Rustler 4X4 VXL bottoming out / slapping

[StDragon]

So I recently purchased a new Rustler 4X4 VXL (own a standard Rustler too) - love it!. Problem is, the bottom chassis is bottoming out and slapping the pavement whereas my near stock Rustler isn't. With both cars, I'm just driving off the front lawn grass, over the curb and onto the street. So....say a 5 inch drop? Not much at all IMHO.

I get that the 4X4 VXL has a lower center of gravity with progressive springs. I just assumed they would be stiffer thus negating that possibility. Some have suggested changing the shock oil to 40 in the front, and 50 for the rear. Would that be too stiff for the stock non-hardened shafts, would I also need to upgrade the shocks? Springs? If I could get away with just changing out the shock oil, that would be preferred if possible.

[Panther6834]

Only increasing the oil weight probably won't help much. I'd first suggest trying some of the parts Traxxas includes. There are pieces for the shocks, which will increase the preload. You can also replace the springs with stiffer springs. If that doesn't help, then (as I did, although for an entirely different reason) replacing the shocks with higher-quality (got Pro-Line ProSpec), AND increasing oil weight (I'm running 40 front, 45 rear), AND installing stiffer springs (I'm running Pro-Line 'hard' in front, 'extra-hard' in rear), would solve your problem...and then some.

~ Coming to you live, from somewhere on planet Earth.

[Luke s]

Yes. Panther6834's idea is a good one. I personally used almost all the spacers in the back, because out of the box it is very sloppy, and in the front I use redcat racing caldera sc 10e big bore shocks at the most plush level possible. They are way more durable than the stockers and cost less than $15. Also you will probably need new rear cvd's (i suggest tekno m6's) and aluminum wheel hexes. Have fun!

[Double G]

Keep in mind that spring rate and oil viscosity work hand-in-hand. Too much spring for the oil will cause the truck to be bouncy. Too thick of oil will cause the truck to feel stiff and have slow or little rebound.

Start off with what you can change easily. As mentioned, start off with putting more spacers to increase the preload on the springs. Or move the shocks to different positions on the arms. Eventually you may want to go to thicker oil.

[Panther6834]

For my currently Rustler 4x4, I considered the Tekno M6s, but, ultimately, decided to go with the Traxxas CVDs. As for the two builds I'm still working on the parts lists for, I'm considering both -Tekno M6 & Traxxas 6851R/6852R CVD. Whereas the first Rusty is for track (but, possibly, not all-out race) use, the two new vehicles are intended specifically for race.

~ Coming to you live, from somewhere on planet Earth.

[StDragon]

Keep in mind that spring rate and oil viscosity work hand-in-hand. Too much spring for the oil will cause the truck to be bouncy. Too thick of oil will cause the truck to feel stiff and have slow or little rebound.

Start off with what you can change easily. As mentioned, start off with putting more spacers to increase the preload on the springs. Or move the shocks to different positions on the arms. Eventually you may want to go to thicker oil.

Yeah, I'll definitely try adding more pre-load. Interestingly enough it came already pre-loaded from factory, not sure why Traxxas didn't just redesign the shocks or mounts from the beginning. As Luke said, it's very sloppy.

BTW, does anyone have matrix or google docs spreadsheet available on the best combination of spring tension paired with oil weighting? If I actually had the knowledge, I'd prolly build one myself and publish.

[StDragon]

So adding extra preload to both front and back definitely was an improvement. Though if anything, via increasing the hight. It gives more shock travel on impact, but still not enough to take the energy.

I'm going to put 40 weight on front and 45 in the rear to see how well that goes. It's a heavy car for sure.

[StDragon]

Good news! So I finally got 40 in the front, 45 in the rear. Re-adjusted the pre-load so that the A-Arms (both front and rear sets) are sitting level. So not only did I eliminate slapping, but I regained some lower center of gravity as well.

If I land hard enough (say, over 1 1/4 ft in height difference), it slaps, but just a little bit. I could go 45 and 50, but at that point I think the shock shafts might start to give out and bend from too much impact stress. At that point, I'd be looking into GTR Shocks with a variable dampening piston kit.

[TwoBelugas]

get Some GTR shocks for these puppies. I always felt that the ultra shocks are a bit overworked in the 4x4 applications, especially if you plan on using heavier tires in the future. On Slash 4x4s you still have light tires and wheels but in a more demanding open wheel car use, even with stock oil, the GTRs I have on mine soak up the bumps much more controlled even with 2.8 Trenchers all around. Hitting road markers at 45-50 tossed mine around a bit when stock, but with the GTRs it’s beautiful to see the wheel move up with the bump but the whole car stays planted and just keeps going in a straight line.

