Brushless LST2 conversion - This is how to do it!!!

[lincpimp]

Ok, here it is. This is the big daddy of monster trucks. Nothing I have fooled with has all of the strength and design this truck has. Plus it has really big shocks!

Electronics specs: Hacker c50 11xl (1500kv), MMM V3, FP 4500 30c 6s lipo, stock twin 590mg steering servos, spektrum 3001 rec. Gearing is currently 63/24, but I plan to get a 26t pinion and run a 59t spur. Current top speed is just shy of 40mph. I have a 10xl c50 to try out, and a 1521 1y (big power!)

So I actually started with an Aftershock. Good part about this model is that it is relatively cheap at $400 new (compared to a 650 dollar lst2), plastic body shocks (still plenty strong, and lighter than the lst2 al body shocks), and the forward only tranny. Also has great diffs with al cases stock. I sold the xr2i radio and nitro motor so I got some money back (about $150 IIRC...)

Bad part is that it comes with the weaker original lst suspension arms, driveshafts and hubs. This is not too bad, but the rear tie rods (like a tmaxx, the truck has matching front and rear hubs, so it has to have rear tie rods, and this truck likes to bend them and rip out the rod ends). I upgraded to the lst arms, hubs, and big 8mm outdrive driveshafts with giant 15x21mm inner bearings. I run 20mm hubs and losi 420 rims with 40 series rubber.

So the mods started with me putting the TiN coated ring and pinion gears and some nova rc 7075 diff cups in the diff cases. Only took one shim to get the gears perfect, and that shim happened to be in the diff stock. This kind of thing indicates good quality machining that is held to tight tolerances. I only upgraded the diffs cause I got a smoking deal on the gears, and figured why not. Plus I plan to thrash this truck and had issues with savage diffs holding up under big power.

After that I swapped the gears in the tranny to get a slighly higher ratio. Simple mod, requires slight clearancing on the inside of the trans case. Completely reversible too. Basically threre are 2 gears in the tranny, a 22t and a 23t, I swaped them to help out my slower turning motor (1500kv on 6s) get to 40mph with my available gearing choices. Picked up a tdr (the dude racing) single speed hub, and a losi 63t TiN coated spur gear. I also got the motor mount from tdr, nice stuff, and the only game in town for lst electric conversions.

Now since the FOC that the aftershock comes with eleminates the reverse and high/low selector (mechanically actuated, kinda cool), and the tdr single speed hub eliminates the OWB, I can use motor brakes! That also means the brake servo is removed, thus making room for a forward mounted battery tray. This is critical to handling, as the fd rear mounted tray is a crap idea (imagine that...).

Made the tray out of kydex (thanks rchippie!) as usual, and mounted it to a pair of custom riser blocks to clear the servo wiring. I did have to cut the hinge portion off the rec box. Hated to do that, but I needed the clearance. The flightpower 4500 30c 6s lipo is almost square in cross section, and I did not want to push it up against the tranny as it would cause issues with the spur gear. I added 2 small posts inside the rec box and use 2 body clips to hold it on, along with the stock front pin. Also made the MMM mount out of kydex, and used the stock upper rear brace screws to hold it down.

I would like to add that was the only mod done to this truck. No holes were drilled in the chassis, nothing clearanced, ground or otherwise messed with. Only aftermarket parts are the diff cups. This is a very well designed truck. The only mod I will be investigating is a single steering servo conversion. Nothing wrong with the stock twin 590mg setup, it actually works very well, but I want a single servo. This will be tried out on my upcoming lst based 6x6 project (you will all want to see this...) and plan to use a 1/4 scale servo too (so cheap and sturdy).

