Issues With Big Blue!?!?!

[Gary Lewis]

Keep in mind that spring rate and spring capacity are two entirely different things.

One is how much it takes to deflect the spring X distance, and that can be progressive as well.

The other is how much the spring will be carrying at its design deflection.

I actually had forgotten that. So the numbers we've been quoting are capacities. Thanks for reminding me.

[ArdWrknTrk]

Not to doubt, but are these people who want a plush ride on road?

Or, are these people who are going on serious overlanding adventure.

Because I don't think the two are the same.

I can't say for sure, but one is "Diesel_Brad" from the FTE forum. While I don't think he does any "overlanding", he certainly uses his trucks like trucks.

And I'm not so sure that the two are that different anyway. While a lot of people use to go overlanding in buckboards, that doesn't mean that modern overlanders should aspire to have vehicles that ride like buckboards. Yes, the suspension needs to be capable of carrying the weight, but it really shouldn't have a huge safety margin on weight capacity because that leads to a harsh ride, which is hard on vehicle and passengers. And for front springs especially, the extra gear for long-term camping isn't really a factor since that's almost all on the rear axle anyway. So it's just a question of whether the front springs can handle the empty weight of the truck. Which in Big Blue's case isn't insignificant...

Bob - Do you know what accessories or engines those folks had? Or what they were going to do with the truck?

I ask because the 460, winch and bumper, and auxiliary battery really put a lot of extra weight on the front compared to what a stock truck with a 351W would have.

An issue I have is that by the time I get this thing together and test the springs I'd be surprised if Brent would want to trade. So I'm thinking that beefing up a little bit would be better. But, that assumes he can find the right springs....

See above, but no, I don't know specifically what everyone was running (although I'm sure Diesel_Brad had at least a 460 if not a 7.3L PowerStroke).

As far as whether it's better to err on the light or heavy side, that's up to you. I think I'd lean toward the light side for the (not overwhelming) reasons I've already given. But that doesn't mean that's the right choice for you.

But do keep in mind (as Jim already pointed out) that you DON'T want to match the TTB spring rate. As already discussed, the solid axle springs will seem much stiffer than the TTB springs due to suspension geometry. So compare to other solid axle vehicles.

I don't think anyone wants a buckboard ride.

But keep in mind that the f-350 front end is miles better in compliance than the 250 and doesn't bottom harshly.

Then add the RSK.

Then the superduty springs.

Even grossly oversprung it would be more compliant than a 250.

Which also brings to mind the consideration of damping rates to match load and spring rate

Compression and rebound are important and you might be best to talk to Billy about your intended use and the front weight of this truck.

I know enough about this in motorcycles but don't really have enough background with trucks off-road to make any kind of recommendations.

[Gary Lewis]

I don't think anyone wants a buckboard ride.

But keep in mind that the f-350 front end is miles better in compliance than the 250 and doesn't bottom harshly.

Then add the RSK.

Then the superduty springs.

Even grossly oversprung it would be more compliant than a 250.

Which also brings to mind the consideration of damping rates to match load and spring rate

Compression and rebound are important and you might be best to talk to Billy about your intended use and the front weight of this truck.

I know enough about this in motorcycles but don't really have enough background with trucks off-road to make any kind of recommendations.

Jim - I sure hope you are right that the "f-350 front end is miles better in compliance than the 250 and doesn't bottom harshly. Then add the RSK. Then the superduty springs." I like the sound/feel of that!

On the damping, I've been looking at the Bilsteins that Sky carries. Sky's website says:

Bilstein 5100 Series Gas Shocks

The Bilstein 5100 Series shock absorber is designed for specific manufactured lift kits utilizing the stock O.E.M. mounting configuration. It features Bilstein's superior single tube high gas pressure design for consistent fade-free performance and long life. Bilstein's patented self-adjusting valving delivers improved damping control and a smooth ride on all road surfaces at any speed.

*Self-adjusting deflecting disc valving

*Use with lift kits utilizing the stock OEM mounting configuration

*Independent rebound and compression tuning

*Limited lifetime warranty

*Superior control for large diameter tires

But, their tab on Ford 85-97 Sizing says:

*You will need to measure if you have a crossover panhard kit

(10" travel front/rear) 2" lift in the front with factory rear height 4wd F-250/350

(12" travel front/rear) 4" lift in the front with leveled rear 4wd F-250/350

(14" travel front/rear) 6" lift in the front with leveled rear 4wd F-250/350

I think from what's been said that I'll have less than 2" of lift - over a '95 F350's height. Is that correct?

