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Shock Rebound, WHat Is The Effect?

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Shock Rebound, WHat Is The Effect?

Old 05-30-2011, 11:00 PM
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Many thanks to everyone for the replies.
I do learn a great deal for the post above.

Guess i have opened a can of worms
Suspension tuning is truly an art.
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Old 05-31-2011, 01:42 AM
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Originally Posted by ???man View Post
Many thanks to everyone for the replies.
I do learn a great deal for the post above.

Guess i have opened a can of worms
Suspension tuning is truly an art.
It's not a can of worms, but it is an art! Each element of a suspension system is of itself quite simple - mechanical levers, hydraulics, oil flow, etc. - but once it is all put together in one system it becomes complex.

I don't think anyone is saying that shock pressurisation is a bad thing, just that it is another thing. Go back to Dale's excellent post - what he's saying is that shock pressurisation will give you some dual rate, but that is probably not significant when compared to the spring rate.

Although YZRAndy and I will disagree about what happens when the shock damps the compression phase of the spring, it is the case that the more supple the bladder, and the less air is behind it, the more linear the shock is in compression.

If it were me, I would have the most supple bladder I could find, and some way for the air above the bladder to be let out when the shock compresses. That way the shock can move up (compress) as quickly as it needs to, and the less likely it is that the car will bounce over a bump. HTH
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Old 05-31-2011, 09:10 AM
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Originally Posted by SlowerOne View Post
If it were me, I would have the most supple bladder I could find, and some way for the air above the bladder to be let out when the shock compresses. That way the shock can move up (compress) as quickly as it needs to, and the less likely it is that the car will bounce over a bump. HTH
Just to add to that one you might want to experiment with rebound a bit. My first choice of racing is 1/8th Nitro Rallycross and we use rebound a lot more on bumpy and low grip tracks. Reason why is the initial damping (first few mm of the piston moment) is a lot softer until rebound starts to build. This gives you the best of both worlds and is very effective in bumpy conditions.
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Old 05-31-2011, 05:18 PM
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Didn't even remember starting this thread lol

You will have to experiment as to whether or not zero rebound is suitable for your track.
I know a few people that have tried the drilled caps on their outdoor asphalt tracks and didn't like it.

Mainly seems to be better suited to high grip carpet etc.

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Old 02-24-2017, 03:05 AM
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Dug that one out... time to restart the conversation

Please behave, gentlemen... Mods moved the other thread was to the Chat Lounge, which is where technical threads go to die as a consequence of posters misbehaving.
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Old 02-24-2017, 04:36 AM
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Originally Posted by Lonestar View Post
Dug that one out... time to restart the conversation

Please behave, gentlemen... Mods moved the other thread was to the Chat Lounge, which is where technical threads go to die as a consequence of posters misbehaving.
thats correct ,
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Old 02-24-2017, 06:54 AM
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Just my own insight but, wouldnt the very high spring rates involved with TC shocks almost completely negate 'rebound'? Seems that just as a simplistic observation that the only pressure applied as rebound is by the elsticity of the rubber diaphragm and the air above it, which both can deviate shock to shock even when both shocks are on the same car at the same time due to Temps and corner weights and if ages differ between each diaphragm. That amounts to grams of pressure at most. And given the average spring rate is anywhere from 15-25 in./lbs. I would think any 'rebound' is negligible with springs installed. I would like to see a hi-res slow motion comparo of different rebound settings with a low spring rate and a high spring rate... cuz at the end of the day all were discussing is time differences in our shocks' full compression vs full extension, correct? I think drilling caps is the ONLY solution to absolute shock setup equality (when it comes to that specific area of discussion that is. I know there are many other variables to the complete suspension system...).
I plan on experimenting with an air over oil shock system, all 4 tied together with nylon hose and pressurized. Harleys have air over oil rear shocks that are adjustable with a low pressure pump that I happen to have in my tool box. Probably going to be a waste of time for something that weighs 1450g but I got time to waste these days.
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Old 02-24-2017, 04:46 PM
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How would a shock slow down the spring extending when there is positive pressure forcing the shock to extend on its own?
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Old 02-24-2017, 09:00 PM
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having a bladder shock vs an emulsion type shock changes dynamically what is going on in the shock. Bladder the volume compensation is in the top. The piston is initially doing much of the compression of the bladder under fast compression until pressure normalizes on top and under the piston, with the bladder compressed due to the volume of the shaft now in the shock body. Emulsion oil and air are mixed evenly, you don't have the bladder at the top with the air bubble that must be compressed too.

only the oil will be doing the dampening, but the air and bladder will act like another spring within the shock that is not desired. Think of it like this... If you were to have a solid piston and you compressed it in a shock with a bladder, the bladder and air would act like a spring within the shock.

all the above is very interesting, but the general idea to be derived is that the rougher the track, the less rebound you want to run, negating somewhat the shock acting like a spring. As well as getting your shocks consistent.



thats why emulsion is the go to in off-road. It lets the shock be the shock, and the spring be the spring, negating all the air in the top and the bladder as well.
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Old 03-13-2017, 03:03 AM
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This is getting totally out of hand...

Red RC ? RC Car News T-Works BD8 & T4 shock cap spacer sets
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Old 03-13-2017, 04:43 AM
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Originally Posted by Lonestar View Post
"Available in a 0.3mm or a 0.5mm variant"... I'll wait until XRay releases their own version in optimized 0.1mm increments.
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Old 03-13-2017, 03:06 PM
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Originally Posted by Lonestar View Post
That is a very good idea, but they seem to only make them for short shocks....
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Old 03-13-2017, 03:26 PM
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Originally Posted by howardcano View Post
"Available in a 0.3mm or a 0.5mm variant"... I'll wait until XRay releases their own version in optimized 0.1mm increments.
We can finally have the luxury rebound adjustments we deserve.
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Old 03-13-2017, 04:41 PM
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So this thread has been VERY helpful as I'm heading back into asphalt season, and the track that I am running in this summer is very bumpy, considering it's a parking lot.

I'm glad it popped back up!
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Old 03-14-2017, 04:40 AM
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As said on the earlier (or later, it depends how you look at it) version of this thread, the best way to experience the true effects of rebound adjustment is to have a buddy change the shocks for you, without telling you what they did, and let you figure out what you really feel - without being influenced by things you'd know otherwise.

Come back and report to us!
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