Couple of questions

[fearo]

Well I got my car up and running, thanks to some of you guys suggestions on my diff problems, thanks!

However, with finding a solution for one question, comes a couple of new questions :D.

first thing, i set up the slipper meticulously and so far it's going great, but there's one thing i've never found the answer too: How do you know if the diff is tight/loose enough. Right now the diff is tightened about 1/2 turn from max, and I setup the slipper from there. Should I try loosening the diff some more or would it be best to leave this be?

Secondly, a motor/power question. I run a Team Orion 3900kv motor with a sensorless ESC, gearing 24/80. The motor does not 'cog' or anything. When I hit the throttle from 1/4 to full, it accelerates perfectly...
BUT: When I hit the throttle like 1/8 of the way (car barely moving), the car makes a weird trembly/stuttering sound. Is this normal, or is this a sign from something that's not right? Overgeared? Diff too tight?

Thirdly, I started reading up on gear mesh between the spur and pinion. At first, because I'm a complete newbie, I had the pinion and spur crammed onto each other as tight as possible. Now I've done the 'paper trick' and also listen to the sound of the car, when placing the pinion further away from the spur. I think I found a good solution, but I've noticed that the car does 'rattle' a bit if I stop accelerating and the car nearly comes to a halt. Again, is this normal?
Thanks, guys.

[Benjab]

I saw this a few days ago:

http://www.oople.com/forums/attachment.php?attachmentid=15476&d=1280086520

http://www.oople.com/forums/attachment.php?attachmentid=15477&d=1280086520

I have not tried any of these methods because i havent bought a macnum or madnrat yet

[sosidge]

Well I got my car up and running, thanks to some of you guys suggestions on my diff problems, thanks!

However, with finding a solution for one question, comes a couple of new questions :D.

first thing, i set up the slipper meticulously and so far it's going great, but there's one thing i've never found the answer too: How do you know if the diff is tight/loose enough. Right now the diff is tightened about 1/2 turn from max, and I setup the slipper from there. Should I try loosening the diff some more or would it be best to leave this be?

It's important that the diff does the diffing and the slipper does the slipping. Best way to get the setup right is to crank the slipper right down to start with, then hold the spur and one wheel in one hand (takes a little contortion!), and try and turn the opposite wheel with the other. There should be no slip unless you apply a significant amount of force. Adjust by 1/8th turn at a time if needed.

The diff should also turn smoothly in normal use - so if you just hold the spur and turn one wheel, the opposite wheel will rotate smoothly.

With the diff sorted, time to set the slipper. Individual preferences vary, I back it off just enough to stop the nose lifting up too easily in normal running, 1/8th turn at a time.

Secondly, a motor/power question. I run a Team Orion 3900kv motor with a sensorless ESC, gearing 24/80. The motor does not 'cog' or anything. When I hit the throttle from 1/4 to full, it accelerates perfectly...
BUT: When I hit the throttle like 1/8 of the way (car barely moving), the car makes a weird trembly/stuttering sound. Is this normal, or is this a sign from something that's not right? Overgeared? Diff too tight?

That IS cogging ;). Only real solution is to run a sensored system.

Thirdly, I started reading up on gear mesh between the spur and pinion. At first, because I'm a complete newbie, I had the pinion and spur crammed onto each other as tight as possible. Now I've done the 'paper trick' and also listen to the sound of the car, when placing the pinion further away from the spur. I think I found a good solution, but I've noticed that the car does 'rattle' a bit if I stop accelerating and the car nearly comes to a halt. Again, is this normal?
Thanks, guys.

A good mesh will sound smooth. I set it by backlash, you should just be able to rock the spur back and forth a fraction of a mm before it engages with the pinion.

[fearo]

It's important that the diff does the diffing and the slipper does the slipping. Best way to get the setup right is to crank the slipper right down to start with, then hold the spur and one wheel in one hand (takes a little contortion!), and try and turn the opposite wheel with the other. There should be no slip unless you apply a significant amount of force. Adjust by 1/8th turn at a time if needed.

The diff should also turn smoothly in normal use - so if you just hold the spur and turn one wheel, the opposite wheel will rotate smoothly.


