Haynes Forums  

Go Back   Haynes Forums > Haynes Roadster Forums > Running gear
FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Display Modes
  #51  
Old 4th October 2012, 02:23 PM
spud69's Avatar
spud69 spud69 is offline
Senior Member
 
Join Date: Jul 2008
Location: Hartlepool
Posts: 1,678
Default

Quote:
Originally Posted by Big Vern View Post
The mushroom should be orientated away from the engine.
The mushroom is not meant to be used to overcome the lack of caster. The mushroom takes into account the upright doesn't pivot about its centre line in the donor vehicle. Martin Keenan devised the mushroom to overcome this problem.
The lack of caster is a design flaw in my view and the design should have been corrected years ago or at least a sticky put in place so new builders would know to build in extra caster as they built their chassis. Rotating the mushroom and adding undersirable toe out to get it to self centre is just bodging round the issue.
5 degrees should be considered a minimum but some people arn't getting anywhere near as much.
You're right Vern, 7:30 this morning was a bit early for my brain working to be honest.

The roadster handles fine the way it is and you don't really want a great deal of self center, in my opinion it's mainly for lazy people driving big cars... There is nothing wrong with toe-ing out a bit more on the rack extensions just to get through IVA, although you cant do this with the mushroom (just the camber which you can also do with the threaded insert).

Suns out this afternoon and i've finished my work for the day so i'm of out in mine to see HandyAndy I'm sure it will be handling fine

Andy
__________________
Haynes Roadster / Saturn GRP Bodywork. Now available direct through http://www.gillhamonline.co.uk/ or contact me direct on andrew.hugill@ntlworld.com

Regards..........AndyH
Reply With Quote
  #52  
Old 7th October 2012, 05:03 PM
Johno's Avatar
Johno Johno is offline
Senior Member
 
Join Date: Sep 2011
Location: Lutton (East Anglia)
Posts: 497
Default

Hi Alga,
Did you sort out your self centering problem?
I've been reading up on it and it all seems a bit daunting to say the least
__________________
Any intelligent fool can make things bigger and more complex... It takes a touch of genius - and a lot of courage to move in the opposite direction.
Albert Einstein

http://s1199.photobucket.com/albums/aa472/JohnoSS1/

Johno
Reply With Quote
  #53  
Old 8th October 2012, 12:37 AM
alga's Avatar
alga alga is offline
Senior Member
 
Join Date: Feb 2009
Location: Vilnius, Lithuania
Posts: 1,249
Default

No, didn't have much time to play with it TBH.

Take a look on this old thread: http://www.locostbuilders.co.uk/view....php?tid=97634
The consensus is that the proper fix is more caster, and one figure given is that 22-24 mm of displacement between top and bottom ball joints should do it (we have 20 mm standard). I'll try slackening the wishbone bushes and ensuring that their play is at the end of most camber angle.

One more idea to try from there -- rotating the mushroom a little bit inwards might increase the KPI angle (as the upper ball joint will have to be threaded further in to return the camber to where it was), while the mechanical trail will be reduced minimally. I'm not sure there will be space on the thread though -- the locknuts are already at the end of the thread, with just -2° camber and mushrooms straight ahead.

I reduced toe to zero, and now the car displays "a degree of self centering evident": if I rotate the wheel by 15 degrees, when driving, it springs back by some 3 or 5 degrees sometimes. This could be enough for IVA, but is nowhere near where I would consider it to have any safety effect.
__________________
Albert
Haynes Roadster FAQ | Haynes Builder Locations
Gallery, build thread in Lithuanian / via Google Translate.
Reply With Quote
  #54  
Old 8th October 2012, 12:45 AM
alga's Avatar
alga alga is offline
Senior Member
 
Join Date: Feb 2009
Location: Vilnius, Lithuania
Posts: 1,249
Default

Quote:
Originally Posted by DRCorsa View Post
alga, one thought. Maybe it's something with your steering column, maybe some awkward angle causing the steering to stuck?
With the front up, the wheels move pretty freely, but I'll check the position of the steering rack again.
__________________
Albert
Haynes Roadster FAQ | Haynes Builder Locations
Gallery, build thread in Lithuanian / via Google Translate.
Reply With Quote
  #55  
Old 27th October 2012, 09:22 PM
Johno's Avatar
Johno Johno is offline
Senior Member
 
Join Date: Sep 2011
Location: Lutton (East Anglia)
Posts: 497
Default

Hi Alga,
I've made some new wishbones which you can alter the caster. I know it's of no help to you now you have yours but I thought I would show you a photo.

