Frame strengthening
- Thread starter bobmuley
- Start date
RobinP
Observer
I see no convenience to adding a plate to the outside of a frame, compared to adding it to the inside of a frame.
And yes, the member would be significantly more stiff if a box section were created. I would never consider adding it to the outside.
I wouldn't bother doing the work with less than 3/16" thick plate if you're working with typical grades of mild structural steel.
But on top of all that, I'd put effort into more and beefier cross bracing if you're trying to reduce frame flex. The stiffness of the connection between frame rail and cross bracing is important, more so than a bigger brace.
And yes, the member would be significantly more stiff if a box section were created. I would never consider adding it to the outside.
I wouldn't bother doing the work with less than 3/16" thick plate if you're working with typical grades of mild structural steel.
But on top of all that, I'd put effort into more and beefier cross bracing if you're trying to reduce frame flex. The stiffness of the connection between frame rail and cross bracing is important, more so than a bigger brace.
DaveInDenver
Middle Income Semi-Redneck
Boxed frames are stiffer, but that's not always preferred since they ride more truck like. I dunno why someone wouldn't want a fully boxed frame if there was a choice, but there you go. It's also heavier, so fuel economy is always a factor.
Anyway, Demello makes Tacoma frame reinforcements, if that's what you're after. I think the reason you see external reinforcements is primarily because it's easier to add than to squeeze in behind the frame and box it in. Not to mention when adding an element inside you have to measure and cut closer and welding is more critical. A lot easier to do with a bare frame and a jig.
http://www.demello-offroad.com//cat...d=108&osCsid=f274fc0ffa8878ced2b8a9433497543d
Anyway, Demello makes Tacoma frame reinforcements, if that's what you're after. I think the reason you see external reinforcements is primarily because it's easier to add than to squeeze in behind the frame and box it in. Not to mention when adding an element inside you have to measure and cut closer and welding is more critical. A lot easier to do with a bare frame and a jig.
http://www.demello-offroad.com//cat...d=108&osCsid=f274fc0ffa8878ced2b8a9433497543d
cruiseroutfit
Well-known member
Lots of reasons really...
The external frame plates do an above adequate job at addressing & solving the issue. They can be installed without removing the bed. They can be installed without removing the spare tire. They can be installed with out removing and re-routing brake, fuel, electrical, emissions and the LSPV. Additionally the shock mounts would need relocating.
Assuming you don't mind some extra work... go for it. It will be theoretically stronger and provide you with some time to get to know the entire rear configuration of your truck.
Here is all the stuff in the way (04' DC):
The external frame plates do an above adequate job at addressing & solving the issue. They can be installed without removing the bed. They can be installed without removing the spare tire. They can be installed with out removing and re-routing brake, fuel, electrical, emissions and the LSPV. Additionally the shock mounts would need relocating.
Assuming you don't mind some extra work... go for it. It will be theoretically stronger and provide you with some time to get to know the entire rear configuration of your truck.
Here is all the stuff in the way (04' DC):
ntsqd
Heretic Car Camper
For boxing in a C-section frame there is no point in using material thicker than the existing. Availability of that thickness may be an issue so I'd shoot for the nearest size available - be slightly thicker or thinner.
My preference is to form the stock into a shallow C-section that *just* fits inside of the stock rails. Figure out the OE bend radius on the inside of the stock rails and use that radius as the minimum bend radius, can go larger.
Then fit it with the edges flush and cupped side out. That exposes the edges of both pieces to a weld bead. Unless you stand the filler section proud, installing it the other way (cupped in) results in the weld bead laying on the outside of the bend. That's nfg.
I have also seen a Ford Ranger frame that was "boxed" by using small diameter tube installed at an angle, each at the opposite angle of the previous. The succession of tubes formed a "truss" type of feature. Still not sure how effective that would be, but potentially is simpler to install.
My preference is to form the stock into a shallow C-section that *just* fits inside of the stock rails. Figure out the OE bend radius on the inside of the stock rails and use that radius as the minimum bend radius, can go larger.
