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Re: [Healeys] BN2 Caster Angle

To: Michael Salter <michaelsalter@gmail.com>
Subject: Re: [Healeys] BN2 Caster Angle
From: Chris Dimmock <austin.healey@gmail.com>
Date: Thu, 7 Jan 2021 20:35:01 +1100
Cc: "healeys@autox.team.net" <Healeys@autox.team.net>
Delivered-to: mharc@autox.team.net
Delivered-to: Healeys@autox.team.net
References: <CAB3i7LL6QkRmhdV5ruX0WVL3YY5aNSPgFb3CMiSxxZTG5oS_dw@mail.gmail.com>
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Michael
You=E2=80=99re adding in a new variable.=20
=E2=80=9CKing pin inclination to contact patch ratio=E2=80=9D=20
And that is a handling killer.=20
You ALWAYS want the Imaginary line following your kingpin To hit the road at=
 the centre of your tyre. Always. No known exceptions in a rear wheel drive c=
ar.=20
Doesn=E2=80=99t matter if the tyres are 12 inches wide or 4 inches wide - ce=
ntre of the tyre.=20
Sage logic always says you widen a wheel inwards. Never huge offset outwards=
.=20
Camber is adjustable by various means=20
- bending shock arms=20
- offset top trunions=20
- Offset bottom trunions=20
- shorter top shock arms=20
Etc.=20
Caster- well that=E2=80=99s harder. Lots harder to change.=20
Castor - You need to move your top shock location, AND move your bottom wish=
bone location on the chassis.=20
It needs to =E2=80=9Ctilt=E2=80=9D
On a =E2=80=9Cjaunty angle=E2=80=9D=20
No. I=E2=80=99m too busy / google it.=20
Camber is easy. Castor requires a shitload more cutting and welding.=20
Perfection is 8 degrees negative at  20 degrees turn in for those seeking th=
e ultimate answer, And that means castor at 20 degrees turn in plus static c=
amber =3D 8=20
Best
Chris

> On 7 Jan 2021, at 6:10 am, Michael Salter <michaelsalter@gmail.com> wrote:=

>=20
> =EF=BB=BF
> Re: Still wondering how adjusting camber, for instance--zero camber is rec=
ommended (newer cars have slightly neg. camber)--for the radial tires most o=
f us run is a hazard (assuming it's done properly).=20
> I would have completely agreed with you Bob until I started doing some bas=
ic designing of front suspension systems.=20
> Although changing the camber may seem like a small thing you would be surp=
rised at how much a small adjustment in any of the suspension angles of dime=
nsions affects other things including "kingpin offset" and "bump steer" each=
 of which can have a profound effect on ride and handling.
> As an example I have a Mitsubishi 3000 GT VR4. This car has 4 wheel steeri=
ng but I don't think that is relevant.=20
> When I bought it fancy alloy replacement wheels had been installed. These w=
heels moved the front tyre contact patch outboard around 1.5 cm.=20
> The car was absolutely horrendous to drive with profound torque steer upon=
 the application of full throttle (320 BHP), appalling "tram tracking" and i=
ncredible tyre wear. =20
> I had another 3000 GT come in for service and as a test fitted the wheels o=
ff that car onto mine. The transformation was absolutely unbelievable; both t=
he handling problems vanished completely. =20
> I almost managed to talk the owner of the other 3000 into swapping his reg=
ular wheels for my fancy alloys but just couldn't do it and came clean by le=
tting him drive my car with the alloy wheels back on.
> Small changes can have VERY LARGE consequences.
> M
>=20
>> On Wed, Jan 6, 2021 at 11:22 AM Bob Spidell <bspidell@comcast.net> wrote:=

>> That's odd; the bearings should be immersed in grease (although I've wond=
ered how well greasing the top trunnion works, as a lot gets squished out).
