breaking diff rings

Cooper · #1 13-10-2008

Hi, speaking for pred X11 team Belgium because the driver his English isn't so well.

We have a circuit in Belgium with a loooong straight, and at the end there is a very steep hill, so you have to hit the brakes VERY hard to prevent yourself from flying 15m high and end up in a tree(I did it with B4

)
We put the pred out to race there and we brake the diff rings all the time, causing the diff gear to sit misformed and stripped away. The car is superb, except this

. I have only had broken diff rings caused by tightening it to hard.
loosening the slipper is no solution because we won't make the double jump anymore.
loosening the diff is no solution 'cause it would slip before the slipper.

what should help is that the outdrive should support the diff ring better, so it wouldn't break anymore.

Anyone else any input?

burgie · #2 13-10-2008

which diff rings are breaking coops - is it the front ones or the back ones?

There must be another problem in the transmission causing the diff to move hence the diff rings breaking i would have thought. Are you sure the diff is sitting in the bearings securely?

Cooper · #3 13-10-2008

at the back

He had it also with transmission I build, can't imagine anything he did wrong.

KevLee · #4 13-10-2008

Are the driveshafts catching or bottoming out in the outdrive under full compression? thats the only thing i can think of that would load the diff plate up that direction.

its a long shot but he hasn't got the wrong driveshafts in there has he?

Cooper · #5 13-10-2008

Could be the driveshaft but I don't think so in my case. Will ask him though to be sure.

I have only broken one because I tightened the diff to hard when it was slipping. A hit against the wheel caused it to break.
If the outdrive would be a bit larger in diameter on the diff ring side this would never be a problem

KevLee · #6 13-10-2008

Quote:

Originally Posted by Cooper

Could be the driveshaft but I don't think so in my case. Will ask him though to be sure.

I have only broken one because I tightened the diff to hard when it was slipping. A hit against the wheel caused it to break.
If the outdrive would be a bit larger in diameter on the diff ring side this would never be a problem

Its worth checking, other than that i'm not sure. Strange as i have not had an issue at all with the plates and thats on some hard tracks!

The outdrive has a small contact area becuase the diff ring is the spring, if you increase the size of the contact area without doing anything else you would lose the spring action.

turbo_brick · #7 13-10-2008

Get him to check the actual surface that the diff ring sits on, I went through a stage of breaking them on high grip surfaces due to a slight mark on the diff half.

Peter

Cooper · #8 13-10-2008

thanks, these are some very useful tips

oh yeah, it always broke at the point where the flat spot is.

Cooper · #9 13-10-2008

thinking now that he might have put to many shims in the the gearbox, this would also create extra stress on the diff rings.

Tom3012 · #10 13-10-2008

try losi xxx diff rings too

Cooper · #11 13-10-2008

Quote:

Originally Posted by Tom3012

try losi xxx diff rings too

they fit without modification?

Cooper · #12 13-10-2008

matdodd · #13 13-10-2008

Ye losi xx4/xxx diff rings worked fine in the X10 diff with no mod

niggs98 · #14 13-10-2008

the rings are the same m8 so will fit without issue. 2 possible things of fault there

1. you are using way to much grease on your diff. the pred diff works very well with just the thinest of smears on both the diff rings and the thrustrace or the ceramic balls will slip and cause problems.

2 if the diff half is worn on the corners of the D it will allow the diff ring to twist slightly causing stress in that area and making the rings snap as if for no reason. it doesnt need a lot of wear for this to happen either

jc79 · #15 13-10-2008

I have had the rings and the thrust races plates go, so im trying steel balls in the crown gear and the thrust race to see if this makes any difference. Just incase the ceramic balls are to hard. as i push my car quite hard

thought i would give these a go at worksop this weekend. I will let you know how i get on with the diffs.

Quote:

Originally Posted by Cooper

thanks, these are some very useful tips

oh yeah, it always broke at the point where the flat spot is.

Cooper · #16 13-10-2008

Thanks guys, the thing about the grease, I was thinking the same. But didn't think that it would also lead to this problem.

I did my homework, now it's up to him to rebuild it properly

cheers !