__________________
Any intelligent fool can make things bigger and more complex... It takes a touch of genius - and a lot of courage to move in the opposite direction.
Albert Einstein

http://s1199.photobucket.com/albums/aa472/JohnoSS1/

Johno
Reply With Quote
  #56  
Old 28th October 2012, 11:44 AM
robo robo is offline
Senior Member
 
Join Date: Jun 2011
Location: scabs
Posts: 1,722
Default

Nice looking lot there . Have you had a chance to shove a caster camber guage on it yet?

Bob
__________________
When The Results Disagree With The Theory: Believe The Results And Invent A New Theory
If I had two brains I,d still be a halfwit

The cave http://s1116.photobucket.com/user/my...deshow/mancave

The build http://www.haynes.co.uk/forums/showthread.php?t=12669
Reply With Quote
  #57  
Old 28th October 2012, 05:27 PM
Johno's Avatar
Johno Johno is offline
Senior Member
 
Join Date: Sep 2011
Location: Lutton (East Anglia)
Posts: 497
Default

Quote:
Originally Posted by robo View Post
Nice looking lot there . Have you had a chance to shove a caster camber guage on it yet?

Bob
Hi Bob,
I don't have a camber/caster gauge.
I do own a digital spirit level which I could eye up with the ball joints I guess. or is there another way of measuring it easily.
I guess you are interested how much you can alter the caster with the rose joints forward and rearward at max?
I will try and find out tomorrow.
__________________
Any intelligent fool can make things bigger and more complex... It takes a touch of genius - and a lot of courage to move in the opposite direction.
Albert Einstein

http://s1199.photobucket.com/albums/aa472/JohnoSS1/

Johno
Reply With Quote
  #58  
Old 28th October 2012, 10:36 PM
robo robo is offline
Senior Member
 
Join Date: Jun 2011
Location: scabs
Posts: 1,722
Default

Quote:
Originally Posted by Johno View Post
Hi Bob,
I don't have a camber/caster gauge.
I do own a digital spirit level which I could eye up with the ball joints I guess. or is there another way of measuring it easily.
I guess you are interested how much you can alter the caster with the rose joints forward and rearward at max?
I will try and find out tomorrow.

I have got a guage that attaches to the rim that does both caster and camber. if you need the loan of it just cover the p+p.

Bob


__________________
When The Results Disagree With The Theory: Believe The Results And Invent A New Theory
If I had two brains I,d still be a halfwit

The cave http://s1116.photobucket.com/user/my...deshow/mancave

The build http://www.haynes.co.uk/forums/showthread.php?t=12669
Reply With Quote
  #59  
Old 29th October 2012, 09:22 PM
Johno's Avatar
Johno Johno is offline
Senior Member
 
Join Date: Sep 2011
Location: Lutton (East Anglia)
Posts: 497
Default

Hi Bob,
Thats very kind of you... I will let you know if I need it.
I did manage to eye up the joints with my digital level with the rose joints set even and it was approx 7.4 degrees.
When I made my new wishbones I did move the top pivot rearward back 5mm which does correspond with DRcorsa's calculation of 7.14 degrees.
__________________
Any intelligent fool can make things bigger and more complex... It takes a touch of genius - and a lot of courage to move in the opposite direction.
Albert Einstein

http://s1199.photobucket.com/albums/aa472/JohnoSS1/

Johno

Last edited by Johno : 29th October 2012 at 09:26 PM.
Reply With Quote
Reply


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

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT +1. The time now is 10:51 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.