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View Full Version : PN Racing Mini-Z 2WD Machine Cut Delrin Limited Slip 64P Spur Gear 51T-54T


PNracing
2009.11.13, 01:53 PM
New design for 2WD Ball Diff replace.
Limited Slip Spur Gear
Machine Cut Delrin
64 Pitch
Save grease V Grooves
Patent Pending number US 61/274, 308
http://www.rckenon.com/public_html/shop2/catalog/images/MR2851-4-c.jpg
http://www.pnracing.us/productsphotos/MR2851-4-b.jpg
http://www.pnracing.us/productsphotos/MR2851-4-1.jpg
http://www.pnracing.us/productsphotos/MR2851-4-2.jpg
http://pnracing.us/2WD-64P-Gear-Ratio.jpg

mk2kompressor
2009.11.13, 02:47 PM
thats a cool concept,when will they be available?

PNracing
2009.11.13, 04:05 PM
thats a cool concept,when will they be available?

Already on web site

color01
2009.11.13, 05:54 PM
Looks great Philip, when do you want to send me one? :D

Tjay
2009.11.13, 06:46 PM
It looks AWESOME!!! Yes Philip, when do you want to sent me two? haha :D

chad508
2009.11.13, 10:44 PM
forgive my ignorance but what is the benefit of it slipping?

mikey
2009.11.13, 11:20 PM
forgive my ignorance but what is the benefit of it slipping?

The benefit is it won't slip when you're accelerating.

LED
2009.11.14, 12:54 AM
The benefit is it won't slip when you're accelerating.

I dont realy understand either. Whats the point in having a ball diff then ?

benmlee
2009.11.14, 03:16 AM
This is basically a one way limited slip differential. You get a slight traction increase during acceleration when balls engage the wedge. But balls in the diff are free to rotate when braking or when no throttle is applied.

Davey G
2009.11.14, 11:03 AM
Lets see if I can spread some knowledge on this new product. On the starting line and when exiting a turn the balls will be forced into the v pocket and jammed up, this will in essence turn into a spool (LOCKED DIFF). This will provide straighter launches exiting the turn. But when off power the balls will center inside the pocket and return to a normal diff. Does this make sense??? Hope I was of some help to you.

chad508
2009.11.14, 10:47 PM
how will it effect coming out the corner? will it try to jerk the car back straight, would it be more prone to traction rolls out of a turn if you get into the gas to soon.

arch2b
2009.11.14, 11:47 PM
the design is intriguing to say the least. i am however skeptical that at this scale, weight is actually works as intended and/or as precisely as intended.

i am very likely wrong as pn puts a lot of effort into their product design but i remain skeptical until i actually get to see this work as described. it does sound cool though :) i'm sure someone in DC will get one and i'll have to ask to get a crack at it for sure.

kudos to pn for putting out another leap forward in mini-z tech. :cool:

ianc
2009.11.15, 12:24 AM
On the starting line and when exiting a turn the balls will be forced into the v pocket and jammed up, this will in essence turn into a spool (LOCKED DIFF). This will provide straighter launches exiting the turn.

I'm not seeing it. Isn't when transiting (and exiting) a corner precisely when you want a smooth diff action rather than for it to be locked up?

But when off power the balls will center inside the pocket and return to a normal diff.

Having smooth diff action on the straight is useless since there is no relative rotational motion between the drive wheels then anyway.

Seems to me (without having tested it) that it would just give you a boatload of understeer. Willing to listen though...

ianc

yasuji
2009.11.15, 01:49 AM
I'm not seeing it. Isn't when transiting (and exiting) a corner precisely when you want a smooth diff action rather than for it to be locked up?



Having smooth diff action on the straight is useless since there is no relative rotational motion between the drive wheels then anyway.

Seems to me (without having tested it) that it would just give you a boatload of understeer. Willing to listen though...

ianc

ok having testsd this my self on my mod pan this is my take on it
having a locking diff equates to more on throttle steering as well as better acleration
try and increase the tention on ur std diff gear it will try to spin the rear tires
and if u loosen it up it will hook up due to better traction
with this gear i felt that it made my car drive out of the corner tighter and quicker while still being the same car every where else
the other thing i like is that i can ad extra grease to prolong the consistancy of the diff rather than it changing after every run loosing its grease
also the width of the gear prolong the life of the pinion giving it a wider contact patch
a narrow contact patch cuts in to the pinion like a knife causing excess slop-more noise and increased frictional losses
this is an A++inovation from PNRacing

color01
2009.11.15, 05:51 PM
I'm not seeing it. Isn't when transiting (and exiting) a corner precisely when you want a smooth diff action rather than for it to be locked up?
Not strictly. Mini-Z's tend to bounce along the RCP, so there are always momentary losses of traction where you're slipping the diff and not applying 100% of your power to the ground. By tightening up the diff, you'll be getting more of it to the ground under acceleration. So the net benefit is that you'll power out of the corner more quickly.

