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Finally got my Bilstein 5150s

RockinChevy

RockinChevy

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I posted this on 4x4mecca as well. Wanted to post in here to get more feedback from you guys too.

After waiting a little over 2 weeks, my shocks are finally here from jackit.com... Did a test fit first thing this morning and to my disapppointment, the shock bodies look too long for compression. I gave jackit.com an email containing my ride height measurements and requested the 14.53" travel with the 255/70 valving.

Current ride height: approximately 5" lift on stock 52" and 56" springs.

Front: 23" from shock eyehole to eyehole. (With cast Ford towers, the shock mount is 5" above stock position.)

Rear: 22" from eyehole to eyehole. I have the DIY4X inboarding shock crossmember.

Well, the Bilstein shock bodies are 19" from upper eyehole to end of shock tube. So they collapse at 20" and extend at 35". So that gives me what, 2-3" before bottoming out? I'm not looking forward to cracking my frame again, though.

Not sure if I should either call them again for a solution and have another 3 weeks cut into my wheeling season or just get some shock hoops? I don't think the shock hoops are any taller than my ford towers anyway.

What do you guys think? Also several people have the 5150s with the 14.53" travel, how are they getting away with making it work, especially with the Ford towers????
If anybody has any pics, post them up, I need to see how much shaft you have before bottoming out.

Thanks.
 
I hate to say it, but I think you need shorter travel shocks. There are multiple mounting locations on the inbording x-member. Can you inboard them further in back? That would help some. On the front you may try going from the cast to stamped Stupid Duty towers. IIRC, the stamped ones are taller. Or you could try hoops in front and going thru the floor in back. Otherwise you'll need shorter travel shocks. Remember, for every 1 inch you reduce the travel, the extended length will drop about 2".
 
I did consider getting some shock hoops this morning, and experiment with the different mounting positions on inboarding xmember... I wanted to check in with you guys first before I do or buy anything else to screw it up even more.. I'm trying to get it driveable after sitting for 2 months.
BGKYK5, you're right. I guess if all else fails, I'll have to exchange for some shorter ones.
I wasn't going to cut through the floor until after I get a rollcage and go 1 tons then I can have some coilovers welded to the cage. My build vision is a bit sketchy so I can't be positive on what direction I'm going with anything.
 
You and Jason have the welder , grinder , and some scrap steel . Make your own taller mounts :thumb:

Seriously , take the Ford Towers , bolt them to another piece like what your sliders are made for , and raise them up more . Just don't get in the way of the steering and brakes .

As for rear , a bar across the bedside wheelwells can be the START of your cage :waytogo:
 
BGKYK5 said:
Oh, and got pics?
Click to expand...

:D

Well, everybody knows what 14" travel Bilsteins look like.. I don't have a camera and didn't really care much for one. I'll go see if I can get some and post up if possible.
 
pauly383 said:
You and Jason have the welder , grinder , and some scrap steel . Make your own taller mounts :thumb:

Seriously , take the Ford Towers , bolt them to another piece like what your sliders are made for , and raise them up more . Just don't get in the way of the steering and brakes .

As for rear , a bar across the bedside wheelwells can be the START of your cage :waytogo:
Click to expand...


True. I couldn't raise the ford towers any higher because it hits the a/c box, couldn't move them forward (so they can be straight up) because the brake line bracket is in the way. I really dont want to mess around with the brake lines.
I guess hoops are the way to go. I'm just having trouble visualizing it and don't want to go through the trouble only to find it STILL doesn't fit.
 
Yeah, like I posted over on Mecca, I made mine with about 14" long piece of 4"sq tube with 3/16" wall and some 2"sq with 1/4" wall for the shock tabs. You can see what I did in my article in the "Product Review" section here. You could do something pretty similar with some c-channel too.
 
Thank you Scott. I have 9 feet of DOM left over so I'll find a local who can bend one for hoops. Still have to check with the rear mounting positions though.

I'll keep you guys updated when I find a suitable solution and yes, I promise to post pics of completed setup.
 
Guys,

Me and Jason did some brainstorming on repositioning the ford towers to extend the uptravel.

First option is to move the tower forward so it's between the stock shock mount and the brake line bracket, plenty of room there but will be a hair close to the steering shaft. Shocks will be close to vertical in this position, will gain approx. an inch.

Second option is to angle the towers up another inch, it will touch the a/c box but allow 3-4" instead of 2-3" mentioned in earlier posts.

Third option is to fab some shock hoops as proposed in members' replies.

Then the fourth option, kinda wild but... thought it'd wouldn't hurt to ask. Just a thought... anybody consider angling the tower 90* in the opposite direction as if the older stamped tower is used? I figure that angles the shocks further away from a vertical equation, but.... does anybody know how much or less this will affect shock performance? Remember, this option is only a thought.

