SMKYTXN'S 2011 DCFBFTMFW Solid Axle Swap

If anything I'd roll them down a hair, but I seriously doubt I'll buckle the upper link. I do plan on beefing up the brackets when I weld everything out.

 

Just a few degrees, 10-15, will help share the load. Center-line mounting offers no 'support' for several degrees in either direction, basically it has to pass thru it's arc until it's long enough to stop the rotation.

 

I could have this wrong but I would assume 10-15* down on the lower links. isn't the upper link suppose to help handle the force your talking about?

 

Certainly, it’s supposed to help, but not do the majority. Think about the twisting motion the axle does under power, it’s trying to drive the pinion towards the ground under a load. With the lowers at the axle centerline two things happen..first you are relying on the upper to basically take the entire load until the lowers pass through their arc and the lower link can now resist the pulling force. Think if that link bracket was just rotated just 15 degrees up, all the twisting forces would be pushing back against the link immediately. Vertical separation is the measurement you’re looking for as well, the upper and lower must be a minimum distance apart in order to properly prevent that twist. May do some searching on Pirate there is a lot of great info. Search ‘vertical separation’ for instance.

 

It doesn’t work like that.

What you describe would only happen if each link were a design in isolation instead of looking st the behavior of the system as a whole. The axle acts as a lever and the links as fulcrum. There will never be a pushing force on the lower link under acceleration regardless of the angle of the mount, the axle pushes against the upper and pulls on the lower to resist rotation. Angling the lower mounts up will only reduce the vertical separation increasing the leverage and therefore the forces applied to the links.

 

Basically we're talking compression and tension members here. With the tires driving forward the lowers are in compression and the upper is in tension. Yes, the axle wants to twist, which pushes upwards on the lower links. So the lower the lower links are on the axle tube the more they act like a compression member. If the lowers where 180 out from the upper, pointing straight down, they'd be the most effective. But then you'd be dragging them on every rock you came across.

I'm probably going to cut the tacks and rotate my lower mounts down a hair. I was looking at the lower links last night and realized I hadn't left any thread showing on the heims, well about two threads are showing. So I will extend them out a few turns and see where that puts the lower axle mounts. I'm certainly not going to cut new ones. That 2.25 x 3/8" wall DOM is spendy. lol

 

I'm well aware of the system as a whole, vertical separation and most definitely not singling out one part...however, the axle housing twists under load and until the lower axle mount passes thru it's arc (the mount will have a distance it travels up and down, While minimal the actual numbers are based on length of the mount from the housing, before it sees resistance.)

Think about this, if the lower link mount was mounted on top of the axle housing, placing the center-line of the joint above the center-line of the axle, then when the axle housing tried to twist in it's downwards motion the link would in fact see a pushing force. I'm not suggesting that's where it should be mounted rather that the mount should be 10-15 degrees above of below center to help share the load.

There are several very well versed guys on Pirate with this, please check them out (ErikB for one). Please understand I'm not claiming to be a link suspension genius.

 

Not to derail the build thread, what you are describing would only apply if the upper were mounted at the rotational center of the axle tube, in which case the lower mount would have to rotate to a sufficient angle to change the distance between the axle end and frame end mount of the lower link. This is not the case. The "arc" in your example pivots upon the axle ends of the upper and lower link mounts, the line drawn between these points is perpendicular to the linear action of the links, therefore the linear force is seen immediately by the link, no additional rotation is required before this happens.

This stuff is a lot easier to discuss visually than via text.

Geometry wise rotating the axle end lower link mount down has a few impacts, the simplest is it increases the vertical separation which will lower the linear stress on the links, joints and mounts. But it will also increase your anti dive and oversteer values, it may or may not be worth the trade off depending on what your numbers calculate out to. In other words it has the potential to make these values more or less desirable and you should run it through the calculator so you can make that determination.

 

Agreed..lol

 

Sorry for derailing SMKYTXN. This is definitely a better derail than usual though.

 

So with the new axles, the brakes and calipers are much larger than stock.
I’m curious how the stock master cylinder will hold up to them or do you have a plan to offset the loss of braking power? I’m not familiar with Tacoma braking system but I’d guess they are not powerful enough?

 

So tell me this..just how is that conversation a ‘derail’? We are discussing the details of the post made by the OP. We are talking about the design the OP pictured.
So we’re just supposed to oohhh and ahhh and not comment or in our mind try and help the guy?

Please share..

 

I'll be using the stock master cylinder, but not the one ton brakes. I'm running 3/4 ton chevy brakes all around. From what I've been told the stock master will do just fine.

 

You definitely didn't get that joke. Frankly I'm glad it came up, I've been looking into that and you guys just started talking about it.

 

Duh it's a tacoma world build thread, no tech discussions!!!

 

So been following along for awhile and I'm all for having tight tolerances and such but aren't you worried some stuff is to tight? From the look of the pictures, if your off even 1/8 of an inch things will go bad? Clean work so far though. Always will be a fan of super low rigs and big tires.

 

That’s mocked at full stuff which represents worst case scenario and clearances are greater at ride height and during normal use, unless you are jumping it’s rare that both sides will be stuffed at the same time. Still ideally the bump stops should be set to stop the axle slightly below that mock-up level because even though the joints are heims stuff still flexes and has potential to make contact.

 

Yes, some of the tolerances are close to 1/8", but as Toyo said the axle is sitting at full bump right now. The axle will be 4" lower than it's sitting now at ride height.

The struts are next up on the to do list. I'll install them such that the axle can't raise any higher than it's sitting now. The ORI's function as the bump stops.

 

Sorry brother not trying to steal your thunder

 

No worries bud!