Ford's new F-150 SVT Raptor made an appearance in my driveway recently, and it created a bit of a stir. My tweenage daughters wouldn't ride in it. My wife didn't want any of her friends to catch her in the thing. They complained of the "kindergarten mess" graphics flanking the sides of it (an option, I told them) and compared it to a real-life sandbox toy (that part's right.)
On the other hand, the Metal Mulisha dude with the flat-billed hat down the street thought it was uber-cool. So do I. Who cares if it broke my floor jack? (To be fair, my aging floor jack popped a seal on the previous walkaround. The Raptor's burliness merely finished it off.)
Anyway, let's get to it...
Starting in the rear, we can see that the Raptor is suspended by a live rear axle, a leaf spring package and some radical-looking shock absorbers -- more on those in a minute.
In this picture the jackstand is hidden behind the brake rotor, where it is supporting the axle directly. The suspension is therefore loaded as if the truck were sitting normally on its tires, which means you can't see the impressive 12.1" of rear suspension travel, the majority of which is "droop" travel you'd only see by jacking the truck by its frame -- or by jumping it.
These leaf springs look fairly soft, with only two main leafs. The third "helper" leaf (black) is short and insubstantial. It all adds up to a more-linear rear suspension that's good at gliding over whoops and ruts in the dirt, but less-than-ideal for high payloads and large trailer tongue weights.
The listed payload for the Raptor is 1,020 lbs, but that's only if the actual truck sticks close to Ford's claimed 5,863-pound curb weight. This Raptor weighed 5,957 pounds on our scales. When we subtract that from the Raptor's 6,950-pound GVWR, we're left with an actual as-equipped payload of 993 pounds for this particular truck.
But this 993 pounds must be further-reduced by the weight of the driver, passengers and any junk in the cab. Yep, you and your buddies are payload. With two 200-pounders aboard, for example, only 593 pounds remain for cargo in the bed (such as a pair of dirtbikes) or for trailer tongue weight (just barely adequate for a 6,000 lb trailer). That's an "or" folks because trailer tongue weight is considered payload. Don't expect to tow much of anything with stuff in the bed, or vice-versa.
But a softer spring package such as this is necessary to allow the long-stroke off-road travel that the Raptor delivers. Besides, the Raptor fulfills the role of dirtbike on its own.
Most modern leaf springs (a true contradiction in terms, that) have thin spacers like these between the leaves to produce a gap that reduces sliding friction between adjacent leaves as they flex.
Raptors sit 2.2 inches higher than a standard F-150 4x4, thanks in part to this 2 5/8-inch lift block between the axle and leaf spring. The lift block incorporates the contact point (white) for the urethane bump stop.
This entire rear axle housing is wider than that found in a standard F-150 4x4, in order to boost the rear track width from 67 to 73.6 inches, a 6.6-inch gain.
I've circled the tag to point out that the rear differential requires synthetic lube.
You're looking at a "Berlin eye" leaf spring end, a type characterized by a little extra wrap that brings the leaf up to the centerline of the eye. Another common leaf spring type unwraps straight off the bottom using what's called a "turned-up eye". The Berlin eye is by no means unique to the Raptor, but it is worth pointing out.
When used at the front end of the spring, like we see here, the extra wrap of the Berlin eye reduces the tendency for the axle to migrate back as the spring compresses and the eye unwinds. (After all, a leaf spring is more than a spring -- it's also a trailing arm that locates the axle.) Rearward axle migration on one side amounts to toe-out, and that can mean roll-oversteer at the loaded outer tire in corners and twitchy-ness when the rear axle strikes a large bump on one side. The Berlin eye helps to reduce these undesireable traits.
You don't need to use a Berlin eye here because the rear doesn't locate the axle in the fore-aft direction. There may be a packaging or manufacturing reason why they did it anyway, or perhaps the #1 leaf is reversible and common to the left- and right-hand sides. That's not usually the case, however.
Furthermore, the spring connects at the top of the shackle, which improves underbody clearance and packaging. The springs have to be located outboard the frame rails, as opposed to under them, to make this work. It also means that the kind of longer J.C. Whitney shackles your dad used to jack-up the back of his Dodge Duster in high school would lower this truck, not raise it.
