abecedarian

well, since you asked... all of them
...
bj spacers push the lower control arm down, independently of any t-bar adjustment.
pushing the lca down means the half-shaft is being pushed down.
cranking the t-bar pushes the UCA down.

anyone care to relate the changes?

...

maybe explain what happens when a "regular quadralateral" becomes a trapezoid?

slosurfer

Correct, they both push the lower control arms down. The difference is that a 2" tbar crank pushes both the upper and lower control arm down, which is just about all your downtravel and now your upper control arm is sitting on it's bumpstop which is the droop bumpstop.

Now a 2" spacer pushes just the LCA down while the UCA is still in the same "stock" position. So at this point the two lifts are sitting the same height with the LCA's in the same spot.

But this is where it changes: Put the two vehicles on a lift so that it lets the front suspension hang at full droop on its droop bumpstops.

The tbar cranked one will not droop much more because the UCA is already pretty much sitting on the bumpstop.

Now the spacer lifted one will droop down till the UCA hits it bumpstop. Therefore it has 2" more droop as there are 2" more distance between the UCA and LCA.

slosurfer

There used to be a pic on Sonaron Steel's website of their mini truck. It was on a lift and one side had bj spacers on at full droop and the other side was untouched and at full droop. It would be perfect for this but I can't find it.

slosurfer

Okay, found it! Yay, google image search!

This has a 4" drop bracket lift on it but the geometry between the UCA and LCA is basically the same. The pass side has the bj spacer and the driverside does not. Both upper bumpstops are the same and that is what stops your droop, therefore both UCA's are in the same position right now.

89pickupsr5

OK i read a bunch of stuff on here about the 1.5 inch bump stops and i think i know what i want to do with them but now i'm curious about these 2 inch spacers

so.....if i purchased/made 2 inch thick bj spacers and relaxed the t-bars to stock height, would there be any negative side effects.....if not how much could i have the t-bars cranked past stock height before i would start having problems off road?

what about the same question with low pro up travel bump stops?

Thanks Drew

Matt16

You would start to loose flex if your upper control arm went up from horizontal as it would if you relaxed to stock height with 2" spacers... so there is no benefit to 2" spacers. Stock hieght with 1.5" BJ spacers works great offroad as the UCA is exactly horizontal.

the drawback to 2" is that the axle with droop past the safe angle for CV shafts and tie rods (which effect the idler arm).

cartune777

lots of good info makes sense, 1.5" spacer no t bar crank is the way to go, unless i drop the diff about an inch

Matt16

Diff drops don't lower the cv's much. That still doesn't address your steering.

leebee

search out sdori ball joint spacer, frank has given very concise explanations on this topic. might as well get it from the source, quite a bit of r&d went into the design.

lee

scuba

iSearch.

cartune777

good read

slosurfer

Dang, I didn't know Frank had that up! I just added that to my favorites, much easier to post that rather than try to explain it. LOL

Also, be on the lookout for Frank's bushing for the idler arms.

89pickupsr5

thanks matt 16
I just had to ask
i'm gonna be goin with the 1.5s and i'm just gonna leave the bumpstops alone get the idler arm brass bushings and the downey brace and call it a day i do appreciate the answer though
Drew

Matt16

good idea. Go hit all the relevant bolts with PB blaster a couple days before the install. I had a hell of a time knocking out the studs holding the ball joints the the Upper Control Arm. I did a writeup on the alignment you'll have to do once the BJ spacers are installed. Here it is: https://www.yotatech.com/forums/f116...ite-up-163432/

elripster

Just read through this...

Yeah for capability, unless you do say only desert/speed stuff, 1.5" is best lift. In fact, I'm running 1" of lift and like the trail flex all the more. One thing that I think is easy to forget is that flex means the wheels can go both up and down. Adding more lift beyond the 1.5" begins to eat into the downtravel. It might look cool but your truck won't wheel as well.



Frank