Still trying to set mad rat diff
 

I've done some searching here and still cant get the diff set up correctly on my mad rat. I have major slippage issues.
I thought it was the slipper clutch at first, so tightened it full and was still getting slippage. I tightened the diff screw to the point where when i turn a rear wheel, the opposite one won't counter-rotate. I still have slight slippage with this set up I just can't find the sweet spot. I can't identify which noise is the diff and which is the slipper either. getting frustrated with this now.

It sounds like you may have everything too tight.

Firstly loosen the diff untill its reasonably smooth when you rotate the wheels.

The way I set the slipper is to take the gear cover off and then when sitting down hold the right rear wheel between your legs so it cant move.
Then hold the spur gear using your left hand and turn the left rear wheel with your right hand.

You need to set the slipper so that the layshaft turns around and the slipper slips.

If the wheel turns and the layshaft stays still then the diff is slipping and you need to loosen it off a bit more (the slipper)

Doing it this way also gives you a feel for how tight things really are, if its very easy to slip the diff then tighten it up a bit. If its very hard to make the slipper slip (even if the diff is holding) then you will need to loosen the slipper to prevent the car doing wheelies.. you may also want to losen the diff to make its action smoother.

If you have raced the car with the diff slipping you may need to replace the diff balls and plates as they might have worn out.. Im not a madrat expert but another member should be able to recomend parts to use (it might be better to upgrade these parts than use madrat ones)
There are also upgrades that can be done to the madrat slipper to make it easyer to adjust.

With a 6.5 motor you will want to slipper to be reasonably loose to keep the power on the track. Many "beginners" set there slippers too tight and then damage diffs.

Having just replaced the diff in mine I can almost be sure you have the same issue, broken thrust balls. If you remove the diff adjusting screw and the thrust bearing you can easily check them to see if they are all there or some have been crushed. The easy way out for me was to buy the complete B-Fast pro kit which is proving to be a much stronger bit of gear

http://www.bfastrc.com/tqracing.html

Here's the link for it, otherwise you could just get new thrust bearings and build the diff really carefully next time but meh, for the small price difference you might as well get the Bfast kit and be done with it

re adjusted again feels much better, still have some noise issues. I'll post a vid from my back garden shortly it should record the noise made.

I got this from a friend.

Thanks everyone, got it up and running and its running sweet. I took the diff apart, ball bearings all a ok. I put some new spare diff washers in anyway, regreased with hispeed diff grease and started again. Set it up again and very pleased with result.

I dont think I need any more upgrades besides maybe a motor mount and hobbypro front wing, just need to beat the B4 guys now.

I decided to get the bfast diff kit as well as a few aluminium upgrades. I even bought the front wing to try to help get the front down. Very pleased with the result.

I still have a couple of issues however, firstly the car rolls over unpredictably at a variety of speeds. I dont have a particularly fast servo its just the rolling over screws up my lap times.

Secondly I enter jumps with crossed fingers, It'll either stay more or less level or simply nosedive and forward flip itself upright. I havent raced with the upgrades yet so I'll see how the brass weight in the front affects things

The alloy front thing with the brass weights is pretty cool now that it has grub screws in it. I remember Thomas with the truck getting one and having the arms be loose at the front but they are really tight and good now that they come with the grub screws

mine jumps perfect sometimes and nose dives a little others, depending where I hit our jump, I'm going to try it today with no lead, just the brass weight hopup. You can also increase your front shocks preload to keep the nose up off jumps.

As for the rolling, what surface are you running on?

As I see you race with shum mini spike, Minke, I think you drive on a grass or carpet track.
You have to tight your shocks on this surface, oil and spring and the roll will disapear.

diff & slipper adjusted 3 times in a row is this right
 

This thread is a bit old but if anyone can help that would be great.
I upgraded my Son's madrat to a 9T 3 phase motor with 2 cell Lipo batteries a while ago but I’ve never been sure if the diff and/or slipper has ever been set up correctly.
The last couple of times the diff (as far as I can tell) has been slipping more so.
I stripped the diff and all looked ok I didn't see any balls broken but there was a circular ring mark with a very fine indent on each thrust plate (if that’s what they are called) from the location of the bearings, reassembled and set the diff & slipper as per zagonielod instructions.

