Go Back  R/C Tech Forums > General Forums > Nitro Off-Road
Shock length question >

Shock length question

Shock length question

Old 12-24-2014, 09:13 AM
  #1  
Tech Addict
Thread Starter
iTrader: (16)
 
Join Date: Nov 2014
Posts: 697
Trader Rating: 16 (100%+)
Default Shock length question

I have read a few comments and need a little clarification on what difference does the overall front and rear shock length have on handling and setup of a 1/8 nitro buggy. If your front or rear arms stop at the droop screws, and the chassis bottoms out before bottoming-out the shock shaft in either compression or rebound, does it really matter?

I am not asking about the shock spring length, because I understand that
different coil lengths, linear vs. progressive, etc. all affect set-up.

Thank you
robracing is offline  
Old 12-24-2014, 10:26 AM
  #2  
Tech Elite
iTrader: (5)
 
Hoese37's Avatar
 
Join Date: Apr 2007
Location: Hutchinson, MN
Posts: 3,819
Trader Rating: 5 (100%+)
Default

It does matter in the terms of piston speed, and where the shock is placed on the arm. A shock will have to travel at a faster speed with the more leverage on the arm. So the farther the shock is out on the arm, the faster the piston speed will be. Having the shock placed farther out on the arm, usually results in an overall longer shock.


Kind of a relevant image. Notice that the longer the stroke, the faster the piston must move to cover the same distance. The blue line represents having the shock placed farther out on the arm. To best look at the image, you only need to pay attention fron the 12 o'clock position, to 3 o'clock.

Last edited by Hoese37; 12-24-2014 at 10:38 AM.
Hoese37 is offline  
Old 12-26-2014, 08:48 AM
  #3  
Tech Addict
Thread Starter
iTrader: (16)
 
Join Date: Nov 2014
Posts: 697
Trader Rating: 16 (100%+)
Default

But all other things being equal, how would overall handling be affected if front shocks were 10, 20, 30mm longer if angles and attachment points on the arms and towers were theoretically maintained? Are we only changing pack with the amount of oil in a longer shock? Thanks
robracing is offline  
Old 12-26-2014, 03:47 PM
  #4  
Tech Master
iTrader: (5)
 
Join Date: Jun 2012
Posts: 1,876
Trader Rating: 5 (100%+)
Default

In my mind it would make not a difference as long as the shaft went in and out the same amount. I have not heard of that being a tuning adjustment before.

Although I know you're not asking about this, but if you can't get enough droop due to the shocks being too short you can unscrew the eye a little.

Having said that I make sure the extended length of both shafts are exactly the same length as measured with calipers because I feel it's good practice.

Additionally depending on your car the design of the shocks could be very precise and not much room available for extra long shafts inside the body when compressed.

For 1/8 buggy, the droop screws usually stop the shaft from going to full extension. Without droop screws or max droop, the piston would be all the way down in the shock body and could cause a suction cup effect when trying to compress from full extension. A longer shaft could prevent that.
My ST-RR EVO is offline  
Old 12-26-2014, 04:09 PM
  #5  
Tech Master
iTrader: (5)
 
Join Date: Jun 2012
Posts: 1,876
Trader Rating: 5 (100%+)
Default

Oops re-read your question and realized I read it wrong. Doing this on my phone so trying to edit the above post will be a pain. New response is I don't think it will make any difference. (Weight excluded)
My ST-RR EVO is offline  
Old 12-31-2014, 11:08 AM
  #6  
Tech Addict
 
razo125's Avatar
 
Join Date: Jan 2004
Location: FearFarm - Arizona
Posts: 663
Default

Originally Posted by robracing View Post
But all other things being equal, how would overall handling be affected if front shocks were 10, 20, 30mm longer if angles and attachment points on the arms and towers were theoretically maintained? Are we only changing pack with the amount of oil in a longer shock? Thanks
I like this topic and hope this thread opens up with some good discussion. I always wondered that also. To rephrase your question so I know I'm hearing it right.
The constant givens are two shock bodies, with equal mounting positions, equal travel limited by droop screws and the upper limit the suspension arm swinging upward, equal piston/oil.

The only difference is the shock bodies. One shock body is longer so it has extra room above and/or below the piston's mechanically limited travel elsewhere on the suspension. (droop setting and the mechanical uptravel of the suspension arms or usable drivetrain angle)

Your question is: How does this extra volume of oil above or below the two different setups affect the shock characteristics in terms of pack/damping?
I'm not a hydrodynamics engineer so my knowledge on this is limited, so please take this with a grain of salt. I also agree with your first thoughts and I can only answer in theory. I also think there will be a difference in pack. How much and where the piston starts to pack will be different. These differences will be larger when the piston is closer to the upper or lower end of travel. All other things being equal, a larger shock body's extra volume above and below the piston, will have less pack because the fluid will have more room to settle and create less turbulence at the piston.

These difference may be negligible and no one can know for sure unless someone tries it on the track.
razo125 is offline  
Old 01-01-2015, 08:58 AM
  #7  
Tech Addict
Thread Starter
iTrader: (16)
 
Join Date: Nov 2014
Posts: 697
Trader Rating: 16 (100%+)
Default

All other things being equal with ride height, spring load, and suspension travel on the car not restricted, I cannot believe that you will notice the difference between say a 55mm and 57mm shock body.
robracing 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 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.