Then fit it with the edges flush and cupped side out. That exposes the edges of both pieces to a weld bead. Unless you stand the filler section proud, installing it the other way (cupped in) results in the weld bead laying on the outside of the bend. That's nfg.
I have also seen a Ford Ranger frame that was "boxed" by using small diameter tube installed at an angle, each at the opposite angle of the previous. The succession of tubes formed a "truss" type of feature. Still not sure how effective that would be, but potentially is simpler to install.
cruiseroutfit
Well-known member
bobmuley said:
Fuzzy line for sure.
Consider the actual failure of the rear frames is extremely rare, and to my knowledge all involved the earlier frame design which terminated the factory boxing further forward than the later frames. The one failure I have read up on involved a heavy rear tire carrier that was placing a lot of leverage on the ends of the frame rails. When the failures are rare at best, failures with the frame stiffener plates are non-existent.
For that reason I personally think the stiffener plates are both adequate and best. Best will change for others, some "best" might be replacing the entire rear chassis with tube.
DaveInDenver
Middle Income Semi-Redneck
Also keep in mind Scott Brady used the Demello reinforcements on his Tacoma and that sucker has a 7,000+ GVWR with a rear carrier and wasn't just driven to the mall and back. It seemed to hold up fine. One thing that would concern me with boxing in the frame would be rust and the Tacoma has some rust issues at the rear section as it is. Personally, the Demello-style deal would strike me as more than sufficient for the task.
taco chaser
Supporting Sponsor
If you plan on jumping your rig daily than box in the rear C. If it is going to be a daily driven trail rig with a spare tire carrier than the plates are all you will ever need. If you box in the rear completely than I would suggest a johnny joint type shackle hanger in the rear, the existing design actually allows the frame to twist just enough so the hanger dosen't rip off the frame in maxed out flex situations. Plus the frame actually has some reinforment in 3 spots creating 3 boxed sections along the rear inner C channel, it's just not completely boxed.
KG6BWS
Explorer
i looked at both options for my 04 dc. i agree with above, the amount of work to box it in isnt worth it. i put on the demello plates and have had no problems. i had a carrier on the back with my tire, a 60" hilift, and 10 gallons of gas, and have had no problems. and being 2wd, my truck gets banged around a lot. there are a lot of places where i have to use more momentum to get up and over then a 4wd would. i dont jump my truck or anything like that so ive found that the outside plates are more than enough. my .02.
SAR_Squid79
Explorer
cruiseroutfit said:
I have reinforcement plates on the rear frame of my Tacoma, those outer reinforcements are doing EXACTLY the job I needed them to do.
Over a year ago I went to Moab. In Moab, on "Moab Rim Trail", my frame flexed, and just like every other Tacoma that's been wheeled hard - my bed hit & dented the back of my cab (& knocked paint off). I had talked to Adam at 4xInnovations - who has a degree in engineering & tons of Off-Road fab experience - about this as well, and he took measurements, and made a template, and laser cut the reinforcement plates out of 1/4" steel, and welded them up. He said that doing a solid plate would be stronger than the Demello type with holes...
Since doing this rear frame reinforcement mod, the rear of my truck no longer flexes, or hits my cab. Like cruiseroutfit said - I didn't have to completely disassemble and redesign and rebuild all the components of the rear of my Tacoma. (truck bed, gas tank, fuel lines, brake lines, shock mounts, electrical wires, etc)
cruiseroutfit
Well-known member
SAR_Squid79 said:
Hmmm, thats surely debatable... I guess it would come down to the way it was installed and the goal one is attempting to achieve. Its my opinion that the holes actually increase the strength and effectiveness of the end product. Interesting your fab guy would go with the top to bottom vertical weld you have at the end of each plate, that generally isn't a sound engineering practice when it comes to welding a frame. I think regardless it won't likely present itself as an issue and obviously solved the problem you had. We have discussed the engineering aspects of frame welds in the past, I'll try and find the thread.
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