Shock oil weight

[ahr43]

For my conventional chassis converted to RC drag racing, using a combo of piston and fluid changes. Up front using 3-hole pistons and 25wt fluid. This allows the front end to come up quickly and transfer weight to the rear. In the rear using a 1-hole piston and 45wt fluid. Idea here is to limit fluid transfer and prevent squat. -AC

 

[Lumikko]

Thanks for the info guys!

My racer is a Team Associated Pro4SC10. It's nice. I like it, just want to tune it more. It is RTR, I'd prefer to buy a kit, but who has time for that?

I think I'm going to go down to 30wt. See what happens.

I have the same truck and have tuned it quite extensively.

The stock shocks have plastic bodies and the bores are not uniform through the stroke. I ran a gauge up and down in there and there definitely are tight and loose areas.

Also, the pistons are way undersized. There’s a lot of oil blowing by. The stock 40 wt oil seems thick enough on the bench (low speed damping) but it has very little ”pack” (high speed damping) when you land jumps and hit bumps at speeds.

Further, the spur gear cover in the bottom is in front of the rear but the chassis in front of it is high. This catches the edges of jumps and really tosses the rear around when it hits anything.

To reduce the rear bucking and tossing around, I added anti-squat (flipped C block mod) and used larger pistons all around. I have oversized Team Durango 12.3 mm pistons drilled to 2x 1.5 in the front, 2x 1.6 in the rear. I turned the OD of the pistons down until they had a ”sliding” fit. This helped firm up the rear when going off jumps, and the spur gear cover is less likely to hit bumps – all this without having to increase ride height or use stiffer springs.

I’ve toyed with the idea of making a wedge-shaped profile that runs below the chassis from the steering posts all the way to the spur gear cover. This would decrease ground clearance under the ”belly” but also prevent bumps from hitting the lump in the back at a steep angle. Sort of drag and slide over the bumps, as with a flat chassis.

Get Tekno EB410 pills (TKR6544) so you can fine-tune the hinge pin angles further.

 

[sylentk]

I have the same truck and have tuned it quite extensively.

The stock shocks have plastic bodies and the bores are not uniform through the stroke. I ran a gauge up and down in there and there definitely are tight and loose areas.

Also, the pistons are way undersized. There’s a lot of oil blowing by. The stock 40 wt oil seems thick enough on the bench (low speed damping) but it has very little ”pack” (high speed damping) when you land jumps and hit bumps at speeds.

Further, the spur gear cover in the bottom is in front of the rear but the chassis in front of it is high. This catches the edges of jumps and really tosses the rear around when it hits anything.

To reduce the rear bucking and tossing around, I added anti-squat (flipped C block mod) and used larger pistons all around. I have oversized Team Durango 12.3 mm pistons drilled to 2x 1.5 in the front, 2x 1.6 in the rear. I turned the OD of the pistons down until they had a ”sliding” fit. This helped firm up the rear when going off jumps, and the spur gear cover is less likely to hit bumps – all this without having to increase ride height or use stiffer springs.

I’ve toyed with the idea of making a wedge-shaped profile that runs below the chassis from the steering posts all the way to the spur gear cover. This would decrease ground clearance under the ”belly” but also prevent bumps from hitting the lump in the back at a steep angle. Sort of drag and slide over the bumps, as with a flat chassis.

Get Tekno EB410 pills (TKR6544) so you can fine-tune the hinge pin angles further.

That is good stuff! You have definitely done a ton of work! I have looked into and will continue to look into all this info.

Unfortunately, I am now a part of the "broken front A arm club". Super embarrassed to admit. Was bending over to pick up something and accidentally pinned the throttle, so there went to truck, straight into the side of the house at mach stupid. Could've been worse. No one was hurt in the incident, just my ego I'm still shaking my head in the I can't believe I just did that...RPM replacement arms on the way.

 

[Lumikko]

That is good stuff! You have definitely done a ton of work! I have looked into and will continue to look into all this info.

Unfortunately, I am now a part of the "broken front A arm club". Super embarrassed to admit. Was bending over to pick up something and accidentally pinned the throttle, so there went to truck, straight into the side of the house at mach stupid. Could've been worse. No one was hurt in the incident, just my ego I'm still shaking my head in the I can't believe I just did that...RPM replacement arms on the way.

I tried the RPM arms and went back to stock. They are way too flexy for track use with lots of grip, The handling is all over the place. Great for bashing, though. Can’t snap when you can virtually tie them into a knot!

 

[nino]

I wouldn't put RPM on anything that you want to go where you want it to go
Another thing that I don't like is that the screw holes strip easily, take off the shocks a couple of times and you need a new set of arms.

 

[sylentk]

OK Yeah. I bought both stock and RPM, just in case I go mach stupid again. The RPM's needed a bit of filing to get to fit, so not impressed, but at least the truck is up and running again. We'll see if I can get them to pretzel. Sounds like a challenge