>>=20
>> I installed the Torrington bearings on my BJ8 years ago; I thought steeri=
ng effort was reduced a bit (but I think part of it was confirmation bias). A=
gree that it would make more sense to install them on the bottom, load-beari=
ng, trunnion.
>>=20
>> Bob
>>=20
>> ps. Still wondering how adjusting camber, for instance--zero camber is re=
commended (newer cars have slightly neg. camber)--for the radial tires most o=
f us run is a hazard (assuming it's done properly).
>>=20
>>=20
>> On 1/6/2021 7:34 AM, Michael Salter wrote:
>>> I installed a couple of sets of those many years ago. Unfortunately the b=
earings were made from carbon steel not stainless and they rusted up after a=
bout 1 year.=20
>>> Hopefully the manufacturers now make them from stainless andor brass.
>>>=20
>>> M
>>>=20
>>> On Wed, Jan 6, 2021 at 9:49 AM Bluehealey <bluehealey@gmail.com> wrote:
>>>> These are the ones.
>>>> https://www.ahspares.co.uk/austin-healey/big-healey/suspension-front/to=
p-trunnion-bearing-kit-pair.aspx
>>>> Well worth doing.
>>>> The other often overlooked source of heavy steering is the Steering Idl=
er. It is rarely lubricated, has no real reservoir for oil, and a poor seal a=
t the bottom. I suggest releasing the ball joints that connect to the drop a=
rm to check it for stiffness. Complete removal of the idler isn=E2=80=99t a d=
ifficult job and is the best way to clean and lubricate.
>>>> The caster is pretty good on these cars (the initial design was good). C=
amber could go from positive to negative to be more compatible with radial t=
yres. Also check and minimise toe-in. This has a radical impact on steering f=
eel when wrong (in either direction).
>>>> If after all that you still have problems, then go for the caster chang=
es you have in mind and tell us about your findings. The Team may learn some=
thing.
>>>> The only other aspect that seems to vary from car to car is bump steer.=
 Some can be horrible on fast bumpies and others are on rails.  I=E2=80=99ve=
 never seen a decent treatise on dealing with this on our Big Healeys.
>>>> Have fun.
>>>> Alan - from my iPad
>>>>=20
>>>>> On 6 Jan 2021, at 13:35, Team.net <lawrence.swift@gmail.com> wrote:
>>>>>=20
>>>>> =EF=BB=BFWhen I rebuilt the front end on my BT7, I had the trust beari=
ngs at the top of the kingpin replaced with bearings - made a huge differenc=
e in the ease of steering.
>>>>>=20
>>>>>>> On Jan 5, 2021, at 10:36 AM, Bob Spidell <bspidell@comcast.net> wrot=
e:
>>>>>>=20
>>>>>> re: "The other two are factory fixed and too dangerous to play with o=
r maintain...even if Kilmartin makes the parts"
>>>>>>=20
>>>>>> How so?