Having smooth diff action on the straight is useless since there is no relative rotational motion between the drive wheels then anyway.
It's not about the straight, it's about the high-speed sweepers on most tracks that more often than not tighten up into the infield section. By allowing the diff to free up again under low throttle load, the car can take the sweepers at full speed, no need to deal with the understeer caused by a tighter diff. You want the diff to be as loose as possible in this section of the track, or you'll scrubbing speed before you even get to the part where you need to slow down.

Hope that helps a bit?

arch2b
2009.11.15, 06:46 PM
makes it much easier to understand for me :) thanks.

JeremyC
2009.11.15, 07:06 PM
Is there a 64 pitch pinion set that is sold? All I can find are individual ones, a set with 3 spur gears...

-Jer

ianc
2009.11.15, 08:27 PM
By allowing the diff to free up again under low throttle load, the car can take the sweepers at full speed, no need to deal with the understeer caused by a tighter diff.

That's what I don't get. As soon as power is applied, it's going to tend to drag the balls back into the narrow portion of the groove thus locking up the diff, so it seems like the only time you're going to get a truly open diff is off throttle, which will not be the case during most long sweepers...

ianc

chung3j
2009.11.15, 10:20 PM
i doubt its going to lock up all the way, and it gives you way more stablility, less likely to spin out. if you want more steering you can just put more camber gain or static camber. you only need a truely open diff when your going through tight hairpins, where the diffrence in rotational speed btw L&R is the greatest. i think its a great design, so you won't sacrifice so much on-throttle stablilty when setting up for tight hairpins. if you happen to play a racing game where you can set the diff like GT4 you would know how great it is to be able to have diffrent on/off throttle diff action. im at about 80% completion and just love 1 and 1.5-way. i highly doubt there are any tracks that have only hairpins or no hairpins, and 1-way lets us have a bit of both on the same setup

color01
2009.11.16, 12:02 AM
That's what I don't get. As soon as power is applied, it's going to tend to drag the balls back into the narrow portion of the groove thus locking up the diff, so it seems like the only time you're going to get a truly open diff is off throttle, which will not be the case during most long sweepers...

ianc
The balls should only be forced into the back of the V-pocket for a few tenths of a second at most, right after you hit the throttle. Once the maximum load is released, 1) there's grease in here and 2) it's machined Delrin, the balls will be out of the V-groove in no time and you'll have your happy free diff again. These aren't full-sized cars, obviously; you need to apply (to scale) a bit more "oomph" to get any sort of noticeable effect out of such a subtle modification as this spur gear, which is why it won't affect anything other than the beginning of the corner exit.

Food for thought: when you hit the throttle with a standard diff spur, the balls will be forced into the back of the pocket anyways, creating a very minor tightening of the diff. The V-pocket in this spur just amplifies the effect a bit in the moment that it's most needed.

Of course, this is just qualitative physics; I can't wait to actually slap this spur on my diff and run a few laps with it. But that is how this new spur *should* work, and how a few drivers have already observed it to work.

Eman
2009.11.16, 12:35 AM
I like the lube reservoir. Brilliant idea. It would be nice to have something similar for the MA's.

Tjay
2009.11.16, 12:39 AM
On-power exit out of a turn: I'm not 100% sure but if it locks up, it will definitely push out of the corner and having the rear wheel to be over powered so that the rear spins around will definitely give the fastest lap but will not be the most consistent car on the track due to tire wear and less battery punch towards the middle of the race.

I will test this vs the current one that I have and see if it'll be any faster/more consistent.

ianc
2009.11.16, 12:52 PM
The balls should only be forced into the back of the V-pocket for a few tenths of a second at most, right after you hit the throttle. Once the maximum load is released, 1) there's grease in here and 2) it's machined Delrin, the balls will be out of the V-groove in no time and you'll have your happy free diff again.

Theoretically, this doesn't seem like a valid analysis to me. All motive force to drive or accelerate the car forward is transmitted solely through the diff balls. If the force being input by the motor is less than that required to push the balls back to the V portion of the groove, then I can agree, otherwise the balls will be in the groove and the diff locked.

Given the relatively high forces being used to accelerate the car out of corners and down straights, it seems likely to me that the diff will be effectively locked in all instances except off throttle...

ianc

pfcparts
2009.11.16, 08:32 PM
I think it looks good. The resevoir and actual
lining to encase the plate is appreciated as it
keeps maintenance down.

