The Rock Lobster 1.9 Rock buggy

[OSRC]

What do you do when your workbench is already littered with projects? Start a new one of course!

So here's something different.... I've wanted to build a Tamiya rock buggy for a while (I think it's fun to take something that was never meant for trails/crawling, mod the heck out of it, and see how it does), but never really found the right platform. Picked up a Hotshot a while ago to convert as I love the look, but the drivetrain seemed too fragile. For whatever reason I was randomly thinking of a few mods to my TL01 drift car the other day and a light bulb went off.

So went off and digging into my parts stash. Found a TL01 core chassis that's been here for years. This thing has to be nearly 20 years old.


Biggest headache is the battery sit crossways in the chassis. But, I was thinking with a bit of dremel work, I could get the battery down in the chassis lengthwise. This chassis works out great since the prop shaft is up high, leaving a huge open space underneath where all the heavy stuff can go... Hmmm....


An hour of semi-careful cutting later...


Looks like a green light to me. So stripped and cleaned the chassis and gears. Amazing that after nearly 20 years, this thing was in mint condition. I remember running it hard as a rally car back in the day, but it's still solid, crack free, and the gears still look new. I locked the diffs, greased it up and bolted it back together.


65t motor is just for testing....after building or tearing down a car, I usually run it for a few minutes on 3v just to set the gears and spread the grease.


Since it's a TL, I had the choice of wide or narrow suspension (options are good!) The narrow suspension was touring car width and looked a bit narrow to me. Went with a longer suspension which looks a bit wide to me...but can't argue with the increased suspension travel and ground clearance. Hex face to face is about 235mm so a bit wider than an SCX10


Not only did I manage to find all the leftover Wild Dagger suspension bits (a miracle) I also found some steel front CVD's that fit. WIN!


Kept it all in the family with some Tamiya XV01 CVA's for now. Need some tuning, but fit and the spring rates feel in the ballpark.


Some Gmade wheels help narrow up the track width a bit, and found this old Baja King body. Looks the part to me! It's red, and for whatever reason the Rock Lobster song popped in my head. And of course, it's been in there the rest of the day....So the project gets a name.




So you might be thinking "this is the dumbest thing I've ever seen" - and you might be right. BUT reading through some of the B2B threads, an independent suspension rig can perform if set up correctly. Plus, my Twin Hammers with its low COG crawled like a spider. So who knows? It's not going to be a comp machine, it's just for fun. I think it'll be fairly capable in any case. Either way, I'm having fun with something outside the norm.

Anyway, more to come...

[Highmark]

That's awesome! I used to have a buggy that was very similar (built by Gimbal) which was fun to drive. You might consider a small planetary gear reduction.

[hillbillyrc]

I feel something out of the norm is welcomed.

Great start waiting to see what's next.

[alexleblanc]

how's the gearing for crawling? that always seems to be the issue with most Tamiya stuff when it comes to making a custom crawler.

[JatoTheRipper]

Originally Posted by alexleblanc

how's the gearing for crawling? that always seems to be the issue with most Tamiya stuff when it comes to making a custom crawler.

He's got a 65T motor in it. That should slow it down...

Very cool. Look great! I can't believe you were able to sneak the battery in the center and still get the chassis halves to screw together with what looks like all of the screws.

[OSRC]

Thanks fellas, the 65t is just for testing. Do have some gearing changes coming.

Moved the shocks to the inner mount on the arms and got a higher stance. Don't want to go too high, but like the way it sits much better.


Yup, that's much better!


How old is this body? AM frequency clearly marked in the inside...


Looks good, but those wide side pods are no longer needed to cover the battery. Let's get chopping! Carefully of course since the chances of finding this body again are slim and none...


Much better!


Steering sorted out with some steel turnbuckles and 5mm pivots.


Battery tucked in its new home. Motor and battery are just above the wheel center line - if nothing else, I've got a heck of a low COG.


Tech wise, with all the electronics and battery on board, as well as the heavy Gmade wheels the Lobster weighs in at a very svelte 1943g (4.3lbs) with a surprising weight balance of 48/52. I'll be adding some weight up front to get it closer to 50/50 and the whole buggy should be less than 5lbs. Not sure I own a crawler this light.

[hoyt]

This thing is cool.

I am picturing this being like a crazy fun IFS/IRS rock bouncer like the outlaw.