If so then I'd need the 10" shock. But, I want Sky to tell me, so I sent them this:

Next questions - shocks and brake lines. I'm looking at your page on shocks and I don't know how much lift nor travel I'll really have. Again, an '85 F250 but with a '95 D60, 2003 Superduty springs, and your kit. What shocks do I need? What brake lines?

[ArdWrknTrk]

Jim - I sure hope you are right that the "f-350 front end is miles better in compliance than the 250 and doesn't bottom harshly. Then add the RSK. Then the superduty springs." I like the sound/feel of that!

On the damping, I've been looking at the Bilsteins that Sky carries. Sky's website says:

Bilstein 5100 Series Gas Shocks

The Bilstein 5100 Series shock absorber is designed for specific manufactured lift kits utilizing the stock O.E.M. mounting configuration. It features Bilstein's superior single tube high gas pressure design for consistent fade-free performance and long life. Bilstein's patented self-adjusting valving delivers improved damping control and a smooth ride on all road surfaces at any speed.

*Self-adjusting deflecting disc valving

*Use with lift kits utilizing the stock OEM mounting configuration

*Independent rebound and compression tuning

*Limited lifetime warranty

*Superior control for large diameter tires

But, their tab on Ford 85-97 Sizing says:

*You will need to measure if you have a crossover panhard kit

(10" travel front/rear) 2" lift in the front with factory rear height 4wd F-250/350

(12" travel front/rear) 4" lift in the front with leveled rear 4wd F-250/350

(14" travel front/rear) 6" lift in the front with leveled rear 4wd F-250/350

I think from what's been said that I'll have less than 2" of lift - over a '95 F350's height. Is that correct?

If so then I'd need the 10" shock. But, I want Sky to tell me, so I sent them this:

Next questions - shocks and brake lines. I'm looking at your page on shocks and I don't know how much lift nor travel I'll really have. Again, an '85 F250 but with a '95 D60, 2003 Superduty springs, and your kit. What shocks do I need? What brake lines?

Spring washer stack valving means the compression damping is speed sensitive, and will absorb harsh hits easier.

Independent compression and rebound adjustments are great for fine tuning the shock. This varies the total orifice size available to each direction of piston travel.

IDK if their Bilsteins are rebuildable, but if they are you can tune the shock by varying the thickness or number of washers of each diameter.

You can also swap the orifice disc those washers cover for one with different profile holes and area.

**Like a reed valve where you could change the ports in the cage, change the thickness of the reeds, or stack progressively smaller reeds to offer a soft initial opening.**

Of course then you need nitrogen to recharge the shock, because it doesn't oxidize the fluid and due to gas law offers progressive resistance as the shock bottoms.

The shock is under pressure to keep the hydraulic fluid from frothing and boiling as it gets forced through the damping orifices. This causes cavitation and heat.

In this way nitrogen pressure is analogous to a radiator pressure cap.

Yes, given what we've found I would say the 10" stroke shock is what you'll need.

**sorry, my inner geek got away with me. LOL **

[Gary Lewis]

Spring washer stack valving means the compression damping is speed sensitive, and will absorb harsh hits easier.

Independent compression and rebound adjustments are great for fine tuning the shock. This varies the total orifice size available to each direction of piston travel.

IDK if their Bilsteins are rebuildable, but if they are you can tune the shock by varying the thickness or number of washers of each diameter.

You can also swap the orifice disc those washers cover for one with different profile holes and area.

**Like a reed valve where you could change the ports in the cage, change the thickness of the reeds, or stack progressively smaller reeds to offer a soft initial opening.**

Of course then you need nitrogen to recharge the shock, because it doesn't oxidize the fluid and due to gas law offers progressive resistance as the shock bottoms.

The shock is under pressure to keep the hydraulic fluid from frothing and boiling as it gets forced through the damping orifices. This causes cavitation and heat.

In this way nitrogen pressure is analogous to a radiator pressure cap.

Yes, given what we've found I would say the 10" stroke shock is what you'll need.

**sorry, my inner geek got away with me. LOL **

Good to know, thanks. There are Bilsteins on the back, so it seems natural to have them on the front as well. I thought 10", but wanted confirmation on the length.

[ArdWrknTrk]

Good to know, thanks. There are Bilsteins on the back, so it seems natural to have them on the front as well. I thought 10", but wanted confirmation on the length.

I checked your link.

At that price and from what I see they aren't rebuildable, but look like a good choice for your project.

[Gary Lewis]

I checked your link.

At that price and from what I see they aren't rebuildable, but look like a good choice for your project.

Thanks! I'm getting quite a list of parts to order from Sky.