Still sticking to the center bearing...? That
limits use to certain diffs or to in completely
converting and forcing use of one type of gear
or buying spacers for return to the original spec... :o

To add, diff grease is pretty sticky so wouldn't
wedging the balls cause them to stick in there
or at least cause some delay until they get
back into position? A large force wedges them in
there, is the off throttle force enough to pull
them all out consistently?

Interested in how it turns out though.


parts

color01
2009.11.16, 11:42 PM
Given the relatively high forces being used to accelerate the car out of corners and down straights...
This is the part where I disagree with you, and am waiting to test on. Of course you're correct that as long as this V-pocket is here, any accelerating force will cause a corresponding amount of locking effect, but I'm trying to assure you here that no amount of motor power at our scale will cause the diff to completely lock up. On a Delrin spur with grease covering the balls, the amount of stiction in this system is waaaaay low, those balls won't lock up until you've got a significant amount of RCP dust inside the diff.

ianc
2009.11.17, 06:33 PM
but I'm trying to assure you here that no amount of motor power at our scale will cause the diff to completely lock up.

No, it won't completely lock up, but the whole point of the design is to produce a 'limited slip' effect to increase stability in certain situations. The ability of the diff to offer increased resistance to differing rear wheel rotational speeds is a measure of the success of Philip's design.

The question is whether the design will provide sufficient 'locking' effect and at the proper times to be useful and not impair handling. Remember that this is only a theoretical discussion at present since no one's actually tested it yet.

On a Delrin spur with grease covering the balls, the amount of stiction in this system is waaaaay low, those balls won't lock up until you've got a significant amount of RCP dust inside the diff.

If the amount of stiction is too low, then you won't get any 'limited slip' action and the design would be pointless to begin with...

ianc

color01
2009.11.17, 10:59 PM
Ian, Grant has already tested it and given his thoughts on it, and I'm pretty sure Dave has as well.

If you think about this for a bit, this spur is basically a crude Torsen or Quaife diff, so I'm fully expecting it to work like one. I'll pick one up over Thanksgiving break and we'll find out. :)

yasuji
2009.11.17, 11:43 PM
Ian, Grant has already tested it and given his thoughts on it, and I'm pretty sure Dave has as well.

If you think about this for a bit, this spur is basically a crude Torsen or Quaife diff, so I'm fully expecting it to work like one. I'll pick one up over Thanksgiving break and we'll find out. :)
i put this spur gear on a 70 t car a few nights ago.....WOW!!
with the std gear i needed to tughten it to a point so it would not slip under accel with that setting the car would get "off throttle push" and steer pretty good thru the sweepers bt was a but sluggish thru "on throttle"chicanes
i installed the new gear and set it to the exact tention on the orin that i normally do and guess what....the car felt the same every where except when i would punch out of the corner it would almost spin the car out..... like the diff was locking up!hmmmm go fig:rolleyes:
so i pulled the car in and felt the diff seemed ok but i loosened it up like a 1/4 turn (if i did this to a std gear it would slip and whine ) holy moly i got more off throttle steering due to a freer diff gear
it transitioned better thru the fast chicane .....AND THE PUNCH OUT OF THE CORNER!!! and it would hold as tight of a line as i wanted..... also equating to a faster lap time 7.2 from 7.4
so now i have tested this on MOD PAN and 2WD 70T.....
whatare U waiting for.....LOL:D

benmlee
2009.11.18, 02:06 AM
To add, diff grease is pretty sticky so wouldn't
wedging the balls cause them to stick in there
or at least cause some delay until they get
back into position? A large force wedges them in
there, is the off throttle force enough to pull
them all out consistently?


parts

The V grooves are not self locking. They are made so ball tend to pop out by themselves if they are not actively being pushed in. There should be no delay in release.

There is definitely locking action on these gears. With a modifed MR02 on the slippery back side of the RCP track, you can feel the increase traction when you get on the throttle.

Traveler
2009.11.18, 09:56 AM
Mine should arrive today! Assume if I want to use this spur on a Kyosho diff I will have to sand the inner diff hub down as is required for the v1 PN 64p spur?

pedrocamp
2009.11.18, 11:53 AM
Ben,are the "V"s cut straight across the gear or at alternating, opposite angles relative to the side faces of the gear? If my understanding is correct the "V"s are straight cut and only add some resistance to the rotation of the ball, not actually force alternating balls into one of the drive plates... thus wedging, and locking, the whole assembly.

benmlee
2009.11.18, 03:35 PM
Ben,are the "V"s cut straight across the gear or at alternating, opposite angles relative to the side faces of the gear? If my understanding is correct the "V"s are straight cut and only add some resistance to the rotation of the ball, not actually force alternating balls into one of the drive plates... thus wedging, and locking, the whole assembly.

