Bomber bounces from drop!?

[tinyT1m7]

I just recently bought a bomber and am now working on the suspension. Setup as of now:

Front suspension:
Proline powerstroke 88mm or close to 3.5"
Top mounted furthest hole from rear
Bottom mounted in furthest hole from rear as well.
Top spring is proline soft(green).
Bottom spring medium (yellow)

Rear suspension:
Proline power stroke as well 88mm
Top and bottom mounting holes closest to front of car.
Same springs as front shocks .

I just replaced the shock oil in all 4 shocks with 35wt and have the pistons rebound all the way out when pushed in; without the springs on.

I do a drop test with all electronics including battery in it from 3 feet and the bomber bounces back up 4 or more inches the higher I go. I am new suspension tuning, but I know this is not normal. What can I do to make the car absorb jumps and not bounce up after landing?

 

[84yoda]

Heavier springs, thicker oil, better foams.

 

[mikebecher]

I just replaced the shock oil in all 4 shocks with 35wt and have the pistons rebound all the way out when pushed in; without the springs on.

Your pistons should not be rebounding the full length with no springs. You have too much oil or there's air in the shocks. Loosen the cap on each shock, hold it vertically and slowly compress the piston to force out the excess then re-tighten the caps. The pistons should then rebound just a small amount (~1/8") as the cap is tightened. It might take some practice but when it's correct the piston will smoothly travel the full length of the shock with nearly the same amount of damping in compression and extension.

 

[Rjohn929]

First rebleed your shocks as already mentioned then, you may be expecting too much with the short shocks on there. Live axles are always more difficult and how often are you dropping straight down anyway?

 

[NitritedCarbide]

Deff redo your shocks.. Sounds like they are hydrolocked. Youtube search on RC shocks for how to.
Cliffnotes- with cap off slowly skroke the shocks after they are filled to remove air bubbles, compress shock when you are installing top cap.
Just a little sample before I did any further tuning to suspension..
<iframe width="560" height="315" src="https://www.youtube.com/embed/q2Onb7HQ3HY" frameborder="0" allowfullscreen></iframe>

 

[tinyT1m7]

Deff redo your shocks.. Sounds like they are hydrolocked. Youtube search on RC shocks for how to.
Cliffnotes- with cap off slowly skroke the shocks after they are filled to remove air bubbles, compress shock when you are installing top cap.
Just a little sample before I did any further tuning to suspension..
<iframe width="560" height="315" src="https://www.youtube.com/embed/q2Onb7HQ3HY" frameborder="0" allowfullscreen></iframe>

That's how I want my bombers suspension! What proline shocks are those and what springs? Could I achieve what you have with non dual shocks?

 

[tinyT1m7]

First rebleed your shocks as already mentioned then, you may be expecting too much with the short shocks on there. Live axles are always more difficult and how often are you dropping straight down anyway?

Would my foams have anything to do with it? The foams are very dense (can hardly be deformed from squeezing) and the whole wheel is 1lb or more in weight each.

 

[Rjohn929]

Would my foams have anything to do with it? The foams are very dense (can hardly be deformed from squeezing) and the whole wheel is 1lb or more in weight each.

Yes they would. If you watch the video above the tires absorb a lot of the impact. They shouldn't weigh that much unless they are intentionally weighted.

 

[mikebecher]

Is this a stock Bomber or did you buy it used? The stock tires and foams are stiff but should not be as dense as you describe and certainly aren't 1 lb each.

 

[gottorque]

Once you re bleed your shocks, take note of how many holes are in your piston. This piston is the valving for the shock, in combination with different shock oil weights.
Fewer holes, smaller holes or thicker oil will all increase damping rate.
More holes, larger holes or thinner oil will decrease damping rate.

With that said, it is likely you need to decrease damping. I just finished my bomber...running 35wt up front and that front end likes to pack up and bounce coming off step downs and jumps. Unlike IFS, damping is shared between both shocks on solid axle, so that must be accounted for. To solve the issue I have, I will try thinner oil up front...perhaps 20 or 25wt.

