A couple of Bronco Raptor suspension questions

[DavidNJ]

I'm a bit new to the Bronco world but I'm confused about a couple of Raptor features.

A lot of work went into the Raptor suspension and it is quite impressive. It is also quite wide which was always a problem with long arm suspensions on otherwise street vehicles.

My first question is about the rear shock placement. With all the custom bracketry that went into the Raptor, why is the lower shock mount below the axle? The front has nothing below the lower control arm so this looks particularly onerous.

The next question is why they didn't use a triangulated rear suspension. To the best of my knowledge, this is common for off-road pickups, Rock bouncers, and solid rear axle Ultra4s. Allows horizontal location without a track bar. The main reason long arm kits for Jeep wranglers don't have it is that the Jeep's fuel tank is in the way. Was that also a problem on the Bronco? That fuel tank also is a problem with using the Ford Sterling 10.5 inch rear axle on a Wrangler. A triangulated suspension is common in kits for XJ Cherokees and WJ Grand Cherokees.

This picture shows the Genrite suspension for the JK Wrangler with double triangulation. Note that the fuel tank has been moved to the back. This kit is very very expensive.

Sponsored

 

[swooshdave]

Placing the lower shock mount below the axle allows for additional shock travel without having the top of the shock in the interior.

I suspect that triangulated rear suspension is ideal for rock crawling and maximum articulation. The Bronco (and Raptor) are more general off-roading so high speed stability is probably being favored over low speed. Plus triangulation would have required massive re-engineering.

I can't find a clear picture of the Bronco R rear suspension but it would be interesting to see what the used there.

 

[Werkedperformance]

front shocks are shorter than rears because they work on a less 1:1 ratio, the wheel moves more than the shock shaft. the rear shocks have to have 14'' of travel. so either you have shocks down low, or inside the cab.

the links are similar because its the same base frame. the panhard mount is the same. easier for production, less cost.

 

[DavidNJ]

Placing the lower shock mount below the axle allows for additional shock travel without having the top of the shock in the interior.

I suspect that triangulated rear suspension is ideal for rock crawling and maximum articulation. The Bronco (and Raptor) are more general off-roading so high speed stability is probably being favored over low speed. Plus triangulation would have required massive re-engineering.

I can't find a clear picture of the Bronco R rear suspension but it would be interesting to see what the used there.

Triangulated suspensions are used in Ultra4. Except where independent suspensions are used and although more expensive, independent suspensions appear to be dominating. Rock bouncers use solid axles (with custom components although GM 14-bolt heritage). However, Ultra4s with IFS have beaten them.

Further investigation shows the fuel tank is in the way. That is also why nearly all Wrangler long-arm kits (other than Genright) are not triangulated. Genright moves the fuel tank.

I'm guessing a packing problem.

They put the rear bolt of the upper control arm in front in double sheer but not the front bold. I've seen a kit that welds tabs to put both in double sheer. I wonder if that is a stock Bronco weak point and if it is it will changed on a future version.

 

[DavidNJ]

front shocks are shorter than rears because they work on a less 1:1 ratio, the wheel moves more than the shock shaft. the rear shocks have to have 14'' of travel. so either you have shocks down low, or inside the cab.

the links are similar because its the same base frame. the panhard mount is the same. easier for production, less cost.

They made so many other little mods I didn't think this would be an issue. It seems common on desert racing trucks and live axle Ultra4s to put the rear shocks on the lower trailing arm. The low trailing arm was one of the massively reinforced pieces in the Raptor.

 

[goatman2]

The rear shock mounts go below the axle to allow for longer shocks without going up into the body. Also, it doesn't really matter since the lower mount is so close to the tire that clearance will rarely be a problem since the axle lifts up with the tire as the tire goes over a rock or rut. you'd have to hit a rock that is right next to the tire that the tire doesn't go over, which would not be the preferred line. The tire should be going on the high spots so the shock would lift up with the tire and clear.

The rear suspension can't be triangulated because of fitment problems with the gas tank. It doesn't really matter here either, since the track bar is very long and pretty flat, so no negative handling characteristics from having the track bar. And, unlike a trophy truck or Ultra4 car, there isn't enough suspension travel for the track bar to be an issue. Trophy trucks and Ultra4 cars have 24-36" of rear travel, and a track bar would be a problem.

 

[DavidNJ]

WJs and XJs also have triangulated rear suspensions in long arm kits without the long travel.

You are correct, the gas tank is in the way just as it is on a Wrangler. I should have looked first.

On the shocks, however, Ford put new rear links, new mounting brackets. Added additional bracing. They could have mounted them to the trailing arm for leverage. They could have punched a hole into the trunk with a cover.

It is interesting how many strengthening changes ford made when on paper it is only 70 hp (~20 %) more power and one size taller tire than the Sasquatch. Are component failures going to be common with other Broncos in off-road use?

 

[DavidNJ]

I guess I'm not the only one who noticed the rear shock mount. Broncbuster is making a skid plate for it: https://broncbustertx.com/products/bronc-shock-skid

 

[DavidNJ]

A Lite Brite video on the Bronco from August 2021...and protective skid plates for the lower rear shock mount was one of the modifications.

 

[kodiakisland]

I see you are new here, but we had this discussion about a year and a half ago. We’d all love to have less crap below the axle, but these days we’re just happy to have a Bronco.

 

[DavidNJ]

I see you are new here, but we had this discussion about a year and a half ago. We’d all love to have less crap below the axle, but these days we’re just happy to have a Bronco.

I wasn't looking for an old post on shock mounts but rather commenting on an oversight in the Raptor.

The Raptor has all new suspension links and mostly new suspension mounting points including things like double shear on one of the upper control arm bolts. This was a known weakness as evidenced from the information and parts for the Bronco.

Is Ford Incorporated a lot of the parts that the aftermarket had made for the Bronco, it's just surprising that they didn't address this one obvious one.

 

[wilbersk]

WJs and XJs also have triangulated rear suspensions in long arm kits without the long travel.

You are correct, the gas tank is in the way just as it is on a Wrangler. I should have looked first.

On the shocks, however, Ford put new rear links, new mounting brackets. Added additional bracing. They could have mounted them to the trailing arm for leverage. They could have punched a hole into the trunk with a cover.

It is interesting how many strengthening changes ford made when on paper it is only 70 hp (~20 %) more power and one size taller tire than the Sasquatch. Are component failures going to be common with other Broncos in off-road use?

Power numbers aren’t out. It could end up being 100+ more HP.

 

[DavidNJ]

Power numbers aren’t out. It could end up being 100+ more HP.

The difference between 400 horsepower and 430 horsepower is pretty minor unless in a competitive racing class and horsepower is the bottleneck. In rock crawling and a lot of other off-road activities wouldn't the power below 2500 rpm or even below 1500 RPM be much more relevant?

 

[wilbersk]

The difference between 400 horsepower and 430 horsepower is pretty minor unless in a competitive racing class and horsepower is the bottleneck. In rock crawling and a lot of other off-road activities wouldn't the power below 2500 rpm or even below 1500 RPM be much more relevant?

In rock crawling yes, but that’s only 1 segment of off-road.

Sponsored