Sharks DESC410R

[Shark413]

Ok my 2-stage pistons showed up so I will be installing them in the Durango BB shocks on my DESC410r. I have already mentioned in a previous post on the advantages of a variable/2-stage piston. I wanted to cover the installation of this particular piston, as there are things you need to watch for to get them work correctly. First a little technical data, the pistons are two parts that are keyed together and on compression close together to seal or restrict some of the flow. On rebound the two parts come apart opening more of the holes and allowing more oil flow. So the rebound will always be faster, which is what you are looking for. Enough compression to handle the big hits and fast rebound to allow the wheels to stay in contact with the track. This greatly increases traction and helps both acceleration and braking. There are several items to watch for when installing these pistons (RC Shox). First when assembling the two parts be sure the small holes line up, sounds simple but it easy to turn the parts so that some of the holes don't line up. Next and a very important step is you must add a small washer to hold the two parts together on the shock shaft. The critical thing is to get the washer centered on the shaft and within the piston. The washer has some play and if you are not careful it can be off and cause a bind. Next you must install the screw or nut to hold the piston to the shaft, the trick here is not to over tighten the screw/nut. Because of the two part piston it is a little thicker and so the shaft does not pass all the way thru the piston. So if you crank down on the screw/nut you wall be smashing the shaft up into the piston, this can damage the piston or cause the piston to loosen up. And last, on the Durango the pistons are held on by small screws, since you can’t really torque them down you need to use thread lock (shaft and screw must be clean). The shocks can now be tuned using various weight oils, springs and even drilling out the holes.


Main parts of the 2-stage piston, bottom and top halves and the retaining washer.


The piston works by closing on compression restricting some flow.


Then on rebound the piston opens allowing more oil flow and quicker rebound.


It is critical to get the washer centered.


Here is an example of the screw/washer not being centered.


Because of the extra thickness the shaft comes up short of being even with the piston. So you have to careful when tightening the screw, don't over tighten or you will damage (split) the piston. Use thread lock to keep the screw from coming loose.

[Slater333]

Let us know what oil and spring combo you settled on.

[Shark413]

I got to do a lot of testing this weekend with the 2-stage pistons. Based on what I had used previously, I started with 30wt up front and the dark blue springs, in the rear I started with 27.5wt and the dark red springs. The track I run at has lots of small and mid size jumps. These are arranged in singles, doubles and one tabletop. There is also a rhythm section, so lots of variation. After running a few packs I could tell the front was too soft, so I went to the Bordeaux colored springs and it was spot on. I also changed out the oil in the rear to 20wt and it was perfect for this track. The truck was planted no matter what I was hitting. The track is a clay/dirt mix kept wet, with decent grip, but it is not totally smooth because the 1/8's tear it up. The 2-stage pistons/shocks soaked everything up with just a hint of chassis slap on the biggest jumps.

Here are a few shots of the track to give you an idea of what my truck is setup for.

[wurster]

Nice track where you get the two stage pistons from ? I would like to try them.

[Shark413]

Originally Posted by wurster

Nice track where you get the two stage pistons from ? I would like to try them.

They are a bit pricey, but are the only ones for the Durango. Fioroni makes some really nice Aluminum dual stage pistons but only for 1/8 scale shocks. RPM also makes some for the Traxxas shocks and Traxxas makes a kit for Revo shocks.

Here is a link to the 2-stage pistons I am currently using in my Durango.
Durango, RC Shox



Fioroni pistons.


RPM


Traxxas

[wurster]

Thanx Shark.I love this truck its taking me some time to get used to it and tune it .it is fast but dose seem slow but at the track it is real fast and handeles awsome.thanx for all tips helps a lot

[Shark413]

Well I finally decided to replace the body. I have been using the stock body since I got the truck back in March 2011 and it was starting to show it's age. I had a Jconcepts Ford Raptor sitting around that I was going to put on my Losi, but I decided the Rango deserved a new shell. I know there is a paint forum but I am not going into any painting details, just wanted to show the new body. I am not a good body painter so I normally go pretty basic on the bodies, one or two colors with no fancy designs, but for this one I decided to do a little more.


Masked off painted the black portions. The logo on top is all paint, because the roof takes a beating and a sticker does not last long up there. Same for the headlights and grill (all paint).


All done with the painting, just need to add a few stickers.


Finished.

[wurster]

Nice looks good there .Im a big fan of yellow

[Shark413]

Just wanted to share something I noticed. I have not had any issues with the diffs, but a while back I had an opportunity to pick up a pair of the machined steel gears, so I bought them and installed them in my DESC410. Recently my DESC410 was down for a rebuild and waiting on parts. So while I was waiting I decided to run the machined gears in my DEX410 buggy. I got the parts to rebuild my DESC410 so I pulled the machined gears from the buggy and put them back in my DESC410. I installed the stock cast gears into the buggy. While doing all this I noticed the machined gears were noticeably smoother. Even with both diffs shimmed properly, you could feel a couple of high spots on the cast gears and the machine gears were buttery smooth. The cast gears are fine if you shim your diff right, but if you want the ultimate in smoothness and efficiency the machine gears are the hot ticket.


Durango machined gear.

[Shark413]

Some follow-up to an item I mentioned earlier. The fit between the battery strap, rear center driveshaft and battery is very close/tight. To get a little more room I said you could use some spacers. You basically take off the rear diff hoop assembly and place washers on both screws, then reinstall. The spacers will raise the rear portion of the driveshaft/battery strap for more clearance. I use a 1mm spacer, you don't want to go crazy because when you add spacers you create more room but you also increase the driveshaft angle and reduce the engagement of the center driveshaft and center diff outdrive.



1mm spacers.


Be sure the spacers/washers are small enough to clear the rear diff case/chassis brace.

[Shark413]

Here is a shot of the entire family.


DESC410r, DEX410r, DEX210.

[Slater333]

Shark what tires and compound are you finding success with at your track? Those look sorta like pressure points but that's just a guess!

[Shark413]

Originally Posted by Slater333

Shark what tires and compound are you finding success with at your track? Those look sorta like pressure points but that's just a guess!

Slater, you can see the track I run at a few post earlier. It is indoor clay/dirt mix which they water a lot. It's pretty bumpy but traction is good when the track is moist. I have used Suburbs, Barcodes, Calibers, Blockades and Holeshots. I like the Holeshots in super soft, but the Barcodes/Suburbs work pretty good too. I found the Calibers have good forward bite, but are inconsistant in the turns. Blockades are good all around tires but don't bite as well as the others on this track. I have some Rebars coming and I hope I can try them out this weekend.

[Slater333]

I'm in FL visiting family and the guys down here swear by hot bodies megabite tires and jc pressure points. Good forward and side bite. I'll be giving those a shot next. Keep u posted. Let us know how the aka's workout!

Btw tried the 30/20wt w bordeaux springs on a tight track w med size jumps. The triple and double combos were really easy and keeping on throttle through the speed portions were great too. Thanks for posting.

[Shark413]

I finally had some time to install the rear bumper. At first I was a little skeptical about the bumper. I had been running my truck since day 1 and having no bumper was never a problem. Then at the Hot Rod Shootout I noticed several of the Team Durango drivers had rear bumpers on their trucks. When asked they said it was for protection/increased durability, so I decided to give it a try. If team drivers use it for protection/durability then certainly a mere mortal like me can benefit as well.

[northkona]

I just bought myself one of these and after picking up some good tips off you from the SC10 4x4 thread many months ago , I'm looking forward to more of your setup ideas . cheers, I can't wait.

[Slater333]

One thing also I thought I'd share to you shark and the folks that I see as a trend down here in south Florida.

I was fortunate to meet Felix law who is deemed the top or one of the tops in south fl and what he runs, amongst others, is either the speed passion gt 2.0 or hobbywing 120a hd esc with hobbywing software and hobbywing programming card. The reason is because according to him they can run lower pinions to gain more punch and use the boost feature to help with end so you can have the best of both worlds. He was saying the rx8 has advanced timing but lacks boost.

Also I saw a ton of tenshock sc411 4600kv motors and again it seems they are ditching the tekin pro4 in favor of this motor because it has more torque.

My guess is that price for motor and esc has a ton to do with it all.

Anyhow, this may be common knowledge but if not hope it helps.

[Shark413]

Originally Posted by Slater333

One thing also I thought I'd share to you shark and the folks that I see as a trend down here in south Florida.

I was fortunate to meet Felix law who is deemed the top or one of the tops in south fl and what he runs, amongst others, is either the speed passion gt 2.0 or hobbywing 120a hd esc with hobbywing software and hobbywing programming card. The reason is because according to him they can run lower pinions to gain more punch and use the boost feature to help with end so you can have the best of both worlds. He was saying the rx8 has advanced timing but lacks boost.

Also I saw a ton of tenshock sc411 4600kv motors and again it seems they are ditching the tekin pro4 in favor of this motor because it has more torque.

My guess is that price for motor and esc has a ton to do with it all.

Anyhow, this may be common knowledge but if not hope it helps.

Slater, good info. I have not personally used Hobbywing esc's but some of the guys I run with do and they love them. I had a TenShock SC401 and it was a good solid motor, just a bit amp hungry and you had to use an esc that could handle the amp draw. I was running it in my Losi SCTE and it was able to pull that heavy monster around. But this was before the sensored 411 motors and I wanted to go sensored so I switched to the Pro4. Sounds like the HobbyWing esc and Tenshock motor are a good combo for the price.

[Shark413]

I was going over my truck this week, cleaning and checking stuff (bearings, any binding in the drive train, bent or broken parts, etc). And I found the front hinge pins were again bent. Not a lot and most people probably would not have even noticed. I probably could have gone another weekend with them but since I had the front end off I decided to replace them. Getting a little expensive changing them out every other week ($4 a pair) so I decided to try and make my own. I bought some steel rod (hardened tool steel) that came in a 3 foot piece for $5. The Durango front hinge pin is just under 2 inches so I could get about 18 hinge pins out of the steel rod (18 Durango pins would cost $75). I actually got two different types of rod, one is Oil-hardened tool steel and the other is Air-hardened tool steel, which is a little harder. I cut them using an abrasive cutoff saw, cleaned up the ends on a grinder and polished them. Next time I bend a pin I’ll try my homemade pins and see how they hold up.



Here is the uncut steel rod.



Homemade rod on top, bent Durango pin on bottom. You can see the right side of the Durango pin is bent slightly.

[Shark413]

Regarding the hinge pins, FireFlysti on RC-Tech mentioned that McMaster Carr carries 3mm metric pins that come in 45mm (front) and 60mm (rear need to trim to 52mm). Not sure how hard these pins are but they are relatively inexpensive and the fronts seem to already be the right size.


"Mcmaster part numbers 91595A143 for front and 91595A146 for rear (need to trim them down to fit), they come in pack of 10 and are rated to 1,600 lbs."