Good point! Kinda ties you in to one brand of lift, doesn't it? Which ever the frame is modelled after is the one it has to be.And if one were to want longer arms, where exactly should they go?
Good point! Kinda ties you in to one brand of lift, doesn't it? Which ever the frame is modelled after is the one it has to be.And if one were to want longer arms, where exactly should they go?
Mostly, I'm wondering how the non-factory control arm mount locations are being determined. Longer arms for the sake of length (contrary to popular belief) is not correct. The reduced weight of the frame will change the dynamics of the suspension and necessarily the mount locations as compared to a well configured mid arm setup.Good point! Kinda ties you in to one brand of lift, doesn't it? Which ever the frame is modelled after is the one it has to be.
Mostly, I'm wondering how the non-factory control arm mount locations are being determined. Longer arms for the sake of length (contrary to popular belief) is not correct. The reduced weight of the frame will change the dynamics of the suspension and necessarily the mount locations as compared to a well configured mid arm setup.
Good point! Kinda ties you in to one brand of lift, doesn't it? Which ever the frame is modelled after is the one it has to be.
I understand about 95% of the words, but follow about 50-75% of the sentences... Fairly sure you operate above my pay grade.
And you never know, I may need to do an 11m drop in
Pressure points from rocks are also a serious concern, when you drop the full weight of the jeep onto the edge of a rock 1/8" wide that's a huge amount of psi. If the outside sheath can distribute that load then great. Keep in mind that there are guys looking for something stronger that solid aluminum stock sheathed on 3x.5 wall Dom tube... Because they bend it.
—
There must have been a time
when we could have said no.
Pretty interesting concept, seems like there are a lot of pros and cons to consider. As someone who will not be subjecting his Jeep to the off-roading extremes of others, here are mine, for what they are worth.
I like the idea of no corrosion, obviously a weak point in the TJ design. This issue comes with a silver lining however- it forces me to look at my frame and suspension regularly, which I should be anyways. To me, the downside of the composite frame is my inability to quickly determine if there is an issue / pending failure. I can see bent rails, xmbrs, cracks, rust, etc. I cannot see pending failures or estimate the remaining life of a composite frame as readily.
As a non-rock crawler, my Jeep is sitting on an 18yr old frame. If I assume the average life of a frame is 15 yrs, I could expect to do the next replacement in the 2030s. Would the average consumer like me want to invest 20% more to have the composite frame? Will I even have the Jeep by then? I guess I am just not seeing the advantage, aside from the "cool" factor for the average weekend warrior.
For a "real" off-roader, I see the advantage of a low center of gravity so I do not see the advantage of a light-weight frame which would effectively raise the COG. Given that builders specifically design to lower COG, I would think composite items to reduce weight from the frame up would be more desired, but I openly admit that I have no direct experience.
Pretty interesting concept, seems like there are a lot of pros and cons to consider. As someone who will not be subjecting his Jeep to the off-roading extremes of others, here are mine, for what they are worth.
I like the idea of no corrosion, obviously a weak point in the TJ design. This issue comes with a silver lining however- it forces me to look at my frame and suspension regularly, which I should be anyways. To me, the downside of the composite frame is my inability to quickly determine if there is an issue / pending failure. I can see bent rails, xmbrs, cracks, rust, etc. I cannot see pending failures or estimate the remaining life of a composite frame as readily.
As a non-rock crawler, my Jeep is sitting on an 18yr old frame. If I assume the average life of a frame is 15 yrs, I could expect to do the next replacement in the 2030s. Would the average consumer like me want to invest 20% more to have the composite frame? Will I even have the Jeep by then? I guess I am just not seeing the advantage, aside from the "cool" factor for the average weekend warrior.
For a "real" off-roader, I see the advantage of a low center of gravity so I do not see the advantage of a light-weight frame which would effectively raise the COG. Given that builders specifically design to lower COG, I would think composite items to reduce weight from the frame up would be more desired, but I openly admit that I have no direct experience.
