How To: Bomber Tummy Tuck

[mikebecher]

I have devised a method to perform the tummy tuck procedure on the Bomber so I though I'd share it here. In my fit of anxiety about cutting up my perfectly good Bomber cage, I failed to take any before or during photos so I've annotated the Axial parts diagrams with what I did. There are after pictures in my Levior Wromber build thread. I'll add some disassembled close-ups in the next post.

This is a work in progress so if you have additional suggestions please let me know so I can modify the procedure. After writing up the whole procedure it seems much more complicated than it did in my head. If something doesn't make sense or is missing please mention it!

There are a couple of things to note about this mod:

1. It requires removing quite a bit of material from the cage lower rails and this is going to reduce the strength. If you drive like Maslin it's likely to break.
2. I did mine with a Wraith skid. The Bomber skid appears to be similar enough that it should work as well.
3. The mod shifts the skid plate forward by about 1/8".

The first task is to trim the cage lower rails and remove all the material below the upper cross member.
Also remove the shoulders around the screw holes on both sides.
The goal here is to prep the upper cross member to receive the skid.
(Both steps need to be done on both rails even though I just have it annotated on one in the picture)



Modify the cage sides to allow screws from the outside, all the way through to the skid. Drill a 1/8" hole all the way through the two screw posts.

If you do NOT want to narrow the cage this is all the trimming that is required but you'll need very long (~45mm) M3 screws to reach from outside the cage into the skid and the mod will be less resilient.

To also narrow the body at the skid, trim about 3/8" off each of the screw posts that were just drilled out. Also cut the other two 'bent' screw posts right at the bend. Once the cage is assembled these can be further trimmed for a better fit.



Another optional step is to trim a bit of the body width. If you trimmed the screw posts as above, the reassembled cage will be stressed and bulge at two of the main cross members. To counter this, trim those cross members as shown here.



Assembling the skid (screw lengths assume the narrow option)...

1. Run a M3x30 screw from outside the cage, through the lower rail and into the original skid screw hole. Before continuing, drill a 1/8" hole in the skid at position #2 to line up with the other cage screw post and a 1/8" hole at position #3 in the lower cage rail to line up with the skid hole. (This is where the Bomber skid is different, you may need to drill the skid to receive the screw as well)
2. Use a M3x25 screw and thin lock nut to attach the other screw post in the forward drilled hole. It might be necessary to remove a small amount of material for the nut to fit.
3. Not visible in this picture - Use a M3x12 screw to attach the lower cage rail at the rear-most screw hole in the skid.
4. Pending - trim the angled screw posts to match up to the original screw hole then drill and attach with an appropriate screw.

[mikebecher]

saved

[Creepy Inc.]

Nice write up! I'm curious as to how much it weakens it.

[mikebecher]

Originally Posted by Creepy Inc.

Nice write up! I'm curious as to how much it weakens it.

It seems pretty stiff all bolted up and I'm confident that it's strong enough for my 4.5 lb, low speed rig. It should be possible to add a sleeve for reinforcement but first I need to see if it helps performance at all.

[Turtlejon]

Originally Posted by mikebecher

It seems pretty stiff all bolted up and I'm confident that it's strong enough for my 4.5 lb, low speed rig. It should be possible to add a sleeve for reinforcement but first I need to see if it helps performance at all.

It's 2 months later, how is the durability?
Would this be inappropriate for a rig that will also see some high speed bumper car rock bashing?

[mikebecher]

I've had no issues with it whatsoever. I run this rig almost daily and it has taken some pretty serious tumbles too. I can't say how it would hold up in high speed bumper car rock bashing but it's easy enough to undo with a new set of side rails.

[Turtlejon]

Originally Posted by mikebecher

It seems pretty stiff all bolted up and I'm confident that it's strong enough for my 4.5 lb, low speed rig. It should be possible to add a sleeve for reinforcement but first I need to see if it helps performance at all.

When you say "add a sleeve," what exactly do you mean?
Thanks again for all of your info on this!!

[84yoda]

You never posted how you like it? Is it worth it? Im going to run it normal but will probably do a tummy tuck later on. Im going to build a comp bomber so to me, it looks totally worth it.

[mikebecher]

Originally Posted by Turtlejon

When you say "add a sleeve," what exactly do you mean?
Thanks again for all of your info on this!!

I thought it might need some reinforcement on that bottom tube but it's been plenty strong bolted up to the skid.

[mikebecher]

Originally Posted by 84yoda

You never posted how you like it? Is it worth it? Im going to run it normal but will probably do a tummy tuck later on. Im going to build a comp bomber so to me, it looks totally worth it.

I love it so far. I'm able to run shorter, drooped suspension with the lower links almost parallel to the ground yet I still have enough clearance to bump over just about everything I encounter. CG is low and it climbs like a champ.

Everything I've done to this Bomber goes toward the goal of completing a no touch run on the stream bed that used to kick my ass. I can now clear all 15 or so obstacles and if I can string them all together in one good run then mission accomplished.

The terrain I'm dealing with is easily competition-level, at least for a class-3 rig. I'm considering offering a bounty for the first person to accomplish the no touch run if I can prove it's doable. So to answer your other question, yes, this is most definitely a worthwhile mod for a comp Bomber.

[shakemandril]

Any pictures of the "stock" vs "mod"?

[84yoda]

Originally Posted by shakemandril

Any pictures of the "stock" vs "mod"?

Levior* - Becher's Bomber Build

[m1009cucv]

got a wraith skid coming. going to try this. bit a time better performance. 5 dollar skid plate. sounds good to me