74Weld Portal Review

[BAUS67]

The stacked spacers though

Needed sum of dat high posative offset for da whells.

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[03SVTL]

It makes sense.... Why does a vehicle bounce? because you are loading up torque and then releasing it.... The springs respond. It is a lot easier to load up torque on the axle and suspension when you have a lever arm.

Portals in the rear affect the anti squat value, ie it increases it due to a combination of factors, one of them being a rise in CG. Anti squat is useful for situations where you don't want the rear to compress, but rather put the power to the ground. That's great if you have traction, but when traction is uneven, you're gonna get that oscillation. Drag cars have high anti squat values, that's why you see the rear suspension extend as it goes down the track. But the minute the track's conditions isn't ideal, they'll readjust the links, mostly affecting the anti squat value.

Trophy trucks is the exact opposite, they want the rear end to squat for maximum suspension compliance over uneven terrain. Most OEM's setup for less anti squat for road compliance.

It's a compromise, just like running 40" tires. I would run 74Weld portals as they're the only proven aftermarket portals to withstand racing conditions. They've been around longer than the YouTube influencers talking nonsense on off road parts. While their portals might be solid, the rest of the vehicle....not really 74Weld's responsibility (ie, I blew up my transmission, driveshaft, and differential when I stuffed in a 3000hp pro mod hemi...what gives?).

 

[5GENIDN]

Portals in the rear affect the anti squat value, ie it increases it due to a combination of factors, one of them being a rise in CG. Anti squat is useful for situations where you don't want the rear to compress, but rather put the power to the ground. That's great if you have traction, but when traction is uneven, you're gonna get that oscillation. Drag cars have high anti squat values, that's why you see the rear suspension extend as it goes down the track. But the minute the track's conditions isn't ideal, they'll readjust the links, mostly affecting the anti squat value.

Trophy trucks is the exact opposite, they want the rear end to squat for maximum suspension compliance over uneven terrain. Most OEM's setup for less anti squat for road compliance.

It's a compromise, just like running 40" tires. I would run 74Weld portals as they're the only proven aftermarket portals to withstand racing conditions. They've been around longer than the YouTube influencers talking nonsense on off road parts. While their portals might be solid, the rest of the vehicle....not really 74Weld's responsibility (ie, I blew up my transmission, driveshaft, and differential when I stuffed in a 3000hp pro mod hemi...what gives?).

I will admit you do know squat.....

I think you might have missed the entire two year conversation about aerospace engineering. While I do not think anyone is blaming 74 for failures influenced by upstream or downstream design changes, there have been some concerns about Loctite though.... We are all blaming the Chinese and Temu. But I should give that discussion a brake (please do not correct that intentional misspelling).

So how exactly is squat/anti-squat causing the "bounce".... I agree it is definitely a factor... My comment was simply amplifying what I thought was obvious.... A longer lever arm exacerbates the conditions in which it exists.

I am trying to suss out your recommendation... Are you saying that we should be "readjusting the links" to address hop? By links I assume you mean trailing arm length. Please advise if you have an idea of some other link to be adjusted. And how concerned should we be about the pinion angle? But that still would not address the "uneven" traction situation. And then there is the issue of articulation that is not really addressed at the drag strip.

Sorry I must be a little slow because I think I am missing the point you are trying to make.

 

[SierraBronco]

It's a compromise, just like running 40" tires. I would run 74Weld portals as they're the only proven aftermarket portals to withstand racing conditions. They've been around longer than the YouTube influencers talking nonsense on off road parts. While their portals might be solid, the rest of the vehicle....not really 74Weld's responsibility (ie, I blew up my transmission, driveshaft, and differential when I stuffed in a 3000hp pro mod hemi...what gives?).

Sa’ar, you forgot about the aerospace engineering

 

[03SVTL]

I am trying to suss out your recommendation... Are you saying that we should be "readjusting the links" to address hop? By links I assume you mean trailing arm length. Please advise if you have an idea of some other link to be adjusted. And how concerned should we be about the pinion angle? But that still would not address the "uneven" traction situation. And then there is the issue of articulation that is not really addressed at the drag strip.

Not the length, the pivot points, probably at the frame to modify the instant center which affects how much anti squat you get. Adjust instant center, reduce anti squat, improve traction over uneven surfaces. The issue posted in the video wasn’t an articulation or travel problem. It was climbing a fairly flat hill, albeit steep.

Pinion angle will depend on how much adjustment you’d need to reduce anti squat. If it’s a lot, that’s a can of worms.

 

[87-Z28]

So how exactly is squat/anti-squat causing the "bounce".... I agree it is definitely a factor... My comment was simply amplifying what I thought was obvious.... A longer lever arm exacerbates the conditions in which it exists.

Exactly this.


The distinction between loading and response is necessary. For the scenario of interest, body rotations in the for-aft and up-down plane must be considered. So pitch motions.

The loading occurs from traction forces at the tire/ground interface generated by torque at the wheel hub. That torque is multiplied by the portal gear ratio. The torque from the portal box also adds a moment at the axle shaft due to the moment arm (leverage). This doesn’t exist in non portal configuration. First plot shows a free body diagram. Second plot shows the increased reaction forces at the lower link due to portals. Link forces in non portal rig are fairly symmetric. Lower link forces for portal rig can double.

Now the response to this loading. If instant center for rear links is located on 100% anti squat line then the links will take all of the load and the springs will not be loaded. This is however not the case with the Bronco platform with oem link hard point locations. Plots 3, 4, & 5 show the “effective” anti squat for oem on 35s (sas), oem on 38s with a 3” suspension lift, and portals on 40s. Notice instant center moves further away from 100% anti squat. Hence the springs will need to respond to applied loading.