Pretty good observation there.
There are actually a few variation of the basic concept that will give different lock up ratio. Grant tried one configuration that has almost 100% lock up at least theoretically. He could probably elaborate more, but his comment was it was too much lock up. You have to have different driving style to make use of it, and lap time did not go down. I tried that same one, and thought it made the car understeer too much when it engages. Going to try that at some lower traction track. Maybe at Inside Line over Christmas.

Phil decided to go with a conservative locking ratio for the rollout. This one is straight forward and simple both manufacturing, cost and operation. Is not as much locking as possible, but it will not compromise drivability either. I think as Phil get feedback from racers in different tracks, he will want to try different locking rations. Maybe even 1.5 way or 2 way locking.

Good thing about this one is it disengages very quickly every time, and is consistent. Is also pretty transparent in the car. In a side locking type, the concern is that the ball wants to roll itself into the wedge. It may be more hesitant to disengage depending on how steep you make the ramp.

But, if it turns out that people want more locking ratio, you can probably work around the issues with a side lock by carefully changing the angles and other dimensions. It will take some more testing. If some people want close to 100% lock, then the configuration that Grant tried could be better still. It unlocks relatively quickly. The only way to know is to keep testing. Numbers and theory will only tell you so much.

pedrocamp
2009.11.18, 04:31 PM
Thanks for your detailed reply. I would expect power on push with a "spool". Be interesting to try in the front of an AWD car though...

hcw0zone
2009.11.24, 05:12 AM
* Thanks!!! PN Racing........

* my car specs are...

MR02 2.4G
PN double a-arm
PN ceramic ball diff
PN dual center shock
PN Multi Length Graphite Disk Damper....

color01
2009.11.28, 07:00 PM
So, as promised I've got a drive on the new spur gear, and although there are some setup issues that need to be worked out, I think this part has potential.

This spur gear definitely locks in the rear end better under acceleration, but it's a relatively mild effect that won't throw off your cornering line. If I needed more rotation, I mashed the throttle harder to rotate the car -- since the diff tightens up under acceleration you get a nice little power oversteer that will put you right back on the line. For some reason, I couldn't get this gear to work with 5 balls, it seems to like 10 balls and with sufficient amounts of grease (fill up the grease wells). After that you can run the diff nut looser than you would normally, since the balls are spaced out more = more torque handling capability. Because the balls are spaced out more though (and the gear itself is a bit heavy), Cristian was right in that this spur gear makes the diff a little slower to spool up or slow down, so turn-in is slightly reduced compared to what I prefer to drive with. Because there's also more traction on the corner exit too, though, the entire car feels too mellow and pushes more than what I think would net the fastest laps.

So, I'll have to change my setup to suit the spur. I'm thinking a one-step softer front tire, maybe PN15's instead of 20's. Then stiffen up the (rear) top spring for a bit more steering sensitivity, and go heavier on the damping to make up for that. That should get the turn-in and exit behavior to be where I want it, and I'll find out if high-speed cornering improves or suffers. Will let you guys know the next time I have a chance to test. ;)

yasuji
2009.11.28, 08:17 PM
fyi....with the std dif grar i run all 10 balls.... with the new gear i run all 10 balls!....
so for me i feel more punch and better accell with this gear with much better diff action!
if i run 5 balls in the std gear i would not be able to drive it....:p

yasuji
2009.11.28, 08:28 PM
ill try 5 balls again......i think ill be able to WHEELIE my pancar.....lol

Samael76
2009.11.29, 04:13 AM
So this one works better with 10 balls instead of 5?

color01
2009.11.29, 09:31 AM
It doesn't make too much sense to me, but tentatively, "yes". I'll try it again with 5 balls after a proper rebuild and see if I was just doing something wrong the first time.

tudor_47
2009.12.04, 05:18 AM
I was installing this last night and noticed that the balls are further out from the axle in this spur... I am a bit concernec as I am not running the PN diff-plates and the balls is right there at the edge of the plates...

I found a set of PNplates and the are somewer around 16mm in diameter and the atomic are 15.4 or 15.5..

So is there a problem running the atomic plates? the balls are inside, but not more.

color01
2009.12.04, 05:45 AM
I'm using the Kyosho pressure plates, I don't know the exact dimensions but I'm sure the Atomic plates are not noticeably smaller. You should be able to use them just fine. ;)

I got my proper rebuild done using 5 balls instead of 10 -- for stock-FET motors, I think this is the way to go. I complained before that there was too much mellowness after switching to this spur, but taking out 5 balls did the trick! The reduction in rotating mass helps the car spool down and up just a tiny bit faster, for more aggressive behavior, and the diff is noticeably freer than any previous that I've built. The slight LSD effect coming out of corners isn't needed, per se, but it does bring the tightness back to normal levels. I'm currently using this gear not so much for the LSD effect but rather for the freer diff I can build with it.