>>>>>>=20
>>>>>>> On 1/4/2021 9:40 PM, gradea1@charter.net wrote:
>>>>>>> I'm with the philosophy "set the toe and let 'er blow" The 1/16-1/8"=
 toe-in is most important for proper tire wear.  The other two are factory f=
ixed and too dangerous to play with or maintain...even if Kilmartin makes th=
e parts. Hank
>>>>>>>=20
>>>>>>=20
>>=20
>> _______________________________________________
>> Support Team.Net http://www.team.net/donate.html
>> Suggested annual donation  $12.75
>>=20
>> Archive: http://www.team.net/pipermail/healeys http://autox.team.net/arch=
ive
>>=20
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>> http://autox.team.net/mailman/listinfo/healeys
>>=20
>> Unsubscribe/Manage: http://autox.team.net/mailman/options/healeys/michael=
salter@gmail.com
>>=20
> _______________________________________________
> Support Team.Net http://www.team.net/donate.html
> Suggested annual donation  $12.75
>=20
> Archive: http://www.team.net/pipermail/healeys http://autox.team.net/archi=
ve
>=20
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ealey@gmail.com
>=20

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<html><head><meta http-equiv=3D"content-type" content=3D"text/html; charset=3D=
utf-8"></head><body dir=3D"auto"><div dir=3D"ltr">Michael</div><div dir=3D"l=
tr">You=E2=80=99re adding in a new variable.&nbsp;</div><div dir=3D"ltr">=E2=
=80=9CKing pin inclination to contact patch ratio=E2=80=9D&nbsp;</div><div d=
ir=3D"ltr">And that is a handling killer.&nbsp;</div><div dir=3D"ltr">You AL=
WAYS want the Imaginary line following your kingpin To hit the road at the c=
entre of your tyre. Always. No known exceptions in a rear wheel drive car.&n=
bsp;</div><div dir=3D"ltr">Doesn=E2=80=99t matter if the tyres are 12 inches=
 wide or 4 inches wide - centre of the tyre.&nbsp;</div><div dir=3D"ltr">Sag=
e logic always says you widen a wheel inwards. Never huge offset outwards.&n=
bsp;</div><div dir=3D"ltr">Camber is adjustable by various means&nbsp;</div>=
<div dir=3D"ltr">- bending shock arms&nbsp;</div><div dir=3D"ltr">- offset t=
op trunions&nbsp;</div><div dir=3D"ltr">- Offset bottom trunions&nbsp;</div>=
<div dir=3D"ltr">- shorter top shock arms&nbsp;</div><div dir=3D"ltr">Etc.&n=
bsp;</div><div dir=3D"ltr">Caster- well that=E2=80=99s harder. Lots harder t=
o change.&nbsp;</div><div dir=3D"ltr">Castor - You need to move your top sho=
ck location, AND move your bottom wishbone location on the chassis.&nbsp;</d=
iv><div dir=3D"ltr">It needs to =E2=80=9Ctilt=E2=80=9D</div><div dir=3D"ltr"=
>On a =E2=80=9Cjaunty angle=E2=80=9D&nbsp;</div><div dir=3D"ltr">No. I=E2=80=
=99m too busy / google it.&nbsp;</div><div dir=3D"ltr">Camber is easy. Casto=
r requires a shitload more cutting and welding.&nbsp;</div><div dir=3D"ltr">=
Perfection is 8 degrees negative at &nbsp;20 degrees turn in for those seeki=
ng the ultimate answer, And that means castor at 20 degrees turn in plus sta=
tic camber =3D 8&nbsp;</div><div dir=3D"ltr">Best</div><div dir=3D"ltr">Chri=
s</div><div dir=3D"ltr"><br><blockquote type=3D"cite">On 7 Jan 2021, at 6:10=
 am, Michael Salter &lt;michaelsalter@gmail.com&gt; wrote:<br><br></blockquo=
te></div><blockquote type=3D"cite"><div dir=3D"ltr">=EF=BB=BF<div dir=3D"ltr=
"><div class=3D"gmail_default" style=3D"font-family:comic sans ms,sans-serif=
;font-size:small">Re:=20
<i>Still wondering how adjusting camber, for instance--zero camber
    is recommended (newer cars have slightly neg. camber)--for the
    radial tires most of us run is a hazard (assuming it's done
    properly). <br></i></div><div class=3D"gmail_default" style=3D"font-fami=
ly:comic sans ms,sans-serif;font-size:small">I would have completely agreed w=
ith you Bob until I started doing some basic designing of front suspension s=
ystems. <br></div><div class=3D"gmail_default" style=3D"font-family:comic sa=
ns ms,sans-serif;font-size:small">Although changing the camber may seem like=
 a small thing you would be surprised at how much a small adjustment in any o=