Springs are only slightly more engaged for portal build (as compared to a typical non portal build on 38s), but applied loading is more severe in portal rig. This will begin to engage pitch motions and thus portal bounce. The applied loading is the cause.

 

[5GENIDN]

Not the length, the pivot points, probably at the frame to modify the instant center which affects how much anti squat you get. Adjust instant center, reduce anti squat, improve traction over uneven surfaces. The issue posted in the video wasn’t an articulation or travel problem. It was climbing a fairly flat hill, albeit steep.

Pinion angle will depend on how much adjustment you’d need to reduce anti squat. If it’s a lot, that’s a can of worms.

While I can see that would be very helpful at the track... Where you have a wrenching bay (a place to work on the vehicle) and you are trying to work on a single obstacle.... one track with one frictional coefficient and you are trying to find the best set up for that one exact scenario (obviously different from "last weeks track". On the trail, every single obstacle is different. In fact the "best setting" will change as you move through the obstacle. adjusting the IC for each obstacle, let alone for each change while traversing the obstacle seems unrealistic. While I will not disagree that it is possible a single setting might be a better overall setting than another, On the trail you just are not going to be changing that constantly. And that will change based on vertical angle and a changing frictional coefficient. Unlike the track, the trail also requires that rear axle to move (articulate) considerably in ways that the track will never see.

I think the point of the discussion was that portals increase "hop" over a traditional axle set up. I honestly do not think that can be argued against.

How I have addressed it is by replacing all of the polymer factory bushings in the upper and lower trailing arms with a more ridged Johnny Joint.... By minimizing as much deflection in the axle angularity as I can helps to address this issue. It sure as hell does not eliminate it though. Now the Johnny joint does have some give because it does use a polymer to encase the hiem. But that is a compromise that benefits ride. They are a lot stiffer with much less give than the stock bushings as far as indentation load deflection (helping to minimize angular deflection).... They are also a lot more flexible and articulatable as far as designed allowable axle articulation. Again it is all compromises. Benefit one area and it costs you in another.

You may well be right that moving the IC would benefit and help minimize hop. I just do not know how you are going to find and adjust the set up for each trail let alone each obstacle while still maximizing clearance and articulation. There are a number of examples in the race trucks.... But they have all gone to no portal in the rear. I think there are several reasons for that but I am guessing because I am not making those decisions for them. I am still running my rear portals, because right now, the trails I am running, it is to my benefit. I still get hop occasionally but I have maximized clearance and then tried to address articulation as a secondary concern (on different trails that would be my primary) I am not a racer though. Currently I benefit more from the additional clearance. I move relatively slow. Again pros and cons to every single set up.

 

[5GENIDN]

Springs are only slightly more engaged for portal build (as compared to a typical non portal build on 38s), but applied loading is more severe in portal rig. This will begin to engage pitch motions and thus portal bounce. The applied loading is the cause.

THIS^^^^

 

[userdude]

I would run 74Weld portals as they're the only proven aftermarket portals to withstand racing conditions.

Just keep in mind, the ones they sell to the consumer are not the "race proven" competition portals. As far as I understand, they're a completely different product with different specs, materials, etc. YMMV.

 

[SierraBronco]

Just keep in mind, the ones they sell to the consumer are not the "race proven" competition portals. As far as I understand, they're a completely different product with different specs, materials, etc. YMMV.

Just remember, it is not the OEM’s responsibility to make sure their parts are stronger than the race proven accessories people bolt on to them.

Wait…

 

[userdude]

Just remember, it is not the OEM’s responsibility to make sure their parts are stronger than the race proven accessories people bolt on to them.

Wait…

 

[Dannebrog53]

I realize it’s a little early to make a determination since the Turn Off-road portals are just now getting into consumers hands and on their rigs. That being said any thoughts on their brake mount design? It would appear that being machined into the housing should eliminate the bolt loosening etc. issues we’re experiencing with our 74Weld portals. Again too early to tell and if we’ve learned anything it’s to wait and see.

 

[SierraBronco]

I realize it’s a little early to make a determination since the Turn Off-road portals are just now getting into consumers hands and on their rigs. That being said any thoughts on their brake mount design? It would appear that being machined into the housing should eliminate the bolt loosening etc. issues we’re experiencing with our 74Weld portals. Again too early to tell and if we’ve learned anything it’s to wait and see.

Yeah they made their brackets part of the structure like Werewolf. I doubt they’ll have any problems with the brakes falling off.

With the brackets I made that utilized the dowels that were originally supposed to be used on the 74 portals we put 7000 or 8000 miles on them without an issue. That pin is responsible for so much force that even with the brackets nesting tightly into the portal housing the 7075 aluminum deformed. They clearly took shortcuts by pulling the pin originally engineered for those brackets. Turns out not everything is a race and sometimes it’s better to do things right rather than quickly.

 

[TruckCamper]

With the brackets I made that utilized the dowels that were originally supposed to be used on the 74 portals we put 7000 or 8000 miles on them without an issue.

I see the issue... everyone knows races are less than 1,000 miles. SO.... you got your use 7-8 times over. You should probably pay extra for that. That's some serious distance! Making me reconsider portals again.

 

[SierraBronco]

I see the issue... everyone knows races are less than 1,000 miles. SO.... you got your use 7-8 times over. You should probably pay extra for that. That's some serious distance! Making me reconsider portals again.

Only cost me two grand to fix what should have been done the first time around!

For the final verdict we gotta factor in all the times that the brakes almost fell off at 200-500 miles

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