The crowning jewel of the Raptor's rear suspension is its Fox Racing shock absorbers, a pair of inverted dampers with a remote reservoir and internal fluid bypass. Let's take them one at a time.
An inverted shock is one where the shock body and the valving & oil it contains are hung off the frame of the truck, leaving the slender piston rod -- hidden here behind a black plastic rock guard -- to be the moving part that's bolted to the axle. You get less unsprung weight this way and the stationary shock body makes it easy to employ a remote reservoir.
In a monotube application a dividing piston isolates the oil and nitrogen gas in separate chambers within the main shock body, but the "dead zone" created by this gas chamber eats into the available stroke of the shock for a given shock body length. I've been told these are twin-tube shocks, so the internal architecture may be a little different.
Either way, the remote reservoir provides extra oil volume to help the shock run cooler. And in the typical monotube application, a remote reservoir allows the dividing piston and gas chamber to be reloacted to the remote unit, leaving the entire length of the shock body available for suspension travel. High-pressure gas would be on the left side of my crudely-represented dividing piston and oil is on the right where it can flow in and out of the main shock body through a passage hidden within the blue fitting.
Most internal bypass shocks have grooves cut into the inner diameter of the main shock body, where the piston and valve rides up and down. Damping force comes from the resistance created when you try to cram oil through tiny passages in the valve, and these bypass grooves allow some of that oil to detour around the valve, thereby reducing the damping force that's generated.
Roughly speaking, an off-road truck wants less damping force in the normal at-rest position to help produce a smoother ride on basic cracked pavement and simple washboard dirt roads, so the grooves are concentrated in the middle third (more or less) of the shock's travel. But you need a lot more damping force when you land a jump, crash into a pothole or otherwise slam the suspension toward the bump stops, so the grooves disappear as you get closer to the ends to force all of the fluid through the valve as the suspension strokes past the central on-road region. Ford says the forces generated near the ends are four times as large.
These are "triple bypass" shocks, which probably means there are grooves of three different lengths inside to progressively build the force as you get closer to the end of the travel. Neat stuff.
Fox may have accomplished all of this via another mechanism, but the principle is the same. Maybe if I ask nice they'll send me one so I can cut it open for another post on another day.
Rear braking duties are the job of single-piston (yellow) sliding calipers. A remarkably open design makes it easy to see the brake pads (white) and the sliding surface of the caliper frame on which they move.
A healthy-sized mass damper protrudes from the uppermost pin on which the caliper slides, indicating that Ford engineers encountered a resonance they needed to quell.
Another huge mass damper hangs beneath one of the urethane isolaters that connect the cab to the frame.
Moving on to the front, we find a double-wishbone suspension with a high-mount upper arm (white) and a massive aluminum lower control arm. Both are longer than those found in a standard F-150 to help produce that 6.6-inch track width increase.
Another Fox shock with the internal bypass feature is in evidence, but because it's a coil-over it can't be inverted and it can't have a remote reservoir -- not without a complete suspension redesign, anyway. In a space-limited situation such as this a motion ratio less than 1:1 is of benefit, because this shock will stroke something like 7 or 8 inches as the tire moves through its 11.2 inches of travel.
You may notice that the tire is still attached. This is the point at which my floor jack died.
The high-mount design allows a relatively small upper control arm to be used, as it's greater distance from the contact patch results in lower forces at the ball joint and pivot bushings.
A long progressive urethane bump stop resides within the coils of the front spring, and it looks like some sort of wedge-shaped mounting adpater was employed to help the upper frame mount line up with the Raptor's more steeply angled shock geometry.
Here we can see where the stabilizer bar (white) attaches to the lower arm. The shock absorber's motion ratio is lower than its mounting point on the lower arm would suggest because of the angle at which it is reclined.
The aluminum lower arm is an expensive piece, but it represents money well spent.
Just so you know who did all of this.
A dual-piston sliding caliper (yellow) handles the front braking chores and they pretty much take up all the available space. The ventilated brake rotors are 13.8-inches in diameter, but some in the industry might refer to this as a 17-inch brake system because a 17-inch rim is the smallest size that will clear the caliper. It's actually a useful way to look at it.
