.5" bump stop gap at stock ride height

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spddm0n

Test Drive
Location
United States
I went under the truck yesterday to crank up the torsion bars and I found that sitting as it is...there is already only .5" of bump stop gap while the truck sits on the ground.

My question is...if I begin adjusting the torsion bars, will it immediately begin to reduce the bump stop gap or will the bars crank up a bit BEFORE the gap is reduced? I may not have any room to adjust at all. Weird.

The only thing I could think of is the previous owner cranked them up already and it has been slightly lifted all along.

Also, when measuring the bump stop gap, is this performed AFTER the truck is set back on the ground or while the front is still raised (tires still on the ground, but pressure off the suspension while cranking up the bars)?

Thanks!

Matt
 
caseycamby

caseycamby

Suspension Lift
Location
Marion, NC
I don't know exactly why you have a .5 inch bumpstop gap at stock height. Care to give a picture or two?

Also, you're supposed to measure the bumpstop gap once the truck is resting on the groud under its own weight completely. Most recommend driving around a bit after you index your bars to allow for settling.
 
robcarync

robcarync

Sliders
Location
Raleigh, NC
Check your bump stop gap when weight is completely on the suspension. If you lift the truck in the front with a jack to relieve the pressure on the torsion bars, that will cause the tires to droop down, and make the bump stop gap more narrow.

If you are lifting the front end with a jack, and you have 0.5" bump stop gap...that is your ride height when you lift the front end. Now drop the jack, and the front end should drop some. Your bump stop gap should be 0.75 or 1 inch, etc.
 
S

spddm0n

Test Drive
Location
United States
Thanks for the replies. Ok, so I re-measured the gap while the truck sits on the ground. It is a bit more than .5", but not much. It's about 13/16" on the passenger side and 3/4" on the driver side.


Here are some pics...
Passenger side bump stop:





These tires larger than stock. They are 265 75R16 (I think about 31.6" tall)
Passenger side front ride height:



Passenger side rear (with new adjustable shackles installed at the 1.5" mark):



So, do you think there is any room to life the front and still get alignment?


I may have to bring down the rear to 1" if I can't get the front up a bit more. :)
 
xterror04

xterror04

Site sponsor
Founding Member
Location
Carlisle, Iowa
You should easily be able to crank the tbars to get some lift with that bump stop gap, if you want more lift hen reindex the torsion bars...
 
T

TJTJ

Skid Plates
Founding Member
Location
NJ
caseycamby said:
Yeah and the larger tires will decrease the bumpstop gap.. Larger tires are essentially a suspension lift.
Click to expand...

LOL

Not really...

YES, the larger tires lift the frame, but, they also lift the suspension/axles too, so are not a suspension lift....but, they will NOT also change the bump stop gap.

(If larger tires are a suspension lift because they also lift the suspension, then a suspension lift is also a body lift because it also raises the body, etc...)

:D




What changes the UCA to upper stop's gap, in this context, is the UCA dropping down closer to the stop.



Adding larger tires doesn't mean the UCA has to droop more...it just means the entire truck is sitting at a higher altitude to start with.


When you rotate the t-bars to a higher ride height, which rotates the LCA down, that droops the suspension more. If you reach the gap you want, say ~ 0.5"....that's all the down travel room you have left to follow the terrain. Luckily, due to the angles involved, 0.5" of gap represents more inches of WHEEL travel than that.

Similarly, you don't need to SHRINK the gap by much to get a lot more than that back in SL lift....a teeny amount of gap represents a LOT of wheel travel, proportionally.


The X is supposed to be ~ 1.5" lower in front than the butt. A LOT of people think the front "sagged" (Newbs especially) and, as ALL trucks are built that way, not just Xterras or Nissans, ALL trucks, an entire industry has sprung up offering "Leveling Kits".

So, if you buy a rig, especially used, or get an alignment by a shop who thinks it should be "level", they could have rotated the t-bars to get a higher front ride height, to "level" it.

As a PML is a 1.5" SL, and, the X is starting ~ 1.5" lower in front....a PML is essentially doing the front leveling part, but then ALSO raising the butt a matching 1.5".


IE: Leveling + Shackles = PML.

:D
 
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robcarync

robcarync

Sliders
Location
Raleigh, NC
No need to re-index here unless your adjusters are bottomed out. You have room with the bump stops. Measure your height as it sits now on the front rocker panels. Lift the front with a jack until you have 0.5" of bump stop gap...and measure at the rocker panels how much higher you are. That is how much lift you will get.

Re-indexing your torsion bars is the process of removing the torsion bar from at least one of the anchors, rotating the bars position in the anchor either direction (typically 1-4 splines), and reinstalling. This process changes the position of the adjuster finger for a specific ride height.


This process is used to solve two specific situations:


1) You have more than 0.5 inches between your stock bump stop and your UCA, you want to raise your adjuster, but the adjuster lever is too deep in the cross member and can’t go any further. You need to remove the adjuster bolt, remove the torsion bar from one of the anchors, and rotate the bar so the adjuster lever is further away from the cross member. This allows the adjuster more room to lift the vehicle.


2) You are at your desired ride height, you have your correct bump stop gap, but your adjuster is hanging down below the cross member. You need to remove the adjuster bolt, remove the torsion bar from one of the anchors, and rotate the bar so the adjuster lever is closer to the cross member. This will allow the adjuster lever to be inside the cross member when you readjust to your desired ride height.

Re-indexing doesn't change how much life you can get. It just changes the position of the adjuster finger relative to the LCA/UCA angle (IE: lift height).

How to Re-Index:


http://xterranation.org/showthread.php?2813-How-To-Re-Index-Your-Torsion-Bars
 
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S

skywalker268

Test Drive
Location
Utah
I know I'm bringing back an old thread here, but is the bump stop gap measured to the top of the rubber bumper, or is it the gap between the UCA and metal piece the rubber bumper is sitting on?
 
robcarync

robcarync

Sliders
Location
Raleigh, NC
To the rubber bumper. You can measure it to the metal piece if you prefer to measure there, but that means the gap you want is the height of the bumper plus 1/2" or so.
 
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