Took it for a test drive at first all seemed ok even got the front end in the air (adjusted the slipper to stop lifting) then a few minutes later the diff started slip. Rechecked the diff adjustment and it was quite loose. It took quite a bit to get it re-adjusted gave it a test drive and after a few minutes it stated to slip again. Readjusted the diff again and as I thought it was about right the diff started to slip again as I was checking for slipper shaft to rotate. After adjusting the diff again took it for a test drive at the moment it seems to be holding.
My question is:
Can anyone explain why I would need to adjust it so many times in such a short space of time and if it starts to slip again what is the best option.
Does any know if the entire ansmann 2wd cars have the same diff setup or is there better options? :confused:
Thanks for any advice

Here is a nice little guide to building an ansmann diff.

http://mrmagoo-rc.blogspot.co.uk/201...ball-diff.html

Ideally you want the diff to be nice and free when you rotate one of the wheels, with the opposite wheel turning in the opposite direction. You also want it to not slip at all during use. So if you lock the slipper up hold both of the wheels you shouldn't be able to turn the spur gear.

Once you have got the diff set correctly you want to set the slipper up. This should be tight enough to not slip too much but not completely tight so that the car pulls wheelies everywhere. Just set it so slips a little bit on intial accelleration but then stops slipping as the car is accellerating.

As you have a madrat there is a Gear differential available. These are easier to set-up and maintain.

http://www.eurorc.com/product/2254/t...ff-set-for-2wd

I believe they availiable via SMD to.

Just do what i did as i had the exact same problem, the diff loosening itself. I just took the complete diff out and put it back in the other way round to the manual instructions. Since then it has never loosened itself. My adjust screw is on the otherside to the manual now and all is perfect. Plus when i took it out i sanded back the diff rings and fitted ceramic balls.

Hi guys
Thanks for your feedback.
I adjusted the diff twice since my first request for help each time it seemed to last longer before it started to slip but after the second time, when it started to slip the diff felt odd as i rotated the wheels it felt loose then tight so i suspect a ball bearing or two has cracked.

metalmickey0: when i stripped the diff to check the state of the bearings i reasembled so that the adjuster bolt is on the same side as the slipper nut i put it this way as i was fed up having to remove both wheels when i was trying to set it up before. is this the opposite way to yours?

Robbiejuk thanks for the links and guild. i did read on this site that geared diffs are not as good as ball diff i think this was mainly due to adjusterbility.

Why do you think the diff kept comming loose, was it the tension bolt working loose or some thing with in the diff its self.
i guess the reason why the ball's would have broken ( need to confirm) is becasue the diff was done up to tight.

i have been reading a lot about how good the B-fast diff set is so i will confirm which set is for the mad rat, if it all works out at lest i'll get some peace from my son.

I would tighten the spur/slipper so its locked
Then adjust your diff on deep carpet by running it up and down till it stops barking and it starts wheelying then run your diff in
Hold each wheel for about 3mins with a little bit of throttle trimed in then swap wheels another 3mins then check the diff again make sure its not barking then losen and set the slipper

Which side is the screw head facing on the car spur or motor side?

The ball diff that came with my Lupuz ie Mad Monkey, gave this problem and I cured it by opening up the bore of the diff so that the central screw couldn't touch anything. It was still causing a problem because the thrust washer seating was not machined true to the rest of the assembly. In the end I made a little spherical seat for the head of the screw to sit on and this stopped it from breaking the heads off said screws.

By this time I had lost all patience with the thing and fitted a geared diff, which is beautiful and no longer causes me to fret over whether or not the diff will make it to the end of the race.

On my brother's Mad Monkey, I had to machine the diff half that holds the bearing because the recess just wasn't deep enough to take the bearing and so prevented the diff balls from being loaded. The only way that he could assemble it with the bits that came out of the box was to thin down the bush that came with the kit to about half its original thickness.