Big Rock new shock oil?

[turfRC]

put in some new shock oil 42.5 wt. now front shocks seem too soft and seem to be sagging some. need different weight oil or new shocks?

 

[turfRC]

i am sorry it was 45 wt. oil

 

[Harriot10]

i am sorry it was 45 wt. oil

All personal preference. I'm running 70wt in my BR and Granite. Both rigs are upgraded with 4s systems and Typhon 6s shocks though.

 

[turfRC]

ok but should i be running heavier weight to stop the sagging

 

[Harriot10]

ok but should i be running heavier weight to stop the sagging

Not necessarily, depends on what kind of bashing you're doing. I go heavy because I was launching my rigs at skate parks and off a ramp. You might just need to add the pre-load spacers.

Send a photo of the sagging

 

[Roger75]

ok but should i be running heavier weight to stop the sagging

Try to add some more spring preload first. I guess the sagging makes you think the shocks are too soft while are not.

 

[RackwitzG]

Try to add some more spring preload first.

Not sure if that solves the problem. More springload raises the ride height of the truck but doesn't make the spring harder. If you want a harder suspension, use a harder spring. My statement is based on the use of springs in RC Touring Cars and is common knowledge there. Can't imagine it to be different in Monster Trucks.

 

[Prowler666]

If all you have done is change the oil and rebuilt them correctly and it wasn't like it before , it sounds like you have not put enough oil in.

 

[razorrc]

Not sure if that solves the problem. More springload raises the ride height of the truck but doesn't make the spring harder. If you want a harder suspension, use a harder spring. My statement is based on the use of springs in RC Touring Cars and is common knowledge there. Can't imagine it to be different in Monster Trucks.

Well, it’s both. I agree that the right fix is to get a stiffer spring, but I don’t think anyone makes a suitable one. But by adding preload, you also get the spring into a stiffer part of its rate (springs are never 100% linear), so it will feel stiffer. The reason you get more ride height even though the spring is now shorter (compressed), is because it is acting stiffer with more preload.

The BRCC springs are too soft IMO.

 

[parcou]

@turfRC

Add my newbie $0.02 which is all its worth. I had a similar issue where I had some rear sag and I was using stock weight 42.5 or 45. My issue I changed my arms I don't think you did that here, maybe. I had binding within my arms where the pins hold the arms to the chassis. I did not know that until I watched an Amain Video that talked about suspension binding. When I took off my tires and shock my arms would not fall freely under their own weight. I always wondered why when I pushed the rear end down...I had to pull it back up a bit to be at ride height...it came back up...not all the way freely only about 90-95% up. Once I fixed that issue per the video, my rear sprang back up like a champ and the ride height was even and leveled out when I pushed it down in the back.

I'm not a vet like Razor, Harriot, etc. but that was an issue to my sagging when I changed the arms they did not move freely. Not your issue may be, but food for thought to check for binding.

Video here

 

[RackwitzG]

But by adding preload, you also get the spring into a stiffer part of its rate (springs are never 100% linear)

There are progressive springs that progressively stiffen when compressed. What happens when you change the ride height is that the piston in the shock changes its position. When the droop is at maximum, the piston has more oil above it to push through and dampens more, and viceversa.

 

[B2Humla]

I have ordered these springs:
90mm springs for 1/8 scale

Not sure if they is a good fit. But I will try them for the rear shocks, and maybe the original Arrma 80mm springs in the front.
I will post a video at Youtube later when I have done some testing.
But would be nice if Arrma could just have some more options here.
I don't want to pay for the 6S type of shocks. But time will tell, maybe that upgrade is the best in the long run.

 

[B2Humla]

For what it's worth... but since I did wrote something about a video... here it is

I use the Arrma 80mm rear springs in the front. And the new 90mm springs in the rear.
So a bit softer in the front, I believe that is good for the steering.
But if this setup is to stiff... time will tell.
I am also using 1000 cst = 80wt shock oil.
Need some test driving outdoor... and some better weather.

Note, also Hot Racing has some springs for Arrma Big Rock. More expensive but you get 3 different stiffnes (wire diameter), also 90mm.

 

[Harriot10]

For what it's worth... but since I did wrote something about a video... here it is

I use the Arrma 80mm rear springs in the front. And the new 90mm springs in the rear.
So a bit softer in the front, I believe that is good for the steering.
But if this setup is to stiff... time will tell.
I am also using 1000 cst = 80wt shock oil.
Need some test driving outdoor... and some better weather.

Note, also Hot Racing has some springs for Arrma Big Rock. More expensive but you get 3 different stiffnes (wire diameter), also 90mm.

I ran 80wt shock oil, Tekno orange springs on Typhon 6s shocks in my Granite and it was still chassis slapping at the skate parks.

 

[B2Humla]

I believe that is ok. Some chassis slapping when jumping high and hard there should always be. If not something else will break.
If the shocks where replaced by a solid iron-rod then the suspension arms, shock towers or something else would break.
Something always break when driving hard, I am just trying to find a setup so the right parts breaks. The small cheap parts.
I am not driving/bashing that hard yet...

 

[SrC]

ok but should i be running heavier weight to stop the sagging

Shock oil thin or thick does not make a shock SAG. Oil does not affect spring height at all. Springs do. Maybe you need to adjust shock preload better. What is shock preload??? Learn about shocks. There are many many videos about them.
I could write an encyclopedia about shocks. I don't want to confuse you any further. Do watch some good RC shock videos. It will help you learn.
Bash on.

 

[Harriot10]

I believe that is ok. Some chassis slapping when jumping high and hard there should always be. If not something else will break.
If the shocks where replaced by a solid iron-rod then the suspension arms, shock towers or something else would break.
Something always break when driving hard, I am just trying to find a setup so the right parts breaks. The small cheap parts.
I am not driving/bashing that hard yet...

I kept breaking front stock hubs, replaced with HR and the pins kept popping outta my rpm arms. I hear ya!

 

[p00kaju]

For what it's worth... but since I did wrote something about a video... here it is

I use the Arrma 80mm rear springs in the front. And the new 90mm springs in the rear.
So a bit softer in the front, I believe that is good for the steering.
But if this setup is to stiff... time will tell.
I am also using 1000 cst = 80wt shock oil.
Need some test driving outdoor... and some better weather.

Note, also Hot Racing has some springs for Arrma Big Rock. More expensive but you get 3 different stiffnes (wire diameter), also 90mm.

Hi. Do you know that are these same springs but just set of 4:
https://www.ebay.com/itm/L2090-1-10...ng-90mm-Long-x-19mm-Diameter-x-4/361073379680

 

[B2Humla]

p00kaju, yes they are.

 

[p00kaju]

p00kaju, yes they are.

Thanks. Ordered those ones. See how it works because I also thinks that Big Rock suspension is quit loose.