Bilstein 5100's w/ Springs?

I have never understood why people mention "nose dive" on here so much. It's never been anything I worry about. I tend to drive like a grandpa on the road, but off the road I drive quite aggressively at times and I have never had a complaint about "nose dive" aka "brake dive".

I suppose a pickup might have more nose dive than a typical car due to the high center of gravity and front loaded weight distribution. If so, welcome to pickup life.

Nose dive is best controlled by suspension geometry, not springs and shocks. However, springs and to a lesser degree shocks can affect it too.

But anyway, based on some of your other posts, I guessing you might know that damping force is proportional to the velocity of the suspension and the spring force is proportional to the displacement of the suspension. When you hit the brakes, the front suspension starts compressing. While it's compressing the shocks and springs are applying a force in the reverse direction. If you hold a constant braking force, the suspension will eventually stop compressing. At this point the shocks are doing absolutely nothing. It's all springs. Shocks are only doing something when the suspension is moving. Springs are what determine how much nose dive there is, not shocks.

CAVEAT: if you really slam on the brakes hard or use non-constant braking force (e.g. pumping the brakes), the shocks come into play more, but it gets complicated.

BTW, I looked up the OME 885s and Headstrong reports they are 590 lb/in. Therefore they are the least capable springs (in the 600, 650, 700 family) at preventing nose dive.

 

It would be super cool if you could somehow put a torque wrench on that compressor and compare the stock spring(s) to a aftermarket spring with a known spring rate.

 

On second thought, it might be hard to compress the exact same length of each spring... I think? I've never used one, but I've seen pictures and videos.

 

I own 5 torque wrenches. 4 being snap-on. I use them often. I can tell you a torque spec by feel.

 

As a daily driver and having always had sports cars... nose dive is a big thing to me. Yes, I understand it's a truck but if I can make it handle better offroad and on road... that's a win.

Example, today I'm driving down the interstate at 70mph and a semi locks it's brakes up just ahead of me. In this situation and just random driving enjoyment, the lack of nose dive helps me keep control of the vehicle. Of course, I'm a layman and some of this could b in my head. I'm on 5100's and stock springs.

Also, there is a very good video of a company comparing many different aftermarket shocks. For the $$$ the 5100 came out on top, even beating out fox, ome, etc. If I find it I'll link it.

 

Can you explain why you think nose/brake dive effects your ability to control the truck?

 

I've seen both of their shock comparison videos. They were very subjective, non-technical, and kinda silly, but better than nothing. Some of their other videos on other topics are quite good I thought.

 

It's basic vehicle handling logic. Again, this is from an on road sports car background perspective. If u want an on road vehicle to handle better... u want less nose dive and less body roll. It's been proven in the race industry for many decades. I have no idea how this translates to offroad. I just know that the 5100's provides less nose dive and less body roll on road while also being very adequate offroad. Just my observations.

 

I don't think (but haven't done the numbers) brake dive significantly increases the front-rear weight distribution of the truck. Brake dive only changes the center of gravity of the truck a small amount which does cause weight to shift to the front, however I'm guessing the effect is quite small compared to the torque applied by the brakes on the front wheels. For example, bicycles have little or no suspension, but it is quite possible to endo by over applying the front brakes.

For similar reasons I often question why people upgrade their leaf springs because they are worried about weight being transferred to the rear due to "sag" when towing. The correct solution is a weight distributing hitch.

The dynamics of body roll are a bit different. The torque is applied by the acceleration of the turn instead of by the deceleration of the wheels and a car is less wide than it is long. Therefore maybe the center of gravity changes might make a bigger difference. Also body rolls changes the wheel camber of independent suspensions and that probably has undesirable consequences.

In any case, I don't think any of us are taking our tacos out to the track, so I don't see how these small things matter much. But then again, I modified my truck and only get it out on the trails 5-6 times a year, so maybe I am being hypocritical. Having been through the process of modifying my truck, I have learned that the mods didn't far little than I had hoped, especially the King shocks.

As I explained above 5100's cannot significantly affect brake dive under typical conditions, because they are dampers not springs.