10 balls on low grip is not a great idea, as we've observed in the past. The diff will lock up as soon as you hit the gas hard enough, and the resulting powerslide is not conducive to fast laps (fun though).

Felix2010
2009.12.04, 07:47 AM
Color0 (And others),

I too noticed the radius of the diff balls has been moved out significantly on the new PN L-S 64p spur gears. I heard from someone the Kyosho ball diff pressure plates (MZW206-3) work alright, but to me the balls look like they run dangerously-close to the outer-edge of the plates. What is your take on this color0? Have you noticed anything weird going on with your diff?

What about when you take-apart the diff and check the plates - Could you please tell me if the "groove" that the balls create runs-off the outer-diameter of the K pressure plates? If the groove runs out to the very-edge of the plates this would cause concern about running this combination spur + pressure plates.

With all the info/tech/new-parts with regards to building the best ball diff possible nowadays, I would not want to risk the chance of have the diff balls running on the outer-edge of the pressure plates. This could cause plate damage and possibly failure (Which always seems to happen at the worst possible time i.e. racing:().

Any updates would be very helpful! Thanks!:D

For now, I'ma stick to using the PN L-S spurs with the PN-MR2045 or PN-MR2047 ball diff, just to be safe. If I can get more info on how the K-plates (And other plates as well, such as 3R,Atomic,etc) perform with this spur, I will rebuild a diff and give it a try.

JuniorWKR
2009.12.04, 11:31 AM
ran mine during a race night for the first time last night and absolutly loved them... i have one on my 03 stock and one on my 03 mod.... both with qtec diffs and they are absolutly amazing... the spur gear definitly favors the on power driving style but will work well with anyone...

the balls work just fine with the kyosho rings and do not run over the edege... i checked the groove last night as i was curious myself... though it is close...

the one thing i must say is that i cannot run that spur with diff grease (i found that the diff grease would keep the balls hung up in the locked position)and use liquid teflon oil made by tri flow (can find in any bicycle shop) (wd40 or 3 in 1 oil also works just as well)... when i went to the oil it made the off power transition much faster and tremendoulsly dropped my lap times... i believe that with this spur you are able to run the diff just that slight bit loser which gives greater rotation through the infeild... that spur gear on my qtec diff spins like a gear diff...

what makes this set up so nice is with the balls being so far out and using the oil there is never a need to rebuild the diff... only when the rubber pressure washer is in need of replacing... after each race i simply spray the diff down with motor spray... spin it up and reapply the oil...

great job pn....

Just a sid enote as i know we had some confusion in our shop... the teardrop for where the balls are placed goes to the rear of the car... so imagine when power is applied to the diff that you would want the balls to be squeezed into the smaller portion of the opening...

lfisminiz
2009.12.04, 06:54 PM
Just for reference, i think so you know the right way to put spur on.....theres a 53 or what ever spur you got that faces out on the diff. Is that right?

lfisminiz
2009.12.04, 06:55 PM
To continue...the # is stamped on 1 side of the diff only.

Tjay
2009.12.04, 07:17 PM
that spur gear on my qtec diff spins like a gear diff...
You're definitely right about that. Might felt exactly the same! Let me dig up the vid I took when I first got this spur to test...


what makes this set up so nice is with the balls being so far out and using the oil there is never a need to rebuild the diff... only when the rubber pressure washer is in need of replacing... after each race i simply spray the diff down with motor spray... spin it up and reapply the oil...

Are you serious? Oil? How about just applying grease on just the balls instead on the plates?

Tjay
2009.12.04, 07:18 PM
^ umm... I can't edit. This is was I meant..

that spur gear on my qtec diff spins like a gear diff...

You're definitely right about that. Might felt exactly the same! Let me dig up the vid I took when I first got this spur to test...

pfcparts
2009.12.04, 08:36 PM
Bought two of the 53t to try on the F1s, but also bought
a set of PN diffs in case they didn't work on the F1 or didn't
play well with other diffs.

Long story short, they won't work on the F1s due to ridges
touching the F1 tires (took a while to figure it out lol) and
I thought they worked fine with the PN diffs with 5 balls...

Thought that they seemed to have a tendency to stick
as well, but I have been using K grease, so will try out
the oils mentioned instead. That and I usually run the
PN diffs tighter than other diffs.

015 rx7 does seem to have a bit more pep off the line,
but I did change to the lighter shaft as well... Did
notice some pulling, but it might be tweak from a long
storage.

