Mini Z - Upgrading Your MR-03 Servo Gears to Delrin & a Metal 4th Gear!

[@hotdognobun]

Thank you for this it really makes a huge difference. Now I to do it to 4 other of my MR03's can't go back to stock

[@TheShopMiniRC]

Definitely makes it more smooth!

[@hotdognobun]

@@TheShopMiniRCI replaced all gears with PN Delrin/Brass but still get a lot of play and car will never go straight. Is that normal

[@TheShopMiniRC]

@@hotdognobun I mean, to be fair, these kyosho servo gears always seem to have a bit of slop. It shouldn’t be more than the normal though.

[@hotdognobun]

@@TheShopMiniRC After inspecting I think it has a lot to do with the steering tie rods that connects to the servo arm. I just added some grease and the slop reduced slightly. Love the easy maintenance on these Mini Z's once you get past how delicate the small parts are

[@robbryan3044]

Just recently acquired (thanks to my former next door neighbor) a couple Mini-Z MR-03s (one for me, and one for my stepdad)...and, now I also added an MR-03 EVO SP. I spent a good party of this afternoon & evening replacing (all 6 of) the stock servo gears with the Delrin gears (will do the same for the EVO, but with the metal 4yh great), to which I've also been "racking my brain" about the servo saver. First, I tried M3 washers, except that their OD was to large, so that didn't work. Next, I was going to try an M3 spacer, but I couldn't find them (I just moved from the SF Bay Area, to Las Vegas, and I'm still a ways away from getting everything unpacked/organized). So, I decided to (temporarily) give up, and consider ordering the Mugen shim set. So, I put the chassis back together, cleared my work space, and system getting ready for bed...and, then it hit me - instead of trying to "tighten up" the servo saver, why not completely "lock it up"? In other words, turn the stock servo saver into a servo horn. As the thin pin running through the center is the 'pivot' point, I see no reason why the three primary parts couldn't be turned into a single part using CA, or epoxy. Looking at the rules for the most stringent of Mini-Z race classes - Box Stock - the rules don't allow one to 'replace' the stock servo saver. Best I can tell, there's nothing in the rules preventing one from modifying the servo saver...including turning it into a servo horn. The shim idea will greatly "minimize" servo saver slop...but, my idea should completely "eliminate" it (of course, there will still be steering slop caused by other things, such as the chassis mounting points of the upper suspension arms).

[@TheShopMiniRC]

Not a bad idea at all. Hard to say if class rules would allow it though. But yes, it would def help eliminate some of the slop. We had to add some grease in our gears to prevent the occasional “shiver” that happened because everything was so loose that the pot would basically bounce the steering left and right if you quickly let the steering go.

[@robbryan3044]

@@TheShopMiniRC Since I'll have to disassemble it again (to epoxy the servo saver), I was thinking about greasing the gears. I've never worked on a servo gear assembly before...but, having built more than a few 1/10 race vehicles, I'm guessing the 'trick' would be to use something that holds well to the Delrin, isn't too thick (no Maxima Marine Grease), and isn't too thin (no Tamiya Ceragrease). This might sound "strange" to some, but I'd be willing to bet that 1Up O-ring grease might be about as perfect as anything. It definitely sticks to plastic, and it's consistency is what I'd consider to be in the upper-low range. If Ceragrease is a '1', Traxxas' 1M black grease a '10', and Maxima a '7', I'd put 1Up O-ring around a '3'.

[@TheShopMiniRC]

@@robbryan3044 I used high viscosity Atomic Ball Diff Grease. Seems good so far.

[@johneppstv]

When getting it out, different groves can be used on the far side. Little tiny ones from side of motor to mid. Helps get out.

[@TheShopMiniRC]

Good tip!

[@reekooism]

Any clues for founding Mr01 servo upgrade ? Even à compatible servo please, mines broken

[@TheShopMiniRC]

Oooof. No idea on that one, sorry

[@zalinahsarpiai73]

What chassis are you using

[@TheShopMiniRC]

That chassis is the Nexx Racing Bison.

[@duanesapp4914]

Do you have part number of the shims?

[@TheShopMiniRC]

either of these should work: www.amainhobbies.com/mugen-seiki-3x5x0.1-0.2-0.3mm-shim-set-30-mugb0763/p1389566 or www.amainhobbies.com/tamiya-3mm-clutch-shim-set-tam53585/p139954

[@wingnutbert9685]

Hey Chief. Sort of sideways off topic. I just got a Emax servo for my DB in the mail. I ordered through amazon canada from Injora (fulfilled be amazon). It came in a clear bag with an Injora cardboard top stapled to it. Thing I found odd was the servo was in the bag, with the parts and screws but the servo box was flattened out an in there too. Just struck me as odd. Why take the servo out of the box, flatten it and put it in the bag? Just wondering if you've ever had this when/if ordering from Injora or amazon? Thanks!

[@TheShopMiniRC]

Injora uses emax and I think they just include the box. I don’t think they actually take them out. My guess is emax sends Injora servos and the boxes and the components. All in mass.

[@wingnutbert9685]

@@TheShopMiniRC The servo is an Emax branded servo. Just thought it weird they'd unbox the servo then include the flattened box in the Injora packaging. Maybe it's how they off load recycling onto the customer! LOL!

[@TheShopMiniRC]

@@wingnutbert9685 haha yeah… maybe. Maybe it somehow saves on shipping.

[@iramtorres3309]

Will this work on a MR02? Or the servo is different?

[@TheShopMiniRC]

I don’t know honestly. I’ve never owned an MR02.

[@TheSwampChicken-II]

Good grief. Working on these things is a nightmare

[@TheShopMiniRC]

hahaha yeah... the mr03 servos are a pain to work on for sure. Thats why we love the low cog, hobby grade cars more. there are a TON of awesome 1/28 chassis options out there. the Kyosho MR03 and 04 are toy grade compared to the Atomic, GL Racing, Nexx Racing, Reflex Racing, MWX, and other low center of gravity, lipo cars.