Now this is what a 4x4 truck tire is supposed to look like: Knobbly tires with lots of sidewall to help take the edge off all those rocks and boulders. And the sidewalls of these BFGoodrich All-Terrain KO tires have three tough sidewall plies to resist rock attacks from, well, the sides.
But how much does a mounted LT315/70R17 tire and rim weigh, exactly? After all, these things are nearly 35-inches tall -- almost a full yard.
All I have to say is this: lift with your knees.
bc1960 says:
09:03 AM, 10/ 7/09
The Duster was a Plymouth. The corresponding Dodge Dart trim was a Demon. I regret being old enough to remember this.
carguy622 says:
09:09 AM, 10/ 7/09
Scares women and children? Hmm... I still think it's a cool truck.
actualsize says:
09:47 AM, 10/ 7/09
@bc1960: I hang my head in shame for getting those two mixed up.
rick8365 says:
09:54 AM, 10/ 7/09
Excellent!
(this reaction is just upon seeing the post title and pic)
crowb says:
10:02 AM, 10/ 7/09
Dan, sounds a bit scary having your floor jack die on you! I'm always apprehensive when I have to work with my floor jack and jack stands. No matter how many times I use them.
isaacl says:
10:21 AM, 10/ 7/09
wow, this is great. I cant thank you enough for going into those FOX part details. The amount of dampening capacity you describe sounds like something the General Lee would have lusted for.
I was wondering if the RAPTOR would make an appearance into the suspension walk-around.
greenpony says:
10:22 AM, 10/ 7/09
Excellent write-up as always, Dan. I enjoy basking in the knowledge of those wiser than I, so that I might some day also be as wise.
huyracing says:
10:58 AM, 10/ 7/09
i want!!!
inlinesix says:
11:45 AM, 10/ 7/09
Yup I have to agree; I like the information in these suspension walk-arounds. I did not like the tires for muddy driving though, at least on my tundra TRD. The tires handled the snow nicely.
rsholland says:
12:14 PM, 10/ 7/09
I know this truck is all about "play," and not about "work" (as in payload capacity), but only 593 pounds carrying capability with two 200 pound guys aboard as equipped? If they offer a Super Crew version (rumored I believe), and load it up with people, it will carry less weight than a Smart micro car!
cruiserhead1 says:
01:10 PM, 10/ 7/09
Dan,
Thank you for the walkaround on the Raptor! This is one I was excited and surprised to see you do!
I'm surprised FOX put the coilovers in this way and not "inverted". It would reduce unsprung weight and is common for them to be run inverted. Sway-Away, Icon, everyone designs their coilovers to run inverted from the Raptor's setup including FOX's products.
That cast LCA is beautiful! Props to Ford for making a lightweight piece rather than cheap-out on a stamped steel unit.
On the payload rating;
Obviously Ford and FOX focused all their efforts on offroad driving performance with no compromise to payload.
In this regard, it is very much like a focused desert runner. You would run a couple spares, fuel and equipment. I like how they set it up.
If you need more payload, you can easily get helper leaf springs or airbags at the rear. It's not a big deal.
The tire/wheel combo is heavy!! Those alloy wheels must be heavy as all be because 35" BFG All-Terrains are not terribly heavy.
The only thing really missing here are some air bumpstops but that is a simple modification.
Well done Ford, well done!
subaru123 says:
03:28 PM, 10/ 7/09
I love the top gear analogy "For those of you who don't know what leaf springs are it would be like going to the doctor and having him take out a jar of leeches"
sodaguy says:
04:31 PM, 10/ 7/09
Dan,
If you are going to be using your floor jack on a frequent basis, you need to purchase a better quality unit. A Hein-Werner 2-ton or 3-ton model would be a good investment.
http://www.tooltopia.com/index.asp?PageAction=VIEWPROD&ProdID=10663
http://www.tooltopia.com/index.asp?PageAction=VIEWPROD&ProdID=48199
I have the two-ton model and it has served me very well.
rick8365 says:
04:41 PM, 10/ 7/09
Thanks - had to wait til I got home to read it - enjoyed it. Every time I was reading and started to wonder why something was the way it was, the next sentence had the answer - well done. I feel like I got most of it but I'm not quite getting the stabilizer bar/lower control arm connection. I am having trouble visualizing how that moves/works.
