skeasor

What are the advantages of running a ball diff in a 1/10 scale car? There is a lot of load on any offroad vehicle and I would imagine that a gear diff would be more suitable. If I remember correctly, ball diffs were created for rc touring cars. Of course the ball diff is much lighter than a gear diff and can easily be adjusted but they must constantly need to be rebuilt to perform well. What other advantages do they have?

PhilipBGreen

iTrader: (2)

I could be miss informed but i believe there geared toward the more serious racer, its alot easier to adjust and saves a ton of time versuses changing diff fluid specialy for the traveling racer, i think there mor consistant coming out of corners less torque steer i think people overdue the whole they need to be rebuilt thing ive been told if not properly set up they burn up easy, but thats why i say more geared toward the seriouse racer i mean lets be honest a race truck usualy never sees the street and is set up to run for only 5 min it usualy only sees the track for 2 days out of the week and 3 heats each day unless you practice alot other than that the trucks cars sit, untill the next race my personal opinion is the top 8 fastest drivers at my track run them so it must be right lol. I wouldnt mind hearing some good reasons myself

tc5 man

I just switch to a gear diff and tune with the diff oil just easier to maintain and not worry about it slipping like a ball diff. One advantage is you can tune the ball diff with it in the truck and its lighter, and drives more free in terms of handling. Gear diff gives you more forward traction and more like a posi lock that depends mostly on diff oil weight .

But just for easier matience and cheaper over the long run without worrying about it slipping a Gear diff is better to me.

t0p_sh0tta

iTrader: (35)

In my opinion, ball diffs offer a smoother and more progressive action, especially on med to low traction. On my 2WD cars (mod 2wd and mod SC), rebuilds come once every 1.5-2 months of weekly racing. If you build them right, they'll last just as long as any gear diff.

Davidka

iTrader: (86)

Actually, ball diff's were first used on pan type on road cars in 1/12 and 1/8 scale (there was no 1/10 on road back then). They quickly found a home on the RC-10 buggy as well as a Thorp and MIP aftermarket versions.

Their advantage is actually that they are smoother under load than conventional gear diff's. When load is applied to a gear diff, all of its parts try to spread the diff apart. A ball diff doesn't experience much more loaded than it does sitting idle so under load the action stays the same. As long as the load doesn't exceed the amount the diff can manage (and a slipper is correctly adjusted) they last a good long time between rebuilds. It's nest not to think of a ball diff as adjustable. It needs to be tight enough not to slip. Most good diff's have a straightforward build sequence so that adjustment is mostly unnecessary.

samnelso

iTrader: (1)

I find the ball diff provides a more consistent diffing action throughout a cycle (stop, start, reverse). Acting with the mechanics of essentially a thrust bearing, there is little diff resistance to a well built ball diff, whereas a gear diff has to overcome the shearing resistance of the fluid. Thus, a ball diff will change direction with much less effort than a gear diff due to the shearing resistance of the fluid.

That's my off the cuff response

ThePanda

iTrader: (68)

To add to what others are saying...

A gear diff that uses oil in it will by design create a more progressive limited slip action the faster it counter rotates compared to a ball diff, so what can happen is that the faster it rotates, the less the diff will actually "diff" and the more it will act like a spool. This is not the preferable set up for most tracks, unless there is little diff action happening anyways, typically some very high grip surface such as carpet.

A ball diff will experience the same "firming up/limited slip" action that a gear diff experiences, but not nearly as drastically as the "firming up" will be mainly caused by friction of the parts, and not by oil, like a gear diff. This lets you have a diff, where you can essentially set one amount of slip, for all reasonable rpm loads the diff will have. Ie, it isn't really noteably progressively limited slip like the gear diffs. Plus a ball diff is more efficient in its transfer of power from one out drive to another. As mentioned it isn't trying to rip apart from the forces of the gears, and doesn't have the same friction going on between the gears/shafts/ parts as a gear diff. It does have the balls, bearings, and the balls against the gear though, but this is minimal.

That's in 2wd anyways, which are so sensitive to how the diffs react in the car. In 4wd buggies people have been having great success with gear diffs, even though the cars still react to very small changes in diff settings, like 2wd. People have just been able to make them work well.

RC10Nick

iTrader: (9)

I went through a period of about a year where I couldn't be convinced that a ball diff was better than a gear diff. But after struggling with rear grip for a season and not being able to find gear diff setting I was happy with (worked great on carpet, though), I went back to a ball diff. Night and day difference immediately. The back end was much more settled and the car was just faster.

I offer no theories or psuedoscience on why the ball diff was better. I just know no matter what I did, the gear diff never worked as well as the ball diff does.

ThePanda

iTrader: (68)

Haha. Ball diff is life for dirt.

However, a gear diff is rather fun to play around with and try to get the car working well.

Rsimps

I find the gear diff helps car rotation into a corner over a ball diff and it is a little quicker on pick up, but overall I prefer a ball diff in my 2wd car. I like gear diffs on the 4wd on grippy surfaces, but would change to ball on a slippy surfaces.

PhilipBGreen

iTrader: (2)

This is all really good info to soak up I think ill hang on to my gear diff, even after my ball diff arrives at my track the ball diff is the way, however after soaking up all of your opinions I think Im going to choose not to look at it as one is better than the other rather both are great tools for different conditions there are many tracks in my area and Im new to the hobby as far as racing so Im obsessed at the moment and travel to the different tracks i think i might even order a second transmission to put the ball diff in and rebuild and keep a good gear diff as well.

tc5 man

If it's on low traction or med grip the ball diff is good on . But on carpet or high traction dirt the gear diff holds up better to be from experience . And you get good rotation with the gear diff depending on what Wt diff oil you use .

skeasor

I'm glad I asked this question because I came to the same conclusion as you did. Neither one is really better than the other but can both be used for different tuning options.

PhilipBGreen

iTrader: (2)

Thanks do you have a weight you prefer or a good starting point weight ? Also I see your from up levittown ive been residing in wisconsin for quiet some time but I was born in philly and lived in upper darby on barrington and 69th st, my whole family still lives back there all over Kensington, fish town, west philly, chester all over any way my buddy says theres this big race in pa he attends every year in pa, it must be pretty big for him to wan to drive from WI Im going with this year maybe ill see ya there.

skeasor

From what I've ready in other threads, 30k is a good starting point but I'm not really sure.