Torsion Bar Question - Rake or No Rake? If Rake- How Much and Why?

[fooldall1]

Did some searching here, came up with a lot of opinions on leveling and rake but there's a lot of variance there on opinions.


I plan on setting up my torsion bars to level the truck, but is this really advisable? I have read also that having a .5-1 inch rake (lower in front) is advised by Toyota for some reason. I'm not clear if this is an actual requirement. A buddy of mine on here has it leveled and reports no issues.

Currently, mine is measuring:

Driver front: 19.25
Passenger Front: 20
Passenger Rear: 20.5
Driver Rear: 20.25

Seems like a odd settling on the car, but this is the same day I replaced the shocks so I should probably re-measure.


Anyway, thoughts?

 

[AimCOtaco]

Rake or die!

OK, so it's not that big a deal but you'll have to decide if you can live with the lost kingpin angle or not, it'll make the steering more twitchy and the truck a little harder to drive. IMHO it's not too bad to run level and low but level at max lift adds the issue of constantly unloading the front end as well as the angle loss. This issue is discussed pretty deeply around here.

You may want to drive it both ways and compare the feel before you decide where to leave it and drop it off for the alignment.

 

[Manhattan]

You're just going to get a new/different/restatement of the previous opinions. This isn't something that's been lab tested and certified... just a bunch of guys turning wrenches on trucks with different suspension setups, with different miles, with different loads, with different...

My truck rode like *%$^ level. Dropped the front down a bit and it was great. One for the "Yes" column.

Why not do this this... level your truck. See if you like it - how it looks, how it rides, etc. Then decide. It's comically easy to dial those TBs down.

Oh, then change your sig line

 

[jerryb]

frame angle is what it is from the factory for a reason. If you don't believe that than nothing anyone says on any forum is going to mean diddly.
Lower your front to the extreme, go drive, report. Then raise the front to the extreme, go drive, report. This will clear it up for anyone way better than reading forums.

 

[TheForger]

When I leveled mine I had a few steering issues especially when it came to going over the speed bumps in my neighborhood. Very twitchy at the apex of the bump and I noticed that went away when I lowered the front to the appropriate rake. Also, if you plan to tow anything you will want the front lower so when you attach a load in the rear it will level out. If your truck is level and you attach a load, the front will be in the air and you'll be staring at the sky when you drive

 

[Jeepster09]

You may want to be a sky pilot....that's where the song came from a "leveled Landcruiser"

 

[ga12r1]

I think most of the steering issues involved with leveling come from a decrease in caster not loss of rake. I say get a set of spc upper control arms and level until your heart is content.

 

[gatormark91]

I think most of the steering issues involved with leveling come from a decrease in caster not loss of rake. I say get a set of spc upper control arms and level until your heart is content.

You beat me to it. Most shops don't know how to set caster well. I had a good shop that took several test drives, and even asked me to come back because they just weren't happy wth the caster on my truck until it was right. I have cranked Torsion bars on 33 BFGs, and it has no issues whatever. And I am very picky about that sort of stuff. The only reason I can see for a meager half inch of rake is to keep your headlight cutoff point in the right place so you don't blind oncoming drivers when towing or carrying a load at night

 

[fooldall1]

You're just going to get a new/different/restatement of the previous opinions. This isn't something that's been lab tested and certified... just a bunch of guys turning wrenches on trucks with different suspension setups, with different miles, with different loads, with different...

My truck rode like *%$^ level. Dropped the front down a bit and it was great. One for the "Yes" column.

Why not do this this... level your truck. See if you like it - how it looks, how it rides, etc. Then decide. It's comically easy to dial those TBs down.

Oh, then change your sig line

Change my sig line?

 

[gatormark91]

Change my sig line?

Change "2000 Stock Land Cruiser - Loving it just the way it is!" to "2000 Stock Land Cruiser - Loving it just the way it is (except for the cranked TBs!)"

 

[jLB]

I'm a dissenter.

