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Old 07-07-2010, 01:35 PM   #1
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Default Negative rebound??

I've been hearing about this over a few years now, but (-)rebound has always been something to avoid. But now I'm hearing and seeing racers using this as another tuning/suspension option.

4 questions -
1.) What is the 'action' on the car of a negatively rebounding shock?
2.) Under what circumstances would you want to use this?
3.) Is negative rebound 'tunable'...in other words, can you make the rebound repeatable in differing amounts as positive rebound?
4.) How does the use of shock oil come into play...if you use 30wt., can you still use it or would you have to go lighter or heavier?

Possibly something new to use in my repertoire , so bear with me guys
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Old 07-07-2010, 02:21 PM   #2
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If i remember right the schumacher axis 2 had u build the shocks with negative rebound, im not sure why but i remember it worked well.
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Old 07-07-2010, 02:29 PM   #3
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Quote:
Originally Posted by JayBee View Post
I've been hearing about this over a few years now, but (-)rebound has always been something to avoid. But now I'm hearing and seeing racers using this as another tuning/suspension option.

4 questions -
1.) What is the 'action' on the car of a negatively rebounding shock?
2.) Under what circumstances would you want to use this?
3.) Is negative rebound 'tunable'...in other words, can you make the rebound repeatable in differing amounts as positive rebound?
4.) How does the use of shock oil come into play...if you use 30wt., can you still use it or would you have to go lighter or heavier?

Possibly something new to use in my repertoire , so bear with me guys
Well, I was always told not to use it, but did anyways. In my mind the spring should keep pressure on the bottom of the shock at all times anyways, so having a little bit of negative rebound shouldn't affect the car in the slightest.
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Old 07-07-2010, 08:18 PM   #4
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Any other thoughts??
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Old 08-17-2010, 08:57 PM   #5
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Any other thoughts??
How bout consistency, Positive pressure tends to bleed under loads. Perhaps negative pressure changes less, or changes as the oil heats up to be no pressure.......? just a thought

I was looking for the MI4lp thread
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Old 08-18-2010, 02:03 AM   #6
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Negative Rebound? Is that like getting dumped by an ugly chick and then end up dating her friend who is even uglier? Where you been bro? lem
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Old 08-18-2010, 02:44 AM   #7
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If by "negative rebound" you mean a shock shaft that is pulled back in to the shock when extended... I would never use it.

In my opinion, RC dampers are very simple, so build them in a repeatable way where all they do is damp as linearly as possible.

To get negative rebound you are going to have to mess around wth bleeding the shock in such a way that it has less oil in it that it naturally builds with. Not easy to do consistently with a bladder shock.

Personally, the only tuning I would consider doing to the difference between bump and rebound is in the bladder (and bladder insert if you like a strong rebound for smooth, grippy surfaces). I just build shocks with a soft (normally the standard) bladder and leave it at that! I might even drill the caps to get rid of the air pressure effect on rebound.

PS a full size car would never use negative rebound - the effect would be "jacking down" where the suspension would not recover quickly enough from bumps and the car's ride height would gradually drop to the floor.
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Old 08-18-2010, 03:19 AM   #8
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Negative Rebound? Is that like getting dumped by an ugly chick and then end up dating her friend who is even uglier? Where you been bro? lem
Hey!!!....I like fat chicks

....under a rock brah, but its all good; I'm back
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