Gloveberg

Guys, I just bought a Duratrax Evader Brushless and while reading a review of it on Big Squid I came across this paragraph:

"Set-up Notes- We quickly noticed the servo saver was set to as weak as possible. As soon as it was rolling you wouldn’t have enough power to do a turn in under a 20 foot radius. So do yourself a favor and give that thing a little more tightening. The saver system on the DTX Evader is very easy to get to, and it turns with just a finger. We would also recommend centering up your steering trim on the radio and re-seeding your steering servo horn so you start out with a neutral setting. Our truck needed to some heavy trim to go straight out of the box, nothing a quick re-seed didn’t fix."

I went through the manual and cannot find anything about "servo saver" or re-seed the servo horn". What are they talking about?

EXT2Rob

My Feedback: (1)

HEY!  Someone who finally bought a BL Evader!  YAY!  Welcome to the boards.

I've never heard of "re-seeding" the steering servo horn before either. Odd term.  I think he means re-centering.  And it's only an issue for you if you're having steering problems (i.e. car's not going straight and steering trim won't fix it.)  If you're not having problems, don't worry about it!  But if needed, it would require your gaining access to the steering servo by removing the front chassis brace and the servo brace. Before you do that, however, it's necessary to center up the front wheels as best you can with the steering trim and note the angle of the servo horn. (It is NOT straight up as you'd think) If at this point, the wheels are still not straight, note which direction the servo horn needs to go to achieve this. Then, recenter the steering trim knob on your transmitter and note the angle of the wheels. If the wheels are now farther off-center, that indicates a few more teeth you'll need to account for.  Once you've removed those braces, the steering bits kinda go limp and the servo saver goes wonky, since those braces hold it all in place. Be careful not to move the servo horn.  Now remove the servo from the car.  Remove the screw holding the horn on the servo and pull it off carefully, and move it in the direction you determined it needed to go by a couple teeth and replace the screw.  Now put it all back together and your wheels should now be almost perfectly straight. Just a little trim adjustment should dial it in.

As for the servo saver itself, there should be some basic info on it in the manual.  At least identify the what the parts look like from the schemactic.  There is a silver thumbwheel used to tighten or loosen the servo saver.  If it's really loose, you will not have much steering.  Just tighten it down if needed.  Mine tended to slip and loosen on it's own and required tightening every so often.

Gloveberg

Thanks a bunch, that makes a lot of sense now. I bought a Brushless Evader and an Arrma Fury at the same time and enjoy them both. I tried the Fury first with it's stock Nimh pack and it was fairly quick I thought but did not prepare me for the Evader and a 2S Lipo. Wow...damn thing will fly...lol

I'm still getting used to them so my driving isn't the greatest but that will come with time.

Gloveberg

Well damn, three packs through and I'm pretty sure the steering servo stripped out.  I can feel the gears inside slipping against each other.  That sucks.

BKoz559

My Feedback: (3)

Did you crash into something? Stripping servo gears happens but, the servo saver usually absorbs shock and helps prevent it from happening in the first place. This is a good time to consider a metal gear servo. You can get a good servo for less than $30. Most major brands will sell for $40-$60 for intermediate level performance and ultra-high speed / torque models will easilly go past $100.

This is an example of a popular brand intermediate servo: http://www3.towerhobbies.com/cgi-bin...?&I=LXUZ87&P=7

Gloveberg

After following thelinkyou posted I'm now not sure if it is stripped because I didn't take the cover off that the linkage goes into. I just assumed that the whole black box was the servo but now I see what the actual servo looks like and it may just be the gears aren't meshing properly. When I move the wheels with the battery unplugged I can feel gears slipping on each other but when you power up it's firm and turns fine with nognashingsounds from the servo (if that makes sense).

EXT2Rob

My Feedback: (1)

wow, that's great you have a local track you can go play on!  Ours got shut down by some guy who moved into the neighborhood, and had enough "influence" to get it shut down cuz it annoyed him.  Same kind of idiot who moves in next to an airport, then complains about the "noise".

I'm surprised that you've stripped the servo THIS soon, but not surprised at all that it gave out. It probably gave up because it's the same one used in the brushed version, and that didn't last all that long on mine. Under brushless power, that servo is gonna take a lot more loading. It's a pretty weak servo.  One of the other things I wish DTX would have upgraded.  But, that's why you can buy one for so little money.  Gotta cut corners somewhere.

