Tummy tuck questions

[Turtlejon]

I have been reading quite a bit about the idea of raising the skid plate higher into the chassis, and I'm seeing some mixed reviews. If the shocks stay the same, wouldn't the CoG be higher? Is the increased clearance worth the higher CoG? Would this negate any benefits of a droop or lowered shock setup? Would it be beneficial to do both?
Thanks!!!

[mikebecher]

I didn't think of it so much as moving the skid up but rather moving the entire chassis down by shortening the shocks. On my Bomber I run the shocks at about 80% droop and still maintain decent skid clearance.

[Turtlejon]

Sure, droop or lower shocks plus tummy tuck, then. Makes sense. Any reason not to? Has anyone regretted doing the TT?

[new2rocks]

Here's my .02. It completely depends on the truck and the rest of the setup, and it's best to think of it separately from other mods like shorter shocks or shock limiters (you can do those with or without lifting the skid). On the TF2, lifting the skid is a no-brainer, because it has almost no effect on CG. The only thing that gets lifted is the t-case, which weighs nothing, so on that truck, there are only pluses. That's why Nick and I created the high clearance TF2 skid. On a rig with a center-mounted tranny and motor (stock SCX10, Wraith, Ascender, Bomber, etc), raising the skid has a bigger impact on CG and can adversely impact performance. Any benefit from less high centering and better clearance on break overs would be more noticeable on longer WB rigs (more susceptible to high centering) than on shorter WB rigs (less susceptible to high centering). So all else equal, a tummy tuck would make more sense on a longer WB rig than on a shorter WB rig, and on one where it either doesn't impact CG much (because it's only lifting the t-case) or where other changes (shock limiters, shorter shocks, etc) could offset the higher CG without otherwise compromising performance.

[Turtlejon]

I am thinking about doing this to a bomber, so long wheelbase, I'll run super droop shocks, pretty low.
I am 50/50 about doing this mod, mainly because of potential durability issues, but also because of any potential performance trade offs.
I'll be doing about equal amounts of high speed U4 bashing, and steep technical crawling.

[new2rocks]

That would be an interesting question for a Bomber. I have just enough run time on mine to know that the center skid gets in the way, but not enough to have a good feel for whether it's worth raising the skid vs. other mods like shortening the WB, switching to a Wraith skid and tranny, etc. My suggestion would be to make your other mods first and see how it performs. You can then test the tummy tuck in isolation to see if it's a net plus or minus from there. Either way, let us know what you decide.

[mikebecher]

I'd like to see the results of just a tummy tuck as well. I've done all the things new2rocks mentioned so it's hard to tell how much just the tummy tuck helps on a mostly stock rig. Heck, if it doesn't work out I'll make you a deal on a new-in-package set of side rails which I won't be using.

[Turtlejon]

Originally Posted by mikebecher

I'd like to see the results of just a tummy tuck as well. I've done all the things new2rocks mentioned so it's hard to tell how much just the tummy tuck helps on a mostly stock rig. Heck, if it doesn't work out I'll make you a deal on a new-in-package set of side rails which I won't be using.

It's really your thread that got me interested in doing the tummy tuck, Mike! Having a good deal on the parts I'd be cutting would totally make me much more likely to try it out!

I really like the idea of running it for a while, and then doing the mod without changing anything else, to isolate the variable. I am moving this week, but luckily there are tons of rocks in my new yard, and a big rocky mountain a few hundred feet away.

I will absolutely do this kind of test once i get set up in NY, and try to take before and after video.

[msrace]

If the skid is moved up with the upper shock mounts remaining the same, you will change how the suspension reacts if the links are mounted to the skid. More than likely this will increase the antisquat and further reduce traction. To me it seems like you are adding width to the lowest part of the rig causing more interference than helping.

[Turtlejon]

Originally Posted by msrace

If the skid is moved up with the upper shock mounts remaining the same, you will change how the suspension reacts if the links are mounted to the skid. More than likely this will increase the antisquat and further reduce traction. To me it seems like you are adding width to the lowest part of the rig causing more interference than helping.

Yeah, I was worried that may be the case. I hear many folks raving about how great the difference is, and several folks, most of whom haven't tried it, sounding skeptical. I am hanging up on the belly quite a bit, so it seems logical to give it a try. I'm going to put it through its paces for a while, and get a real feel for it, and then I'll mod it, I guess...

[Turtlejon]

Well, if you are running droop shocks, or lowered suspension, and a tummy tuck, wouldn't the geometry be basically the same as stock?

[Highmark]

A "shorter" body / frame is almost always better (until it hinders suspension geometry) for crawling. That could mean more ground clearance, or a lower center of gravity or a mixture of the two.

For a lower center of gravity you would adjust the pre-load in your shocks and / or raise their mounting points on the frame to bring the body down so that you're maintaining the same ground clearance and geometry, but a lower center of gravity. Think of it as lowering the frame over the skid, not raising the skid into the frame.

[Crawlin' Lobster]

I thought of it this way; Skid and trans stayed in the same place and everything else in the chassis got lower. As long as you run a droop setup.

[Hal]

TT in the Bomber may be a problem with the link mounts. Mine has a 60/40 droop setup on the shocks. I would think with the motor high up as it is with this tranny you would want to keep it low as possible. I was thinking doing shorter rear suspension using the Verterra rear arms. I don't get hung up too much now, but I run a pretty tall tire. I have the TSL Swampers 2.2 so for me it makes sense to maybe try a shorter wheel base. Interested to see what you do and how it works.

[Natedog]

Originally Posted by msrace

If the skid is moved up with the upper shock mounts remaining the same, you will change how the suspension reacts if the links are mounted to the skid. More than likely this will increase the antisquat and further reduce traction. To me it seems like you are adding width to the lowest part of the rig causing more interference than helping.

This dropping the widest part of the frame lower is why I didn't do it.

If you do tummy tuck, you gotta raise the upper shock mounts to get the full cog benefit.