2004 6.0 NV4500 Tahoe

[randeez]

i meant it in the nicest way <3

yes the coil over assembly is at its max extended length until you put the weight of the vehicle on it, which you want it to compress the spring into the happy zone (ride height) of the shock.

you need to determine the length between mounting points at ride height, spec a shock that has a decent balance between compression and extension at that height. the shocks have a spring length to follow for the most part, 8"10" 12" or so. that allows the full use of travel by the shock without running into coil bind on the spring.

if the spring wasnt captured then yes, he would just be moving the lower perch.

from the site he linked:

SETTING THE RIDE HEIGHT RIGHT

Chances are you picked up that set of adjustable coilovers for no other reason than to establish a specific ride height. Many coilovers allow you to do this in two ways: by compressing or uncompressing the spring by way of a pair of jam nuts at the spring perch—which will alter preload—or by threading the shock's base up or down—which will alter shock travel.


he cant alter the shock travel as expressed, it has a set compressed and extended length

 

[Dantheman1540]

Damn shots fired from the Randy!

But he is right that preloading doesn't change the spring rate. "By now you ought to understand preload won't change your spring rate, and when applied conservatively, it won't affect handling. Every spring should be subjected to at least some preload."

 

[Dantheman1540]

On another note Summit thinks my Hellwig package was damaged in transit and repaired by UPS. They are sending me a whole new 7702 kit bar, bushings, brackets, and end links. If someone is interested in a front bar let me know, would prefer to not have to ship it.

 

[pwtr02ss]

View attachment 268285

Don't get me all hot and bothered this early in the morning.

 

[Dantheman1540]

Don't get me all hot and bothered this early in the morning.

Thank you! It is winter so being hot and bothered is a good thing.

 

[iamdub]

i meant it in the nicest way <3

yes the coil over assembly is at its max extended length until you put the weight of the vehicle on it, which you want it to compress the spring into the happy zone (ride height) of the shock.

you need to determine the length between mounting points at ride height, spec a shock that has a decent balance between compression and extension at that height. the shocks have a spring length to follow for the most part, 8"10" 12" or so. that allows the full use of travel by the shock without running into coil bind on the spring.

if the spring wasnt captured then yes, he would just be moving the lower perch.

from the site he linked:

SETTING THE RIDE HEIGHT RIGHT

Chances are you picked up that set of adjustable coilovers for no other reason than to establish a specific ride height. Many coilovers allow you to do this in two ways: by compressing or uncompressing the spring by way of a pair of jam nuts at the spring perch—which will alter preload—or by threading the shock's base up or down—which will alter shock travel.


he cant alter the shock travel as expressed, it has a set compressed and extended length

Now I'm confused as to what we're talking about. Talking about his coilovers uninstalled, unloaded, sitting on his work bench, at the supplier's warehouse, etc. is pointless as far as I'm concerned. He has them installed. They are compressed X amount- both the springs and the shocks. If he were to raise or lower the perch, the spring and shock piston/rod would raise or lower that same amount. This would lift or lower the truck. But the load capacity, spring rate, ride quality, etc. wouldn't change. The spring wouldn't compress unless he raised it so much that the shock's length were maxed out and he continued cranking up on the perch.

 

[randeez]

Now I'm confused as to what we're talking about. Talking about his coilovers uninstalled, unloaded, sitting on his work bench, at the supplier's warehouse, etc. is pointless as far as I'm concerned. He has them installed. They are compressed X amount- both the springs and the shocks.

If he were to raise or lower the perch, the spring and shock piston/rod would raise or lower that same amount. raising the perch doesnt raise the spring from a position stand point, it applies preload. you can only lower the perch until there is no preload on the spring, if you lower it beyong that the spring will be loose in the shock when suspension unloads

This would lift or lower the truck. correct with the springs ability to support weight though.

But the load capacity, spring rate, ride quality, etc. wouldn't change. pretty much correct, load capacity and spring rate dont change. you can put too much preload in the spring and ride quality will suffer if youre using wrong spring rates, ie if dan wanted 36" fender height so he added abunch of preload where the truck would sit another 1.5" higher. he would have a lot more energy stored in the spring to overcome before he would have any compression on his suspension.

The spring wouldn't compress unless he raised it so much that the shock's length were maxed out and he continued cranking up on the perch. im not sure where we are not connecting, for these coilovers that is exactly what has to happen. you cant have the spring loose between the perches.

if the extended length is 20" a spring with no preload is going to compress with the vehicle weight on it.

the same 20" shock with 4" of preload on the spring is not going to compress at all until you over come that stored energy. its still 20" long tho

 

[iamdub]

I still don't get it. There is no "preload". The weight of the vehicle is on the coil, so the coil is loaded. I guess you could call that its "preload" since there would be more loads to come as he drives. It would be loaded more (dynamically) as the suspension is compressed during driving. But, it's just loaded nonetheless. With the weight of that corner of the vehicle on the coil, it will compress a certain amount until the spring rate and the weight acting on it balance out and that's it.


Here's my angle:

If I were to hold my hand out and set a lightweight spring in it (think wastegate spring), then set a 5 lb book on top of that spring but kept my hand perfectly still, the spring would compress X amount. If I raised my hand, you're telling me that the spring would compress (assume more preload) while the book would remain at or very near the same height in relation to the ground?

I bet that if Dan cranked up on the perch as far as he could without hitting the maximum extension of the shock and measured the coil's overall height, then lowered the perch as far as he could without the shock hitting its internal bump stop or any other suspension component hitting whatever limits its movement and measured the coil's overall height, the two measurements would be the same, within a tiny fraction. There would be a little weight change acting on the spring due to the shifted weight of the vehicle.

 

[randeez]

theres no preload unless you tighten the coil past the "free" length. setting the jam nut up against the spring to where it can barely move within the shock is for the most part the free length.


your analogy doesnt work because we are always starting with the shock at fully extended length before you put any weight on it. the two mounting points can never be further apart than the shock. for your analog to work it would be like putting the jack under the control arm and lifting. youre moving the mounting points not putting preload into the spring

if you start with a 20" shock and put an 800lb/inch spring on it with no preload. 2400lbs is going to compress the spring 3 inches.

same 20" shock but you put an inch and a half of preload on the spring (1200lbs) when you put 2400lbs on it there is already 1200lbs pushing back out so only 1200lbs of it further compresses the spring. because our mounting mounts are a fixed 20"apart you've only brought them 1.5" closer together with the truck weight

dans going to have to do the science

 

[pwtr02ss]

I'm completely lost but I'm enjoying the read