deep dive by 74weld on portals

[userdude]

@Bored @Snacktime @5GENIDN @Sjortiz

So the ramification of more unsprung weight is reduced suspension response? Is this in general, or in shock load like hitting a pothole at some amount of speed? Does this cause a more lumbering feel in driving, especially at higher speeds? Will this be affected by larger (heavier) tires, I assume negatively?

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[5GENIDN]

I think you are right with most if not all the things you said, I’m waiting confirmation from @74Weld on the Dana’s 60s

when it to the suspension, that’s were I’d say you don’t really have to worry, you can always improve the shocks without affecting height much

Well the suspension will be interesting to experience. My past experience with larger/heavier tires and wheel tells me that it does change ride characteristics both in positive and negative ways. I did have Accutune re-valve some Kings for me. They replaced the King digressive valving with their linear valve and then they added restriction disks based on my vehicles weight. They are sitting in my garage just awaiting the portals as we speak. I expect my ride will improve over the stock ride but the characteristics will change... I do not doubt that at all and I can mathematically prove to myself the additional unsprung weight will have a negative effect. Anecdotally I can confirm that based on past experience. The springs and valving will counteract that. To what degree remains to be seen. Again my expectation is that ride will improve but that is only theoretical until I have it all up and running. Then I will know how well it all works together.

It is all theory until I have it all running.... I am shooting for sometime in January maybe
February if the portals and rack ship soon. ( I am old and I work slowly; I do not feel the need to rush anything).

 

[5GENIDN]

@Bored @Snacktime @5GENIDN @Sjortiz

So the ramification of more unsprung weight is reduced suspension response? Is this in general, or in shock load like hitting a pothole at some amount of speed? Does this cause a more lumbering feel in driving, especially at higher speeds? Will this be affected by larger (heavier) tires, I assume negatively?

I would not say reduced suspension response...

It is a lot more complicated than my explanation but I am a bit simple and try to break things down to their simplest form so I can understand the physics behind it SO>>>

Your wheel and tire move up and down as you traverse bumps.... That wheel and tire have mass...

a simplified view is that as they strike a bump and move upward a force has to act upon that mass to stop its upward movement. The larger that mass is the larger the force needs to be to stop that movement OR the longer period of time the same force has to act against that mass.

Now the force acting upon that is NOT simple spring rate... the force is generated by gravity. the weight of the vehicle is what is generating that force and the spring rate is adjusting how that force is applied. Shock dampening also effects this force application.

Much smarter people than me have been calculating this stuff for decades. I am relying on them. I honestly believe my ride will improve with the new coil overs I have awaiting the portals. YES the unsprung weight has a negative influence on ride. BUT... larger radius tires have a positive influence. My new springs and shocks will have a positive influence. It is all theoretical until I get it all put together and out on the road. And when you do theoretical shit there is always surprises.... both good and bad.... We will see.

 

[userdude]

I would not say reduced suspension response...

It is a lot more complicated than my explanation but I am a bit simple and try to break things down to their simplest form so I can understand the physics behind it SO>>>

Your wheel and tire move up and down as you traverse bumps.... That wheel and tire have mass...

a simplified view is that as they strike a bump and move upward a force has to act upon that mass to stop its upward movement. The larger that mass is the larger the force needs to be to stop that movement OR the longer period of time the same force has to act against that mass.

Now the force acting upon that is NOT simple spring rate... the force is generated by gravity. the weight of the vehicle is what is generating that force and the spring rate is adjusting how that force is applied. Shock dampening also effects this force application.

Much smarter people than me have been calculating this stuff for decades. I am relying on them. I honestly believe my ride will improve with the new coil overs I have awaiting the portals. YES the unsprung weight has a negative influence on ride. BUT... larger radius tires have a positive influence. My new springs and shocks will have a positive influence. It is all theoretical until I get it all put together and out on the road. And when you do theoretical shit there is always surprises.... both good and bad.... We will see.

I'll have to read that a few times to get it, thanks. Unsprung weight and the issue with gear tolerances that Snacktime mentioned seem like things that are hardest to counteract. Really interested in seeing how a stock Bronco drives with just portals on and off road, I think that would be instructive. Although I realize that going hardcore has consequences, knowing to what extent is difficult to say without butt-in-seat time (lack of comparative experience).

 

[5GENIDN]

I'll have to read that a few times to get it, thanks. Unsprung weight and the issue with gear tolerances that Snacktime mentioned seem like things that are hardest to counteract. Really interested in seeing how a stock Bronco drives with just portals on and off road, I think that would be instructive. Although I realize that going hardcore has consequences, knowing to what extent is difficult to say without butt-in-seat time (lack of comparative experience).

As far as the additional lash introduced by the portals.... I understand what Snack is saying. Yet, I do not "THINK" it will have as much effect as what Snack believes it will.... I may be wrong, maybe he is right, but again... It is all theory.

 

[Merc4x4]

I'll have to read that a few times to get it, thanks. Unsprung weight and the issue with gear tolerances that Snacktime mentioned seem like things that are hardest to counteract. Really interested in seeing how a stock Bronco drives with just portals on and off road, I think that would be instructive. Although I realize that going hardcore has consequences, knowing to what extent is difficult to say without butt-in-seat time (lack of comparative experience).

