the other hand traction will be way better.

Posi traction locks both right and left wheels together so they spin the same all the time. Normally your trucks are open (unlocked)diffs.

twobnvd

My Feedback: (1)

Thanks man. I only locked the back. I just wanted a bit more traction and a better bite when starting off. I appreciate the reponse.

bigwaltc

This is what I have in my XL works great http://www3.towerhobbies.com/cgi-bin...&I=LXNWS7&P=SM [sm=shades_smile.gif]

usmc_VTOL_mech

I locked the back of mine once and broke dogbones like there was no tomorrow
And the things was almost impossible to get to go straight under hard acceleration cuz the rear always wanted to slide around
I didn't like it locked at all

twobnvd

My Feedback: (1)

So one of you doesnt like it and the other does. Intresting gues Ill have to take it for a test ride and see how it works. Thanks for the reply guys. Bigwalt did you lock both or just the rear? Any idea why it wouldnt go striaght was it on dirt or pavement?Wondering if it was just spinning tirescausing the unstable ride? I mainly bash in the dirt jumping, hill climbing ect.

bigwaltc

I never broke any dog bones but mine is on a XL with the bigger ones. If you are going really slow it is a little hard to make a tight turn the truck wants to push a little but if you are in dirt you just gas it and steer with the gas you will get used to it after a while. I like it. My front diff is open with grease in it [sm=shades_smile.gif]

usmc_VTOL_mech

twobnvd
I am gonna take a stab at it why bigwalt likes it and I don't
I am gonna guess bigwalt is a basher
most bashers seem to like them locked

I on the other hand am a racer
racers like using the diff oils to tune the truck to the track and we like LOTS of steering
When i am racing and pin the throttle I REALLY need the truck to go straight where i point it...I don't like the rear to get loose or try and "guess" where it's gonna go

Just try it and if it works good for what you use the truck for then great....
If you don't like it you can always unlock it and not really be out of a bunch of cash ya know

twobnvd

My Feedback: (1)

Oh that makes much more sense. I to Bash.. So it should work for my purposes and I understand completly what you are saying on a track you have to maintain all the control you can get. Makes plenty of sense. Thanks for clearing that up.

bigwaltc

Yes Brother I don't race. If I did race I would agree with you 100% about tuning your Diffs for the track. Maybe I should tell about my Savage background before giving advice [sm=shades_smile.gif]

twobnvd

My Feedback: (1)

Awh man its all good any advice is better than none. I am a basher as well so it should be good to go. Thanks again.

Lilredmachine

If you nail the throttle on a truck with an open diff and the tires have uneven grip, the one with less grip will slip more and spin faster, however this shouldn't affect the straight launch of the truck as the wheel with grip has less power going to it so it sort of balances out. Or at least the lurching to one side is manageable.

If you run a locked diff, the tire with less grip won't spin any faster and the tire with the grip will have all the power of the loose one, driving the truck in the opposite direction to the side of the truck the grippy tire is on. Hence it is nearly impossible to drive a serious off road race truck in an offroad race over varying terrain with a locked diff.

I bash with my bashing vehicles, which tend to have locked diffs and race with with my race vehicles which tend to have either light or heavy oil in the diffs.

thzero

Roughly what sort of diff oil weight are you using front/rear for looser track conditions?

wht92lude

you could put a spool in it? I don't know if they make a spool for a savage diff, as I have never owned a savage.

fabrimacator21

They don't make a true posi unit for savages. Posi would be the equivelant to a very heavy diff oil when it comes to rc.

they make spools but no posi unit as far as I know.

I'm guessing you meant spool when you said posi?

twobnvd

My Feedback: (1)

No I took the diff apart and ran jb weld in side the hub as the gears were shot. Both wheels turn identical now and are locked. I also just put a k4.6ho in it as it was a 25. I also put a x two speed trans, steel spur gear and just ran it for about ten minutes.,.... OMG This thiing is crazy. Grips and pulls wheelies with ease. If you dont throtte down it tries to pull the flux flip just doesnt have that much juce but it is a major improvement for bashing.. I am sure alot is atributed to the motor, But when pulling a 360 in the grass it either pulls a wheelie or tears a azz load of grass up when you throttle it up.. No more running in the yard or I wont have any grass left.. LOL Thanks for all the advice guys..

bigwaltc

Here you go http://www3.towerhobbies.com/cgi-bin...&I=LXNWS7&P=SM this is what I run [sm=shades_smile.gif]

usmc_VTOL_mech

Thezero
i like it set-up with 10,000 in the front diff and 7000 in the rear
good balance between steering control and traction grabbing
The front with the thicker oil tends to "pull" the truck thru the turns

BudBud

I have been just packing the rear one with Mobil One Automotive Wheel Bearing Grease and calling it good. I am just a basher though. [8D]

thzero

Thanks... gives me an idea of baseline. I went with 10k in both front and rear to start with to see how I like it.

rclugnut10

My Feedback: (1)

i really like my 7k all around but may want something thicker up front... or maybe a tad thinner in the rear, i dunno its been FAR TTOO LONG since i've gotten to bash it...

the lug

thzero

Ok...

bigwaltc

IMO I think that is great for racing but to thin for bashing [sm=shades_smile.gif]