tire ballooning in the rear, but not front...

i had been noticing that my rear tires balloon a lot and the front tires don't as much for some time. check everything out and looks good. finally, the front diff gave out. so i dropped in a new one, put her back together and now the front tires don't balloon at all and the rears go way out!
the fronts peel out in reverse. everything seems good. i'm gonna rotate the tires and see if the symptoms follow the tires or the location.
anyone run across this?
i notice the rear tires seem much more unbalanced too.

p.s. my setup...
emaxx 3905
1515/1Y
MMM
4s/6s
stock tranny
traxxas cvd's all around (and center)
FLM 3905 diff cup
100k rear, 120k front
axial terra-izers

[What's_nitro?]

Well, I can tell you that the front tires are going backward because you put the front diff in upside-down. Just flip it over so the diff spur gear is on the other side of the diff input pinion. As far as the rear tires ballooning more, with the front tires pushing back, that would amplify the symptoms. Are your rear shocks set up very stiff? That will cause more weight to stay in the front on acceleration and so the rear will slip more. How is the F/R balance of the truck? Are the batteries/motor in the stock locations? (sorry, I'm not the E-maxx pro on here :/ )

[jayjay283]

you could always put this in CD LINK fill it wil diff locker fluid, and all 4 tires will spin the same provided you have the same diff fluid in the front and rear diffs.

Originally Posted by What's_nitro?

Well, I can tell you that the front tires are going backward because you put the front diff in upside-down. Just flip it over so the diff spur gear is on the other side of the diff input pinion.

the diffs are in correctly. what i was saying is that the front diff is getting power because if kicks up dirt when i nail reverse.

Originally Posted by What's_nitro?

Are your rear shocks set up very stiff? That will cause more weight to stay in the front on acceleration and so the rear will slip more.

yeah, pretty stiff all around; 2 UE white springs at each wheel with 50wt. i don't think this is the problem, as i've had this setup for a while now and this behavior just started.

Originally Posted by What's_nitro?

How is the F/R balance of the truck? Are the batteries/motor in the stock locations? (sorry, I'm not the E-maxx pro on here :/ )

51% - 49% (F/R). everything in stock location.

Originally Posted by jayjay283

you could always put this in CD LINK fill it wil diff locker fluid, and all 4 tires will spin the same provided you have the same diff fluid in the front and rear diffs.

the purpose of a CD is to allow the front and rear to spin at different rates. i have the stock tranny that spins the front diff and the rear diff at the same rpm, so the front and rear tires should spin at the same rpm.

well i ran it again and bent a rear cvd.
luckily, i had a replacement. while i had the wheel off, i went ahead and rotated the wheels, front to back.
put it back together and the behavior follows the wheels!
there are two out of the four wheels that balloon like crazy and wobble bad.
i built all four of them at the same time with proline low profile 40 series inserts. they have not gotten wet.
why would they all of a sudden do this?
anything i can do?
maybe they are full of sand. i did run in sand the other day that my front diff blew. maybe since only the rear were spinning, they got full of sand through the air vent hole.
how can i get the sand out without taking the tires off the wheels? they are glued.

i was gonna say it sounded like some bad wheels, you can pinch the outside of the tire and cut a hole in the tire, that allows stuff to get out of the tire, i do this on all mine, works good

you say cut a hole on the center line of the tire, or near the sidewall.
center line makes more sense...

[jayjay283]

Originally Posted by FunkedOut

the purpose of a CD is to allow the front and rear to spin at different rates. i have the stock tranny that spins the front diff and the rear diff at the same rpm, so the front and rear tires should spin at the same rpm.

The purpose of locker fluid is so they dont, I was going to point out the obvious like your tires are full of mold from water or your bearings are shot but being RCM I thought we were past this and was pointing out something to consider. That diff goes in the stock tranny BTW. GL

when i held the exacto and hovered over the tires, i had flashbacks of doing the same thing to the stock tires to let the water out. it's hell getting old.
anyway, cut the holes and the sand poured out! then i spun it up and a bunch more flew out. problem solved.
thanks for your help guys.

Originally Posted by jayjay283

The purpose of locker fluid is so they dont, I was going to point out the obvious like your tires are full of mold from water or your bearings are shot but being RCM I thought we were past this and was pointing out something to consider. That diff goes in the stock tranny BTW. GL

jj, don't put anything past me. as you can see, i'm capable of forgetting all kinds of things. state the obvious.

as far as the center diff goes, i never figured you meant to take out a solid axle and replace it with a differential only to lock it again with locker fluid...
...you know, this being RCM and all.

[jayjay283]

lol sorry wife made me rub her nasty feet im grumpy. Yeah more or less just a straight through solid axel, that way you could find out whats wrong but still just dump out the fluid and put whatever you want in it later. No offence bro

actually, i was interested in putting that cd in my maxx but i haven't moved on it because of the plastic cup.
the way i see it, if plastic wasn't good enough for the cups in my diffs, it wouldn't hold up in the tranny either.
when FLM (or anyone else) makes an aluminum cup for that, i'll jump.
anyone tried it with brushless?

yes the holes were in the center lol, im glad this helped you

[What's_nitro?]

Originally Posted by FunkedOut

the diffs are in correctly. what i was saying is that the front diff is getting power because if kicks up dirt when i nail reverse.

Ahh, I see. I had a picture in my head of the truck throwing dirt forward and back, digging a hole until it was resting on the skid plate.

[What's_nitro?]

Originally Posted by FunkedOut

when i held the exacto and hovered over the tires, i had flashbacks of doing the same thing to the stock tires to let the water out. it's hell getting old.
anyway, cut the holes and the sand poured out! then i spun it up and a bunch more flew out. problem solved.
thanks for your help guys.

Wow, that's a lot of sand! I'd expect better run times now, too.