Raptor Frame bent
Member
Joined: Jun 2011
Posts: 29
Likes: 3
From: KY
If I bought a new Jeep Wrangler Rubicon and took it rock crawling, I would not be going back to Jeep for warranty work if I broke an axle. I think this is a very similar situation. Don't race or offroad a vehicle you can't afford to wad up and then walk away from. That's just how I see it, though.
First Tiger of G.R.O.S.S.
Joined: Dec 2010
Posts: 909
Likes: 13
From: Herndon, VA
This guy's posts over in the other forum is fantastic and really describes what the problem is. The summary (for those who don't want to read it) is that the bump in the road they are hitting is 18" high and quite short, which amounts to a huge impact at speed causes the frame behind the axle at the bump stop to be pushed up, creating the appearance that it was bent up in the middle.... here is his post:
Linked Here
Linked Here
Ok, I ran some numbers, and they are eye opening.
Assumptions:
The "kicker" or "dirt speed bump" is one Raptor tire diameter accross, and is shaped like two ramps joined together (like a flattened triangle).
Case #1:
Kicker height is 18" (flattened to 12" by your tires)
Truck speed is 60MPH (88 fps)
The bottom of the tire has to move up 12" in .0166 seconds. this is an average speed of 60.24 ft/s
To generate this suspension speed, the truck would have to free fall 56 FEET!!!!! That's an impressive number, but what does it mean?
It means that the truck is recieving an impact equavalent to the first 12" of a 56 FOOT DROP WITH THE SUSPENSION ALREADY HALF COMPRESSED! My best guess is that the suspension acounts for about 6" of that, the tires for maybe another 3-4", the axle for some fraction of an inch, the truck vertical motion for another small fraction of an inch (no time to respond), and the rest? It all goes into deforming the frame by 1"-2".
This also tells me that even if the frame were boxed in that area, or if it was 3 times thicker, it would still bend. Even if the frame was reinfored enough to hold, the next likely point of failure is the axle, which would bend, stranding you.
Case #2:
Kicker Height is 12" (flattened to 9" by the tires)
Truck speed is 45 MPH (66ft/s)
The bottom of the tire has to move up 9" in .0221 seconds, an average speed of 33.94 ft/s vertical.
To generate this suspension speed, the truck would have to free fall about 18 feet! This is a MUCH less severe impact! More importantly, the impact is only 9" long (insert obvious joke here). Additionally the truck may be able to absorb it without requiring metal to deform.
The suspension can absorb 6", the tires their 3", the axle a tiny bit, the truck can move upwards a bit more, and all you probably have is tortured bump stops.
So those of you who have jumped their Raptors (and the most vertical air I've seen is maybe 8-9 feet) and said they don't have bent frames? This is because hitting an 18" kicker at 60MPH is about 7 TIMES as severe. PLUS your suspension is fully extended when you jump, cushioning the fall better, unlike the speed bump example.
Conclusion? If you hit something like a speed bump or "kicker" taller than your available suspension travel, plus tire "squash", at HIGH speed, you will bend metal.
The ONLY way to adress this issue is increase suspension travel to be greator than the intended acceptable "bump". Or god forbid (*sniff), slow down. Reinforcing the frame will either fail to work (bend anyway), or cause something else to fail (like the axle).
Nobody designs trucks to withstand those forces (like the first foot of a 56 foot drop with already compressed suspension), that would be incredibly impractical (and they'd sell one a year at $300k). I do not believe there is a design flaw, I believe that somebody found a situation that exceeds its strength.
I would love to join in the next Raptor Run, jumps are fine, short gullies are fine, just look out for the big kickers when you are burnin' up the dirt!
Assumptions:
The "kicker" or "dirt speed bump" is one Raptor tire diameter accross, and is shaped like two ramps joined together (like a flattened triangle).
Case #1:
Kicker height is 18" (flattened to 12" by your tires)
Truck speed is 60MPH (88 fps)
The bottom of the tire has to move up 12" in .0166 seconds. this is an average speed of 60.24 ft/s
To generate this suspension speed, the truck would have to free fall 56 FEET!!!!! That's an impressive number, but what does it mean?
It means that the truck is recieving an impact equavalent to the first 12" of a 56 FOOT DROP WITH THE SUSPENSION ALREADY HALF COMPRESSED! My best guess is that the suspension acounts for about 6" of that, the tires for maybe another 3-4", the axle for some fraction of an inch, the truck vertical motion for another small fraction of an inch (no time to respond), and the rest? It all goes into deforming the frame by 1"-2".