I have thoroughly researched this truck (the lst forums are great) and it is by far the best I have tried. It is a bit heavier than an erevo, but it is bigger and definately stronger. Plus the design is very simple and effective. It takes about 1-2 mins to get the diffs out, maybe 8 screws total. But the drivetrain is very strong, so after the diffs are shimmed (the stock aftershock diffs very prefectly shimmed out of the box, btw) no real need to get at them, unless you want to experiment with various weight fluid. Suspension comes off easy too, tranny has 4 bolts, not much to remove to get the servos out. The most burried part is the steering bellcranks and they are not difficult to get to either. Less than 10 screws removes either bulkhead assy (no need to do it to get to the diffs). Bumpers are big and flexible, and my only complaint is the lack of a wheely bar! I can put a muggy wing mount on, and use the wing to keep the truck on the wheels! The tranny is very strong, all metal gears and the bevel output allows the motor to be mounted transversly behind the tranny, eleminating most of the torque twist and adding force to keep the front wheels on the ground (touring car tech here).

Ok, now for the pics, thanks for the patience and feel free to ask me anything about this truck!

[sikeston34m]

That is one fantastic looking truck!

Hmmm.........no slipper?

You said you got the motor mount from tdr? Where's that at?

[lincpimp]

Originally Posted by sikeston34m

That is one fantastic looking truck!

Hmmm.........no slipper?

You said you got the motor mount from tdr? Where's that at?

Heres the site: http://tdracingrc.com/

The lst has a very different slipper, much like a dry basket style clutch on a bike. It has quite a few disks and pads, the pads are round with teeth that engage the basket that is keyed to the input shaft, and the disks look like steel brake disks that have a hex punched in the center, a hex shaped collar slides over those disks which are staggered in between the pads and the spur is attached to that hex collar. A sping that rides on a thrust bearing keeps pressure on the assy. This slipper can take some abuse, I had it 1 full turn loose and it was barking like crazy, but did not heat up much. I did a few full throttle runs on the blacktop too, then tightened it down and no issues.

[Unsullied_Spy]

That's very nice! Have you looked into getting RPM arms for it? Those look like the same arms my Muggy came with stock, and they broke pretty easily. The RPM arms come sized for the LST/Aftershock and need their adapter kit (plastic washers) to fit the LST2/Muggy. Also, the stock turnbuckles (on the RPM arms) are pretty weak so you'll want to upgrade to Lunsford turnbuckles as well but once you've got all that they're really tough.

[lincpimp]

Originally Posted by Unsullied_Spy

That's very nice! Have you looked into getting RPM arms for it? Those look like the same arms my Muggy came with stock, and they broke pretty easily. The RPM arms come sized for the LST/Aftershock and need their adapter kit (plastic washers) to fit the LST2/Muggy. Also, the stock turnbuckles (on the RPM arms) are pretty weak so you'll want to upgrade to Lunsford turnbuckles as well but once you've got all that they're really tough.

I had a look at the lst arms from rpm and really do not like the shims needed to adapt them to the lst2 hubs. I will stick with the arms I have, and maybe upgrade when/if they cause me issues. I will most likely redesign the mounting to eliminate the spacers if I do go with the rpm arms....

Thanks for the lunsford tip!

[Unsullied_Spy]

Originally Posted by lincpimp

I had a look at the lst arms from rpm and really do not like the shims needed to adapt them to the lst2 hubs. I will stick with the arms I have, and maybe upgrade when/if they cause me issues. I will most likely redesign the mounting to eliminate the spacers if I do go with the rpm arms....

Thanks for the lunsford tip!

I wasn't much a fan of the adapters at first, but after breaking my 2nd pair of arms I said screw it and bit the bullet ($100+ for the arms, adapters, and turnbuckles ).

No prob, I sheared a turnbuckle off after about 1-2 minutes after putting the new arms on and I had to trim down the plastic in order to extract the remaining bit of turnbuckle

[lincpimp]

Originally Posted by Unsullied_Spy

I wasn't much a fan of the adapters at first, but after breaking my 2nd pair of arms I said screw it and bit the bullet ($100+ for the arms, adapters, and turnbuckles ).

No prob, I sheared a turnbuckle off after about 1-2 minutes after putting the new arms on and I had to trim down the plastic in order to extract the remaining bit of turnbuckle

I will see how it goes. I do not break much, but i do like to bash. I have a design to mod/strengthen the rpm arms in my head, so I may give it a try. Wish rpm made a solid upper arm, the trunbuckle looks like a bad idea, especially considering rpm's nylon blend...