Thanks for the write up.
roadburner says:
07:52 PM, 10/ 7/09
I take this aluminum Snap-on 1.5 ton jack/stands set to the track:
http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=76808&group_ID=19931&store=snapon-store&dir=catalog
At home I have a 25 year old Craftsman 3 ton that still works flawlessly.
actualsize says:
08:17 PM, 10/ 7/09
@rick8365: Is it stab bars in general or this specific mount?
@floorjack ideas: I'm mad at Alltrade, the company that made my departed 3.5-ton jack, because they offer no rebuild parts for "liability reasons".
My new one must be aluminum, because I'm tired of hoisting this 100+ pound beast in and out of car trunks and truck beds. It must have a 2-ton or greater capacity. I don't like the single front roller. I would like the minimum height to be 3.75 inches or less. Most difficult of all, I want to see it before I buy it.
zoomzoomn says:
04:46 AM, 10/ 8/09
carguy622 says:
09:09 AM, 10/ 7/09
"Scares women and children?"
That alone makes me want one!
rick8365 says:
06:34 AM, 10/ 8/09
Dan,
Both, I guess.... It is a little clearer to me in looking at it again. If the stabilizer is aka an anti-roll bar then I kind of understand how that works - as the truck body rolls to the side through a turn that bar resists via a torsional twist action - the thicker the bar the higher the resistance. And, in order for that to work, the body/frame has to be connected to the bar and the ends of the bar to the ground via the suspension/tires. I guess the bar can actually help reduce dive under braking too? Please clarify if I'm out to lunch. I think when I was looking at it yesterday I was thinking that by "stabilizing" it was serving more of a fore/aft locator role which didn't work in my head - and why would you need that with the upper and lower As? Assuming I am on the right track and all that said re: the bar....I don't really see how that vertical connecting bar or rod is up to the task in a couple of ways. How would that spindly rod be strong enough to transfer or carry the load it would have to carry? Or, does the rest of the suspension and the leverage of the bent part of the stab bar help to such a degree that there isn't the load I am thinking there would be? The other thing that doesn't add up is how that vertical bar can allow for the long travel in the suspension even if it is relatively inboard in the arc. I guess in that case the suspension can actually hang to some extent on that skinny piece during a jump?
Thanks for asking.
RE: the light weight floor jacks - I was a member of a part time Winston Cup team / pit crew for 2 or 3 seasons when those jacks were first appearing - what a difference. I can't blame you at all for wanting to go that way now. I think the light weight is the right call even at 2 or 3 times the price. The old heavy ones are like dead weight to move. In fact, I might have already bought one if I was you and moving it around from place to place like you said you've been doing and kept the old one just for use in your garage/driveway. Your specs/requirements sound great - good luck and keep us posted.
actualsize says:
09:12 AM, 10/ 8/09
Stabilizer bar = anti-sway bar = anti-roll bar. Some people say sway bar. Others say roll bar, though that term can be confused with a rollover protection safety device in a race car. The term Stabilizer bar is most commonly used in the industry, though anti-roll bar comes in second.
In turns, you've basically got it right. But these devices do nothing for brake dive because in that instance both lower control arms, and therefore both ends of the bar, move together, in unison (aka in-phase), so there's no twist in the bar. It simply rotates in it's frame-mounted pivot bushings, an action that generates no resitance. No bar twist = no load.
And that's also why "that skinny piece" sees little or no stress during a jump. The skinny stabilizer link only has to be strong enough to carry the force that the stabilizer itself bar can generate by being twisted. Ignore the suspension loads from jumping - the springs take care of that.
cruiserhead1 says:
10:06 AM, 10/ 8/09
The lightweight alloy floor jacks are great. The only drawback is that they are relatively expensive.
In fact, many offroaders carry them on board (especially Baja and desert racing support vehicles/ prerunners).
bodyblue says:
11:10 AM, 10/ 8/09
Dan, thanks for these walkarounds ........they are a hoot! You make things easy to understand. I am willing to listen to an expert on any subject.
rick8365 says:
06:25 PM, 10/ 8/09
Thanks, Dan. I didn't know that there were pivot bushings in th middle of the stabil-anti roll-roll bar. I guess I thought it was firmly attached in the middle so that it worked more in a halves. It make the most sense to allow the twist action to go the length of or be resisted by the length of the entire bar. And, I guess that it is either one side or the other acting on it at any given time.
