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Caster Shims - would they help?

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sinecure Want another... :(

1,031 posts · joined Mar 2006 ·

#614186
My 71 type3 based kit is very low, and the steering at speed is VERY light and twitchy.

I've been told caster shims may help. Am I on the right track?

Thanks,

Mick.
A POSSE AD ESSE.

I live in my own little world, but it's okay, they know me here.

MickH Hairy Gutted Sloth

3,389 posts · joined Sep 2003 ·

#614188
Yep. Hows the beast going???
tssnq.com.au

VWCOOL 23 Windows of Awesome

5,158 posts · joined Jun 2003 ·

#614203
The usual Beetle caster shims won't fit... But yes, more caster (ie: +3 or more deg) is good for steering feel and stability

Do you need it 'low'? You might be amazed at what an inch or two in extra ride height can do

[ Edited on 28-9-2007 by VWCOOL ]
Pay your debts, CxxT

sinecure Want another... :(

1,031 posts · joined Mar 2006 ·

#614295
MickH wrote:Yep. Hows the beast going???
Very well, Mick. Interior stripped at the mo' for new carpet, console and dash.

Pics up soon!

:thumb
A POSSE AD ESSE.

I live in my own little world, but it's okay, they know me here.

sinecure Want another... :(

1,031 posts · joined Mar 2006 ·

#614297
VWCOOL wrote:The usual Beetle caster shims won't fit... But yes, more caster (ie: +3 or more deg) is good for steering feel and stability

Do you need it 'low'? You might be amazed at what an inch or two in extra ride height can do

[ Edited on 28-9-2007 by VWCOOL ]
Unfortunately (sort of), I wouldn't want to raise it, as the body is really designed to sit this low (full, legal 125mm under car clearance), that's why I wanted dropped spindles. The only set available would cost me around $750 landed.

I've seen caster shims for VW for sale, but no-one differentiates the models. I assume the difference between beetle and type3 is significant.

A few have suggested that these shims are only effective if your car is raked (mine's lowered the same front and back).

BJ camber adjusters and 'lowered' BJ's have also been suggested to improve the feel. What do you guys think?

Thanks for the help,

Mick.

[ Edited on 29/9/2007 by sinecure ]
A POSSE AD ESSE.

I live in my own little world, but it's okay, they know me here.

VWCOOL 23 Windows of Awesome

5,158 posts · joined Jun 2003 ·

#614350
yes its a shame a lot of kit car bodies were designed for lowered chassis where it would have been far more sensible to produce a body with lowered wheelarches 😉

One inch raised might be all that is needed to get some caster back without looking 'raised'

Beetle shims fit between teh lower front axle tube and chassis; Type 3s have a full-circle rertainer but you may be able to re-engineer this section of the chassis to tilt the beam...?

You know Type 3s have some camber/caster adjustment at the top arm...?
Pay your debts, CxxT

Joval Learner Dubber

19 posts · joined Aug 2007 ·

#614421
Could it be down to bump steer? Inverting the tie-rods at the spindles should restore the angle, but you may need to get bushes made up.

sinecure Want another... :(

1,031 posts · joined Mar 2006 ·

#614438
VWCOOL wrote:yes its a shame a lot of kit car bodies were designed for lowered chassis where it would have been far more sensible to produce a body with lowered wheelarches 😉

One inch raised might be all that is needed to get some caster back without looking 'raised'

Beetle shims fit between teh lower front axle tube and chassis; Type 3s have a full-circle rertainer but you may be able to re-engineer this section of the chassis to tilt the beam...?

You know Type 3s have some camber/caster adjustment at the top arm...?
Yes, the design of the Purvis is easier, being based on the swing axle beetle chassis, with lowered floor pans to compensate for the roof height. Apparently, DRB used the type3 because their kits were so heavy (1300kg for mine, around 800kg for the Eureka).

There is only about three inches between my bumpstop lugs (no bump stop rubbers were present when I got the car) and the landing surface for them. Factory bump stops only just fit at rest, so I'm making a new, lower set.

Isn't one 'notch' on the suspension around two inches? If I could raise by only an inch, I would be very happy with that. As far as tilting the beam, would this actully help as the car is not raked at all?

I've looked at the suspension adjustments in the manual and intended on having a fool around with them, I just wanted to make sure that there wasn't something relatively straightforward (like shims or dropped spindles) I could do to correct the geometry.

Thanks,

Mick.
A POSSE AD ESSE.

I live in my own little world, but it's okay, they know me here.

sinecure Want another... :(

1,031 posts · joined Mar 2006 ·

#614440
Joval wrote:Could it be down to bump steer? Inverting the tie-rods at the spindles should restore the angle, but you may need to get bushes made up.
I suspect bump steer has some degree of influence, but it does wander at speed on a dead flat surface (Mt Cotton driver training facility). Do you mean inverting the tie-rod ends where they attach to the spindle? Would this have a similar effect to 'lowered' BJ's?

Thanks,

Mick.
A POSSE AD ESSE.

I live in my own little world, but it's okay, they know me here.

