XRAY - Model racing cars

It is currently Thu Oct 19, 2017 04:09:41

All times are UTC + 2 hours




Post new topic Reply to topic  [ 6 posts ] 
Author Message
 Post subject: Zero Rebound / Air-free / Squeak-free Shocks
PostPosted: Fri Feb 24, 2017 15:53:18 
Offline

Joined: Sun Feb 05, 2017 23:43:32
Posts: 2
Location: Germany
Hello there,

I just finished building my new XB4'17 and completed my first training session at our local track. Car worked really well.

The problem I am having is related to building the shocks. It seems I can't accomplish Zero (or little rebound), Air-free, Squeak-free at the same time.

I followed the manual but so far no luck. The moment you turn the shock upside down you know there is air in them and they start to squeak.

Any advise is appreciated.

Regards,
-Markus


Top
 Profile  
 
 Post subject: Re: Zero Rebound / Air-free / Squeak-free Shocks
PostPosted: Wed Mar 01, 2017 12:30:12 
Offline
team driver
User avatar

Joined: Tue Apr 25, 2006 16:50:44
Posts: 178
Location: Czech Republic
Hello

This is how emulsion shocks work! All other do same...


Top
 Profile  
 
 Post subject: Re: Zero Rebound / Air-free / Squeak-free Shocks
PostPosted: Wed Mar 01, 2017 19:29:57 
Offline

Joined: Mon Sep 13, 2004 22:18:00
Posts: 33
Location: Seattle, USA
mtt wrote:
... The moment you turn the shock upside down you know there is air in them and they start to squeak.



There is always some air inside a properly bled emulsion shock; the air compresses to make room for the shaft as it enters the shock. Without the air the shock locks up. If the shock has been sitting awhile and is right side up then the air mixes quickly into the oil on the first piston stroke. If the shock is upside down and has been sitting awhile the air is right next to the seal so it will squeak more on the first stroke. So don't turn the shock upside down.


Top
 Profile  
 
 Post subject: Re: Zero Rebound / Air-free / Squeak-free Shocks
PostPosted: Wed Mar 01, 2017 21:44:49 
Offline

Joined: Sun Feb 05, 2017 23:43:32
Posts: 2
Location: Germany
Thanks guys.

I normally don't turn them upside down - just wanted to illustrate the effect I get.

Again, my problem remains that the shocks squeak the last 5mm when I push the chassis to the ground and it just doesn't feel and sound right.

What is the benefit of emulsion shocks used in the XB4 vs the bladder shocks used in let's say the XB8 or a T4.

Regards,
-Markus


Top
 Profile  
 
 Post subject: Re: Zero Rebound / Air-free / Squeak-free Shocks
PostPosted: Wed Mar 01, 2017 23:08:31 
Offline

Joined: Mon Sep 13, 2004 22:18:00
Posts: 33
Location: Seattle, USA
mtt wrote:
... Again, my problem remains that the shocks squeak the last 5mm when I push the chassis to the ground and it just doesn't feel and sound right. What is the benefit of emulsion shocks used in the XB4 vs the bladder shocks used in let's say the XB8 or a T4.

If the shock feels uneven on the first stroke after sitting awhile, that's normal. If it feels uneven after it has been worked, then it has too much air inside. You might be getting too much air into the shock during bleeding (if you keep the shock compressed whenever the bleed screw is off, it is hard to get too much air), or the cap is not sealing, or the o-rings are torn or otherwise not working properly.

As to why emulsion shocks rule 1/10th offroad, my guess is that the benefit of no membrane rebound pressure outweighs the need for more frequent topping up. With the heavier cars and longer races in 1/8 offroad the engineering tradeoff is different. In 1/10 TC the shock travel is very short so that changes things again, though there are some emulsion shocks used on non-XRAY TCs.


Top
 Profile  
 
 Post subject: Re: Zero Rebound / Air-free / Squeak-free Shocks
PostPosted: Thu Mar 02, 2017 13:44:21 
Offline
team driver
User avatar

Joined: Tue Apr 25, 2006 16:50:44
Posts: 178
Location: Czech Republic
Emulsion shocks are better for 1/10 offroad.
Car is light and run only 5 min so there is no problem.

If your o-ring are right then everything should be fine.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 6 posts ] 

All times are UTC + 2 hours


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group