Interesting thread. I understand the gist of most of what is being discussed, but not all the engineering terms. Looked some of those up and skimmed the others...I'm a Bio/Chem major/minor now working in software development LOL.
OP, sorry if I missed this somewhere. With the type of design you are looking at, and costs you are noodling over, how many frames would you estimate you would need to sell before you could make this a reality?
I would think the weight would be an great advantage in some situations, like the Suzuki Samurai (less likely to sink into the mud or whatever type of soft terrain you may be on). But, a lower weight can cause traction issues on hills etc. Your point about COG is a good one (rollover potential etc.)...however I suppose this would be a good opportunity to have super beefy replaceable steel skid plates to add back some weight down low. You gain more armor, but still are at stock weight with a frame that won't rust (win/win). Perhaps a newly designed frame could come with some better options for attaching such armor.
Well Bio/Chem Major ... I am interested in Inorganic Polymers as Matrices (Polysialtes to be precise) and Inorganic Fibre reinforcements ... but don’t give up your day gig! ... just yet ...
Costing ... ya ... a real pain! ... steel products are, with the exception of casting/forging ... toolless ie no real NRC (Non-Recurring Costs) so minimal upfront costs ... purchase the stock profiles and tack them together ... perfect for test “mules” to determine functionality of the geometry ... not so for product performance where inertial properties dominate.
Composites require not only the application design (NRC) but also the “metallurgy” of the Laminate Constituent Materials (scheme), Frame Configuration dedicated Closed Form Tooling (Aluminum)(NRC) and shop infrastructure (CAPEX) ... etc etc
So after some research ... a “high performance” composite Jeep Frame should have a 10-15 year production life of up to 250 frames a year in ~6 differrent Configurations (CJ, YJ, TJ, LJ, JK, JL) NRC and RC costs, CAPEX and OPEX with 20% EBIT will be met at 250 frames/year ... not realistic for the first 2-3 years but Y4/5/6 will cover at the curve peak.
This is of course only a moderate ROI and so other vehicle Ladder Frames need to be taken on ... this reduces the CAPEX/OPEX costs for all frame types with Jeep common materials and processes ....
Hope this explains things a little ... as far as realization time ... the VCG issue needs to be resolved and simulated in a Frame Design. If ignored the 10-15y production life is at risk ... not a good idea ...
A subframe would run counter to the goal of a lift...that is increased under body clearance. In fact, a lot of us using wranglers to off-road in actually move the transmission and engine higher in the frame to increase that clearance under vehicle.So here is an idea for those with interest in low VCG (Vertical Center of Gravity) vehicles.
Given that the full suspension travel cannot be realized at the Vehicle CL ... one
could reduce the VCG on tilt/overturning moment sensitive vehicles ... install a subframe below the typical frame front, to which the Engine/Transmission mass is attached to the subframe .... theoretically a 4-6” lift would provide room for a subframe at the OEM VCG ... especially with Composite Axle Housings, Yokes ...
Too much “wacky tabbaky” or is this something to think about ...
A subframe would run counter to the goal of a lift...that is increased under body clearance. In fact, a lot of us using wranglers to off-road in actually move the transmission and engine higher in the frame to increase that clearance under vehicle.
Your idea would solve some driveline vibration issue though...similar to a T-case drop.
There is differential clearance, which is achieved by using larger tires. Then, there is chassis clearance, which is what I refered to as under body clearance in my above post.
On a Wrangler, the common low point is the skid plate under the middle of the body. That defines the Breakover angle. The less vertical height that has, the lower your breakover angle. The skid plate also contains the transmission mount...which is important to driveline angles. Go too high with the skid or with the springs, without correcting the pinion angle, there are problems. A lot of guys will install a 3 inch lift, then need to drop the skid an inch to get the drive shaft to quit vibrating. Totally counter productive, unless your only goal is bigger tires.
So, I'm hesitant to suggest you design something to actually lower the drive train. I think you'll find it to not be popular. Not to say you can't come up with something clever, but you're fighting perception again