8s rigs 10mm shock alternative?

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Most of my knowledge comes from racing 1:1 cars years ago so I don't have direct experience with anything similar in RC. I was not a great driver but I have some chassis engineering and setup chops. Look at and measure or estimate the hole size in the pistons on these shocks and the number of holes and compare to the stock shocks. That should give you some idea, but I wouldn't go too high too fast. You are looking to find a weight that moves similar to the stock setup in the front and it's going to take you some testing to find the right weight, but I suspect if you goo too heavy you won't know if you are just barely too heavy or miles beyond. Practically, I'd go with whatever weight heavier oil seems like a significant step that you can easily/cheaply get your hands on. If you have 80wt, go with it and see.
I really appreciate your input. I also have in the back of my mind that the overall oil volume is likely slightly smaller on the rovans because the volume taken up by the larger shaft. just looking at the 2 shock tubes (not sure if this is the right name) they are similar sizes, but if you take in to account the additional volume taken up by the larger shaft, the rovan would theoretically have less oil volume.

They do also offer a remote reservoir https://www.rovanrc.com/product-rv85442s which would add more oil volume and adjustable dampening, but i'm trying to see if i can get a workable solution without them if possible. This solution is going to be pricey enough without adding another $84.

Just for reference for those curious who haven't clicked the link and looked at pricing, a pair of shocks is $72, so a complete set would be $144, and if you add remote reservoirs you would be at $228 for the set.

I will probably head to the hobby shop today during lunch so should have results of the heavier oil later today.

Thanks to everyone following and contributing to this journey :)
 
Ok the hobby shop only had 80wt, so I just rebuild the shocks with that. I was hoping to pick up 90 and 100 too but they were out of stock on that. I also picked up a set of the heavier arrma springs. I'm pretty sure that's what I was already using in the test because I had bought some for the rear in the past, but i got a new set to make sure. I put some tape on them so now i wont get them mixed up.

It's looking better but I still don't think we are there yet. Its still a noticeable quicker rebound compared to the front. Not quite as bouncy but i think I still have some tuning to do. I took it out and drove it around in front of my house and it seems to handle pretty good, but I didn't really jump it at all so it wasn't a very good test.
 
So thinking more, and doing some research I think I’m going to try mixing some 3000cst(185wt) diff oil at 25%. Based on calcs I have found that should net me 100wt. This should allow me to keep testing without waiting for a shipment of 100wt to come. I think ultimately the piston holes are too big and I’m compensating with heavier oil. I also wondered about potentially filling the holes with epoxy smoothing the surface and drilling smaller holes. Rovan also sells race pistons but I would assume those holes would be larger not smaller but I could be wrong there. I need to investigate further on that.
More to come!
 
If you have spare pistons for it you can always try plugging one of the holes in it. Well you can try it anyway, but you might end up needing a replacement. :D

Hmmm. I think the Arrmas come with additional shock pistons, maybe you could modify those to fit these shock shafts and bodies? If the bore is the same inside it might work. Assuming the ones in these shocks now are bigger holes or more holes.
 
This thread reminds me of when I was trying to cure the issues with my totally garbage losi dbxl shocks. If you have a DBXL then you already know your shocks suck. They were filled with heavy weight diff fluid and were horrible. I ended up making my own pistons with 4x 1.9mm holes. I now run 50wt all the way around and I love it!

20210115_131313.jpg
 
This thread reminds me of when I was trying to cure the issues with my totally garbage losi dbxl shocks. If you have a DBXL then you already know your shocks suck. They were filled with heavy weight diff fluid and were horrible. I ended up making my own pistons with 4x 1.9mm holes. I now run 50wt all the way around and I love it!

View attachment 122439
Thanks for your input. With the fact that i'm using these shocks not in the vehicle they were designed for I somewhat expected these challenges. Getting custom pistons might be the route I need to go eventually, but I am really hoping I can resolve in a way that is more direct fit for people. That may not be possible, but I will see this to the end for sure ;-)
If you have spare pistons for it you can always try plugging one of the holes in it. Well you can try it anyway, but you might end up needing a replacement. :D

Hmmm. I think the Arrmas come with additional shock pistons, maybe you could modify those to fit these shock shafts and bodies? If the bore is the same inside it might work. Assuming the ones in these shocks now are bigger holes or more holes.
It did not come with extra pistons, it was a fully assembled shock with nothing else included. I thought about your idea of using the arrma pistons, and was going to check fitment if the heavier 100wt shock oil is not viable. I'm really hoping the solution will be something that can be replicated with off the shelf shock oil, and i think 100 is the highest i have seen readily available in the popular brands
 
