- Thread starter
- #1
Just got back from Moab and time to give an honest assessment on this somewhat controversial/debated upgrade. People have a tendency to abstain from saying anything bad after spending such a crazy amount of money on an accessory, but that’s not me and I owe nothing to 74Weld. No notes were taken real time so this will mostly be a rambling of words as they’re thought of. I’ll try to keep the different topics separated.
Drove on the interstate at mostly 85ish mph and of course there is no gear noise despite what @tmason10 tries to claim about straight cut gears in portals. We have zero CEL’s and adaptive cruise/lane assist still work without issue. Checked temps on the first fuel up after about two hours of driving. Rear portals at 160F rear diff at 192F. Front portals 91F front diff (32 spline spicer) 212F. All running new Maxima full synthetic oil. 75W140 in differentials as recommended by Dana. 75W90 in portals to 74Weld spec. Fuel economy on 40” Toyo Open Country MT at 30 psi 12.2 mpg. Increased to 14 mpg for the rest of the trip. Cruising RPM might be 2400 with the ten speed auto.
On the trail you will absolutely crawl in 4L M1. It’s fantastic. The clearance is ridiculous as anyone would expect. All the benefits that anyone has ever mentioned are very real so we’ll focus on…maybe not “negatives”…but things we learned. The first big thing we probably all realize is the vast increase in scrub radius. Pushing that 110 pound 40” tire at seven psi plus wheel plus beadlocks plus portal out 3.5” away from the pivot points is a lot for the steering rack to move. It wasn’t unexpected that there would be times the rack wouldn’t be able to keep up, but it did happen more often than we would’ve liked. Definitely need to plan the lines out where the steering can be done while moving as often as possible. Continuing the scrub radius discussion, the toe-in under droop is further exaggerated by the extension of the portals. This is made even worse with a yoke for heims rather than the Ford ball joints.
I’ll include a pixelated close up from Hells Gate where passenger tire is straight but driver is toed in under full droop. I thought maybe we knocked the alignment way off on high dive and I just hadn’t noticed it, but after she got to the top I measured it out and it’s fine. Another interesting observation is that this combination of IFS and huge scrub radius made it very important to be smooth with throttle control and braking modulation. Sudden lifting of the front from throttle or diving under braking can cause a deviation from the planned line whereas under the same scenarios it wasn’t an issue on rigs equipped with a long travel suspension. Mrs. Sierra Bronco has a newfound ambition to become proficient with two footed driving and pushing through the brakes. Will also do more experimenting with the one pedal driving option to see if that is better than what humans can accomplish. We’re definitely happy that our Wildtrak has rock crawl mode to help with throttle response, but driving skills will be improved on as well.
Also when planning lines it’s important to note the additional clearance will make the rig behave differently compared to similar builds without portals. We reached out to a local that is also a guide and Bronco Offroadeo instructor as we hadn’t done Cliffhanger or Pritchett before and wanted an experienced person with us. This wasn’t his first Bronco on 40’s, but it was the first one with portals. On the way down from Cliffhanger there’s an optional obstacle where you pivot your rockslider off of a rock to straighten up with the drop. Ours started to pivot, then popped up over the rock and hoo lawdy was it close to rolling. He was beating himself up on what happened when we pointed out we’re likely 4” higher on the frame compared to the other rigs, with UHMW skids, and our body mounted sliders are 1.5” higher due to the body lift. Then it all made sense. Lesson learned.
Reliability wasn’t an issue. The Bronco took some massive hits on the front end but luckily all the LCA mounts had been strengthened and we also welded on double shear UCA mounts. The front passenger corner basically took the full 6100 pounds from a five foot drop (slide) with the tire turned and while metals were likely fatigued, nothing bent or broke. Not sure if the one ton bearing packs and lugs would’ve made a difference over what the other portal options come with, but it was certainly nice knowing they were beefy as hell. Don’t forget the steering knuckles. Or 1” shafts from the RK coilovers.
