TTB coil-over spring rates/lengths

[Polarcub]

really depends alot of the mounting position or the shocks too.

They will be directly over the beams on this one...

[funinthesun95]

really depends alot of the mounting position or the shocks too.

And in steps the pro.....who I would ask

[Deleted Account]

lol thanks Willy... how far out on the beam since its 4 over?

[Polarcub]

lol thanks Willy... how far out on the beam since its 4 over?

Not sure yet I will have to ask Bryan when I talk to him but I am sure we will be going as far out as we can my guess is about 2" further out than stock?

[SteveG]

Multiple coil-over threads merged....

[Polarcub]

Thanks Steve

[PaulW]

After a long search for something else I came across a couple of invoices. So here is what I have on my Bronco.
Jeremy at Spirit Racing and Brett King did the front design
Springs: Top 3.75x8x450, Bottom 3.75x22x450
Shocks: 3.0" King #30RC-R-14,
Hydraulic bumps: King 2.5"
Thus the dual rate is 225
Now days after the springs have sagged I and sitting on the bottom spring in order to get my camber to normal. The collar has been adjusted twice so far.
This maes the ride is solid over the small irregular road surface.
I wonder what these guys would suggest now.
Travel with the relieved crossover joint is about 18"
PaulW

[Polarcub]

Thanks Paul that actually is a help

[BDKW1]

How many times did the bypasses come off the truck for tuning changes?

Zero.......

There's your problem...hope he didnt pay king. Harshness isnt going to go away without pulling those shocks apart.

I wouldnt worry too much about the bypasses being a bit out of place, you should be able to close them off 100% and tune with valving, piston and spring cross over if you really had to.

2" is a shit ton or ride height to add and ride height is rarely operating height.

OK, so to fallow up on this. The front CO's had a double 20 stack on top of the regular stack kinda like a rate plate. I ditched one of the shims and opened up another bleed hole. This made the front 100% better. No more highspeed spikes and the little chatter went away. The shocks also don't cook the oil as bad.

The rear also has these but with it's motion ratio I don't think they will be a factor. Made some changes to the rear to try and put more heat into the CO's and take some out of the BP's. We'll see if it works in a couple of weeks.

Specs as of now

Front CO
.015 comp with a single .020 rate plate/,008 rebound with 3 holes open.

Front BP
Double stack .020 comp/.008 reb

Rear CO
.015 with 2 X .020 rate plates/.008 reb

Rear BP
double stack .020 comp/.008 reb.

Also, don't like the dump valves. When we ran them in the TT it felt like they didn't close fast enough and gave a little extra float. Never felt right.

[D1cker1]

I have King Dual Rate Coils
the Top one is 3.6.500
The Bottom is 3.22.700

These came off a Tundra w a LS1

Will this be too Stiff of a ride.. Or should i just see if its too my liking

Will be Running a bypass and Bumpstop On 4.5 Ext Beams

[Travisfab]

Springs: Top 3.75x8x450, Bottom 3.75x22x450

I am far from a suspension guru, but it doesn't work in my head to call this a dual rate, maybe I'm missing something or naive, but I just dont see the point.

[PaulW]

Springs: Top 3.75x8x450, Bottom 3.75x22x450

I am far from a suspension guru, but it doesn't work in my head to call this a dual rate, maybe I'm missing something or naive, but I just dont see the point.

====
Suspension design basics.
Each spring is 450lb/inch when both are operating in series the rate is 225 lb/in. No way that will hold up a Bronco. The reason you want dual rate is because we all want extreme suspension travel and a single rate cannot accomplish that. Compare with a stock setup with one spring and very little suspension travel and a single spring is good enough. This is the classical way to set up a pavement vehicle it 2 - 4" of travel like your hot rod Mustang.
Thus 2 rates are operating as the suspension cycles. IE. High rate then low rate as the suspension cycles or opposite.
There is a collar to control when the rate changes based on the suspension deflection. Leave out the collar or use a single spring and you have single rate. In the case of 2 450s the rate would be 225 with no collar.
Another way to do in is to use a progressive coil which have the property of a varialble rate based on deflection. This is also used, but dual rate argueably better. And even a progressive with 2 springs allows even more tuning for the rates, but is more complicated than simply 2 single rate springs in series with the required collar.
In the case of many Broncos like mine you cannot even see the collar because of the inner fender liner which hides everything above the lower spring. Study a racer where everything is exposed and you will see all the different locations of the collar. Go to contingency at as many races as you can and study suspensions. Or read a suspension design book which has pictures and more details.
PaulW

[d-rek]

Springs: Top 3.75x8x450, Bottom 3.75x22x450

I am far from a suspension guru, but it doesn't work in my head to call this a dual rate, maybe I'm missing something or naive, but I just dont see the point.

Because you have two springs in a series the effective spring rate is determined by 1/k=1/k1 + 1/k2 with K being spring rate in lbs/in. So for simplicity let's say you have a 100 lb/in spring. You put 100 lbs on the spring it deflects 1 in. Now stack two springs on top of each other and your total deflection is 2 in so now your effective spring rate is 50lbs/in.

[BDKW1]

I have King Dual Rate Coils
the Top one is 3.6.500
The Bottom is 3.22.700

These came off a Tundra w a LS1

Will this be too Stiff of a ride.. Or should i just see if its too my liking

Will be Running a bypass and Bumpstop On 4.5 Ext Beams

That will be way to stiff. Your main spring should be a 400 and the tender should be the lighter one they carry, I think it's a 150?

[D1cker1]

I spoke to king and the tech said it depends on how its mounted.. If its mounted vertical then my rate will work..

I'm considering trying it, but maybe taking it to mirage

[Travisfab]

the tender should be the lighter one they carry, I think it's a 150?

You sure about that?

[BDKW1]

the tender should be the lighter one they carry, I think it's a 150?

You sure about that?

No LOL. Which is why I went and looked it up just now. The other thing that doesn't make sense is the 22" long 3" spring, they only make those in 3.75.

Are these 2.5's or 3.0 shocks?

[D1cker1]

3.75 are for 3" shovks

[MOSS2]

Springs: Top 3.75x8x450, Bottom 3.75x22x450

I am far from a suspension guru, but it doesn't work in my head to call this a dual rate, maybe I'm missing something or naive, but I just dont see the point.

You only get dual rates if you use the crossover nut. The combined rate of the two springs is 225 per inch and when it hits the crossover you have the lower spring rate of 400. Seems like a pretty drastic change to be hitting right around ride height to me but I guess it works. doesnt matter if both springs are same rate to get two rates.

[PaulW]

I spoke to king and the tech said it depends on how its mounted.. If its mounted vertical then my rate will work..

I'm considering trying it, but maybe taking it to mirage

===========
The angle viewed from the side reduces the force genetated by the spring on the beam. Example a 10 deg tilt the factor would be 0.98. and 20 deg would be 0.94. Yes the king guy is correct, but in the real worlsd it does not make much difference. The classic design for a Bronco results in a tower that is close to vertical.
The angle viewed from the front is a smoke screen for a Bronco with swing axles because the angel is variable based on the deflection. Of course if one is designing a buggy with drastic angles then the cosine adjustment is very important.

Bottom line is study the rates on the other thread and see what the guys are using. The 500 that kicked off the King comment is pretty stiff. Try it then go buy something less and see what you think.
PW