[A few] MRC Questions/Comments

[JeepinOR]

Hey all; great 'site! The reading I've been doing here the last few weeks has been quite educational: until this week, my only experience is with RC "toys" as an adolescent, so the knowledge base here is very helpful for me. After getting my MRC and doing a bit o' stock crawling, I've a few questions motivated from my observations of my new rig that don't seem to be directly answered here (implied probably, but some of this info is a bit confusing for me still).

I've front/rear lockers on the way from RCBros, but that's all so far.

-the MRC manual suggests on one page that the shocks are prefilled with 30wt oil; on another page it reads 100wt. The shocks seem quite slow to react, so I'm guessing it's 100wt? (I've no basis for actual comparison - just my rig and lots of videos. But I'll try some 50wt from the LHS when payday comes.) In retrospect, they may have felt a bit tighter right out of the box, as opposed to after the first good crawl. Is there a break-in period or is it in my head?

-I flipped my tranny, battery tray, and was going to mount the battery on the servo, but after doing more reading to make sure I did it correctly (it seemed too easy) I found a minor debate about "postive timing" and the possibility of damaging the stock MRC motor running it backwards. Are the risks a real possibility to consider, or is damage inconsistent enough to justify the benefits? (A motor upgrade may be down the road, but is not first on my list.) Admittedly, I grew concerned after reading about this so I returned it to stock form for now. I was going to mount the battery on the servo anyway, but the wiring is too short; so rather than just splice and make the leads longer, it's probably prudent to add some Deans connectors while I'm at it? (I have yet to research the Deans concept, but it seems that they're popular connectors that ultimately make upgrading electronics/wiring easier to mess with in the long run?)

-My reading and observations of the stock tires/foam suggest that the stock foams are a bit hard(?). The tires felt kind of squishy in my hands but on the rocks it seems like the tires would benefit from "more give." Softer foam, yes? ...I didn't think they were, but some of my rocks, I guess, are on the slippery side, so I'm thinking Blue Claws and budget Axial bead locks for now.

-I'll get to a sporting goods store for some weight, but for now I'm curious about those running steel/airsoft BB's in their tires. The stock foam seems rather big in the stock tires - are the BB's placed between the foam and rubber, between the foam and rim like the "lead rope," or are the BB's taking place of the foam?

I suppose this is enough for now! If you've read this far, I appreciate the effort!
Again, great site. Thanks.

[TImmy6216]

i just tore one of my extra wheels apart (to learn) and yea the foam will not allow the bbs to rol around like ya want. i pulled the foam out and the wheels are VERY soft. in my opnion id say go with the lead rope. then you can up grade your foam and what not and you dont have bbs to deal with

just my 2 cents

[RcBro]

Originally Posted by JeepinCA

-the MRC manual suggests on one page that the shocks are prefilled with 30wt oil; on another page it reads 100wt. The shocks seem quite slow to react, so I'm guessing it's 100wt? (I've no basis for actual comparison - just my rig and lots of videos. But I'll try some 50wt from the LHS when payday comes.) In retrospect, they may have felt a bit tighter right out of the box, as opposed to after the first good crawl. Is there a break-in period or is it in my head?

The 100wt is a mis-print, they are filled with 30wt. Thinner weight will allow more articulation however you'll quickly fine out the stock shocks aren't very tunable.

-I flipped my tranny, battery tray, and was going to mount the battery on the servo, but after doing more reading to make sure I did it correctly (it seemed too easy) I found a minor debate about "postive timing" and the possibility of damaging the stock MRC motor running it backwards. Are the risks a real possibility to consider, or is damage inconsistent enough to justify the benefits?

I've ran it both ways with out a problem. The entire motor and esc combo on the MRC has been hit or miss with some people. Some have horrible luck and blow theirs up rather quickly, some have been running the stock equipment sense day 1 with no issues.

Deans plugs are a great upgrade for any RC who has a large amount of current flow. My personal setup I'm still running stock connectors as I don't feel deans is needed as the AWG of wire is to small to allow a large amount of current flow in the first place. If and when I do upgrade I'll go with the mini deans plug rather then the regular deans.

-My reading and observations of the stock tires/foam suggest that the stock foams are a bit hard(?).

An upgraded tire will be a huge improvement over stock!

-I'll get to a sporting goods store for some weight, but for now I'm curious about those running steel/airsoft BB's in their tires.

Most use bb's in place of foam, however I feel the memory foams that come with the tires are a perfect match, bb's simply down allow the tire to flex as they take up room and do not shrink upon rolling over an obstacle.

Answers in read. Enjoy

[fordwheeler]

as for your esc,you could make a tray on the frt. three link connector(the upper susp. link) & mount esc there,its tight but it will fit.then your bat can set on top of servo. no wire splicing necessary

[cutlaSS]

RcBros pretty much answered your questions. But I just wanted to add to your question about tranny flip. I did the flip but I run a HH mini torquemaster which has 0 timing, I only did this for clearance. I see no other real benefit like a AX10 tranny flip.

[JeepinOR]

Great info - thanks!

[JeepinOR]

For the stock tires I ended up adding some flattened lead rope around the rims which added 1.5oz each tire; and, in the end I found that empty tires ran better than the stock foam on the [new!] rock garden in the backyard. I also added 1.5oz to the front axle and moved the battery to the top of the servo - just these things really improved COG and climbing ability.

But...I ended up getting some Blue Claws and Axial bead locks. The bead lock mod for the stock tires was "ok" - but these Axials seem to hold a bead pretty nicely. I've yet to get 'em on the rocks, but the compound of the Blues sure is a lot stickier than the original tires. That'll be good on my slippery locks, I hope. I'm looking forward to trying some G8 Flats, too.

