CB Drop, Axle Shims...Neither or both for 2" Lift???

So I've read and read threads and there seems to be no set answer so I thought I would toss this question out there for those with more experience. I'm looking to add only a 2" lift in the front and rear to maintain factory rake. I know this can produce vibrations and from what I've read it's caused by the angle changes from the transfer case through the 2 piece drive shaft/carrier bearing to the rear differential. From what I understand the angles need to cancel each other out but I don't know where to even check all of the angles plus I don't have an angle gauge and honestly I wouldn't know what I was looking at/for if I did...lol. I have the parts for the lift plus a CB drop and 3* axle shim. I'm looking for input or thoughts on what others have done with this much lift and whether I need to add the CB drop, axle shims, both or none. Should I add neither until I drive it and see if there are vibrations? The CB drop would be an easy install but if I need the axle shims I would prefer to do that at the same time as the rear suspension. Appreciate any input. Thanks

 

I did carrier drop and a 2° shim. Rule of thumb is 1° per inch of lift in back. Have had it 4 yrs now, and no vibes or problems.

 

I think the answer is always going to be, it depends. Some people have to use shims or cb drop or both or nothing. Best bet is to try and measure the D/S angle then match it after if possible.
Just as an FYI I’m in no way an expert or knowledgeable in this but I have read the threads on vibes quite a bit.
After you lift it drive around for a while. If no vibes your gtg. If you have some, try the cb drop. If it works great! If not, you can get and add in shims, I’d recommend the slotted ones so you can loosen the u bolts and slide them in. If that works great, if not, pull the cb drop.
You might also want to buy a magnetic angle finder and check different spots on the D/S.

I’ve reduced mine by 12 fender washers on each side to drop the c/b and got my angles to a near 0° difference in change.

 

Thanks. Appreciate the input. Do you think I should add washers to the CB drop since I already have the 3* shim to offset the extra degree or just best to get a 2* shim to replace the 3*?

 

Yea I've read a few threads about vibes also. I've seen where some also add the washers to the CB drop to find the sweet spot. The current 3* shims is from headstrong and are slotted. Also looked at getting a magnetic angle gauge but I'm not sure of all the angles to measure and then how to determine where to adjust. If I'm not mistake the angles need to me measured in more places than just the driveshaft. This is where things start to confuse me. Thanks for the info.

 

Lol, I was/am still confused. Some talk about measuring at the output of the xmsn and the diff input. I always got different readings so eventually just measured from the bottom of the driveshaft. Someone had pictures, I’ll see if I can find them. The c/b can also be adjusted slightly left or right at the cb mount and if that’s off center it might cause issues.
How bad are your vibes?

 

I don't have any vibes yet as I haven't installed the lift, just being proactive for when I do install. I did see a post with pictures somewhere but to me it's still not clear where to check angles. I would think checking the 2 d/s angles would work but the post had measurements taken in many places and that is the part that threw me off.

 

Maybe this’ll help some. Don’t mind the numbers there already. I used straight metal scrap against the flanges to get those measurements.

 

I have done both, a CB spacer on a 2nd gen with a 3 inch lift, and this time an axle shim also with a 3 inch lift on a third gen. Neither had any vibrations ever

 

So I have read this pdf over and over again and still not 100% clear on it. If the output flange is at 0 and the pinion is off by 2 then I would need a 2* axle shim to make it 0? Then I would need to drop the CB until the 2 drive shafts equal 0? I think my head is going to explode.

 

How many degrees is the axle shim you used on a 3" lift? Thanks for the info

 

I used a 3 degree steel shim from Wheelers

 

Gotcha. Thanks. I have a 3* already but think it may be too much for 2" lift. Not sure if I could make adjustments to the carrier bearing drop to offset this or not. May need a 2* shim instead.

 

With 3° shim you would want lesser of a carrier bearing drop. If you increase it it would cause a greater driveline angle. This is for your 2" lift. A 3°maybe be ok for you. I mentioned 1° is a rule of thumb. Every lift/truck is different.

 

Thanks. That's what makes this so hard. It's amazing how different these trucks can be. Yea I was thinking if I go 3* the CB drop may be too much. Guess I could use a few washers instead to make it less of a drop or just get a 2* shim to try. I could always try and sell the 3* if I order the 2*. They aren't expensive.

 

The single best piece of advice I would give you is to measure your current angles and record them. Then simply try to get back to them post lift. This is assuming you are currently vibe free.

It would be very easy to see where you end up at and where you need to be.

I originally had a 3º shim, then added a CB spacer, then removed the shim, then added washers to the CB to get my truck happy. Every truck is different though. Good luck.

 

Appreciate the input. I'll plan on starting in this direction. Since my shims are slotted they shouldn't be too hard to install after the lift so I can start with adjusting the CB some and see where that gets me. Thanks

 

I'm planning a 2" rear lift and looking for the same info on this subject. Based on this thread I guess I'll start with a 2* shim and hope for the best.

One piece of advice I have to share is about the carrier bearing drop. From what I understand dropping the carrier bearing is a sloppy fix. The two pice drive axle works with three u-joint only because the angle between the first and second is nearly straight, in spec at .5 -.9* for every you joint that is bent you need a second u joint to bent at that same angle to cancel out the vibration, and the tacoma only has three which means the first u joint is not meant to be bent. if you drop the carrier bearing you are increasing the vibration produced by the u joint at the transmission and because the carrier bearing u joint is bent to mirror the u joint at the pinion lowering the carrier bearing might solve the vibration between the carrier bearing and the pinion but its creating more of a vibration at the transmission. Its much better to keep the angle at the transmission as close to straight as possible and correct the vibration with a shim at the pinion angle.

There is also apparently another issue that arrises when the angle of the joints exceed 10* such that your always trying to keep the as close to the same and less than 10*. Keep in mind also that if you have a smart phone you have an angle finder. You just have to find the "working angle of each joint which is the difference first and second drive shafts and then the second drive shaft and the pinion angle.

When I get into it I'll take some picks and post back and share how it went. Fingers crossed that 2* works and I don't have to shell out for a second set of shims and dig back under the truck for if its a degree off.

Here is a link to a good video on the subject.

https://youtu.be/f1m-Fh5kiRU

 

Thinking about a 2 degree shim on mine. Any luck with yours? Thanks.

 

2* shim is installed under new Icon RXT leaf pack and set at option 2 which is supposed to be a 1.75” lift and no drive shaft vibrations are detectable. I didn’t have time to take official angle and lift measurements but seems to be working great so I’m just going with it. The front is set at 1.8” lift.