We were speculating between the stamped and cast towers, and I can almost see it won't make a difference but I don't want to jump on it and find it makes things worse.
 
if you do go shock hoop route, please post pics as I would like to see how you make it on the driver's side (damn steering shaft) I'm looking for ideas
 
You've probably already figured out that when you inboard shocks in the rear, you don't need a massive travel shock because the shock doesn't have as much stroke as when it's installed pure vertical orientation.

You can probably use something quite a bit smaller out back and still not use all of it's available travel.

BTW -> To calculate shock "effectiveness" all you need to do is measure it's installed angle and compare that to 90*.... the shock will lose effectiveness proportionately as it's layed-down.

90* = 100% effective damping
45* = 50% effective damping
0* = 0% effective damping (laying paralled to the axle, so it can't do anything to control oscillations)

You can figure out any value in between those numbers with a little quick math.


:usaflag:
 
**Nerd Alert**

That will get you pretty close, but it is actually a non-linear trig problem. You need to take the sine of the angle.

angle = damping

90 = 100.0%
80 = 98.5%
70 = 94.0%
60 = 86.6%
50 = 76.6%
40 = 64.3%
30 = 50.0%
20 = 34.2%
10 = 17.4%
0 = 0.0%
 
Had to go back and check my "bible".....Herb Adams - Chassis Engineering book.

He shows values consistent with what you posted. Do me a favor and post the formula you used... :deal:


:usaflag:
 
It is just the sine of the angle multiplied by 100%.

Damping Effectiveness = sine(angle)*100%

I did it in Excel, but most "scientific" calculators have sine and cosine functions as well.
 
Pretty much what everyone is already saying, no matter what you decide try to keep the shocks as vertical as possible. I feel doing that with mine, along with good monotube shocks, has made all the difference. My truck handles awesome on the street/highway. I would argue better than it did the day it drove out of the assembly plant. And this is with 52/56 springs and obviously no sway bar.
 
*wannabe nerd alert*

Just thinkin' out loud here...

With super flexy springs, I think mounting the shocks vertical helps a ton (still retain the overall deflection capability of the springs - flex... but spring rate is "enhanced" by the shock's resistance force... the spring and shock resistance are addative... and the super flexy spring "needs" the help).

However, when the springs have a higher spring rate (shorter springs... not 52/56's/more leaves/HD), I'm thinking that mounting the shocks on the correctly calculated incline might actually help.

In this configuration, the spring doesn't really need help to do it's job on jounce (wheel travels up), but the shock does its most effective job (100% effective vertical) on rebound. This due to: if, for example, the right front wheel has experienced jounce, the (on level ground) "inclined" shock is now vertical in relation to the axle... thus in it's most effective configuration for the right front wheel's return trip to level ground (rebound). I'll have to get out the old vehicle dynamics book to check the math... if I can still make sense of the dampened system equations.

Does this make any sense... or am I just crazy?

Either way, breaking the shock's "resistance" force (tension or compression) into component forces (at 90 degrees to each other) leads to the correct equation to calculate a shock's efficiency (basic trig/geometry problem... utilizing the definition of sine).
 
You are correct that the shock damping force and spring force are addative, but obviously the shock damping force is ~roughly~ proportional to the speed of the deflection and the spring force is ~roughly~ proportional to the distance of deflection. That works great with flexy springs in certain cases. In low speed off-roading when the axles don't move up and down very fast, you pretty much only get the spring force (flexy), and on quick turns on road you get an effectively stiffer suspension due to the shock damping. However if you are doing donuts or long turns, the axle won't be moving fast enough after the initial turn-in for the shocks to help out much.

You also have to watch out that you don't weaken the shocks too much with stiff springs. The damping effect of the shocks is intended to stop the spring from bouncing up and down after a bump. Leaf springs do have some internal damping, but if you go too weak on the shocks the truck will bounce down the road. Stiffer springs require more damping to prevent oscillation.
 
*Gets out his pocket protector and taped glasses*

More than you ever wanted to know

The damping ratio (fraction of critical damping) is equal to c/(2*sqrt*(k*m)) where:

c = damping coefficient of damper (shock)
k = spring rate
m= mass (sprung mass)

IIRC, most passenger cars and light trucks use a damping ratio around 0.7.

The above equation assumes damping and spring rate are linear. Shocks and leaf springs are never linear.

The bottom line is that if you increase your spring rate (for example by a factor of 4), you need to increase your damping coefficient (in this example by a factor of 2), to maintain the same damping ratio.

*puts away pocket protector and takes off taped glasses*
 
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