I added a Castle BEC and wired it up with Deans. Running the MRC around a bit this morning, the ESC still got a little warm (though not as much as usual, I think) and the CCBEC got a little warm, too (but certainly not uncomfortably warm to the touch). There's current flowing, so I'm hoping the CCBEC warming up a little is normal? (It's all wired per the Castle diagram.)
A HiTec servo is on the list, so I'll be ready for that...

I also made up a ghetto four-link plate for the rear just for kicks (I don't have a shop equipped enough to make a nice plate; so I'll get an aftermarket four-link from someone online). For clearance I had to move the shocks outboard, and I moved the links inside the chassis. In my limited experience, it seems to have helped with the torque twist, but it's not as "loose" (as the original three-link) when moving the axle back and forth with my hands. It seems to have decent articulation, it just seems to take a hair more muscle to manually move it to and fro. Is that normal, too?

Please feel free to advise, criticize, or comment as you feel!

[soundcolor]

Originally Posted by JeepinCA

For the stock tires I ended up adding some flattened lead rope around the rims which added 1.5oz each tire; and, in the end I found that empty tires ran better than the stock foam on the [new!] rock garden in the backyard. I also added 1.5oz to the front axle and moved the battery to the top of the servo - just these things really improved COG and climbing ability.

But...I ended up getting some Blue Claws and Axial bead locks. The bead lock mod for the stock tires was "ok" - but these Axials seem to hold a bead pretty nicely. I've yet to get 'em on the rocks, but the compound of the Blues sure is a lot stickier than the original tires. That'll be good on my slippery locks, I hope. I'm looking forward to trying some G8 Flats, too.

You'll love the G8 flat irons. The blue claws are great have their strengths and weaknesses. So do the Flat Irons. Its good to have both. I would definatly get a set of the G8's, WAY better than regular flat irons.

I added a Castle BEC and wired it up with Deans. Running the MRC around a bit this morning, the ESC still got a little warm (though not as much as usual, I think) and the CCBEC got a little warm, too (but certainly not uncomfortably warm to the touch). There's current flowing, so I'm hoping the CCBEC warming up a little is normal? (It's all wired per the Castle diagram.)
A HiTec servo is on the list, so I'll be ready for that...

A little warm is perfectly fine. As long as they dont get hot your fine. Just keep a watch on it. If you are running at high speed (kinda relative with a crawler) Then the electronics are going to get alot warmer than if you are slowly crawlin around.

I also made up a ghetto four-link plate for the rear just for kicks (I don't have a shop equipped enough to make a nice plate; so I'll get an aftermarket four-link from someone online). For clearance I had to move the shocks outboard, and I moved the links inside the chassis. In my limited experience, it seems to have helped with the torque twist, but it's not as "loose" (as the original three-link) when moving the axle back and forth with my hands. It seems to have decent articulation, it just seems to take a hair more muscle to manually move it to and fro. Is that normal, too?

Four links have alot more controlled movement than a three link. It should be a touch "stiffer", but not all that much. You shouldn't be able to notice it that much. One thing you need to do is to make sure that you dont have any of the links in a bind. You said you moved the links inside the chassis, That may well be causing the binding you are noticing as the upper links my be contacting the TVP's. Just be sure to check for binding and adjust accordingly.

Please feel free to advise, criticize, or comment as you feel!

Heres some other things to do.
Add some internal limiters to the shocks, and change to at least 50wt oil.
(do a search for the internal limiter mod, I just did a write up on it)
Get metal lockers, Get metal lockers, Get metal locker, Get metal lockers
At least front and rear. Alot of people never have a problem out of the stock center locker (its plastic too) but I figured since I had the truck apart, I might as well do it. Can't hurt.
Get some wheel wideners, the flat irons will rub the lower links when articulated and with the tires turned. Wheel wideners stop it completely.
Get your trucks COG down as low as possible. You still want to have ground clearance, but get it down. My lower links are completly level and run in a straight line from the skid to the axles. I have had zero problems with ground clearance.
Thats a good start. Search around here for some more mods.

Cheers

[JeepinOR]

Yep; front and rear lockers were actually the first thing I ordered from RCBros.

I really like the Blue Claws. The first battery pack I ran with them, I was very impressed - super sticky. I rinsed off the dirty tires for the second battery pack and they still did very well, but they weren't quite as sticky as they were fresh out of the packaging. I'll try some Simple Green... Hands down, though, these Blue Claws totally outperform the stock tires. I'm making lines in my little rock garden that I couldn't make before. In fact, I'm going to have to complicate the garden a bit, as these tires really perform.
It rained the other day and though the Blue Claws did well, the added slick did make them slip a little more, of course...
G8 Flatties will be my next tire purchase, I think.

I assumed that the CCBEC should be plugged into the MRC's RX's auxillary plug and ran it that way for two batt' packs, but then found some posts that suggest plugging it into the "Battery" plug; the MRC's RX "options" are AUX and BIND. The rig works with the CCBEC in either plug - does it really matter? Maybe if/when I want to utilize the 3rd RX channel, it will matter...?

My rear ghetto-four link isn't binding in the rear; though I did mount the links on top of the four link plate, rather than below as I've just noticed in many pictures. I think it changed some geometry up front(?), as I recently noticed that the stock battery on the servo rubs the body at/near full flex. Maybe I didn't notice it before--when everything else was still in stock position--but I don't think so.