LOSI LST XXL Conversion ideas

[mistercrash]

My truck is resting right now until I get the new TiNi shock shafts and a couple more parts in the mail to fix it. On the shock with the snapped shock shaft, I also noticed that the shock cartridge had started to come out of the shock body. So I searched on the LST forums for a fix and I came up with the idea of straps to limit suspension droop. I used zip ties that are secured to the upper arms and sandwiched between the shock towers and the CF plates I made to reinforce them. I'll be trying those out when the truck is fixed.

Compressed


Resting


When the suspension is extended, the straps let the arms drop almost fully, just shy of full extension to releave the stress on the shocks.

[mistercrash]

So I have a snapped shock shaft and a bent one. While I'm waiting for the new shafts to arrive and start playing with my truck again, I searched the web to find stronger shock shafts. I couldn't find any. I'm thinking that 5 mm shock shafts would be stronger then the original 4 mm shock shafts. Problems would be, where to find them and how to make them work in the shock cartridges.

Is there any manufacturer that makes 5 mm shock shafts and cartridges? If you know of any, please tell me.

In the meantime, I started looking at the stuff I have in the garage to try to make my own. My E-Revo's pushrods are 5 mm in diameter and are about the right length. Just a little too long. They have M4 threads on each end.



So I grinded one end to make it short enough to match the LST shock shaft. The center hole of the shock piston would have to be drilled to 4 mm and a 4 mm washer with a 4 mm lock nut would be used to secure the piston to the shaft. Then to shorten the opposite end to match the length and put some M5 X 8 threads on the shaft.



With the shock piston drilled to 4 mm and the shock ball end drilled to 4.2 mm, this is what it looks like assembled, with the stock assembly next to it for comparison.



The shock cartridge has to be disassembled to enlarge the center holes of the cartridge and the snap cap to 4 mm. The spacer between the two O rings inside the cartridge either has to be drilled or a new spacer has to be found or fabricated. I had a spacer with a 4 mm hole in the middle but it didn't have the right length so I cut it to match the length of the stock one as close as possible.



I was able to squeeze the new 5 mm shaft in the cartridge using the stock O rings but it is too tight so a new set of O rings with a 5 mm ID and 2 mm cross section (9 mm OD) would be needed. I could get durable Viton O rings for cheap from this guy on ebay.

http://cgi.ebay.com/10-x-Viton-o-rin...item4145e04d6e

So what do you think? I made one shaft to see if it could be done without to much trouble. Would this be something that would benefit the LST?

[brian015]

I just happened to come across these:

http://cgi.ebay.com/Losi-LST-Shock-s...item2eae749e8d

4.93mm diameter

quote: "These are replacement shock shafts for the Hot Racing Reservoir Shock Shocks that fit the Team Losi LST ( lst255r06 lst255r08 )."

[mistercrash]

Brian I saw those and even though they look really nice, they are to short for the LST2 shocks I'm using. IMO, the only way to make them work properly with the LST shock cartridges is to do exactly what I plan to do which is to open the cartridge, enlarge the holes for the shaft and replace the O rings with ones with a thinner cross or thickness. Unless the Hot racing reservoir shocks use a cartridge that fit the LST2 shock body. I'm not sure. Maybe they could work but I wouldn't get the full extension that I have with the stock length of the shock shafts, it is something like 87 mm long if I remember correctly. Thanks for searching I appreciate it.

On an another note, I gave up on my E-Revo to go with the LST because I find it is tougher and easier to work on. But there are things on the E-Revo that I really liked. The tranny for one which I installed on the LST but also the Traxxas VDPs (Variable Damping Pistons) in the shocks. So I am going to try it on the LST with these little valves I made out of a piece of thin polycarbonate from some packaging that was lying around in the recycling bin. I know Hot racing makes pistons with tapered holes which are supposed to have the same effect, I'm just trying to do it on the cheap.
The valves block 10 of the 24 holes of the piston on compression which should give better, stronger damping, and the valves bend slightly to let the oil pass through all 24 holes of the piston on the rebound.



I made a second 5 mm shock shaft and ordered the Viton O rings I linked before. When all the parts get here, I can finally try out those shafts on the front end with the VDPs front and rear.

[brian015]

Originally Posted by mistercrash

Brian I saw those and even though they look really nice, they are to short for the LST2 shocks I'm using. IMO, the only way to make them work properly with the LST shock cartridges is to do exactly what I plan to do which is to open the cartridge, enlarge the holes for the shaft and replace the O rings with ones with a thinner cross or thickness. Unless the Hot racing reservoir shocks use a cartridge that fit the LST2 shock body. I'm not sure. Maybe they could work but I wouldn't get the full extension that I have with the stock length of the shock shafts, it is something like 87 mm long if I remember correctly. Thanks for searching I appreciate it.

