Go Back  R/C Tech Forums > General Forums > Electric On-Road
Negative rebound?? >

Negative rebound??

Negative rebound??

Old 07-07-2010, 01:35 PM
  #1  
Tech Champion
Thread Starter
iTrader: (31)
 
JayBee's Avatar
 
Join Date: Mar 2004
Location: 12TH-MAN COUNTRY
Posts: 6,819
Trader Rating: 31 (100%+)
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
JayBee is offline  
Old 07-07-2010, 02:21 PM
  #2  
Tech Elite
iTrader: (24)
 
303slowdown's Avatar
 
Join Date: Sep 2008
Location: Rapid City SD.
Posts: 2,299
Trader Rating: 24 (100%+)
Default

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.
303slowdown is offline  
Old 07-07-2010, 02:29 PM
  #3  
Tech Master
iTrader: (3)
 
Danny-b23's Avatar
 
Join Date: Feb 2009
Location: Saskatoon, SK, Canada
Posts: 1,357
Trader Rating: 3 (100%+)
Default

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.
Danny-b23 is offline  
Old 07-07-2010, 08:18 PM
  #4  
Tech Champion
Thread Starter
iTrader: (31)
 
JayBee's Avatar
 
Join Date: Mar 2004
Location: 12TH-MAN COUNTRY
Posts: 6,819
Trader Rating: 31 (100%+)
Default

Any other thoughts??
JayBee is offline  
Old 08-17-2010, 08:57 PM
  #5  
Tech Master
 
Join Date: Aug 2006
Location: Auburn Wa
Posts: 1,882
Default = )

Originally Posted by JayBee View Post
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
Sterling Racer is offline  
Old 08-18-2010, 02:03 AM
  #6  
piper48
Guest
 
Posts: n/a
Default

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
 
Old 08-18-2010, 02:44 AM
  #7  
Tech Elite
 
sosidge's Avatar
 
Join Date: Dec 2001
Location: Bristol, UK
Posts: 3,998
Default

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.
sosidge is offline  
Old 08-18-2010, 03:19 AM
  #8  
Tech Champion
Thread Starter
iTrader: (31)
 
JayBee's Avatar
 
Join Date: Mar 2004
Location: 12TH-MAN COUNTRY
Posts: 6,819
Trader Rating: 31 (100%+)
Default

Originally Posted by piper48 View Post
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
JayBee is offline  

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.