Cole Trickle

I was wondering, what's the advantage with ball diffs?

Gear diffs are way smoother.
Gear diffs are maintenance free.
Gear diffs aint got any power loss, due to a too lose setting.
Gear diffs weighs the same as ball diffs (at least, when the outdrives are made of the same material).

As far as I can see, the only advantage of ball diffs, are the adjustability. But then again, according to some of the setup guides, it aint the right way to adjust under- / oversteering balance.

I might be wrong somewhere..... Can someone please enlighten me about what's the big deal?

dtm

You are building the ball diffs wrong if the gear diff is smoother! However, you are right, ball diffs are used to tune the car....it is a very effective way.

Cole Trickle

My ball diffs are working fine, actually, they are smoother than most of the other cars, that I've touched.

The following comes from http://home.tiscali.be/be067749/58/

"...You *can* use them to alter your car's handling. If you adjust your front diff a little tighter, you'll experience more understeer entering a corner, but more steering and a little more front traction exiting it. The car will also feel more stable. If you tighten the rear diff, it will become easier for the rear end to break loose. But I don't recommend using diff tightness to alter under/oversteer balance. The reason is that a tight diff scrubs off speed in the corners. A car with loose diffs will coast through the corners more easily, without scrubbing off much speed."

Sounds quite reasonably.

Any comments?

dtm

Sounds reasonable. I almost always run a front one way and the rear diff tightness is a very good tuning tool to achieve the right balance.

IMPACTPLAYR

iTrader: (7)

Please show me where this magical gear diff is that weights the same as it's balldiff counterpart???

Gear diffs do have their place n higher demand situations, where there is alot more power being applied.... like nitro.

Gear diffs are tunable, if they are sealed you just use thicker diff fluid/lube for a stiffer diff........

Cole Trickle

I'm talking about HPI's diffs for the Pro2 etc. The ball diff with steel outdrives, weights the same as the gear diffs in my Sport2.

But of course, there's graphite diff hubs available (have already ordered). It should be possible to make graphite diff hubs for gear diff's.... Those would probably only be suitable for EP cars, however, they would be maintenance free !!!!

MTL_RS4

Where did you order your graphite ball diff's? everywhere i looked they are backordered... I would really apriciate it!

popsracer

I HATED Ball Diffs when I tried them on my HPI Nitro Cars. The reason I sold my RC10GT, was too many problems with the ball diffs getting gritty.

On my HPI Pro-3 they have been trouble free. Just clean and relube every few races.

Cole Trickle

That's a lot of cleaning..... after 2½ years with gear diffs.... I never cleaned them. Wasent needed...

About my ball diffs in my Pro2; One diff got gritty after only two batteries. But the rear one have now run about 18-20 batteries and it still runs great.

By now, I agree that ball diffs can be smoother. However, gear diffs have absolutely no slip, yet they aint got that tight feeling, when turned.

gotpez

A ball diff built properly should be MUCH smoother than a gear diff. Within the gear diff, there will always be some gear lash.

In touring cars, the diffs are usually encased inside a transmission housing. This should keep any foreign material from getting into a diff and making it gritty. If a ball diff inside a case is getting gritty, it is more likely due to being built improperly and slipping. Once a ball diff slips, the balls will begin to wear a groove in the diff ring and flat spots will appear on the balls themselves. This is usually what causes the gritty feeling. They don't need cleaned, they need rebuilt with new components.

Don't make the mistake from the old off-road days and let your diff slip. All that does is destroy it.

Jeff Gilligan

popsracer

I guess I should have said about every 4 race days more or less. Depends on how dusty the Tracks are.

gotpez;

That's a TC3 mentality, in MOST Belt Driven cars, the Diffs are exposed to the elements. I have a Machinists eye scope to inspect the Balls and rings. So far everything has looked good, just a little grit to wash out.

DZ

iTrader: (4)

what do you use in gear diff to make them really tight almost to the point of lockig them. an old mechanic told me that they used to use bananna peels in chevys to help tighten the diffs and also helped quiten them could that possibly work in an rc diff.

cheers

Cole Trickle

DZ, heavier grease and/or springs. HPI got a kit with springs in 3 different tensions.

Cole Trickle

Thanks Pops and Gotpetz. I'm definately in the learning phase about ball diffs. My diff, which feels gritty, I'll tear it apart, when my graphite diff hubs arrive, then I'll see. (I'm not running that diff right now, since I'm using a one-way diff).

MTL_RS4

O.K I got the graphite ball diffs for my pro2... can someone tell me: At what point they sould be tighten? it's a bit of a struggle right now. Looks like i can't tune them properly. I have to rebuilt them every 2, 3 races...