bkfamily1

My Feedback: (1)

Eddie, I saw where you said in the Mega E thread that you use like 7K in the front and 3-5 in the rear. And in the MXB-3 thread you again said 7 front 3 rear and 10 center. In the RXT racing setup thread, Harry says 3 front 5-7 center and 10 rear. I currently have 3 front 7 center 10 rear based on Harry's info. Can people explain to me the reasons for putting thicker or thinner in the front rear and center? And when it makes sense to use what where?

Thanks!

firebird78

the way I understand it is, the heavier the oil less the diffs slip....basically meaning if you put thick oil in the front your rc would want to hop due to the the inside tire going into a turn is rolling faster then the outside tire...with the center diff you can control how much power your putting to the front wheels by using thicker or thinner oil...the thicker you use the more equal power you get from front to rear...the rear diff is pretty much the same as the front...the thicker oil you use the more equal the power is to each wheel

ehroof

Almost most of the times you want the front to grab more equally, unless you lock the diff, it will slip, more slip and it will tend to pull in the direction of the tire that is pulling and that can make it hard to control.

bkfamily1

My Feedback: (1)

I get the idea that thicker means less slip. But what conditions would make Eddie want to put thick front thin rear versus Harry the opposite? Is it different conditions? Different personal preferences? Or different vehicles? The MXB-3 (where Eddie commented) and the RXT (Harry's) are both 4WD 3 Diff. So why opposite diff oil setups front versus rear?

Sorry for my lack of experience, but I would really like to understand how to use the diff oils to improve handling.

ehroof

I think Harry made a mistake and meant the opposite, I have never heard of anyone putting thinner in the front and thicker in the rear.

bkfamily1

My Feedback: (1)

OK. Now the "equal drive in the front" idea makes sense. You do not want it to pull to one side. Cool. But you know me - full of questions! So how does the rear diff oil affect handling? How about the center? When do you want unequal in the back (thinner oil) versus equal in the back (thicker)? And when do you want unequal and equal front to rear with the center diff?

Thanks!

ehroof

lol, you want the rear to push thru on the turns so with one of the rear tires pushing it wont make the rear kick out that much. Its basically what you want all the time, the front will pull you thru while the rear tracks behind so you wont fishtail thu a corner as badly as when the rear tires are pushing equally.

bkfamily1

My Feedback: (1)

Now that is what I call support - not only does Eddie explain in the forum, he even calls me to be sure I understand. [:-] Wait a minute - does that mean he thinks I am slow to pick it up?? [&:]

I think I get it now.

In the front, you want both wheels driving all the time so you get good handling and steering without pulling to one side or the other. The thick diff oil is especially needed when turning as one wheel will tend to lose traction as the vehicle leans into a turn, and you do not want the power going to one wheel.

In the back, you want the wheels to be able to turn different rates as you turn. If they can not, you will lose traction in the rear and tend to fishtail when turning. So thinner diff oil is in order.

In the center, you want both front and rear to be driving so you can get maximum grip on the ground. So again, thick is in order.

I will change mine around and report back how it reacts. Current is 3F, 10R, 7C - I am going to 7F, 3R, 10C.

Swamp3r

I dunno if you have ever driven a front wheel drive car in snow compared to a rear wheel drive car in snow, but thats the way I would explain it to you. Rear wheel likes to kick it`s rear out(no control) while a front wheel drive likes to pull through a turn.

bkfamily1

My Feedback: (1)

Good analogy. I have a 4WD Jeep Wrangler, so snow does not slow me down. But I have driven rear and front wheel drive in snow, and I get what you mean. Thanks.

Swamp3r

That was the best I could explain it. And sand or rough terrain would be the same or a track with light rc`s it would be like snow the traction I mean. I shouldda said that earlier. Your not an idiot so I know you understand.btw I haven`t seen a vid from you in awhile your slackin man.

{GBI}Harryball

Hey Brian, I got your message. I run on a sandy track so I run thinner in the front. I perfer the fronts to spin at our club races, believe it or not it gives me and edge that I love, Its more difficult to control, but Im pretty good with it. Eddies right about the heavier in the front to keep the wheels from spinning, I set my stuff up based on track conditions. For me On hard pack I what the front diff heavy in sand I want it light. I put my settings in the RXT thread based on my local track conditions. Let me know if you have any other questions.

Tony

bkfamily1

My Feedback: (1)

Thanks, Tony! I appreciate you taking the time to help me understand. Hope things are well and that we see you around from time to time.

{GBI}Harryball

No problem, glad I could help. Ill be around.. Just been sick with neumonia and havnt had the time to do much of anything other than deal with life. LOL. Let me know if you need anything else. My setup is pretty mean.

ehroof

hope your feeling better bro, quit smoking!!!!

Redharris

Based on what I have seen at the Various Pro Races at the Tracks around my House,,,,,The Pros and accomplished Amatuers run Lighter fluid in the Front Diff, most of the Time.
You can Tell by looking at the Tire wear patterns on their Buggies and Truggies. The front Tires are always nearly Bald at the end of the race. This indicates to me that they are Spinning the Fronts a lot more to aid in Steering.

They run this way, even though the tracks around here are Hard Packed......

bkfamily1

My Feedback: (1)

Well, I switched the oils around on my RXT.

Was: front 3,000 rear 10,000 center 7,000
Now: front 7,000 rear 3,000 center 10,000

She was under steering when I was turning under power, then tending to come around in the back once it got turning. I imagine that will make a difference in how she handles! Can't wait to get out and run!

Thanks to everyone for the input. If the weather holds, I will report back in a couple days.

{GBI}Harryball

Yea that would be a good idea.

Exactly, I love the way the truggy pushes into the corners, it allows me to power thru them.

ehroof

Its really up to how you drive i think, i prefer the front to pull the trcuk thru the corner. I find that thicker in the front and thinner in the rear keed the rear from trying to kick out an come around.

genitor

Found this while doing some research:
http://www.rc411.com/pages/howto.php?howto=24

It pertains to 1/8 scale but it really helped me understand how diff oils affect handling.