Suspension tuning

[number9]

SCX10 chassis sitting on Traxxas Big Bore 4962 shocks. Truck weighs 6#. Slow, crawling driving style.

Setups ive tried so far.

1) 2-hole pistons, 30wt oil, Axial springs, black 1.04 front, purple 1.43 rear.
(Too much body roll on side hill. Did decent otherwise.)

2) 2-hole pistons, 30wt oil, Axial springs, purple 1.43 front, orange 1.75 rear.
(Body roll improved, but still too much of it. Overall seemed pretty good)

3) 2-hole pistons, 10wt oil, Traxxas springs that came on the shocks front/rear, can't find the spring rate of these anywhere)
(Body roll / sidehill much improved, suspension damping was really nice, body seems to stay more level over obstacles while the axles follow the terrain. Springs are a tad too stiff tho and opposite corners don't bottom out crossing a ditch at an angle, so truck teeters and rolls over.)

Out of the above setups, #3 seems headed in a nice direction. Springs a few steps softer than the Traxxas reds may be real nice, if I can find out what # they are. I've got 3-hole pistons and 20wt oil I've not played with yet tho, so don't want to overlook what they may provide.

What are you guys with similar truck weight and driving running for springs / pistons / oil?

[number9]

So just to update, I got tired of trying to find the listed spring rate of the Traxxas Big Bore red springs, so I measured them with a (cheap) fish scale and they look to be around 2.5#/in. Based on that, I've ordered the Axial AX30218 2.07#/in springs. Hopefully these will work out just right.

[MAGNUMB]

What kind of foams you running?

[number9]

Originally Posted by MAGNUMB

What kind of foams you running?

Pro-Line Hyrax 1.9's with the stock foams that come in them.

[MAGNUMB]

Sometimes I find playing with foams a lot easier that messing with shocks.
Now that you have a decent baseline maybe try different foams unless your tire is so stiff foams don't play into it??

[number9]

Another thread reminded me to update.

I’ve got the Axial red springs in now and still running 2-hole pistons with 10wt oil. Also have since got CI Little Nova Comp Cut / Med outer foams in front with Dueces Wild single stage firm in rear.

Really liking how the truck works now, with a stiff spring / light damping setup. Still want to try the 3-hole pistons with this setup, and may drop the rear springs back down to the Axial orange just to double check.

[JDIDING]

in my 10.2 I set the truck to be about 3/4 compressed on the shocks at ride height with the softest springs I possibly can run.
I use stock rtr shocks with a extra 2mm hole in the piston and 10wt oil,, I try to keep damping as light as possible just enuff to keep the truck from bouncing around
the lower the ride height can be the better to keep the CG low, I do a lot of trail comps, rock crawling, and TTC type events

[Duuuuuuuude]

Originally Posted by JDIDING

in my 10.2 I set the truck to be about 3/4 compressed on the shocks at ride height with the softest springs I possibly can run.

This.


Crawlers can get away with a surprisingly soft spring. Many will go hard to combat torque twist and rollovers, but those are symptoms of other issues.

Shocks/springs are typically the easiest part of suspension tuning on a crawler, and not nearly as critical as it would be on a track driven race rig.

[number9]

^ Can you expand on that? On an off camber or sidehill situation, especially if dropping a wheel in a rut, what other tuning aspects can improve resistance to rollovers? Maybe I’m missing something else that I could be looking at.

[Duuuuuuuude]

Off camber + dropping a wheel in a hole is always tough. It's just making a bad situation worse.

The biggest thing is getting your weight low and forward. If you don't do that, all the tuning in the world won't save you.

As low as possible is best, but there are limits to how far forward you want to shift it. I typically aim for the balance point to be close to where the front lower links bolt on to the skid or chassis. That seems to be the sweet spot.

Chassis tuning will also help. Not all rigs come set up well, some don't even give you options (scx10, for example...)

Here's a thread that will help. Keep in mind that it is heavy reading, and it may take a while to absorb and understand. Proper tuning takes time and effort, but it's well worth it.

Another 4 Link Thread


Many years ago I helped a buddy set up his comp rig. Neither of us knew what we were doing, and he ended up with a poorly tuned rig with lots of added wheel weight to compensate. It did "ok". A few years later I had it in my hands again to give it a once over, and after applying my accumulated experience, I put it on a massive diet, corrected the poor chassis tuning, softened the shocks/springs way up, and the end result was a very capable lightweight rig that surprised the hell out of us both.

edit: to explain to you how relatively unimportant shock tuning is (it matters, but not nearly as much as other things do), I couldn't tell you what shock pistons or oil I have in any of my rigs. I really don't know. The oil is probably 35wt, because somehow I ended up with a bunch of it at some point.