This also tells me that even if the frame were boxed in that area, or if it was 3 times thicker, it would still bend. Even if the frame was reinfored enough to hold, the next likely point of failure is the axle, which would bend, stranding you.
Case #2:
Kicker Height is 12" (flattened to 9" by the tires)
Truck speed is 45 MPH (66ft/s)
The bottom of the tire has to move up 9" in .0221 seconds, an average speed of 33.94 ft/s vertical.
To generate this suspension speed, the truck would have to free fall about 18 feet! This is a MUCH less severe impact! More importantly, the impact is only 9" long (insert obvious joke here). Additionally the truck may be able to absorb it without requiring metal to deform.
The suspension can absorb 6", the tires their 3", the axle a tiny bit, the truck can move upwards a bit more, and all you probably have is tortured bump stops.
So those of you who have jumped their Raptors (and the most vertical air I've seen is maybe 8-9 feet) and said they don't have bent frames? This is because hitting an 18" kicker at 60MPH is about 7 TIMES as severe. PLUS your suspension is fully extended when you jump, cushioning the fall better, unlike the speed bump example.
Conclusion? If you hit something like a speed bump or "kicker" taller than your available suspension travel, plus tire "squash", at HIGH speed, you will bend metal.
The ONLY way to adress this issue is increase suspension travel to be greator than the intended acceptable "bump". Or god forbid (*sniff), slow down. Reinforcing the frame will either fail to work (bend anyway), or cause something else to fail (like the axle).
Nobody designs trucks to withstand those forces (like the first foot of a 56 foot drop with already compressed suspension), that would be incredibly impractical (and they'd sell one a year at $300k). I do not believe there is a design flaw, I believe that somebody found a situation that exceeds its strength.
I would love to join in the next Raptor Run, jumps are fine, short gullies are fine, just look out for the big kickers when you are burnin' up the dirt!
Ford Master Certified
Joined: Jun 2011
Posts: 307
Likes: 125
From: Texas City, TX
This guy's posts over in the other forum is fantastic and really describes what the problem is. The summary (for those who don't want to read it) is that the bump in the road they are hitting is 18" high and quite short, which amounts to a huge impact at speed causes the frame behind the axle at the bump stop to be pushed up, creating the appearance that it was bent up in the middle.... here is his post:
Linked Here
Linked Here
Senior Member
Joined: Mar 2011
Posts: 2,225
Likes: 169
I've been following the other thread and the overall problem pretty closely...
When I bought my truck (2011 FX4 SuperCrew), I strongly considered a Raptor instead. I ride off-road moto's (KTM's), even been on the same road in the video. The idea that a factory truck could even approach the kind of terrain and speeds that something like a KMT 950 Super Enduro can handle intrigued me. Ultimately, I decided the 6.2L was a NO-GO for me, and that my fast off-road fun would likely continue to be on moto's, and I wanted something better on-road, hence the FX4.
But I don't think that this is anything close to abuse, considering how the Raptor has been marketed. That isn't a "jump" in the video. That's a surprise lip that at most caused the truck to come down a bit hard on the bump stops. That kind of stuff should NOT be bending frames, and I think Ford has a problem here.
Bad News: Yup, we have the same frame.
Good News: Non-raptor owners without the killer Fox suspension and travel likely are going to slow down well before the lip, just because the ride is beating the crap out of them.
Bad News: F150/Raptor frames aren't as strong as we thought!
Good News: The F150 frame is really a multi-piece frame. The rear portion of the frame, the part that looks like it may be getting bent, can be replaced separately. Definitely not a trivial job, but it is repairable. Check out post #132 in the other thread for the details.
When I bought my truck (2011 FX4 SuperCrew), I strongly considered a Raptor instead. I ride off-road moto's (KTM's), even been on the same road in the video. The idea that a factory truck could even approach the kind of terrain and speeds that something like a KMT 950 Super Enduro can handle intrigued me. Ultimately, I decided the 6.2L was a NO-GO for me, and that my fast off-road fun would likely continue to be on moto's, and I wanted something better on-road, hence the FX4.
But I don't think that this is anything close to abuse, considering how the Raptor has been marketed. That isn't a "jump" in the video. That's a surprise lip that at most caused the truck to come down a bit hard on the bump stops. That kind of stuff should NOT be bending frames, and I think Ford has a problem here.
Bad News: Yup, we have the same frame.
Good News: Non-raptor owners without the killer Fox suspension and travel likely are going to slow down well before the lip, just because the ride is beating the crap out of them.
Bad News: F150/Raptor frames aren't as strong as we thought!
Good News: The F150 frame is really a multi-piece frame. The rear portion of the frame, the part that looks like it may be getting bent, can be replaced separately. Definitely not a trivial job, but it is repairable. Check out post #132 in the other thread for the details.
Last edited by pfbz; Jul 5, 2011 at 12:00 PM.
Senior Member
Joined: May 2011
Posts: 884
Likes: 3
From: Wisconsin
This is the result of idiots driving trucks. Hellooooo, the raptor IS NOT A BAJA RACER. Ford's Baja racer is not an F150 with springs and suspension "tuning". Its a purpose built off road frame with some f150 "components" (mostly if not entirely the engine). The raptor has "more off road" ability than an FX4 but its not an "off road racing" worthy vehicle, the bent frames are just a predictable result.
If any of the morons that damage their trucks in this way had any military expirience they would understand. Military vehicles are rated for all conditions, ergo, a five ton truck means five tons off road, on road the capacity almost triples. Commercial vehicles are exactly the opposite, they are rated for their maximum on road capacity, off road capacity is at best one third of their "rated" capacity.
BTW Ford offers the strongest fully boxed ladder frame in the industry, the dummy that wrote the article doesn't even understand what fully boxed means. If you had taken a pickup by any other manufacturer and put it through the same sort of abuse it probably would have ended as scrap.
Willingly, or not, Ford has marketed the Raptor as something it is not, its not a Baja racing worthy vehicle. What would you expect? Fords Baja racer probaly costs a million bucks plus. The cone heads that use it as such should not be surprised that it breaks when used as one. Its akin to the goofballs that raise their trucks 3 inches, fit them with monster wheels and then complain that their truck sucks too much gas and becomes a handfull to drive on the road
If any of the morons that damage their trucks in this way had any military expirience they would understand. Military vehicles are rated for all conditions, ergo, a five ton truck means five tons off road, on road the capacity almost triples. Commercial vehicles are exactly the opposite, they are rated for their maximum on road capacity, off road capacity is at best one third of their "rated" capacity.
BTW Ford offers the strongest fully boxed ladder frame in the industry, the dummy that wrote the article doesn't even understand what fully boxed means. If you had taken a pickup by any other manufacturer and put it through the same sort of abuse it probably would have ended as scrap.
Willingly, or not, Ford has marketed the Raptor as something it is not, its not a Baja racing worthy vehicle. What would you expect? Fords Baja racer probaly costs a million bucks plus. The cone heads that use it as such should not be surprised that it breaks when used as one. Its akin to the goofballs that raise their trucks 3 inches, fit them with monster wheels and then complain that their truck sucks too much gas and becomes a handfull to drive on the road
m825smoke
Joined: Nov 2008
Posts: 16
Likes: 0
From: Colorado
I've been following the post on Raptor forum, and the first time I read it I ran outside and checked mine! I've ran mine pretty quick down some back roads, but nothing like on the video! I bought mine because I wanted an off road truck, and hunting! Nothing against the other guys, but spent some money on this truck and I really don't drive it like I stole it and probably won't! MHO is Ford make the best line of trucks,and hopefully Ford finds a fix for those guys!
Senior Member
Joined: Mar 2011
Posts: 2,225
Likes: 169
This guy's posts over in the other forum is fantastic and really describes what the problem is. The summary (for those who don't want to read it) is that the bump in the road they are hitting is 18" high and quite short, which amounts to a huge impact at speed causes the frame behind the axle at the bump stop to be pushed up, creating the appearance that it was bent up in the middle.... here is his post:
Linked Here
Linked Here
Last edited by pfbz; Jul 5, 2011 at 12:29 PM.
Senior Member
Joined: May 2011
Posts: 884
Likes: 3
From: Wisconsin
I've been following the post on Raptor forum, and the first time I read it I ran outside and checked mine! I've ran mine pretty quick down some back roads, but nothing like on the video! I bought mine because I wanted an off road truck, and hunting! Nothing against the other guys, but spent some money on this truck and I really don't drive it like I stole it and probably won't! MHO is Ford make the best line of trucks,and hopefully Ford finds a fix for those guys!
m825smoke
Joined: Nov 2008
Posts: 16
Likes: 0
From: Colorado
What I'm saying is, if it's a problem with the bump stops or placement of them, suspension, or frame, they let everybody know, and not just write it off as abuse! I don't drive my truck like a crazy man, but would really be pissed if it's some wrong with the way the truck was built.
First Tiger of G.R.O.S.S.
Joined: Dec 2010
Posts: 909
Likes: 13
From: Herndon, VA
I'm not saying you are wrong, but if this guy is full of crap, I'd like to read how and why as opposed to a blanket "that is absurd math"