In summary, we found a lot of things we can improve on with our driving and spotting now that we have an idea of how the portals affect vehicle behaviors when wheeling. The effects of scrub radius increase makes sense when you think about it after the fact, we just didn’t anticipate it at the time.
Drove on the interstate at mostly 85ish mph and of course there is no gear noise despite what @tmason10 tries to claim about straight cut gears in portals. We have zero CEL’s and adaptive cruise/lane assist still work without issue. Checked temps on the first fuel up after about two hours of driving. Rear portals at 160F rear diff at 192F. Front portals 91F front diff (32 spline spicer) 212F. All running new Maxima full synthetic oil. 75W140 in differentials as recommended by Dana. 75W90 in portals to 74Weld spec. Fuel economy on 40” Toyo Open Country MT at 30 psi 12.2 mpg. Increased to 14 mpg for the rest of the trip. Cruising RPM might be 2400 with the ten speed auto.
On the trail you will absolutely crawl in 4L M1. It’s fantastic. The clearance is ridiculous as anyone would expect. All the benefits that anyone has ever mentioned are very real so we’ll focus on…maybe not “negatives”…but things we learned. The first big thing we probably all realize is the vast increase in scrub radius. Pushing that 110 pound 40” tire at seven psi plus wheel plus beadlocks plus portal out 3.5” away from the pivot points is a lot for the steering rack to move. It wasn’t unexpected that there would be times the rack wouldn’t be able to keep up, but it did happen more often than we would’ve liked. Definitely need to plan the lines out where the steering can be done while moving as often as possible. Continuing the scrub radius discussion, the toe-in under droop is further exaggerated by the extension of the portals. This is made even worse with a yoke for heims rather than the Ford ball joints.
I’ll include a pixelated close up from Hells Gate where passenger tire is straight but driver is toed in under full droop. I thought maybe we knocked the alignment way off on high dive and I just hadn’t noticed it, but after she got to the top I measured it out and it’s fine. Another interesting observation is that this combination of IFS and huge scrub radius made it very important to be smooth with throttle control and braking modulation. Sudden lifting of the front from throttle or diving under braking can cause a deviation from the planned line whereas under the same scenarios it wasn’t an issue on rigs equipped with a long travel suspension. Mrs. Sierra Bronco has a newfound ambition to become proficient with two footed driving and pushing through the brakes. Will also do more experimenting with the one pedal driving option to see if that is better than what humans can accomplish. We’re definitely happy that our Wildtrak has rock crawl mode to help with throttle response, but driving skills will be improved on as well.
Also when planning lines it’s important to note the additional clearance will make the rig behave differently compared to similar builds without portals. We reached out to a local that is also a guide and Bronco Offroadeo instructor as we hadn’t done Cliffhanger or Pritchett before and wanted an experienced person with us. This wasn’t his first Bronco on 40’s, but it was the first one with portals. On the way down from Cliffhanger there’s an optional obstacle where you pivot your rockslider off of a rock to straighten up with the drop. Ours started to pivot, then popped up over the rock and hoo lawdy was it close to rolling. He was beating himself up on what happened when we pointed out we’re likely 4” higher on the frame compared to the other rigs, with UHMW skids, and our body mounted sliders are 1.5” higher due to the body lift. Then it all made sense. Lesson learned.
Reliability wasn’t an issue. The Bronco took some massive hits on the front end but luckily all the LCA mounts had been strengthened and we also welded on double shear UCA mounts. The front passenger corner basically took the full 6100 pounds from a five foot drop (slide) with the tire turned and while metals were likely fatigued, nothing bent or broke. Not sure if the one ton bearing packs and lugs would’ve made a difference over what the other portal options come with, but it was certainly nice knowing they were beefy as hell. Don’t forget the steering knuckles. Or 1” shafts from the RK coilovers.
In summary, we found a lot of things we can improve on with our driving and spotting now that we have an idea of how the portals affect vehicle behaviors when wheeling. The effects of scrub radius increase makes sense when you think about it after the fact, we just didn’t anticipate it at the time.
Sponsored
Last edited:
...nice save. Thanks for sharing.