Hoping to get the same results with oil though. :eek:

Still iffy on it, but hope to get it cleaned and set up
correctly this weekend with the oil tip here.


parts

color01
2009.12.04, 09:06 PM
I too noticed the radius of the diff balls has been moved out significantly on the new PN L-S 64p spur gears. I heard from someone the Kyosho ball diff pressure plates (MZW206-3) work alright, but to me the balls look like they run dangerously-close to the outer-edge of the plates. What is your take on this color0? Have you noticed anything weird going on with your diff?
The groove goes all the way to the edge of the plate just before it "rounds off" the edge -- you have to be careful which way you orient your plates, if you have the more-rounded-edge side facing the balls, the balls will indeed be riding on the rounded edge and you'll be in trouble. The other side, however, is flatter, and that works perfectly fine.

What about when you take-apart the diff and check the plates - Could you please tell me if the "groove" that the balls create runs-off the outer-diameter of the K pressure plates? If the groove runs out to the very-edge of the plates this would cause concern about running this combination spur + pressure plates.
The groove almost reaches the edge on the sharper-edge side of the pressure plates -- there's maybe 0.3-0.5mm left, it's very close but not dangerously so since the plates and spur are all bearing-supported. I'm not too concerned about the function, but rather, the exposed balls do allow dust to get in and grease to come out. Dust getting in doesn't seem to be a problem -- the diff remains smooth after several runs -- but grease coming out is definitely a symptom of the smaller pressure plates.

With all the info/tech/new-parts with regards to building the best ball diff possible nowadays, I would not want to risk the chance of have the diff balls running on the outer-edge of the pressure plates. This could cause plate damage and possibly failure (Which always seems to happen at the worst possible time i.e. racing:().
The one thing I would not do with this V2 spur is to run Reflex's thin pressure plates. Yes they're light, but the thinner plates can flex more, which could be a very bad thing when combined with the smaller Qteq diff hubs and the V2 spur. I could definitely see plate warping or failure in that instance. But the standard Kyosho plates are thick enough, and the PN plates are most definitely thick enough (and larger in diameter so this would be a moot point).

If I can get more info on how the K-plates (And other plates as well, such as 3R,Atomic,etc) perform with this spur, I will rebuild a diff and give it a try.
Do it, now. ;)

Felix2010
2009.12.05, 07:15 AM
Thanks for all the help color0. You truly are a gentleman and a scholar :D(This is something my dad always says to me, it is meant to be funny, but also serious at the same time. Just to be clear, I know how things can get misinterpreted when writing rather than when actual speaking to someone):)

Do it, now. ;)

Yes sir!!!!:D:D:D

BTW - I just built a diff with Qteq hibs and K plates, but I know for a fact that I glued the plates with the rounded-edge facing the balls... :( That side just came out better after sanding them.... Oh well, there's always another diff to build in this game... Or my PN MR2045 diff.

Thanks again for all the help my man!!

JuniorWKR
2009.12.05, 10:18 AM
will have to check.. didnt reference it to the placement of the number on the spur... all i know for certian is the teardrop haas to be towards the back... so when the diff spins the tires foward it locks the balls into the smaller part of the opening for the balls...

JuniorWKR
2009.12.05, 10:25 AM
Are you serious? Oil? How about just applying grease on just the balls instead on the plates?

yes... all of the guys at MHS are now running oil instead of any form of grease on the diffs... it makes for a smoother faster cleaner diff... its easy to just spray with motor cleaner, spin the tires with your remote(and watch all the dirt come out) and reapply the oil...

the three major oils being used at this time are
1. tri flow with teflon
2. 3 in 1 oil
3. wd40

my only choice would be the triflow with teflon... but the other guys are having success with the other oils too...

try it... i dont think yoiu will be disapointed... and the luxury of never having to rebuild the diff again every time you regrease it will make life alot simplier too..

i have also heard of guys out there running dry graphite on their diffs... i have not yet tested this theory but will when i get the channce...

Davey G
2009.12.05, 11:38 AM
All the guys?? Sorry Junior....I completely disagree with this. I definitely am not running oil. I use AE or Trinity Silicone diff lube.

CristianTabush
2009.12.05, 12:26 PM
I second Davey... Running oil is not sufficient to provide consistent differential action. Given that ceramic balls are self- lubricating sort of, is the reason why oil might seem like enough, but it is not really good enough. Silicone diff lubes are engineered to aid in smoother and more consistent engagement and also to keep the dirt out of your rotating parts. With as light of lubricants as you guys are using, you are essentially running "dry diffs". The problem with this is that they actually get dirtier. RCP and tire dust will actually stick to the balls and rings easier.

I use silicone diff grease, either Kyosho or our new light diff grease and probably re-build my diffs after like 3 months. I re-build them more often because I am trying a different spur gear or gear ratio combination...

color01
2009.12.05, 05:46 PM
Slightly off-topic I guess, but related: how light of silicone lube is it OK to use? Ever since I ran out of diff grease I've been using the same 1000wt silicone lube that goes in my disk damper. It's no grease, but it is thick enough not to sling off the balls. I wonder if there were be any improvement in cleanliness or diff longevity by using a thicker grease.