The greater unsprung mass makes it harder to keep the tires on the road (traction) and increases the work handled by the suspension (springs, shocks) increasing wear.

https://www.driveautosports.com/performance-blog/unsprung-mass-whats-this-mean-to-you/

https://www.roadandtrack.com/car-culture/a42485579/big-wheels-and-unsprung-weight-explained/

Credit: Paul Carter - driveautosports.com

 

[userdude]

The greater unsprung mass makes it harder to keep the tires on the road (traction) and increases the work handled by the suspension (springs, shocks) increasing wear.

https://www.driveautosports.com/performance-blog/unsprung-mass-whats-this-mean-to-you/

https://www.roadandtrack.com/car-culture/a42485579/big-wheels-and-unsprung-weight-explained/

Credit: Paul Carter - driveautosports.com

Interesting. Why not just go with some overlanding springs like Dobinsons to counteract?

 

[5GENIDN]

The greater unsprung mass makes it harder to keep the tires on the road (traction) and increases the work handled by the suspension (springs, shocks) increasing wear.

https://www.driveautosports.com/performance-blog/unsprung-mass-whats-this-mean-to-you/

https://www.roadandtrack.com/car-culture/a42485579/big-wheels-and-unsprung-weight-explained/

Credit: Paul Carter - driveautosports.com

Those are a couple of really good reads.... I have followed Keith Tanner at Flying Miata for years - (mentioned in the RT article)... I think it is inferred in the RT article; the area where unsprung weight has its greatest effect is at speed.... The faster you go the more effect it has.

 

[5GENIDN]

Interesting. Why not just go with some overlanding springs like Dobinsons to counteract?

Think of it this way... are you addressing the cause or the symptom?

Less unsprung weight addresses the cause, spring and dampeners can be used to address the symptoms.

 

[userdude]

Think of it this way... are you addressing the cause or the symptom?

Less unsprung weight addresses the cause, spring and dampeners can be used to address the symptoms.

Of course, I was asking the obvious question to see where it goes. I figured someone be like, "but those springs are heavier..." lol

 

[Merc4x4]

Interesting. Why not just go with some overlanding springs like Dobinsons to counteract?

I'm no expert, I'll simplify a lot, and most of what I type is conjecture, but...
Springs hold up the sprung mass and we're talking about increasing the unsprung mass. Increasing the spring rate without increasing the sprung weight will create a stiff ride. The R&T article mentions the ratio between unsprung and sprung weight is what you need to look out for.

So, I guess a full storage system, kitchen, RTT, front and rear winches, bumpers, skids with high rate springs would balance the additional unsprung weight of the portals.
Kind of a joke about all the stuff people carry. I don't know the 'magic ratio' or if one even exists.

 

[userdude]

I'm no expert, I'll simplify a lot, and most of what I type is conjecture, but...
Springs hold up the sprung mass and we're talking about increasing the unsprung mass. Increasing the spring rate without increasing the sprung weight will create a stiff ride. The R&T article mentions the ratio between unsprung and sprung weight is what you need to look out for.

So, I guess a full storage system, kitchen, RTT, front and rear winches, bumpers, skids with high rate springs would balance the additional unsprung weight of the portals.
Kind of a joke about all the stuff people carry. I don't know the 'magic ratio' or if one even exists.

Interesting. If I gather what you're saying, going from stock to portals, heavier-than-stock (hopefully lower slung) weight like more steel armor, winch, etc. combined with stiffer springs will make the balance more equal than just adding springs to a stock with portals? (This is fascinating, since we only seem to add weight as we update our rigs for off roading.) I assume this is too complicated for it to be reduced to a ratio as you say...

 

[Merc4x4]

Interesting. If I gather what you're saying, going from stock to portals, heavier-than-stock (hopefully lower slung) weight like more steel armor, winch, etc. combined with stiffer springs will make the balance more equal than just adding springs to a stock with portals? (This is fascinating, since we only seem to add weight as we update our rigs for off roading.)

Yes, that is my reasoning.

I'm guessing the common 2.5 coil-overs, especially with remote resi, can handle the increases in forces from the weight of the portals.
Increasing the spring weight would help push the tires down to road surface, but if your Bronco is too light for the heavier springs, it would ride harsh and at the extreme would cause the Bronco to ride around at the top of the shock, limiting amount of down travel. Bad for subjective ride and off-roading.

I have no idea how much real-world effect the portals will have. I would image most people getting the portals will add weight from bumpers/skids/winch.

Maybe just an armored Bronco with a bit heavier springs on a quality 2.5 coil over will make for a great handling and driving rig? You will post slower times due to overall weight increase, but we're not competing. At least, I'm not concerned about lap times; I just want a fast, good handling, 4x4 (within reason).

 

[Snacktime]

My concern is not the how it drives when new. It's the as time passes how the wear and tear effects the vehicle. Heavy suspension adds more force to the mounts and parts. Wearing out parts that are only replaceable not upgradable. That extra 20-40lbs oscillating for 25k miles is a massive amount of wear.

My interest in portals is figuring out weak point and addressing them.

Portal Modification List should include.
1) Welding the rear axle tubes
2) boxing the rear lower suspension mounts
3) boxing the rear axle link mounts
4) boxing front control arm mounts

Need to address anything that flexes as you going to put more leverage on it.

 

[userdude]

My concern is not the how it drives when new. It's the as time passes how the wear and tear effects the vehicle. Heavy suspension adds more force to the mounts and parts. Wearing out parts that are only replaceable not upgradable. That extra 20-40lbs oscillating for 25k miles is a massive amount of wear.

My interest in portals is figuring out weak point and addressing them.

Portal Modification List should include.
1) Welding the rear axle tubes
2) boxing the rear lower suspension mounts
3) boxing the rear axle link mounts
4) boxing front control arm mounts

Need to address anything that flexes as you going to put more leverage on it.

Most people are "yeah!!!" or "what are they?", and there's value in having people with experience who aren't invested in the hype as part of the conversation. I appreciate your feedback.

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