That Hitec servo is good. Nice to "buy American".  But if you're on a strict budget, check out HobbyPartz.com
http://www.hobbypartz.com/60gexidised2.html
Just as good a servo for half the price.

EXT2Rob

My Feedback: (1)

A couple other things you might want to consider looking into, to prevent future headaches....

Your shocks - the bottom cap tends to unscrew. When this happens, and you don't notice, it will break off the threads and your shock is done.  Glue the dang things!  Do it, now.   And get some thicker shock oil. I like 35wt.

Drive pins - The stock roller pins used to drive the rear wheels don't stand up to brushless power very long. I got tired of replacing them so often. My local hobby store guy showed me "music wire". Essentially thin metal rod (0.047in if I remember). That stuff NEVER breaks. it will also work in the diff.....the pins inside the diff that hold the outdrive cups in place, under the bevel gear.  That pin will break and can hose your diff gears if not caught right away. You can buy 3ft lengths of this stuff and make drive pins till the end of time, for the cost of a half-dozen stock pins.

The Diff - Thank God DTX made a metal diff for the Evader!  But, like most RTRs, the assembly details (using LokTight, proper greasing) can be a little lacking.  Be sure that all eight diff-housing screws are tight and thread-locked. If those screws come loose (all it takes is a couple), you can munch your diff gears in a hurry.  I took mine completely apart and cleaned all the holes with solvent, applied Blue thread-lock, and reassembled it after greasing it, and let it sit over night. Never have had an issue since. (Just don't loose the shims)

Grease - From the factory, the tranny and diff don't come with much grease.  Personally, I like Trak-Power Gear Grease. WAY better than anything I've gotten from a tube. I know the diff is "fluid filled", but I dispensed with that and used the Trak Power grease in it too, as well as the tranny.  Never have gearbox issues anymore!

Gloveberg

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EXT2Rob

My Feedback: (1)

Tell me you didn't order a DTX replacement!![X(] That car needs a decent, metal-geared servo with a respectable torque rating. DTX doesn't say, and it's tough to find it spec'ed anywhere, but the stock servo is only good for around 60oz/in That one I linked easily doubles that, and will last you years.

Too bad about the hobby shop track not pulling in many folks. If he'd done a short course track, he might've. Hope he makes a go of it.

Oh and tires? Yeah. Built to last, not perform. Any good mainstream (ProLine, JConcepts) stadium truck tire/wheel combo will will be scads better than the stockers. Then watch out! That puppy will be a rocket. I use RPM Slingshots for the Losi XXT. Irun on my own dirt off-road track on my property, so I've got ProLine Dirt Hawg IIs on the front with Gladiators on the rear. Sounds like you're street-running? Put some foam on the front bumper for a while. Curbs kill.

BKoz559

My Feedback: (3)

If the servo doesn't make unsusual sounds that it didn't make before then you're probably good to go.

You can tell if the servo saver is loose by powering on the truck so the servo will hold it's position. Then grab the front tires and try to steer them with your hands. Look down at the servo while you do this and if the servo output shaft stays still but you can still move the tires then the servo saver is giving. It needs to have some tension but, if it's easy to move the wheels then you can try increasing tension on the spring.

Gloveberg

No I did order the one you linked to 

EXT2Rob

My Feedback: (1)

If you find the servo saver keeps loosening frequently, like more than once during a run, a little blue thread lock may be needed to hold it where you want it.

Gloveberg

See this is where things are confusing me. When I move the wheels with power off it feels like gears are slipping on each other but when I power it up things seem more firm. Steering with the front wheels elvated seems fine with no gnashing sounds or anything but I do see/feel what I feel like is a slight notchiness in the steering.

I really hope I'm making sense because you guys are being super helpful and I do appreciate it.



Jimmy

Gloveberg

I hate to seem dumb but what exactly is the servo saver? I see the linkage that attaches to what I'm assuming is the output shaft of the servo so is the saver what attaches to the output shaft?

EXT2Rob

My Feedback: (1)

Yeah.  Pretty much all that mess o linkage under the front brace in front of the servo has to do with the Servo Saver. The SS itself is the assembly with the thumb wheel. It allows a little twist to take the shock of a hit off the servo. When the thumb wheel is set really loose and hold one wheel while trying to move the other you can watch how it works. Simple, but effective.