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Ok so next round of testing =fail. I Originally thought I had 3000cst diff oil, but it was 3000 wt. So I redid the calc and I added what I'm guessing to be 10%, which should have got me in the neighborhood of 100-120wt. Unfortunately it didn't improve much on the dampening. So little improvement, that I feel like I would have to go very dramatically higher in wt to make a difference. It still rebounds way to quick (I may be using the wrong terms here so don't throw me on the coals lol)

I think looking at the pistons is the right approach (as you guys have mentioned). I took a look at a stock piston I had laying around (I had switched out with m2c pistons previously, so I had the stock ones) and it has 8 much smaller holes. If I had to guess they are likely half the size if the ones in the rovan pistons. I have not had a chance to look to see if they are the same diameter as the rovan pistons, but I will likely do that tomorrow. I do know that the rovan pistons are thicker, or at least it appeared so. I think the next step is going to require a more detailed dive. I think I need to go buy some calipers so I can accurately measure things and I need to take the piston off of the rovan so I can compare more accurately. I have an unopened set of m2c pistons that if the diameter is the same I will likely try to use those once tested with the stock prototype, because I really like how they have the rubber ring to minimise blow by.

I guess the summary is that this might take some time to get sorted. or maybe i'm just out $72 :cool:
If you don't have a 3d printer, come up with a design send me the stl and I'll print them for you and drop em in the mail. Free of charge of course. Lmk.
I do not have a 3d printer, and may take you up on that if that's the direction I need to go with this . thanks a bunch man!!
 
Try this. Like seriously. Those are rovan 1/5 scale shocks right? If im not mistaken, the dbxl came with.......wait for it..........3000cs diff fluid in the shocks. I do not know what that is in diff fluid? 2--3k perhaps. Whatever the equivalent is.

20210125_213832.jpg
 
Try this. Like seriously. Those are rovan 1/5 scale shocks right? If im not mistaken, the dbxl came with.......wait for it..........3000cs diff fluid in the shocks. I do not know what that is in diff fluid? 2--3k perhaps. Whatever the equivalent is.

View attachment 122466
Thanks a bunch. So that 3000 is exactly what I was using to thicken the 80wt. It’s from my Losi scte diffs. Lol. So apparently they call it 3000cs but in the tube it says 3000wt. I don’t have enough to fill the shocks but I do have some 5000 and I could maybe make a concoction with 3000, 5000 and a little bit of 80. I can use the calc I found to figure out what to mix. I really appreciate you sharing this. I was really hoping to keep this upgrade as straight forward as possible for people at the end of the day so if I could avoid changing the pistons that would be ideal.
So you mentioned that you did not like the setup of the dbxle shocks and that’s why you went with custom pistons and lighter oil. Can you talk to your experiences so that I don’t go down this road unnecessarily?
 
thoughts on possibly using lighter springs? You can keep going higher and higher in oil weight but those shocks are designed for a mush heavier rig, so maybe try lighter springs and/or pistons with smaller holes. I don't know, my thoughts
 
Thanks a bunch. So that 3000 is exactly what I was using to thicken the 80wt. It’s from my Losi scte diffs. Lol. So apparently they call it 3000cs but in the tube it says 3000wt. I don’t have enough to fill the shocks but I do have some 5000 and I could maybe make a concoction with 3000, 5000 and a little bit of 80. I can use the calc I found to figure out what to mix. I really appreciate you sharing this. I was really hoping to keep this upgrade as straight forward as possible for people at the end of the day so if I could avoid changing the pistons that would be ideal.
So you mentioned that you did not like the setup of the dbxle shocks and that’s why you went with custom pistons and lighter oil. Can you talk to your experiences so that I don’t go down this road unnecessarily?
If they are that far out, pull a piston out and cut a plug the right size and super glue it in. If you plug one of the holes it will make a significant difference. Or plug all of them and drill 4 new smaller holes in between. Worth a shot because these pistons are pretty useless for your application.
 
Found these......$30 cheaper (Save $60 for full set), they say orange but look Red??
But the price is what attracted me to them to be fair. I'd prefer not to spend $140 on shocks.
Last O8S Bash I broke three ends and bent 1 M2C Rod.....and I landed right every time:eek:

https://www.rovanrc.com/product-rv8545103r

Maybe try the O8S springs??