Felix2010
2009.12.06, 07:12 AM
I am with Davey and CT - I thought one big reason for using a ball-diff-specific silicone grease was that under operating pressure, with anything less the viscosity of the oil/grease will break-down to where the diff balls will have no lubrication between the pressure plates. With the right viscosity grease, there is a micro-layer of grease that stays on the plates and balls, even if you can't see it, it kind of bonds between them and keeps things running nice and smoothly.

In the diff tutorials out there, it seems more common now to not soak the plates and balls with grease, but instead just use enough grease to completely coat the balls. After a short break-in period, the diff action should be consistent.

The idea of using oil is interesting, I can see how too-much grease can affect the diff action with the new PN LS spur. But I am going to try to get this spur to work with grease.:D

CristianTabush
2009.12.06, 11:52 AM
Slightly off-topic I guess, but related: how light of silicone lube is it OK to use? Ever since I ran out of diff grease I've been using the same 1000wt silicone lube that goes in my disk damper. It's no grease, but it is thick enough not to sling off the balls. I wonder if there were be any improvement in cleanliness or diff longevity by using a thicker grease.

It is really your choice. It is actually a tuning option as well, the lighter the grease, the lighter the engagement of the differential. I would not go much lighter than 1000 though as it will simply sling off the first time you hit the gas. Like Felix said though, silicone does seem to bond to the surface and form a film over the parts that helps keep everything running smooth.

In many cases though, the greases actually have fillers in them, such as fiberglass dust that helps and aids in the engagement of the parts. This at least is the case with "Differential Lubes" such as Associated Stealth Grease, Reflex Diff Grease and Kyosho differential grease. Without these fillers, they are merely called "silicone grease" and not differential grease (notice Atomic for example, has both and they look almost the same).

briankstan
2009.12.06, 02:02 PM
in regards to where the balls run on the diff. I took a picture so it's clear that the balls run right along the outside of the plates.

this is with the Kyosho Diff plates. as you can see the balls are visible at the edge. it this ok, anyone notice any ill effects of it?

http://mini-zracer.com/forums/attachment.php?attachmentid=28629&stc=1&d=1260126077

color01
2009.12.06, 02:19 PM
In many cases though, the greases actually have fillers in them, such as fiberglass dust that helps and aids in the engagement of the parts. This at least is the case with "Differential Lubes" such as Associated Stealth Grease, Reflex Diff Grease and Kyosho differential grease. Without these fillers, they are merely called "silicone grease" and not differential grease (notice Atomic for example, has both and they look almost the same).
You learn something new every day. :) Thanks for this tidbit, Cristian, the filler seems like a very good reason to get myself a refill of diff-specific grease.

lfisminiz
2009.12.06, 03:58 PM
Well BrianK.....thats how mine all look. The little running ive done so far, they run well. But ill let the experts chime in on this. I would like to know too.;)

JuniorWKR
2009.12.06, 04:06 PM
has anyone tride f1 plates yet? they are larger... was eying it up on my f1 and i think they will fit.. if they do they should cover the entire ball

EMU
2009.12.06, 04:37 PM
The Inside Diameter of the F1 plate is different than the MR02 plates. Therefore, it wont work well with an MR02. I forget if its larger or smaller. Either case, it wont work. If its smaller, it just wont fit. If it is larger, it wont be balanced even if you glue it to the diff half.

egonzalez
2009.12.07, 03:11 PM
I am with Davey and CT - I thought one big reason for using a ball-diff-specific silicone grease was that under operating pressure, with anything less the viscosity of the oil/grease will break-down to where the diff balls will have no lubrication between the pressure plates. With the right viscosity grease, there is a micro-layer of grease that stays on the plates and balls, even if you can't see it, it kind of bonds between them and keeps things running nice and smoothly.

In the diff tutorials out there, it seems more common now to not soak the plates and balls with grease, but instead just use enough grease to completely coat the balls. After a short break-in period, the diff action should be consistent.

The idea of using oil is interesting, I can see how too-much grease can affect the diff action with the new PN LS spur. But I am going to try to get this spur to work with grease.:D


I have been using 3n1 oil on my diff for months and I have had very good success as far as diff action is concerned. I'm not as good as some racers that have previously posted, but it definitely works for me. Now, If I could only find an oil to put on my hands that would make me a better driver?:D

CristianTabush
2009.12.07, 03:21 PM
I have been using 3n1 oil on my diff for months and I have had very good success as far as diff action is concerned. I'm not as good as some racers that have previously posted, but it definitely works for me. Now, If I could only find an oil to put on my hands that would make me a better driver?:D

Just because something is "good enough" does not make it the best alternative. We are just trying to point you guys in the right direction...