.....still don't see how the skinny rod allows for the range of travel that suspension goes through. Obviously it does, it just doesn't look possible.
All interesting stuff.
zsh says:
03:10 PM, 10/ 9/09
How do you think one of these would hold up in a Baja 1000 or Dakkar Rally type of race? I'd love to see Ford sponsor a team with minimal upgrades to the truck (just safety and whatnot).
actualsize says:
04:43 PM, 10/ 9/09
ANd I'd love to be able to give you a first-hand account if they decide to do that.
aznraptor says:
12:17 AM, 10/11/09
Great Work Dan
always love the suspension walkarounds
very informative and interesting to read :)
cah11705 says:
06:16 PM, 10/12/09
Having worked with those tires, i can say that they seem to be much heavier than a typical light duty truck tire, which would help explain the weight.
kjmiller1 says:
08:44 AM, 10/14/09
Ha, I would have thought the front shocks would be considered "inverted".
Those leaf springs look pathetic and very unlike most desert truck packs, but I guess they work - probably due to having triple bypasses.
Are all of the suspension mounting points stock? Is the frame identical to a standard F-150?
Make a quad cab version with that new little diesel I've heard about :)
subytrojan says:
11:36 AM, 10/14/09
Maybe Chris can help you get a Baja 1000 ride, Dan! :o)
mathew8487 says:
02:45 AM, 12/16/09
Very informative post. 2010 Ford F150 SVT Raptor three times more stiffer than the normal F150 than also is a very comfortable ride. They can carry a load of 1000 pounds and a 6000 pound towing capacity. interiors are also quite spacious. Performance of the Raptor was undoubtedly outstanding. For more details refer http://www.macktruck.org/
eyesoreracing says:
03:48 PM, 01/29/10
Dan,
Get a Harbor Freight aluminum jack. They're dirt cheap and seemingly unbreakable. I had a $300 Griot's Garage aluminum jack blow a seal (and all the assembly fasteners siezed, rendering it unfixable) after less than 2 years. I've put a lot more "miles" on my $60 Harbor Freight aluminum jack with no issues.
cello_one says:
07:48 AM, 08/ 5/10
Dear Dan:
I would much prefer to see a permanent lift installed in the driveway outside the house instead of replacing the floor jack. You know, a nice 4 corner lift system with adjustable frame contact points. Maybe get a 10 ton limit so you can jack up the next freight liner IL has in the long term fleet. Since you are in So. Cal. you don't even have to worry about switching the hydralics out for the winter. You could plant some climbing ivy on the 4 corner supports to make the HOA happy...
Great walk around! My wife really likes the Raptor! *sigh* I REALLY tried but we couldn't justify it... Too many 1,200 mile weekends to visit the inlaws - no sand dunes, no whoops, only one washboard gravel road...
patrickw says:
11:51 PM, 08/16/10
Thanks, Dan for a great article. Well written, informative, authoritative, humorous, good use of pictures; A+!
adamb1 says:
06:30 AM, 08/17/10
I would like to see a compare/contrast with the Dodge Powerwagon. The Dodge is set up more as a rock crawler than a desert runner. The Dodge is probably more useful for truck duty being built on a 3/4 ton chassis and having a crew cab. The power output is similar between the two. Powerwagon has an interesting suspension set up with the disconnecting sway bar up front.
half_ton says:
07:19 AM, 08/17/10
Dan,
EXCELLENT work as always. Now that you have shown us both which suspension do think is more inovative; Raptor or Ram?
famof3kids says:
10:29 AM, 08/17/10
Great information...I love reading these.
Now we just need one for the motor and body.
garyabq says:
05:11 PM, 08/21/10
Thanks for the info. Maybe a bit more detail than I would have found out on my own. However, being the owner of a white Raptor -- which we've had a lot of fun taking off-road -- I can say that all of this "stuff" seems to work very well. We (wife, grandson and I) just returned from taking our truck up the Medano Pass Primitive Road in Great Sand Dunes Nat. Park. That trip made the $43K I spent on this truck money well spent! And going four-wheeles off the ground airborne in the deep sand area around Castle Creek was an added bonus. Thanks Ford!