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Discussion Starter · #1 ·
Since I fitted my ball diff, there seems to be a lot of resistance or friction in the driveline, how tight should they be? if i lift the car off the ground and put it on full lock at high throttle, it makes a wierd chugging noise like something is rubbing, but the wheels and dogbones etc are clear.


And the car doesnt seem to roll as well as it used to
 

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Ball diff has absolutely no participation in your drivetrain, so it shouldn't affect it at all. Chances are you've probably just built your car back differently... is your belts now "guitar-string" tight??






Forgot to tell you earlier... the ball diff kit comes with 2x 850 bronze bushings right?? You should replace these with bearings.
 

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Discussion Starter · #3 ·
They are both brand new belts.


The front diff went to the back, and the ball diff in the front


there is a little bit of rubber tube that goes in the drive cups, you have to cut it to length, one longer and one shorter.


the cups themselves have the screw in them, and i think that is why one is longer than the other cost one of them has the nut for the screw, but now the dog bones seem really tight, could that be the problem? tamiya have specified the lenghts in the instructions and i cut them to that lenght, but maybe the rubber tube is too long??


what about the chugging under lock? could the diff be causing that? or would it be more likely electrical drain on a flattening battery caused by the servo?





yes I was wondering about those metal bushings and why there wasnt bearings there instead....
 

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Discussion Starter · #4 ·
Also on the Diff, you cant spin the wheels like the gear diff. With the gear diff you spin a wheel (car off the ground) and the opposing wheel spins the opposite direction.


With this ball diff, it is a lot harder to turn the wheel (more resistance) and the opposing wheel seems to rotate the same direction, does this mean i need to loosen the screw inside?
 

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Discussion Starter · #5 ·
Also it seems to have a pull to the right under power yet tracks straight off throttle...





very wierd
 

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azenis said:
Also on the Diff, you cant spin the wheels like the gear diff. With the gear diff you spin a wheel (car off the ground) and the opposing wheel spins the opposite direction.


With this ball diff, it is a lot harder to turn the wheel (more resistance) and the opposing wheel seems to rotate the same direction, does this mean i need to loosen the screw inside?

no no no!



Ball diff is RC's Limited Slip Diff (LSD); that just means its working fine!!


Ball diff will stop your car "diffing out" in corners, when your inner wheel slips and you lose all drive.


How tight your ball diff is will affect your corner handling too; that's why its best to have 2 (to allow adjustable F/R diff balance) or none at all.


(nb at MINIMUM TIGHTNESS, your balls mustNOT be slipping on the rings even at full throttle.)
 

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Discussion Starter · #7 ·
Ahh cool, thought it may have been something like that... damn another $50 to spend on the car for another diff doh!!


nothing worse than having balls slip i know.... ;)


how do i know when they are slipping on the rings at full throttle though?
 

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azenis said:
They are both brand new belts.

that's the cause of your extra drag then!



there is a little bit of rubber tube that goes in the drive cups, you have to cut it to length, one longer and one shorter.

Don't need the rubbers if you use unis.






Just received parcel of TA04-compatible CVD unis today... they look very good, rebuildable too. Machine work is pretty good, nice & smooth.


I bought some extras just in case anyone else wanted some too. Would cost just A$25/pr *posted*.





what about the chugging under lock? could the diff be causing that? or would it be more likely electrical drain on a flattening battery caused by the servo?

What's the frequency of the chugging?


If its once per rotation of your wheels, then check the dogbones.


The belts can also be formed into their bagged shape, give them time to recuperate.


On occasion your layshaft can also get bent... your spurgear might be changing mesh as it turns. Don't try bending the kit one back straight (snap!), just buy the hopup hard one.
 

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azenis said:
nothing worse than having balls slip i know.... ;)

Raw naked balls sliding on cold greased steel... ewwww!



how do i know when they are slipping on the rings at full throttle though?

jam the 2 outdrives with 2 flat screwdrivers as levers, then try turning the center pulley with your hand.


You should not be able to turn the pulley against the outdrives at all, otherwise its too loose.
 

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Discussion Starter · #10 ·
So it should loosen up as the belts stretch a bit?? I dont remember it being this tight when it was new, but maybe its to do with the "low friction belts?"


Yes the front one is about as tight as a guitar string...


Tell me about these Unis you have, are you selling them? $25 posted a pair is sounding good, are they the same for front and back?? Why dont you need the rubber tube when you have them?


The chugging may be the dogbones more than the belt or layshaft as it only happens when on full lock, if the wheels are straight ahead it doesnt do it. I will check the frequency when my batteries are recharged :)


Can I test the ball diff for ball slippage without removing it from the car?
 

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azenis said:
So it should loosen up as the belts stretch a bit?? I dont remember it being this tight when it was new, but maybe its to do with the "low friction belts?"

no, its just how you rebuilt the car. If you know what to look out for (hard to explain in words) you can build the TA04 to have loose front belt or very tight.


Don't worry, it should sort itself out after you've run it a bit and hit a few kerbs.





Tell me about these Unis you have, are you selling them? $25 posted a pair is sounding good, are they the same for front and back?? Why dont you need the rubber tube when you have them?

Bones are loose and can move, you don't want them falling out when they move too far... thus the rubber spacers. Unis are fixed at the axle end, so they aren't going anywhere.


Yep, $25 posted.I bought them just to see what quality they are... pretty good! I got some extras just in case anyone else needed them. (otherwise I'm told that place charges a bomb in 'handling/postage' if that 1 tiny item is all you're buying.)





Can I test the ball diff for ball slippage without removing it from the car?

yeah, grab & jam the belt whilst you try and turn the wheels together same direction...
 

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Discussion Starter · #12 ·
The diffs sit in bearings that sit in cups in the gear case, the layshaft sits in bearins in a hole, i cant see how it can go together differently?


anyhow it would explain things... car seems very slow to what it was :(
 

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The main clue is with how you screw on the top plate. The hard bit is making it stay that way once you are running.
 

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Discussion Starter · #14 ·
bl00dy hell im about to get rid of this car for a shaft driven car i have just started to kill another rear drive belt!!! BRAND NEW TODAY!!!!!


pulled the car in to check it and it smelt funny and i looked at the rear belt there is all this powder and then i notice the middle of the outside of the belt is wearing down toward the teeth





NOT HAPPY JAN
 

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Discussion Starter · #15 ·
zoomer said:
The main clue is with how you screw on the top plate. The hard bit is making it stay that way once you are running.

so it is in effect flexing the chassis in like a bananna?
 

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azenis said:
bl00dy hell im about to get rid of this car for a shaft driven car i have just started to kill another rear drive belt!!! BRAND NEW TODAY!!!!!


pulled the car in to check it and it smelt funny and i looked at the rear belt there is all this powder and then i notice the middle of the outside of the belt is wearing down toward the teeth

What's going on???


There must be something seriously wrong there.


If you lived uphere I'd offer to give it a look over....
wanna post it over?



All my 04s don't chew belts like that.





Maybe take some pix of the rear gb.
 

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Discussion Starter · #17 ·
yeah will get some pix when i pull it apart AGAIN. flamin thing didnt last a whole battery pack!!!!





Time for the XRAY i think.....
 
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