VWCOOL 23 Windows of Awesome

5,158 posts · joined Jun 2003 ·

#614445
Simply turning one notch will change ride height by around four inches but VW provided different numbers of inner and outer notches (splines on the torsion bar) that allow fine ride height adjustments of around 8mm. Ie: turning the torsion bar back one spline on the inner and forward one on the spring plate will raise the car by 8mm. Easy in theory BUT can be very frstrating in practice... and it depends on the torsion bar diamter and weight of the car etc. You may need several attempts to get the ride height you desire. I got one wrong a week ago and it is now 2in higher than I planned! (But I have expected that as I was installing stiffer torsion bars)

PS: Dropped spindles allow you to lower a car and retain factory caster; they will not restore factory caster on a lowered front end, IYKWIM
sinecure wrote:
VWCOOL wrote:yes its a shame a lot of kit car bodies were designed for lowered chassis where it would have been far more sensible to produce a body with lowered wheelarches 😉

One inch raised might be all that is needed to get some caster back without looking 'raised'

Beetle shims fit between teh lower front axle tube and chassis; Type 3s have a full-circle rertainer but you may be able to re-engineer this section of the chassis to tilt the beam...?

You know Type 3s have some camber/caster adjustment at the top arm...?
Yes, the design of the Purvis is easier, being based on the swing axle beetle chassis, with lowered floor pans to compensate for the roof height. Apparently, DRB used the type3 because their kits were so heavy (1300kg for mine, around 800kg for the Eureka).

There is only about three inches between my bumpstop lugs (no bump stop rubbers were present when I got the car) and the landing surface for them. Factory bump stops only just fit at rest, so I'm making a new, lower set.

Isn't one 'notch' on the suspension around two inches? If I could raise by only an inch, I would be very happy with that. As far as tilting the beam, would this actully help as the car is not raked at all?

I've looked at the suspension adjustments in the manual and intended on having a fool around with them, I just wanted to make sure that there wasn't something relatively straightforward (like shims or dropped spindles) I could do to correct the geometry.

Thanks,

Mick.
[ Edited on 1-10-2007 by VWCOOL ]
Pay your debts, CxxT

sinecure Want another... :(

1,031 posts · joined Mar 2006 ·

#614472
PS: Dropped spindles allow you to lower a car and retain factory caster; they will not restore factory caster on a lowered front end, IYKWIM

Yep, my plan was to reset the car to factory front height, fit the drops, then measure and adjust both front and rear again.

I guess I'll spend a few days playing with the splines when I can get some time off, bringing it up 16-24mm.

Thanks for all the advice guys!

Cheers,

Mick.
A POSSE AD ESSE.

I live in my own little world, but it's okay, they know me here.

Joval Learner Dubber

19 posts · joined Aug 2007 ·

#614570
I've no experience with type3s but certainly on a lowered beetle on standard spindles the increased tie rod angle causes wandering,
which is more noticable at speed as you travel further before correcting (AFAIK) this can be counteracted with caster shims to make the steering a little heavier,
On beetles you need to drill/ream the spindle to fit an inverted tapered bush to allow the rods to bolt underneath the arm.

This is based on experience but I could be talking shite, I'm sure somebody more technically minded can clear this up :P

Craig Torrens 6 times Australian, 7 times State Hillclimb Class Champion

8,040 posts · joined Jan 2003 ·

#614696
Joval, all you need to do is rotate the steering box on the beam to bring the tierods back to a respectable angle.:thumb


sinecure Want another... :(

1,031 posts · joined Mar 2006 ·

#614762
Craig Torrens wrote:Joval, all you need to do is rotate the steering box on the beam to bring the tierods back to a respectable angle.:thumb
Thanks, Craig. This may be a stupid question, but by rotate do you mean invert?

Cheers,

Mick.
A POSSE AD ESSE.

I live in my own little world, but it's okay, they know me here.

Joval Learner Dubber

19 posts · joined Aug 2007 ·

#614867
Hmm, but if you change the angle of the steering box won't you have to fit a joint on the end of the column?

68AutoBug Beetle Restorer - Experience over 138\% - YIKES --

11,654 posts · joined Aug 2002 ·

#614919
You need more castor on the front wheels

so the steering wheel returns to straight ahead

after going round a corner etc...

My beetle is lowered and I did have the shims but took them out because the tyres were rubbing on the guard edges...

and now the steering wheel doesn't return to straight ahead, but its not a problem....

Lee
- Helping keep Air Cooled VWs on the road - location: SCONE in the Upper Hunter Valley - Northern NSW 320 kms NNW of SYDNEY---

sinecure Want another... :(

1,031 posts · joined Mar 2006 ·

#618301
http://forums.aussieveedubbers.com/viewtopic.php?tid=65772

Would these fit a 71 type3? I've seen very similar advertised as OK for all rear (type3, beetle), but linkpin front only, and as bj front for type3/beetle. I'd like them for the front, but will buy them anyway for the rear to simplify minor adjustments there after the front end adjust.

What do I measure apart from compressed height, bush diameter and position?

BTW, bought these to replace the front bump stops altogether:

http://cgi.ebay.com.au/Chrysler-Valiant-Upper-bump-stop-M-D-I-tech-S-to-CM_W0QQitemZ170159807163QQihZ007QQcategoryZ31251QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

1.4 inch high by 1 inch wide with 0.9 inch of thread so perfect (I hope!).
A POSSE AD ESSE.

I live in my own little world, but it's okay, they know me here.