Closed (for now): Group Buy: IEDLS Polyurethane Carrier Bearing

I think your theory is primarily correct.
I have 2.75-3" of lift in the rear with .5" spacer on the CB and the driveshaft is very close to level, but the pinion angle is fairly steep. Another 1/4" spacer might make the driveshaft perfectly level.
I think that's close enough to give this a try.
@12TRDTacoma can you put me on the list?

 

Example is I installed Dakars and had horrible take off shine. I put in .5" spacers to lower my CB and it somewhat went away. I'm now hoping the 1" difference from this CB will cure the remaining vibes.

 

That's the exact same with me.

 

I am waiting for Jeff @ IEDLS to let me know when I can reopen the list for a third wave of group buys.

As long as you drop down the poly carrier bearing .5" to put you at 2.5" mounting surface to center on it (assuming you are at 2.75" of lift at the pack) you should be good to go. If you go to 3" lift in the rear at the pack you will have to lower the poly carrier bearing .75" additional to get within a good tolerance range. If you run 2.75" leaf pack 2.75" carrier bearing you should be in even better standing in the tolerance range.

Assuming my presumption about the correlation between the leaf packs and carrier bearing heights may be related is correct.

How much lift is on those Dakars?

 

I'm not in dire need so I can wait.

On my Dakars I removed the large overload and initially got 3" of lift, but I just remeasured and I am at 2.5" of lift. My original suspension was totally worn out.

 

Thank you for the pictures!

I am not fully understanding your concept with the rear lift though. I have to go measure again, but my hub to fender is about 26" in the rear, which is a little high right now, needs to come down a little.

But with the hub to fender at 26", thats about 3.75" lift over stock?(I don't know because my suspension was worn out) Using your concept what would you say about that?

 

Oh damn. Those sure settled a bunch.

Dude screw the hub to fender measurements. They are totally unrelated to this and irrelevant. Measure your leaf pack from the very bottom of the lowest leaf to the very top of the highest leaf of the bunch in the pack. Leave out the U bolt plate from the measurement. That will tell you how tall your pack is, this should also tell you how much you should need to space your carrier bearing down from the stock mounting location.

 

Ohhhhh, that makes sense. How much the axle has been moved downwards. So oem the carrier is 1" down, the IEDLS is 2" down. If the leaf pack is 3" thick then the IEDLS should have a 1" spacer??

Sorry I'm going full derp, I thought you were talking about lift heights. I need to lower my rear end...

 

So basically lets say you have a 2.5" lift measure overall at the rear leaf pack. You want the Carrier bearing to be AT least at 2.25" at centerline. So the bearing from mounting surface sits at 2" dropped right away. In order to be in good standing with your overall driveshaft angles and prevent vibes you should definitely drop the bearing an additional .25" from the mounting surface. Which you could easily do so by going to ace and buy some M10 washers. buy enough which measure out to .25" in height mount them in between the mounting surface and the carrier bearing upper plate you just created. Done.

If you want to get it exactly how stock was, you will want to either sit at 2.5" at the bearing and at the pack or 2.75" at the bearing and 2.5" at the pack. I hope that makes sense.

Example: My pack sits at 2.25" of overall height. My carrier bearing (including the 1/8 upper mounting plate I made for it) makes it sit at 2.125" which is very close to what stock was on my application before lift, which explains why in this particular case I am 100% vibe free at all speeds.

For reference, stock was 1" at the carrier bearing from mounting surface to bearing centerline and the leaf pack was .75" thick.

 

im sorry but leafpack thickness has nothing to do with axle positioning vertically. I could have a 2 leaf pack that is SUPER arched netting 6in of lift and have a leaf pack thats thinner than stock.

Its angles boys this is what you gotta look at.

IDEALLY. You would setup the trans/tcase output joint operating angle between 0 and 1* (by raising the cb). Then using degree shims tilt the pinion up or down so that the center joint and rear most joint (pinion) are at equal and opposing angles. Due to how the joints are rotationally phased this would allow the center joint and rear most joint to cancel out oscillations / velocity changes caused by joints with angles on them.

Less than ideal but still better would be lowering the CB to the point where the front joint at the trans/tcase and center joint angles are equal and opposing, and the pinion is closest to zero. Problem with this is. 1. driveshaft hangs lower (read more exposed). and 2. with suspension movement the center joint angle will change which will make it to where the front and center joints do not cancel eachother out.

Now what actually works in practice. Something close, but you have to take into consideration for axle wrap, carrier bearing slop etc etc etc... so playing with CB positioning is the easiest thing.

The main reason why spacing your CB down with the stock CB got rid or reduced driveline vibes was the fact you were reducing the angle at the CB causing less side load and less oscillation within the CB itself. But a close to zero angle is definietly not proper as the front and rear joints of the 3 piece driveshaft are 90* rotationally out of phase. This will cause higher frequency vibes often felt around 55+ mph.



I for one will be getting it to where the trans / tcase output is close to zero, then equal and opposing for center and pinion.


Also the person above is likely correct, the mounting option for DCSB that goes above the stock mount will likely not work due to the gusseting of the stock mount. No biggie, spin the CB 180 * and make some spacers.



TLDR version. There is no one setup or easy formula that will apply to every truck, get your angle finder out and take the time to measure angles.

 

I was waiting for you to straighten us out.

 

See. I had a feeling I was definitely wrong about all of this. It was just a hunch.

 

I was just thinking about one of these...I'm in for the current/next list!

 

It's all good. There's more than one way to make this work, but everyone needs to be prepared to fiddle with it a bit.

 

Yeah that's the thing, even the stock one is a problem as is straight from OE as many of us have seen on here. The jury is out even more so on the height you need to set it to when you lift it. Because at that point, you messed with the rear end height. At that point it's open game.

 

Also finding rear angles while the truck isn't moving is great, but when moving it may experience axle wrap, therefore changing the angles, therefore creating vibes, even though the angles were "correct". Is this not true?

 

Interesting to learn of your experiences.....i just installed the Dakars and have the EXACT same experience. This lead me to check out this group buy. Hoping to get it figured out when the new CB goes in because mine is BAD!

 

I measured it this morning on the comparator and it's 1.965 from the flange to the center. That was uncompressed. When I measured it last night I was trying to compress it in the mount and came up with 1.940, so the difference is negligible.

 

I'm considering shims under the leaf pack to help with pinion angle.

 

It's possible. Try to video the driveline for a short distance.