bilinvic's Gmade GS02 BOM

[TrailDawg362]

Great pics and information here, Thanks for that. "thumbsup"

I know that a lot of buyers like the cantilever rear suspension feature, but I've yet to see anyone go with the standard upright shock/shock hoop configuration. I'm wondering if that might cure some of the twist I've been hearing about.

 

[bilinvic]

Almost caught up now....Saturday I took the BOM out for its inaugural run up Mill Hill with my crawling buddies. I'm very familiar with this area and know what lines should be accomplished and what lines are seriously difficult. It ended up being a 5 hour session and I have to say, the BOM's performance was pretty darned good....but there's room for improvement. There a couple of lines that the BOM prevailed!!!

First thing I noticed was I needed to extend the wheelbase about 10mm. A 12.3" wb is the minimum for the terrain we have here on Vancouver Island. The other thing I noticed was the rig was a little too tipsy and it was quite sudden, no time to save. Softer front shock springs was likely going to help the side-hilling balance. I was also experimenting with a triple stage tire foams and they ended up being too soft resulting in the tires folding over. They are now gone!

The only issue I had was the forward bolt on the driver's side shock hoop backed out and was lost. I thought my servo was acting up...luckily it was just the shock hoop / Panhard mount moving around. I may shave the plastic nub that the bolt screws into and replace it with an Axial narrow Nyloc if there's room between the servo and chassis frame.

I'm a fan over over-driven front differentials so hopefully Gmade or the aftermarket will step up with one.

Regarding the HH Revolver motor, it performed awesome despite the space age sounds! I have the Mamba X setup for Rock Racer / Crawler mode. The motor reacts quite nicely between these three modes; in rock racer mode the low end resolution is quite good, the middle drag brake mode, the resolution is even better and in the last stiffer drag brake mode the resolution is incredible ( I refer to the last mode as the parking brake). I routinely cycle through these three modes while crawling as it really does help with the overall performance. I'm currently using an 11t pinion with the stock 45t 32p spur gear. Speaking of pinions, The output shaft on the Revolver motors is quite long compared to a regular motor. Because of this, the cover for the pinion/spur gear and motor will not clear the extended shaft and I had to modify the cover to allow the gear and pinion to protrude out. Leaving this cover off is not an option as it secures the motor mount in place.

 

[bilinvic]

Great pics and information here, Thanks for that. "thumbsup"

I know that a lot of buyers like the cantilever rear suspension feature, but I've yet to see anyone go with the standard upright shock/shock hoop configuration. I'm wondering if that might cure some of the twist I've been hearing about.

Your welcome. Yes, the standard rear shock hoop set-up would definitely help, but the fun is trying something different and making it work. More on the rear suspension soon...stand by!

 

[bilinvic]

As you may have noticed, the driver's side mirror ripped a hole in the vent window....there's only one way to fix that; Red Tuck tape and clear plastic bags.

 

[TrailDawg362]

Agreed. Also hoping for front overdrive. Someone here or on the FB page was going to try the SCX10-2 gears. Rear upper link risers are also on my list of things to try. My BOM is sitting at my LHS. Hopefully picking it up this week, time allowing.

 

[bilinvic]

I'm positive 10.2 diff gears won't work. The BOM differential is not setup for a high pinion. I compared the gears in my hands when I was building and the BOM gears are larger.

 

[TrailDawg362]

That's disappointing news. Gmade, are you listening?

 

[bilinvic]

In an effort to extend the wheelbase, I discovered that the rear differential is severely limited in travel because of contact with the suspension cross-member. I tried everything including reversing the direction of the cantilever suspension but there's just no way to make it work that I can see. I decided to try out the angled shock configuration thinking that this will probably degrade its crawling performance....but I could get the extra WB I'm looking for. I swapped the rear upper link ends with two RPM Jato length link ends and the two skid side link ends on the lower links. This results in an extra 9mm of WB for a total of 322mm (12.68"). This configuration also saves weight on the rear chassis. I added an additional frame cross-member for extra frame stiffening.

I dumped the diff fluid from the rear shocks and filled them with 60wt shock fluid.

I also changed the front springs to softer Traxxas TRX4 green stripes.

I'm trying something different with the tires as well, I used Proline 2-stage foams, but only the inner rigid foams leaving an air gap (tires are not vented). They feel really good and will not fold over.

So....with these changes I took the rig out to my backyard proving grounds expecting to be disappointed. Man 'O man was I wrong; the BOM's crawling performance was incredible, in fact it accomplished a line that none of my other crawlers (including 2.2 rigs) have ever done and as most of you know, I have some pretty serious crawlers in my collection! Needless to say, I will keep this configuration for the next crawling session out in the real world.