NOW I get what you're saying.....there's nothing wrong with your servo, dude.  It IS possible to move the wheels back and forth while hearing the gears in the servo move. Completely normal.  With the car OFF.  I missed that.  You're all good to rock-n-roll. Good you got that spare servo on the way tho, you'll need it eventually.

BKoz559

My Feedback: (3)

Take a look at this .pdf file, it should be a helpful resource for you.

The "saver" is a spring loaded device in the steering linkage that will give if the tires are given a sudden jolt. This helps prevent the shock of striking an object from damaging your servo gears. On your truck, there is a basic arm attached to the output of the servo. A threaded link then attaches that arm to a set of bell-cranks which are two pieces that are joined by a fixed plastic link between them. One of these two cranks is the servo saver assembly. It's not the easiest thing to get your fingers or a pair of pliers in there but, there is a textured nut that you can twist to put more tension on the spring. If you view the truck from behind, the saver is the crank on the left. The adjustment nut is on top; between the crank and the top plate of the chassis that covers all of the steering components. Most of the time it's set just fine from the factory.

Like Rob is saying, the gears make a whinning sound if you twist the tires back and forth by hand. If the truck is powered then you should hear the servo buzzing as it tries to fight and keep the tires straight.

When you steer with the radio, the tires will have brief "jerky" spots mid-travel. This is pretty common and is usually a result of natural slop in the linkage and the geometry of the components. It's no concern.

Gloveberg

See that's the thing, with the car off when I move the wheels I don't hear the gears in the servo moving, I feel them slipping on each other. With the Fury when I move the wheels with the truck off I can hear the slight whine of the servo and feel the gers meshing and moving.

Gloveberg

Thanks BK, I had already downloaded and printed every thing Duratrax had on the Evader and put into a handy folder

Like I told Rob my main concern is that with the truck off I don't hear the servo whine as I move the wheels but rather the gears slipping on each other. That being said when I power up the servo buzzes and seems to drive fine. Weird.

But now I do understand what the saver is what it does

BKoz559

My Feedback: (3)

I think you're feeling the servo saver giving. Does the action feel springy when you try to move the wheels by hand?

Gloveberg

The saver isn't giving, the entire linkage all the way to the servo shaft is moving it appears.

EXT2Rob

My Feedback: (1)

So it sounds AND feels different from the Fury?  Hmmm.  It's been quite a while since I played with the stock DTX servo, but I wouldn't think the servo gears should "slip" or feel notch-y as you describe. Sounds like something is defective.  But, if it's driving OK, guess it's just "run it till it breaks", since you do have a better one on the way.  Wish I could be more positive of what's going on.

Anyone know if the Fury has metal gears in its servo? That would be unusual for an RTR.  But the trannys are all-metal, so maybe......?

BTW, where are you doing most of your running?

Gloveberg

With the Fury you can move the wheels side to side with the truck off and hear the servo do that little "whine" and feel the slight resistance and gears meshing, with the Evader you move the wheels side to side and you can feel the gears mesh and the whine but then feel them slip. That being said though you power up and the wheels center and you can feel the resistance of the powered servo and other than some slight notchiness as you steer it works fine. Like you said, I have another servo ordered so I'll run it until it fails...lol

Not sure how sturdy the stock Fury servo is but it's a fun truck. I tried it on with 5000mah 2S Lipo instead of the 1500mah Nimh that it came with and it really woke up. Down side? It applified what both RCNightmare and UltimateRC said about the tires. They're not very good...lol.

So far I've been practicing my driving at the local park so it's been around 80% grass and leaves and maybe 20% asphault or concrete. Only had one really bad spill and I would call that bad because it cartwheels a few times then slid on the roof (those scratches bummed me out) but compared to some stuff I've seen on YouTube I'm like the gentlest basher ever...lol

When I get more comfortable I'll take them up to the dirt oval and give 'em a run.

EXT2Rob

My Feedback: (1)

Oooo...yeah cartwheels can cause bent axles.  I ruined several CV axles that way.  Bad things tend to happen if you go full-throttle for too long!  In fact, I've kind given up on those CV axles for that reason. Gone back to dog bones and short axles.
At least you got those first scratches out of the way now, hey?

Gloveberg

True...lol.