First of all, thanks for taking the time to answer this! As it sits now, when I hold one wheel and the spur, it takes a significant amount of force to turn the wheel. When it finally does move, the slipper pads do too, so that sounds good?
BUT: what you said about the diff turning smoothly in normal use is interesting, and to be honest I'd never tried just holding the spur and turning one wheel. When I do that I DO feel a little interference in the rotation of the other wheel. Should I loosen the diff until this goes away?


That IS cogging ;). Only real solution is to run a sensored system.

I thought cogging was a certain hesitation when applying the throttle, even if you whacked it on full throttle? Because like I said, it only does that when I'm applying a minimal amount of throttle.



A good mesh will sound smooth. I set it by backlash, you should just be able to rock the spur back and forth a fraction of a mm before it engages with the pinion.

i set the mesh while applying some throttle and then moving the motor back and forth. there is a fraction of a mm between them, like you described. It's probably that 1/2 mm of 'play' that I hear when the car almost stops?

[fearo]

Sosidge? Anyone?

[Battle_axe]

Sorry fero I didn't see your post

The diff setting seems about right as for the slipper you want it to slip before the diff and only really for the first 2 feet of the car moving

You are getting cogging from your esc try gearing down a little but don't worry to much

As for half a mm backlash that sounds too much you really want the smallest amount possible

[fearo]

Thanks battle_axe.
Should I loosen the diff until wheel 2 turns freely when I hold the spur and wheel 1? Right now the rotation of wheel 2 isn't that smooth when I try this trick.

[sosidge]

Thanks battle_axe.
Should I loosen the slipper until wheel 2 turns freely when I hold the spur and wheel 1? Right now the rotation of wheel 2 isn't that smooth when I try this trick.

I think you are missing the distinction between diff and slipper adjustment. Carefully re-read my earlier post and the two documents linked to by Benjab. That really is all there is to it.

[fearo]

No no, I understand what you meant, it was a typo! I meant to write: 'should I loosen the diff...' (I edited my earlier post)

The thing is, I know how the slipper works, I know how to set it, and I know how it reacts in my madrat. What I'm asking here is if my diff is too tight. Right now it's a half turn from fully cranked, and the 2nd wheel does not turn smoothly when I hold one wheel and the spur.

[sosidge]

No no, I understand what you meant, it was a typo! I meant to write: 'should I loosen the diff...' (I edited my earlier post)

The thing is, I know how the slipper works, I know how to set it, and I know how it reacts in my madrat. What I'm asking here is if my diff is too tight. Right now it's a half turn from fully cranked, and the 2nd wheel does not turn smoothly when I hold one wheel and the spur.

Does it slip?

The diff should neither slip nor be tight in its action. If you can't acheive both at the same time, the diff probably needs careful rebuilding.

[fearo]

I think it probably does slip a little. I am going to loosen the diff a little until it moves freely and then set the slipper accordingly. I will post back with the result. I just rebuilt the diff a few days ago very carefully, so that's not the problem.

[fearo]

well.. I'm really confused. I set up the diff and slipper for the 1000th time, and it all seems fine BUT, I can't get the second wheel to rotate smoothly when I hold the spur and turn one wheel. It gives a very harsh feeling which only goes away when I turn the diff WAY WAY loose.

Any help?:(

[Battle_axe]

Sounds like the diff is built wrong I will post back in a second with a link to my post on how I build mine

[Battle_axe]

Here you go fero http://www.oople.com/forums/showpost.php?p=392866&postcount=4

[sosidge]

well.. I'm really confused. I set up the diff and slipper for the 1000th time, and it all seems fine BUT, I can't get the second wheel to rotate smoothly when I hold the spur and turn one wheel. It gives a very harsh feeling which only goes away when I turn the diff WAY WAY loose.

Any help?:(

I don't like to tell people to read my original posts twice in one day, because it makes me sound like an arse, but here goes... as I posted earlier...

The diff should neither slip nor be tight in its action. If you can't acheive both at the same time, the diff probably needs careful rebuilding.

To re-iterate - ALL parts should be in new, or known-good condition, and thoroughly cleaned. The main balls should be lightly smeared with clear silicone grease. The thrust bearing should be well packed with black grease. The diff should be set hand-tight on initial assembly, and adjusted in the car.

If all that is already the case, then it is probably simply the case that you cannot build a good diff with the Ansmann parts. There is probably some way of substituting Kyosho parts in there which will be of far superior quality (the Ansmann is basically a copy of the RB-5).