From my experience, it is not the rake so much as it is front height (which decreases caster and droop) that negatively affects ride/handling/steering. When you start lifting the rear ~2" and then try to "level" it is where you tend to run into problems

That said, neither of my 100 series is currently setup to run level, because it looks pretty stupid with the reverse rake you get when you put anything in the rear.

 

[jerryb]

what happens is people talk about rake, knowing full well it's caster Etc that changes when you just raise one end of a vehicle. If people make changes, and compensate both front and rear to maintain the same rake, or frame angle or whatever you want to call it to make it easier. And alignment can remain in factory spec then it's all good.
You start shifting weight around from front to rear, willy nilly, you will have problems.
the amount if weight on each front wheel is a known measurement. You messing with that without compensating for the rear will fxxx up your program.
Torsion bars make it easy for people to fxxx up. That's why there are threads like these on all torsion bar vehicles and coil overs, helper springs, etc.
I do believe that there are a lot more allowances for trucks and suvs compared to track cars. Obviously I suppose.
it really is simple though, lower your LC two inches in front and go drive. Raise it four inches from there and go drive. That's the only way it will become immediately clear regarding front to rear weight ratio and the corresponding changes in allignment.

 

[abuck99]

Keep it simple- 1" variance between front & rear.

 

[fooldall1]

Change "2000 Stock Land Cruiser - Loving it just the way it is!" to "2000 Stock Land Cruiser - Loving it just the way it is (except for the cranked TBs!)"

Thx Mark,

Keep it simple- 1" variance between front & rear.

Thanks for the advice, everyone!

 

[ewrk1989]

I just did an AHC delete in favor of OEM springs/shocks and have been testing out a couple different torsion bar settings.

Measuring droop is easy, as you can go from the center of the wheel up to the apex of the wheel well.

Well, measuring rake seems like a different story. I noticed that the apex of the rear wheel wells is actually lower in the rear, compared to the front. Visually you can see it, but I checked by holding a piece of wood at the top line of the body cladding. I measured the rear wheel well to be 1.5" lower than the front.

So what exactly are people measuring against when they say they have 1" or 2" of rake?

Last night I adjusted the front to have 50mm droop. This actually made the vehicle level (I measured the rear height and added the 1.5" wheel well difference). Well, it handles ok but makes the front end look high because of the wheel well difference. If I stay within the recommended 50-70mm droop range, then I can really only lower the front by about 20mm/.80 inches. With me in the driver seat, it might be 1" on an unloaded vehicle. I don't know if that's enough to ride level with a load in the back! Any thoughts?

I pulled a generic picture from the internet to show the height difference...

 

[abuck99]

70mm of droop will give you better caster numbers, better handling, might be a bit easier on CV axles. I find measuring wheel well lip to the top edge of the rim gives me the most consistent measurement time after time

Thats an interesting observation on the variance in wheel well height- but the 1" difference (rule of thumb for "rake" thats discussed here,) is simply an easy to follow reference number to ensure the rear measurement is at least 1" higher than the reference number measured up front.

Technically speaking the FSM method for determining front & rear heights is far more complicated (and kind of ambiguous) takes more math and effort to follow (pictured).

 

[ewrk1989]

Ah ok, well I think I'll adjust and try for something closer to that 70mm. I will use this as my camper vehicle, so there will be some weight in the back. Don't want to be sagging all the time!

At 50mm right now, it just seems not particularly ideal. Drives ok but looks and feels a little strange sitting there. It also did increase the vibration I have (which I believe is coming from one or more of the front diff bushings). When I had it lower, things were a good deal quieter. I think this could make sense, in that a CV shaft at an angle would be more likely to induce radial loads that tired rubber bushings do not feel like dampening.

The FSM procedure looks...interesting. They tell you to adjust the value by pushing on the body...not adjusting the torsion bars!

I will stick with droop and rake. I do see what you mean about it being more of a reference number in the back, rather than a measurement from an absolute datum.

EDIT: And this might be a stupid question, but we want even measurements left-to-right up front, correct? I ask because the rear springs are different to accomodate fuel. Up front, there's usually just my 250lbs on the left side...