JuniorWKR
2009.12.07, 04:11 PM
i have always used the associate diff grease and just on the balls... but always found the diff to be slow and inconsistent from the start of the race to the end... and especially with the 64p limited slip spur i found the grease would keep the balls from disengaging to long... when i went to the oil and again i use oil that has teflon in it same as you would put in your cars engine it creates a very fine coat of protection oneverything... that along with the ceramic balls which are supposed to be self lubricating but i dont know if they are have been giving me the best results... when i built my qtec diff with pn light weight shaft and limited slip spur i drop 2 tenths off my mean and over 4 tenths off my hot lap... i could never break 10. 5 on our current layout and now with this set up of the diff being the only thing i changed on the car i hitting 10.1's... i dont know if im doing anything wrong but i just cant get the same performance outta grease.... whenever i used grease and i would rebuild my diffs i always had these crusty black grooves on each side of the tplate so i know as they grew on the plates it would effect the ball rotation.... i have never gotten this with the oil...

i can only say that i have only ever used the associated grease and have never tried yours... that may be a reason also.... but until i can get the same performance outta grease as i do with oil im gonna have to stick with the oil...

CristianTabush
2009.12.07, 04:27 PM
As you are entitled to do so, but anywhere you go with any car, any RC car company will use silicone lube and not teflon oil or 3 in 1, there is a reason for this. From my impression it seems like you are using too thick of lube, since the light stuff is what is working best for you. Try breaking in your diff before hitting the track by holding each wheel (one at a time) for 30 seconds while hitting about half throttle. This should sling out the excessive grease that is giving you the inconsistent behavior on you car before you hit the track. If you are not doing this, you are sending a fresh diff, packed full of grease to a dirty RCP Track. Naturally, the dust will stick to the grease and create a dark black paste as you have been experiencing, which will definitely make the differential act erratically.

Personal recommendation to those of you using the spur out there, is to not worry about the "reservoirs" for lube. If it is to thin, it will seep out and go everywhere, if it is too thick, it will build a nasty paste inside the actual differential. If the diff was actually sealed, they would be very useful, but unfortunately they aren't.

egonzalez
2009.12.07, 04:28 PM
Just because something is "good enough" does not make it the best alternative. We are just trying to point you guys in the right direction...

I appreciate you pointing me towards the right direction and everything the you do for the miniz community. That being said, I not saying this is the best alternative.... All I'm saying is that it works for me. That's why we visit this forum to see different perspectives and opinions. In other words, I'm not arguing nor do I disagree with you, just sharing my opinion.

JuniorWKR
2009.12.07, 04:49 PM
contact Maj and send some of your diff grease to MHS... he orders alot of stuff from you and im sure he would defintly stock some of your diff grease...

i will definitly give it a shot as there is no harm in trying something on these cars... i will do everything you stated to do.... on grease the balls and break the diff in before it hits the track...

CristianTabush
2009.12.07, 11:52 PM
I appreciate you pointing me towards the right direction and everything the you do for the miniz community. That being said, I not saying this is the best alternative.... All I'm saying is that it works for me. That's why we visit this forum to see different perspectives and opinions. In other words, I'm not arguing nor do I disagree with you, just sharing my opinion.

I totally understand you are not trying to argue, so no sweat. Forums are for discussions and sharing ideas. Sometimes things come across a little different because we are not face to face, but I think everyone on these forums is very polite and proper in the way they handle themselves...

Junior, let Maj know that you want it stocked ;)

Felix2010
2009.12.22, 10:36 PM
I have been running one of these new PN Limited-Slip spurs on my PN MR2045 ball diff, and I have to say these spurs are excellent. They engage very nicely, the "locking" action isn't overstated at all, it is just enough to push the car straight when going harder on the throttle. The wide teeth are super-smooth too, especially when I used a PN machine-cut 64p pinion.

Great stuff PN. I will be swapping this diff into whichever car I am driving:D:D

LED
2010.04.03, 02:02 AM
Hi Huys I need some help figuring this out..
I want to test this spur but I also need a little more on power steering mid corner.
Is it a smart idea to put this on then?

From what I found so far they say you need to thigthen the diff for more on power steering mid corner, but then again if it locks isnt the car trying to go straight then ?

Thx

color01
2010.04.03, 04:24 AM
You should probably use other adjustments to give you more midcorner steering while relying on the increased traction of the PN spur for the corner exit. The spur definitely induces a little bit of understeer/traction on power so you shouldn't think of using the spur solely for increased on-power steering -- you typically won't get that result.