Shocks/shock springs/shock oil advice for an RC I want to jump with

[MAZ]

My Hyper ST build is pretty much done now but I'm having issues with the shocks that I'm using. They're from a Hyper SST which is fine in itself but the issue I'm having is that the springs aren't heavy duty enough. This causes the chassis to sit a lot lower than I'd like. I plan on getting used to jumping the Hyper once its ready but I don't want to smash the thing to pieces because the springs are far too soft

 

Its doesnt help that I think the ST is a heavy beast lol

 

(Pic of the shocks I have for reference)

 

 

I've tried some Mugen shock springs which were supposed to be quite stiff but they really really weren't.

 

Does anyone know where I can get much stiffer rated shock springs from? 

 

Alternatively - how about replacing the shocks for some heavier duty ones?

 

Are the Arrma Kraton shocks beefier with a stiffer spring? 

I don't know anything about arrma stuff at all so any advice on them would be great. 

Also any help or tips on what I could do about beefing up the shocks would also be really appreciated 

 

Many thanks 

 

 

[wombat]

On the shocks you pictured the preload adjusters are fully wound up, have you tried winding them down a bit, also thicker shock oil could help, plus adding springs inside the shock under the piston

[m4inbrain]

We really need to stop spreading the myth that thicker shock oil helps "stiffening" a car. It doesn't. It slows down the compression/extension, but pressure required to compress the spring is exactly the same. It slows down the compression by increasing pressure inside the shock - all you do is increase the potential to blow the top off the shock, or bend the shock shaft because the shock doesn't compress fast enough. 

 

As a rule of thumb. Oil is used to tune how fast your car goes from full compression to full extension and vice versa. Not how much force full compression takes. 

 

The only way to increase spring pressure "or stiffness" is by using stiffer springs. There's no other way. Everything else is wrong. 

 

Now, you actually do want somewhat soft springs and reasonably light oil on a basher. Within reason. Otherwise they won't last (generally by either breaking the piston inside the shock, or bending the shock shaft). 

 

There's a simple test. Adjust the ride height to where you want it (as was pointed out by wombat - directly under the shock cap is a collar that you can wind down, adjust that down to increase ride height to where you like it), take the rig and drop it from 3 feet. That tells you exactly what you need. If the chassis hits the floor, you need stiffer springs. If it wobbles or waves, you go up a little in shock oil weight - it should drop on the wheels, compress the shock all the way without slapping on the floor, then extend straight up without any oscillation to "resting position". If it goes up all the way to full extension and then settles back down in the "droop" from the weight, your oil is too light. 

 

That's your general tuning starting point. That's how most RTRs behave at least, and i found it relatively easy to tune from there.

[MAZ]

Thanks for the replies guys, much appreciated 🙂

 

The shock collars are fully wound to give as much preload as possible and the shocks themselves are positioned as vertically on the shock tower as possible. The shock oil isn't too thick either tbh I can't remember what weight oil is in them. 

 

@wombatand @m4inbrain any recommendations on a good starter shock oil for doing jumps and stuff? 

 

I need to mess about with the wheel hubs before doing a drop test (I've got some hub extenders that need fitting) 

 

I'll get the wheels back on later today and throw it on the floor a bit to see how it looks. I do think I'll need stiffer springs though 

 

@Stormbringer have you got stock shocks on your ST? If so, have you had any suspension issues due to the tanky weight of the Hyper ST? 

[Stormbringer]

Im using the standard shocks with grey springs and not had problems with it sagging but there is a fair bit preload on the shocks 

there might be mention on what im using here

 

[m4inbrain]

35 minutes ago, MAZ said:

@wombatand @m4inbrain any recommendations on a good starter shock oil for doing jumps and stuff? 

 

 

Never owned a Hyper ST, but my personal starting point would probably around 60-70wt. 

[locky]

Try Associated 60wt shock oil. The Hobao orange springs are the hardest option in their range. I've used Associated bronze springs in the past which were the hardest available. Have a look at the latest RC8T manual as they usually list spring options. These springs went onto Hong Nor bige bores which look the same diameter as the Hobao's. This snippet is from the latest RC8TE manual...

[MAZ]

Did the drop test on the truggy from about 3ft and it slapped the ground pretty hard.

It definitely needs stiffer springs 🙄

 

I'll also have a look at what shock oil I've got. I might have some 60wt as it goes 🤔

 

I'm going to head over to my local(ish) model shop tomorrow and see what they're got 

[JonnyUK]

13 hours ago, m4inbrain said:

We really need to stop spreading the myth that thicker shock oil helps "stiffening" a car. It doesn't. It slows down the compression/extension, but pressure required to compress the spring is exactly the same. It slows down the compression by increasing pressure inside the shock - all you do is increase the potential to blow the top off the shock, or bend the shock shaft because the shock doesn't compress fast enough. 

 

As a rule of thumb. Oil is used to tune how fast your car goes from full compression to full extension and vice versa. Not how much force full compression takes. 

 

The only way to increase spring pressure "or stiffness" is by using stiffer springs. There's no other way. Everything else is wrong. 

 

Now, you actually do want somewhat soft springs and reasonably light oil on a basher. Within reason. Otherwise they won't last (generally by either breaking the piston inside the shock, or bending the shock shaft). 

 

There's a simple test. Adjust the ride height to where you want it (as was pointed out by wombat - directly under the shock cap is a collar that you can wind down, adjust that down to increase ride height to where you like it), take the rig and drop it from 3 feet. That tells you exactly what you need. If the chassis hits the floor, you need stiffer springs. If it wobbles or waves, you go up a little in shock oil weight - it should drop on the wheels, compress the shock all the way without slapping on the floor, then extend straight up without any oscillation to "resting position". If it goes up all the way to full extension and then settles back down in the "droop" from the weight, your oil is too light. 

 

That's your general tuning starting point. That's how most RTRs behave at least, and i found it relatively easy to tune from there.

 

Spot on there, I'm glad someone else gets how shocks work. 

I've given up commenting on various Facebook RC groups when they always say to put thicker oil in to stiffen springs.

Incorrect advice just causes more problems.