On an another note, I gave up on my E-Revo to go with the LST because I find it is tougher and easier to work on. But there are things on the E-Revo that I really liked. The tranny for one which I installed on the LST but also the Traxxas VDPs (Variable Damping Pistons) in the shocks. So I am going to try it on the LST with these little valves I made out of a piece of thin polycarbonate from some packaging that was lying around in the recycling bin. I know Hot racing makes pistons with tapered holes which are supposed to have the same effect, I'm just trying to do it on the cheap.
The valves block 10 of the 24 holes of the piston on compression which should give better, stronger damping, and the valves bend slightly to let the oil pass through all 24 holes of the piston on the rebound.



I made a second 5 mm shock shaft and ordered the Viton O rings I linked before. When all the parts get here, I can finally try out those shafts on the front end with the VDPs front and rear.

Yeah - I couldn't remember the length of the LST shock shafts - I guess those are closer to the muggy shock length.

Anyways - I'm interested to see how you like your VDP setup - I'm pretty happy with the rc-raven springs on my big truck - but I could definitely see this helping - I have some .030 lexan I might try out.

[Bondonutz]

The Hot Racing Jet Vent pistons are great, I found they make a big difference on the big jumps.

STAY AWAY from HR Titanium shafts, Total JUNK !

[mistercrash]

Thanks Bondo, nice to know that the HR pistons work like they are supposed to. If the valves I made don't work like I want then I'll definitely get the HR pistons.

[mistercrash]

Originally Posted by brian015

I'm interested to see how you like your VDP setup - I'm pretty happy with the rc-raven springs on my big truck - but I could definitely see this helping - I have some .030 lexan I might try out.

.030 will be too thick and too stiff. The valves won't bend up to let the oil flow through. The ones I made are .006. The thinner the better actually but it still has to be just stiff enough to hold it's flat shape when resting and flexible enough to bend slightly to let the oil flow.

[mistercrash]

I had these Proline 40 series Mashers mounted on Axial 8 spoke over sized chrome wheels. The chrome was flaking off and it just looked ugly. I dipped the wheels and tires in Acetone for 36 hours and ended up with very clean wheels and tires but it ruined the foam insert. I took the chrome off the wheels with Easy-Off oven cleaner and then dyed them with black Ryt dye. I purchased Racers Edge two stage 40 series foam inserts and put an extra layer of foam around the middle part. This over stuffs the Proline Mashers, making them firmer and gives a nice crown that I like. I like the 40 series Mashers on the LST because I think they are the perfect size for the truck. The same width as the Losi 420 series ATX but a tad smaller on the diameter.

[brian015]

Originally Posted by mistercrash

.030 will be too thick and too stiff. The valves won't bend up to let the oil flow through. The ones I made are .006. The thinner the better actually but it still has to be just stiff enough to hold it's flat shape when resting and flexible enough to bend slightly to let the oil flow.

You're probably right - i have some thinner lexan I can try.

[mistercrash]

Has anyone ever thought of getting rid of the E clips on the LST's suspension? I did some web searching and it looks like the 4 mm hinge pins with E clips could be replaced with M4 X 0.7 X 55 mm 12.9 grade socket head cap screws. These screws don't have threads all the way. only at the end, leaving a long shoulder before the screw head (not sure but it looks like around 40 mm long) that could act as the hinge pin. Put an M4 washer on the screw, slide the screw in, put a second washer and a lock nut and cut the excess threads with a dremel. No more E clips. I also thought about using the shock shafts but the screws would be easier. I know there's other Losi RCs that use threaded outer hinge pins but I'm not sure of their dimensions and I won't pay 5 bucks plus shipping just for two.

Here's a link to the screw I'm thinking about.
http://www.fastenal.com/web/products...5PF0000&ucst=t

The image in the link is not representative of the real screw which does not have threads all the way up to the head. I found a CAD drawing of the 60 mm and 50 mm screws but I couldn't find a drawing of the 55 mm screw. The 60 mm screw has a shoulder of 46 mm, the 50 mm screw has a shoulder of 36 mm. A little more than 38 mm is needed so the 55 mm screw with an estimated shoulder of 40/41 mm would be perfect.

[JThiessen]

JAILBIRD found these http://www.teamstrc.com/ebproductdet...mainid=3&id=68
You might get away with sckt hd cap screws if you are still running all plastic parts there, but the finish on them is not meant to be used as a bearing surface. Thread length on them should be around 14mm - so your guess of 40mm was close. Probably function ok though. Use a nylock nut.

[mistercrash]

Someone on the LST forums gave me the link to the ST Racing threaded hinge pins also. Like I said to him, $20 plus shipping for 8 bugs me a bit. They look good though but for $0.65 for a screw and the Nylock nut, I can have the same thing, maybe better for so much less. All it needs is a little effort on my part to make the surface of the shoulder smooth. I'll just chuck the screw in the drill press on high speed and use fine sand paper to smooth out the shoulder. It'll work very well I'm sure of it.

[JThiessen]

Tightwad!!!

[mistercrash]

Tightwad? What does that mean. Language barrier I'm French remember... If it means that I'm a cheap bastard then you would be right