I really wanted the cantilever suspension to work because it's not the normal upright shock configuration, but the "V" shock set-up isn't traditional either so I can live with that. I just ordered the billet cantilever pivots from Junfac too...ugh!

On another note, the parts I ordered from Junfac are scheduled for delivery today....only three days from South Korea; not too bad eh?

 

[soze]

Just curious. Do you know if the "V" shock setup has any effect on torque twist? Is it any better/worse vs the cantilever setup?

 

[bilinvic]

Much, much better. The torque twist was essential eliminated. I really expected it to be worse than the cantilever configuration.

 

[Natedog]

Interesting find with the rear suspension, my TF2 does better with the rear shocks less angled over, I moved them to the outermost holes at the top. Angled in more like this, the rear of the truck would dump over much easier and quicker when crossing a sidehill crevice or hole. Thicker oil and stiffer springs might combat the dump too, but I'm already at 3000 diff fluid in those shocks. I know different trucks, but interesting similarity of shock position and effects. Nice job stretching wheelbase a bit, frame reinforcing, and shock mods, keep up the great work!

 

[2mtech]

Good that you found a configuration that works for you, and illuminated a set up that makes the rig a contender. Too bad though, I really wanted the cantilever to work too as that's one of the main draws of the truck. The V set up is kinda trick too, though, yeah.

...not too bad eh?

FINALLY an "eh" comes out...you ARE a Canuck! :lmao:

 

[bilinvic]

Interesting find with the rear suspension, my TF2 does better with the rear shocks less angled over, I moved them to the outermost holes at the top. Angled in more like this, the rear of the truck would dump over much easier and quicker when crossing a sidehill crevice or hole. Thicker oil and stiffer springs might combat the dump too, but I'm already at 3000 diff fluid in those shocks. I know different trucks, but interesting similarity of shock position and effects. Nice job stretching wheelbase a bit, frame reinforcing, and shock mods, keep up the great work!

You have to remember that cantilever shocks utilize super stiff springs unlike the much softer spring rate on the TF2 shock springs and this is what I reckon makes this configuration work. The springs on the stock Twin Hammers cantilever front shocks are crazy stiff as well as the springs on a Traxxas Summit. The vertical dampening is very stiff, which is fine for crawling, but the rear suspension articulation remains quite flexible.

Good that you found a configuration that works for you, and illuminated a set up that makes the rig a contender. Too bad though, I really wanted the cantilever to work too as that's one of the main draws of the truck. The V set up is kinda trick too, though, yeah.

FINALLY an "eh" comes out...you ARE a Canuck! :lmao:

I agree, the "V" config doesn't look as good. After a few hours out on the rocks, I will be able to determine if this set-up will be optimal or not. I still would like to make the cantilever config work though. I spaced the axle shock mounts out with aluminum spacers in order to get the ride height lowered and to avoid the springs from rubbing the frame rails in full articulation. I also added rubber "bushings" (external shock limiters) to the rear shocks to prevent over-flexing!

LOL...that "eh" slipped out!!!!"thumbsup"

 

[Natedog]

Looked again and yes I see you're still using the original cantilever springs which look (and need to be) very stiff. What rate does G-Made say the front/rear springs are?

 

[bilinvic]

The manual doesn't include spring specs other than size. Their option springs are listed as soft or hard!

 

[Natedog]

Thanks, really wish all manufacturers would state the actual spring rates, makes tuning much easier. :ror:

 

[2mtech]

Did you apply any grease or other lube to the CVD's? Kinda seems like the lubricant vs dirt magnet conundrum...

 

[HumboldtEF]

The output shaft on the Revolver motors is quite long compared to a regular motor.

I opted to trim the shaft on the motor down to size, I used a pinion to find the ideal length and left it in place as a cutting guide, taped up the motor to hopefully prevent any metal particle getting into the motor, and its still working fine.
These must be longer because they're using flight based parts.

Great build, and thanks for sharing your testing. Oh and I'm super jealous of your back yard, it looks amazing "thumbsup"

 

[OSRC]

The more I see of this truck, the more I like it. Just pulled the trigger on one...

Thanks as always for the informative write-up!

 

[bilinvic]

Did you apply any grease or other lube to the CVD's? Kinda seems like the lubricant vs dirt magnet conundrum...

I usually spray silicone lubricant into the CVDs to clean them and then I apply a drop of 3in1 oil to lubricate...same thing for the driveshafts.