But agree....small piston holes should help too
 
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Found these......$30 cheaper (Save $60 for full set), they say orange but look Red??
But the price is what attracted me to them to be fair. I'd prefer not to spend $140 on shocks.
Last O8S Bash I broke three ends and bent 1 M2C Rod.....and I landed right every time:eek:

https://www.rovanrc.com/product-rv8545103r

Maybe try the O8S springs??

But agree....small piston holes should help too
that's for one shock not a pair. its the same shocks i got but in orange. already using O8s springs. the rovan ones were way too soft. check out the 1st video link i posted
thoughts on possibly using lighter springs? You can keep going higher and higher in oil weight but those shocks are designed for a mush heavier rig, so maybe try lighter springs and/or pistons with smaller holes. I don't know, my thoughts
the rovan springs are too light. i think its because they were designed for the front of the rovan
If they are that far out, pull a piston out and cut a plug the right size and super glue it in. If you plug one of the holes it will make a significant difference. Or plug all of them and drill 4 new smaller holes in between. Worth a shot because these pistons are pretty useless for your application.
yea its likely that addressing the pistons is going to be in the near future for sure. I do think I may try the 3000cs fluid first before i start digging into the pistons, just because that's an easy thing to try. While I have them open this time I will compare size of the stock arrma pistons vs the rovan ones.
 
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Thanks a bunch. So that 3000 is exactly what I was using to thicken the 80wt. It’s from my Losi scte diffs. Lol. So apparently they call it 3000cs but in the tube it says 3000wt. I don’t have enough to fill the shocks but I do have some 5000 and I could maybe make a concoction with 3000, 5000 and a little bit of 80. I can use the calc I found to figure out what to mix. I really appreciate you sharing this. I was really hoping to keep this upgrade as straight forward as possible for people at the end of the day so if I could avoid changing the pistons that would be ideal.
So you mentioned that you did not like the setup of the dbxle shocks and that’s why you went with custom pistons and lighter oil. Can you talk to your experiences so that I don’t go down this road unnecessarily?
The dbxl is notoriously front heavy. Not a well balanced vehicle. After numerous attempts at trying different fluids I gave up and decided to make my own. If you were able to pull off a jump you were lucky. It always wanted to nose dive. Rebounding was very very soft and slow.
 
So next test done with heavier shock oil. It should have been in the neighborhood of 3000wt (didn't have enough 3000, so mixed in some 5000wt and a little bit of 80wt) we are getting much closer but not there yet. I also looked closer at the pistons during the process and they are a slightly larger diameter compared to the stock arrma ones, so if I decide to go the piston route I will need to fill and redrill these or get some new ones made. I think I will continue down the road of trying heavier oil a few more times before I go the piston route, just for ease of execution for myself and others in the future.

Here is a link to the video that show the current rebound at 3000wt
https://www.instagram.com/p/CKkwSk1nKvo/?utm_source=ig_web_button_share_sheet
 
So next test done with heavier shock oil. It should have been in the neighborhood of 3000wt (didn't have enough 3000, so mixed in some 5000wt and a little bit of 80wt) we are getting much closer but not there yet. I also looked closer at the pistons during the process and they are a slightly larger diameter compared to the stock arrma ones, so if I decide to go the piston route I will need to fill and redrill these or get some new ones made. I think I will continue down the road of trying heavier oil a few more times before I go the piston route, just for ease of execution for myself and others in the future.

Here is a link to the video that show the current rebound at 3000wt
https://www.instagram.com/p/CKkwSk1nKvo/?utm_source=ig_web_button_share_sheet

That is MUCH better. Looks pretty good actually.
 
That is MUCH better. Looks pretty good actually.
Yea but if I dropped it from about 2 1/2 to 3 foot it slammed the chassis to the ground. Thinking of trying 5000wt or maybe even straight to 7k. But I think I’m getting somewhere for sure. Now to be fair all I’m really testing is rebound etc. how it will actually drive and handle might be a different story. A fun experiment though.
 
Yea but if I dropped it from about 2 1/2 to 3 foot it slammed the chassis to the ground. Thinking of trying 5000wt or maybe even straight to 7k. But I think I’m getting somewhere for sure. Now to be fair all I’m really testing is rebound etc. how it will actually drive and handle might be a different story. A fun experiment though.

If go up in weight but be careful not to over do it. With a single rate you want to tune with the rebound or you can easily end up too stiff. I would get it so the rebound is a little slower than stock but not much more, then try adding preload.
 
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