[mewalsh100]

Well, it looks RAD as hell. And, to me, screwing around with pieces and parts and creating something cool and unique is way more than half the fun!

[chino63]

I like it! I had a Tamiya Humvee and without the body was impressive. Needed better tires and deeper gearing but was a blast to drive. Keep posting, I'd like to hear more feedback after a long crawl session.

[OSRC]

Tucked some weight in the front arms to get the weight balance a little better..


Robbed the swaybars off my onroad TL. Rear fit perfectly! Really helps keep the Lobster from over-flexing.


Front...not so much. the wire is a bit too short. Took it off for now, though keeping my eye out for one that fits.


Made a small battery holder/electronics tray. Just mounts over the battery opening with velcro. Holds the battery in place and gets the electronics as low in the chassis as I can get them.


Motor combo is my trusty Xacto motor and 3:1 reduction. The whole assembly is only a bit longer than a standard 540 can.


Wired up and ready to go! Not too messy... most of the wiring hides in the chassis.


Made a temporary body mount in the rear just to hold the body on and decided to go for a test run...figured I'd go see how it did before investing any time on bodywork and other stuff.

[OSRC]

Inbetween monsoons, got the Rock Lobster out for a test run. Pay no attention to the 1/2 mounted body...

All in all, it's a way fun little beast. Kinda like a mini rock bouncer. I'd bet it drives just like a B2B, just smaller. The shocks felt soft all around on the bench, but really felt decent out in the yard. Had just the right amount of flex. Rally need a front swaybar of some kind, but otherwise it's pretty good right off the bench.


Did quite a bit of three wheeling in my test area, but was never out of control - just had to let the suspension settle and it dug right out. My TRX-4 fails over this block all the time - no problems here (as long as I hit it right).


Against my better judgement, I took it out on the rocks. Was thinking more of a trail rig, so this terrain is a wee bit more hardcore than I had in mind. Slowly moving my test area to another part of the yeard, so it's a little rough right now. Did ok actually - drove just like any other low slung crawler - use tire placement and throttle where you have to.


Got right up my 2 hardest spots, even with the new tires that hadn't even broken in/massaged yet. Very stable when climbing and descending.


Got bound up later and shattered a CVD. Knew that was going to happen eventually..the smallish driveshafts are going to be the limiting factor for this rig. Still, think it's worthy of some more tinkering. Mostly cause it looked so cool out there flexing over the rocks!

Got a few body and chassis mods in mind, hope to have it done before out next trail run. Defintely need to do something with the rear of the body.

Video of said backyard test...forgive my novice video skills, haven't bothered to make one in years:

[superdenk]

Very cool. Definitely something unique. Seems to work pretty well. Kinda makes me wanna dig thru my pile of parts and old cars and see what can be put together. Nice work.

[hillbillyrc]

Looks right at home on the obstacles.

You thought about a motor guard or cover? Or is it tucked out of the way. Also would a boat side sliders be beneficial or more of a hinderance since it is low cog.

[PoorManRC]

Dang Bro!! That is seriously COOL!!! Fairly capable too. The whole idea is extremely clever, and it looks like you've sparked a few other guys to dig through their old stuff. Myself included!!
I've got a TT-02, with Aluminum hop-ups, collecting dust waiting for some Miracle to finish it. I may have to brush off the cobwebs and see what it could be turned into!!
Looking forward to seeing what you come up with next!

[89redranger]

Awesome little rig!

A Twin Hammers front sway bar should fit the front nicely and is sold in a kit with three different rates. Give me a bit and I can get you some pics/dimensions. I don't use them so I have a few stashed away.

Sent from my SM-S975L using Tapatalk

[OSRC]

Originally Posted by PoorManRC

I've got a TT-02, with Aluminum hop-ups, collecting dust waiting for some Miracle to finish it. I may have to brush off the cobwebs and see what it could be turned into!!

I was debating turning my TT02B into some kind of off road creation, but it's still in good shape and didn't have the heart to hack it up. The TL was perfect since it was long neglected and track was a bit narrower. Modern buggies are a bit wider

Originally Posted by 89redranger

Awesome little rig!

A Twin Hammers front sway bar should fit the front nicely and is sold in a kit with three different rates.

Thank you, I did find another rear swaybar that I can mount on the front.


Not sure what I want to do with this yet. Not sold on the wheel/tire combo, and would love to narrow it up a bit.

[alexleblanc]

you should be able to cut down a wraith sway bar and make it fit in the front.