 

[tinyT1m7]

Bought it used. The wheels aren't stock. But I figured these are better foams. The tires are pitbull growlers.

 

[tinyT1m7]

Is this a stock Bomber or did you buy it used? The stock tires and foams are stiff but should not be as dense as you describe and certainly aren't 1 lb each.

I just took the beadlock apart and rim off. The foam feels as dense as a pool noodle. Is that for more hard terrain I guess?

 

[mikebecher]

Can you post pictures? You might need to vent the tires. If they're airtight the foams are irrelevant and that will definitely cause a lot of bounce. You can vent with 4 holes per tire, about 2mm in diameter. I use an old soldering iron, but some guys have a leather punch to do it more cleanly.

Your tires (and foams) should give a lot like in NitritedCarbide's video. If you look closely at the tires before he lifts the rig you can see how they're a bit flattened at the bottom as well. This is what you want in tire/foam density.

 

[tinyT1m7]

Once you re bleed your shocks, take note of how many holes are in your piston. This piston is the valving for the shock, in combination with different shock oil weights.
Fewer holes, smaller holes or thicker oil will all increase damping rate.
More holes, larger holes or thinner oil will decrease damping rate.

With that said, it is likely you need to decrease damping. I just finished my bomber...running 35wt up front and that front end likes to pack up and bounce coming off step downs and jumps. Unlike IFS, damping is shared between both shocks on solid axle, so that must be accounted for. To solve the issue I have, I will try thinner oil up front...perhaps 20 or 25wt.

There are 2 holes in the piston. Should I drill a third? The shocks are only 88mm fully extended. Maybe I should get rid of these and buy some longer ones.

 

[tinyT1m7]

Can you post pictures? You might need to vent the tires. If they're airtight the foams are irrelevant and that will definitely cause a lot of bounce. You can vent with 4 holes per tire, about 2mm in diameter. I use an old soldering iron, but some guys have a leather punch to do it more cleanly.

Your tires (and foams) should give a lot like in NitritedCarbide's video. If you look closely at the tires before he lifts the rig you can see how they're a bit flattened at the bottom as well. This is what you want in tire/foam density.[/QUOTE

There are two vented holes in the rim.

 

[mikebecher]

OK, those are Crawler Innovations foams and are actually quite good but you've got the single stage version which are more suited for speed. With these foams the holes in the rim doesn't allow for proper venting because the foam actually blocks the holes and you still need to vent the tires. If you want to do any serious crawling you should get some CI dual stage foams which have the same closed cell center and a soft open cell outer ring which conforms to the rocks.

 

[SCREAMER]

Those are Crawler Innovations Deuces Wild closed cell foams. I run those on my IFS Bomber unvented and it is by far the plushest truck I have. You need to work on your suspension.

Mike beat me to it and his advice is sound. These are not the best foams for crawling. You want double deuces which are dual stage. Great thing is they're pretty cheap.

 

[Rjohn929]

I don't think you would have to drill more holes in the pistons. Just use a thinner oil. I think you have more going on then just oil weight though and you should investigate all the ideas here.

I run Proline Powerstroke rears on the front and rear and XT's with no spring as helpers on the rear. The rears are 10wt in both sets and the fronts are 15wt if I remember correctly (the fronts might be 20).

<iframe width="420" height="315" src="https://www.youtube.com/embed/dmtl8vQvaoU" frameborder="0" allowfullscreen></iframe>

You should be able to get pretty close with the stock shocks with some tuning.

 

[tinyT1m7]

I have powerstrokes too but they are 88mm. The shorter ones. Which length do you have? I just refilled my shocks and the piston is only rebounding a 1/8" like the other guy said.

 

[Rjohn929]

I have powerstrokes too but they are 88mm. The shorter ones. Which length do you have? I just refilled my shocks and the piston is only rebounding a 1/8" like the other guy said.

That should help you a ton. I have the longer ones but others use the shorter ones and have good results.