Traxxas would have people like me lining out the door for an “ultimate” edition Rustl4r with the Slash ultimate Aluminum bits and GTRs. The 130 dollar premium is a deal once you add up the cost even at eBay chop shop prices.

[StDragon]

get Some GTR shocks for these puppies. I always felt that the ultra shocks are a bit overworked in the 4x4 applications, especially if you plan on using heavier tires in the future. On Slash 4x4s you still have light tires and wheels but in a more demanding open wheel car use, even with stock oil, the GTRs I have on mine soak up the bumps much more controlled even with 2.8 Trenchers all around. Hitting road markers at 45-50 tossed mine around a bit when stock, but with the GTRs it’s beautiful to see the wheel move up with the bump but the whole car stays planted and just keeps going in a straight line.

Yeah, I'm pretty much sold on the idea of GTR shocks. Perhaps in the next month or so. Perhaps sooner if I bend a shaft or two. Hope not as I'm not a "basher" kind of driver. But I do admittedly push it at times.

Traxxas would have people like me lining out the door for an “ultimate” edition Rustl4r with the Slash ultimate Aluminum bits and GTRs. The 130 dollar premium is a deal once you add up the cost even at eBay chop shop prices.

Agreed. Hindsight is 20/20 and all that. But knowing what I know now, I would have purchased a Rustler 4X4 Ultimate had the SKU been available.

[NitroStarGT]

Owners manual says the Rustler 4x4 comes stock with 50w in front shocks and 30w in the rear?? What up with this?

[StDragon]

Owners manual says the Rustler 4x4 comes stock with 50w in front shocks and 30w in the rear?? What up with this?

Apparently so for the 4x4 VXL - as stated on page 25 "From the factory, shock oil is set to 50W in the front shocks and 30W in the rear shocks."

Yeeeeahhhhh, I'm not feeling like the fronts were ever shipped with 50 in the front.

[NitroStarGT]

I dunno what to try now??

[NitroStarGT]

I poured the stock oils out and refilled the rear with Losi 50w and the fronts with 40w. Set preload at drive shafts just above level. The drop test appears even with a 2s 5000mah lipo. Will run and check.

[StDragon]

Yeah, i'm thinking 45 in front and 50 in rear might be the best. Though IMHO I wouldn't go any thicker unless you've got shocks with hardened steel shafts.

[NitroStarGT]

Well I ran it on 2s and then 3s. Seemed a little bit better but the lowered preload made it not roll over as much. Had a lot of fun. It is freezing outside LOL.

[Luke s]

Yeah, i'm thinking 45 in front and 50 in rear might be the best. Though IMHO I wouldn't go any thicker unless you've got shocks with hardened steel shafts.

I agree. My front shocks might have been just a bad batch, but I doubt it. I emptied out the oil (on accident due to the stupid shock caps busting) and with no oil my shock bore bent like crazy. To be fair, I am very hard on my cars when I bash, but these stock traxxas shocks are just crap. I have heard lots of good stuff about traxxas's gtr shocks though.

[tazzzz]

I had the same problem,,,,I put 60wt oil in the shocks then crank down the springs a bit,,,problem solved....I also put a set of big bore aluminum shocks on ,,,was tired of the caps and springs rests coming off,,,,,haven’t encountered any problems in that area anymore......

[olds97_lss]

Not the rustler... but probably similar in weight, the stampede 4x4 vxl. I run the GTR's front rear with the vdk and drilled out pistons to 1/16" (I think) with 60 wt associated oil and VG variable springs. It still slaps the ground, but isn't overly stiff while absorbing a lot of the impact before the chassis does. I mean... when your getting 5+ feet of air under it, if it doesn't hit the ground, your going to have problems everywhere else. Especially when you get 10+ feet under it. Also, the 7200mah 3S pack I'm running isn't the lightest...

I just wanted a setup that didn't have me blowing shocks out all the time and having it land so hard that I was destroying the truck when airing it out. This is where I ended up.

Funnily enough... I did snap my chassis in half a couple weeks ago. It was 32F outside and I was airing it out pretty good. If I didn't have my homemade roll bar on there with aluminum straps on the sides of the chassis, it would have fallen completely in half.

No crack before... and this after: