GermanLook Forums  

Go Back   GermanLook Forums > Technical Section > Suspension

Reply
 
Thread Tools Display Modes
  #1  
Old May 6th 2011, 10:01
Bruce. Bruce. is offline
Registered User
 
Join Date: Jan 2011
Posts: 83
Thinking out loud: beam design mod?

Could this work?

As we all know, the standard torsion beam front suspension is not ideal for mainly one reason. When the suspension compresses there is no change in camber. So as the body rolls in a bend the outer front wheel moves into positive camber and grip is lost. The fix is a very fat roll bar to reduce the front body roll drastically but this has a bundle of issues for a road car.

So, you can design a fancy new wishbone suspension system and a few have but they are a big redesign and very expensive. Or you can cut up the inner wings / framehead and convert to 1303S macpherson struts.

However, I wondered if there was another possible option.

1st, leave the bottom trailing arm / torsion leaves set up as per stock. 2nd, remove the top torsion leaves and cut the end of the torsion tube at a slight angle. plate over the end and drill for a large mounting bolt. fab a custom top trailing arm with balljoint to link to the stub axle. Add coilover shocks (to replace the missing torsion leaves).

The idea is for the top arm to move in a different pivot axis (not parallel to the bottom arm) so that the top balljoint is moves inwards as the suspension compresses.

It would need a custom top arm and a carefully modified beam. However, the top arm would not be carrying the suspension loadings so wouldn't need to be as strong as the original part. Also need better maths skills than me to figure out the correct angles.

I keep thinking I've missed something (bumpsteer perhaps? loss of caster with bounce?)
Reply With Quote
  #2  
Old May 6th 2011, 10:52
typ4boy's Avatar
typ4boy typ4boy is offline
VW consumer products reseller and researcher
 
Join Date: Nov 2002
Location: england
Posts: 246
Quote:
Originally Posted by Bruce. View Post
Could this work?

As we all know, the standard torsion beam front suspension is not ideal for mainly one reason. When the suspension compresses there is no change in camber. So as the body rolls in a bend the outer front wheel moves into positive camber and grip is lost. The fix is a very fat roll bar to reduce the front body roll drastically but this has a bundle of issues for a road car.

So, you can design a fancy new wishbone suspension system and a few have but they are a big redesign and very expensive. Or you can cut up the inner wings / framehead and convert to 1303S macpherson struts.

However, I wondered if there was another possible option.

1st, leave the bottom trailing arm / torsion leaves set up as per stock. 2nd, remove the top torsion leaves and cut the end of the torsion tube at a slight angle. plate over the end and drill for a large mounting bolt. fab a custom top trailing arm with balljoint to link to the stub axle. Add coilover shocks (to replace the missing torsion leaves).

The idea is for the top arm to move in a different pivot axis (not parallel to the bottom arm) so that the top balljoint is moves inwards as the suspension compresses.

It would need a custom top arm and a carefully modified beam. However, the top arm would not be carrying the suspension loadings so wouldn't need to be as strong as the original part. Also need better maths skills than me to figure out the correct angles.

I keep thinking I've missed something (bumpsteer perhaps? loss of caster with bounce?)
Hey Bruce we are in the process of putting a 51 split bug shell onto a 73 1303 floorpan with built in strut mounts keep your peeled new thread starts next week.........
Reply With Quote
  #3  
Old May 9th 2011, 07:50
Bruce. Bruce. is offline
Registered User
 
Join Date: Jan 2011
Posts: 83
Looking forward to that!

Cheers
Reply With Quote
  #4  
Old May 9th 2011, 08:20
evilC's Avatar
evilC evilC is offline
Registered User
 
Join Date: Jun 2008
Location: UK Where Leics is more
Posts: 644
Hi Bruce,
I can see your logic but I would need to model the arrangement to see the effect but intuitively the amount of effort involved would not generate a better arrangement than a strut or wishbone suspension with the same amount of work and then it wouldn't be adjustable to allow fine tuning? Its probably doable but I can't think why you would?
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

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

Forum Jump


All times are GMT -4. The time now is 07:29.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
© www.GermanLook.net 2002-2017. All Rights Reserved