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  1. #1
    RC Competitor
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    Confused about Spur/Center Diff...

    So I was looking for a metal 54t spur gear to order and all I can find is metal center diffs from robisons ( which is what i would prefer ) but if something else exist i will consider.I ve read mixed reviews on using a slipper over center diff ( i think i said that right )..can some one help me out i just want something that wont break or strip.

  2. #2
    RC Competitor
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    No reason to have metal spur gears

    Stock traxxas 50, 52 or 54t work well

    Traxxas centre diff is good for 2s lipo only

    FLM (Fast Lane Machine) have one that is good for higher powered setups

    Centre diff varies torque between front and back under load

    Slipper is 50/50 split front to back

    Cheers
    Last edited by crusey_temp; 02-22-2011 at 12:06 AM.

  3. #3
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    People always say to keep the slipper for bashing and use the diff for racing, but I never understood why. Under what circumstances would the slipper actually be better, even when bashing? Seems like all else being equal you will always get the best traction using the center diff. Or do people just tell bashers to stick with the slipper since many/most bashers run 3s?

  4. #4
    RC Competitor
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    so what comes stock is just a spur gear, its not a center diff or slipper right? and probably the best thing for bashing is slipper, right ?

  5. #5
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    It comes with a slipper although I can't think of any situation in which a slipper is better than a true diff.

  6. #6
    RC Racer
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    Dec 2010
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    Texas
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    I agree with dsiomtw, what is the problem with using the center diff for uses other than track racing. The slipper (in 3s) almost makes the truck handle like it is 2wd and allows it to do wheelies very easily.

    Slipper in Slash 4x4 = Rustler

    Center Diff in Slash 4x4 = 4wd HPI Sprint 2 on-road car (excellent handling car)
    Rusty VXl
    Spartan
    HPI Sprint2 VXL
    Slash 4x4 PE

  7. #7
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    Jan 2011
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    solomon, kansas
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    The center diff with with 3s will not function as well as running it with 2s its just too much power for the center diff to operate right I think if u want high speed runs the slipper is the way to go if u want traction on a course or track the center diff is the way to go the flm center diff might to better idk for sure I don't a flm diff, I run the slipper for 3s I have ran the diff on 3s and broke the center diff but that's just me maby it works for other people on 3s just my 2cents
    Yes Castle Creations is in KANSAS

  8. #8
    RC Competitor
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    I'm pretty sure the flm diff or some other diff will hold up with 3s. I can't imagine one of the aftermarket companies not making one that will. I'm just starting to look into it now. Maybe someone with a flm or other aftermarket diff can chime in?

  9. #9
    RC Enthusiast
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    There is nothing inherently wrong with the Traxxas center diff. However, for best results you have to tune it according to your driving conditions and skill. The front and rear diffs must also be tuned at the same time. The whole drivetrain is really one system with many subsystems that all have to work together.

    Out of the box, the front and rear diff have a coating of heavy silicone fluid/grease (100k - 300k ?, Traxxas doesn't state the specs) on the gears. The center diff has a coating of 100k diff fluid on the gears, so that the case is only about 1/2 full. This combination is not really ideal for most conditions, but it has great potential for tuning.

    The point here is that for bashing, it is much easier to leave the front and rear diff as they are and simplify your tuning by adjusting a single slipper clutch nut. Tuning the diffs requires much trial and practice with various weights of diff fluid -- timely and costly. And if you over or under fill them your results will never be consistent. Over torque the bolts, pinch the seals, overfill and they'll leak. Using an aftermaket center diff won't change any of that. Lot's of precision maintenance involved. So, for everything but precision maneuvers (racing) the slipper clutch in combination with the stock front and rear diff specs has become the rumored best choice. It works, it's simple, there is far less to go wrong and break.

    If you're after straight-away raw power and speed on a hi-traction surface, lock down the rear diff and give it all the cells your motor and ESC will handle. For top speed what you really want is posi-traction and lots of room.

    On the other hand, if you want to drive hard in loose, rough conditions without spinning out, jump and land under power with control, and power up coming out of tight, dusty turns maintaining your track, then a tuned 3-diff drivetrain and a 2s lipo is the way to go.

    I've driven with the slipper installed with stock front and rear diffs, and with a tuned diff setup (7k front, 5k rear, 45k center). For bashing the slipper was fine. It was not nearly as refined on our local dirt track. The diff setup was far better, but I'm still tweaking the mix. Haven't broken anything yet, but that's not for lack of trying

  10. #10
    RC Competitor
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    You make some good points. But it seems like even with very minimal or no tuning a center diff is going to be better than a slipper for bashing. More traction is always good, whether you're racing or trying to climb the side of a hill and jump 20 ft in the air.

    Are you suggesting that the stock setup with a center diff, under bashing conditions, doesn't yield better overall traction than the simple 50/50 split the slipper provides?

    Your points are well taken. My point is that like I said, with very minimal or no tuning a center diff should still provide more overall traction under any conditions than the slipper, shouldn't it??
    Last edited by dsiomtw; 02-25-2011 at 10:11 AM.

  11. #11
    RC Enthusiast
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    dsiomtw,

    Before tuning my setup I tried it stock with the slipper and stock with the center diff. Adjusting the slipper for your current traction conditions is fairly easy and quick, and it does help to adjust it. Can't do any adjustments to the 3-diff setup without tearing down and rebuilding the diffs every time. But even without tuning, the 3-diff setup gave a better off-road experience.

    Keep in mind not everyone is looking for a real off-road experience, though. If you desire tire spinning, full throttle starts and wheelies on demand, you do not want a center diff. You want a very tight slipper clutch and stock front and rear diffs. My unofficial tackiness test: rubbing the diff grease/fluid between my fingers suggests that the diffs are preset to provide more power to the rear than the front (imagine that). But, if you want the best 4-wheel drive, off-road capabilities, you will want to use a 3-diff setup. The two setups are designed for different results. Both have there uses.

    JasonG,

    If it ain't broke, don't fix it.

    I'd stay away from metal spur gears. There is nothing wrong with the stock Traxxas gears: metal pinion and plastic spur. They are well designed and very durable. They mesh and wear against each other well and do not require lube. It's the preferred setup. Metal to metal requires lube which attracts dirt and sand that grind gears. Meshing metal to metal is trickier, as well. Every bit of metal you add, means more weight on an already hefty truck. Your stock gears will not strip if meshed correctly.

    For ease of maintenance and less parts to maintain and break, the stock slipper clutch offers good service. If you want a better off-road experience, give the Traxxas center diff a try. It's an easy and very affordable upgrade. If you didn't get one with your model, you can find very good deals on Ebay if you are patient. Don't upgrade just to upgrade, though. It's an easy trap. So many possibilities. Spend time having fun with your Slash. You will know when you have outgrown your setup.

    Good luck and enjoy.
    Last edited by cooleocool; 02-25-2011 at 09:01 PM. Reason: merge

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