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The only thing I don't like about the wishbone's is usually the point of rotation is not where the link converge causing the connecting joint to be humongo.
True. But I guess you could also build it so that the two halves converge on the housing of a cartridge joint....however seeing as that single connection is providing the bulk of the propulsive force to the chassis, I'd want it to be kind of over built anyway...
The joint at the conversion will be a 1" Uniball, check the load rating on one of those.
The project is in concept phase, and won't be started until I build a new rear axle. I don't want to cut up my current axle mounts, as it makes the unit less sellable, and I need a larger rear axle for planned tire upgrade in 2008.
The project is in concept phase, and won't be started until I build a new rear axle. I don't want to cut up my current axle mounts, as it makes the unit less sellable, and I need a larger rear axle for planned tire upgrade in 2008.
This is why I never regeared my D44. An XJ D44, with locker, disc brakes, 3.55 gears, stock shock mounts and perches, was a very sellable item. Between selling that and my D30 locker it paid for my whole new rear axle assembly.
I didn't quite understand what you're wanting to do here (reason for this thread). Are you doing a wishbone upper and a wishbone lower? It'd be sort of a neat thing to see.
The joint at the conversion will be a 1" Uniball, check the load rating on one of those.
The project is in concept phase, and won't be started until I build a new rear axle. I don't want to cut up my current axle mounts, as it makes the unit less sellable, and I need a larger rear axle for planned tire upgrade in 2008.
The joint at the conversion will be a 1" Uniball, check the load rating on one of those.
The project is in concept phase, and won't be started until I build a new rear axle. I don't want to cut up my current axle mounts, as it makes the unit less sellable, and I need a larger rear axle for planned tire upgrade in 2008.
I'm sure it's plenty strong enough but I just wonder if it would cause any additional wear issues, possible fatique issues, and the links might end up being heavier then needed. But I guess the extra beef is probably nothing to be concerned with. I'm so used to designing for super lightweight and optimizing parts I tend to forget that is doesn't always matter on trail rigs.
I'm sure it's plenty strong enough but I just wonder if it would cause any additional wear issues, possible fatique issues, and the links might end up being heavier then needed. But I guess the extra beef is probably nothing to be concerned with. I'm so used to designing for super lightweight and optimizing parts I tend to forget that is doesn't always matter on trail rigs.
Crash, here's some calcs for you as I haven't seen any yet.
Bending stiffness is determined by SyI/c where Sy= yeild strength, I=moment of inertia of the cross section, c=distance from the neutral axis to the furthest distance on the cross section
For your baseline of 2" dia .25" wall tube you have a moment of inertia of .53594 in^4 and if Sy of the DOM you were using was roughly 42.8ksi (c=1", of half of 2"), the bending stiffness is 22938 lb*in
For a 2" square section with .25" walls you have a moment of inertia of .91109 in^4 and using the same yeild strength as above (with c=1") the bending stiffness is 38994 lb*in, which is over 50% stiffer than the baseline material.
For a rectangular section 2" x 3" with a .120" wall the moment of inertia is 1.41073 in^4 and using the same yeild strength as before (c=1.5") the bending stiffness is 40252 lb*in which is almost twice as stiff as your baseline.
This is the same calculation SAE required us to use when I was in still in school and designing our schools mini baja roll cage. It is a very good way to determine if a specific material you want to use for something is at least as good as things that are acceptable now or have worked in the past with out maintaining the exact same cross section.
I noticed you mentioned having a .250" thick bottom section for bashability and possibly a .125" top section so I assumed the same .125" for the walls and the moment of inertia is 1.81219 in^4 (slightly higher than the .120" wall rectangle I showed in the last post) which would give you a bending stiff ness of 51707 lb*in
I also looked at maintaining the your required strength at a loading not going thru the log axis of the cross section. At 30 degrees the .120 wall 2" x 3" rect. tubing will have a moment of inertia of 1.39989 in^4 which isn't much lower than the initial calc of 1.41073 in^4 for the loading along the long axis. I'm pulling my calcs from engineersedge.com calculators as my reference manuals are all at work so I 'm not sure if I believe that small of a reduction in moment of inertia due to rotating it 30 degrees.
Anyways, sorry my calcs are so late as the original post was started months ago, but I thought at least someone may be able to benefit from it even if your already started on your winter project.
No problem, sorry I didn't see this thread sooner. I'm just starting on my first few custom parts right now with a traction bar/crossmember/rock rails.