[Unsullied_Spy]

Originally Posted by lincpimp

I will see how it goes. I do not break much, but i do like to bash. I have a design to mod/strengthen the rpm arms in my head, so I may give it a try. Wish rpm made a solid upper arm, the trunbuckle looks like a bad idea, especially considering rpm's nylon blend...

I haven't quite learned the art of jumping my Muggy, so it sees a lot of bad landings

I wish they had a solid upper as well. I don't care about adjusting my camber, but I do care about straight-up durability.

http://www.youtube.com/watch?v=occUrFLw58U
This was my first time out, all things considered it held up well but I heard those kids yelling something to do with "run it over" and wanted my $1,000+ out of the way!

[lincpimp]

Originally Posted by Unsullied_Spy

I haven't quite learned the art of jumping my Muggy, so it sees a lot of bad landings

I wish they had a solid upper as well. I don't care about adjusting my camber, but I do care about straight-up durability.

http://www.youtube.com/watch?v=occUrFLw58U
This was my first time out, all things considered it held up well but I heard those kids yelling something to do with "run it over" and wanted my $1,000+ out of the way!

That vid was cool! I would love to have a track like that close by, looks like a blast. Your muggy seems a bit ass heavy, maybe move the batt farther forward on the chassis? I did a bunch of testing with the savage for battery placement, and farther forward always made it jump and steer better. That is why I put the batt in front of te tranny on the lst. I can't imagine how bad it would handle with the batt in the fuel tank position like most do it. That is just too much weight out back, unless all you want is wheelies!!!

Interesting how the lower arm broke off on the inside. I will run my truck with stock arms, and upgrade when they break. I may leave the stock upper arms and just swap the lowers... Who knows...

[killajb]

Awesome looking rig Pimp'n..

How does it handle? I've been reading a lot about LSTs as well and the weight distribution issues with the battery in the back. Just wondering how turning "feels" with the battery and motor mass positioned that way in a large vehicle.

Unsullied: I have a Muggy conversion as well and ended up going with the RPM arms after breaking the stock ones. Aside from that, the rear diff housing was somehow cracked (bought it used and apparently it came with a slight fracture that was further propagated with 1515 power!) and now I'm waiting on a rear diff pinion and ring gear combo. Otherwise, a big dancing bear if I ever saw one!

[BL-Power]

Thats a really nice conversion, but i think a Neu 1521 or a KB45XL would be a more adequate motor

The battery tray is very well made, the lipo is protected really good. The weight distribution with the lipo in front is also nice, other conversions are often so ass-heavy.

[lincpimp]

Originally Posted by killajb

Awesome looking rig Pimp'n..

How does it handle? I've been reading a lot about LSTs as well and the weight distribution issues with the battery in the back. Just wondering how turning "feels" with the battery and motor mass positioned that way in a large vehicle.

Thanks, I do try to make em look good...

I am currently using traxxas 50k diff fluid, which seems to be just the right thickness to keep the truck straight and it still turns fine. It will lift an inside rear tire on hard turns, but it does as well as the revo.

Originally Posted by BL-Power

Thats a really nice conversion, but i think a Neu 1521 or a KB45XL would be a more adequate motor

The battery tray is very well made, the lipo is protected really good. The weight distribution with the lipo in front is also nice, other conversions are often so ass-heavy.

Thanks, I do have a 1521 1y to put in. Honestly the hacker c50 xl has plenty of power, I even have the punch control set at 50%. No real need for more power, but I do want to run higher gearing. Plus the hacker will go in my 6x6 lst based project, as that truck will be geared for about 35mph max.

The battery tray was easy to make, just cut the kydex to the right shape with a bandsaw and folded the sides up with a wood block, bench vice and a heat gun. The rear mounted battery setups must handle like crap, way too much weight in the back.

[traxxasrevony]

hey linc where could i get some of this kydex.

[Arct1k]

kydex

http://www.knifekits.com/vcom/produc...oducts_id=11296

[lincpimp]

Originally Posted by Arct1k

kydex

http://www.knifekits.com/vcom/produc...oducts_id=11296

That is the stuff, but what I am using looks to be thicker than .093... It is great stuff and really easy to work with.