 

See your not entirely correct damping can 100% affect brake dive. Given their digressive valving i do believe it could work in the favor of reducing the affects.
So ontop of the base valving profile you need to consider low vs high speed compression. After years of dialing in mountain bike suspension I can say with confidence low speed compression valving would greatly change the amount of dive and roll you will feel. Sane principal as when we would just to keep a bike from fully bottoming out in slower g out compressions as opposed to those fast hard hits.
So not to say your logic is out of back but it's a bit to much of a blanket statement when there's a bit more to it.

Having said all of this I have no real world experience with a 5100 directly and my suspension set up is aimed to smooth out small chattery back roads rather than have support on road. My soft swaybarless set up rolls front back side to side on road.

 

Wow, I did not realize that the old Toytec report on 3rd Gen stock spring rate was still the only reported rate measurement by most accounts, at least on TW.

 

Here is a thought experiment for you.

Given a truck with springs and shocks.

Remove the springs all at once. What happens?

The truck slowly lowers onto the bump stops.

Remove the shocks all at once. What happens?

Nothing.

Remove both the springs and shocks. What happens?

The truck crashes down onto the bump stops.

The springs are what determine the ride height under a static load. Brake drive becomes a static load once the dive reaches its lowest point.

It is true that shocks can affect the rate at which the truck dives. The greater the amount of damping, the slower it will dive. However it’s not clear if 5100’s have more damping as the manufacturers do not publish any specs.

So in conclusion, if we are talking about the total amount of brake dive under steady braking (i.e. the maximum amount the front suspension compresses), shocks have no effect. If we are talking about the speed at which the truck dives and then rebounds, shocks do matter.

As an aside, mountain bikes (I have one) tend to get ridden a lot more aggressively than your typical truck, thus the dynamic behavior of brake dive matters more. For example, there is greater tendency to slam on the brakes and then release them before the brake dive reaches steady state. The rate of dive is also probably effects the rider's balance. So I can understand your view point.

As a second aside, I also used to ride dirt bikes and they have brake dive as well. It was the least of my worries though. I was much more concerned about the suspension behavior going over bumps and dips, landing after a jump, etc.

Does brake dive give people an uneasy feeling?

 

You need to look at this a little more all around as opposed to seeing damping as 1 linear pattern. That's why I'm specifying low vs high speed here. Once I'm back I'll crank my low speed on my elkas and see if I can get a video displaying this. Until you have played with valving and had fully adjustable suspension it's a tough one to comprehend. But if you can slow down how fast the truck would sink without springs guess what it'll affect body dive and roll.

 

I understand the damping constant of shocks is not necessarily a constant (i.e. linear), but that does not change anything I said above.

 

Read the section on mountain bikes I added in an edit that you might not have seen.

 

Also read this carefully:

"So in conclusion, if we are talking about the total amount of brake dive under steady braking (i.e. the maximum amount the front suspension compresses), shocks have no effect. If we are talking about the speed at which the truck dives and then rebounds, shocks do matter."

 

This is like talking to a wall. Speed at which a shock compresses directly affects the felt nose dive while braking. I am not arguing the overall movement of the suspension travel I'm arguing the control that a shock has over the compression rate ontop of a spring rate. Take your own experiments and brake without shocks and only on springs and tell me there is no difference on the amount the front end dips under braking force.
That's why the digressive valving profile of a 5100 may indeed reduce some of the felt effects of braking dive/body roll. Compared to a linear or progressive set up.

I'm not following the other fellas argument that we want less nose dive for handling as technically you do want some squat for better weight transfer especially on taller vehicles as opposed to a road car. But simply talking a shocks impact on ride characteristics.

 

Well, your experience will vary based on spring and strut choice, but OME struts don’t have an adjustable preload setting, so each strut will move through the full range on movement. Ride stiffness will vary based on spring choice.

I went with OME because I wanted an increase in load capacity as well as lift height. I went 3” and I don’t know that 3” is possible with Bilstein 5100, but I may be wrong about that.

As far as comparison, I definitely bottomed out more often with Bilstein 5100s, but that may have been due to preload setting.

 

I don't think you understand that I am agreeing with you about shocks effect on the dynamics of brake dive. These words are straight from the words you quoted me: "shocks do matter". Please re-read what I wrote and perhaps pick out specific phrases you disagree with.