f the suspension angles of dimensions affects other things including "kingpi=
n offset" and "bump steer" each of which can have a profound effect on ride a=
nd handling.</div><div class=3D"gmail_default" style=3D"font-family:comic sa=
ns ms,sans-serif;font-size:small">As an example I have a Mitsubishi 3000 GT V=
R4. This car has 4 wheel steering but I don't think that is relevant. <br></=
div><div class=3D"gmail_default" style=3D"font-family:comic sans ms,sans-ser=
if;font-size:small">When I bought it fancy alloy replacement wheels had been=
 installed. These wheels moved the front tyre contact patch outboard around 1=
.5 cm. <br></div><div class=3D"gmail_default" style=3D"font-family:comic san=
s ms,sans-serif;font-size:small">The car was absolutely horrendous to drive w=
ith profound torque steer upon the application of full throttle (320 BHP), a=
ppalling "tram tracking" and incredible tyre wear.&nbsp; <br></div><div clas=
s=3D"gmail_default" style=3D"font-family:comic sans ms,sans-serif;font-size:=
small">I had another 3000 GT come in for service and as a test fitted the wh=
eels off that car onto mine. The transformation was absolutely unbelievable;=
 both the handling problems vanished completely.&nbsp; <br></div><div class=3D=
"gmail_default" style=3D"font-family:comic sans ms,sans-serif;font-size:smal=
l">I almost managed to talk the owner of the other 3000 into swapping his re=
gular wheels for my fancy alloys but just couldn't do it and came clean by l=
etting him drive my car with the alloy wheels back on.</div><div class=3D"gm=
ail_default" style=3D"font-family:comic sans ms,sans-serif;font-size:small">=
Small changes can have VERY LARGE consequences.</div><div class=3D"gmail_def=
ault" style=3D"font-family:comic sans ms,sans-serif;font-size:small">M<br></=
div><div class=3D"gmail_default" style=3D"font-family:comic sans ms,sans-ser=
if;font-size:small"><i></i></div></div><br><div class=3D"gmail_quote"><div d=
ir=3D"ltr" class=3D"gmail_attr">On Wed, Jan 6, 2021 at 11:22 AM Bob Spidell &=
lt;<a href=3D"mailto:bspidell@comcast.net"; target=3D"_blank">bspidell@comcas=
t.net</a>&gt; wrote:<br></div><blockquote class=3D"gmail_quote" style=3D"mar=
gin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1e=
x">
 =20
   =20
 =20
  <div>
    That's odd; the bearings should be immersed in grease (although I've
    wondered how well greasing the top trunnion works, as a lot gets
    squished out).<br>
    <br>
    I installed the Torrington bearings on my BJ8 years ago; I thought
    steering effort was reduced a bit (but I think part of it was
    confirmation bias). Agree that it would make more sense to install
    them on the bottom, load-bearing, trunnion.<br>
    <br>
    Bob<br>
    <br>
    ps. Still wondering how adjusting camber, for instance--zero camber
    is recommended (newer cars have slightly neg. camber)--for the
    radial tires most of us run is a hazard (assuming it's done
    properly).<br>
    <br>
    <br>
    <div>On 1/6/2021 7:34 AM, Michael Salter
      wrote:<br>
    </div>
    <blockquote type=3D"cite">
     =20
      <div dir=3D"ltr">
        <div class=3D"gmail_default" style=3D"font-family:comic sans ms,sans=
-serif;font-size:small">I installed a couple of sets of
          those many years ago. Unfortunately the bearings were made
          from carbon steel not stainless and they rusted up after about
          1 year. <br>
        </div>
        <div class=3D"gmail_default" style=3D"font-family:comic sans ms,sans=
-serif;font-size:small">Hopefully the manufacturers now
          make them from stainless andor brass.</div>
        <div class=3D"gmail_default" style=3D"font-family:comic sans ms,sans=
-serif;font-size:small"><br>
        </div>
        <div class=3D"gmail_default" style=3D"font-family:comic sans ms,sans=
-serif;font-size:small">M<br>
        </div>
      </div>
      <br>
      <div class=3D"gmail_quote">
        <div dir=3D"ltr" class=3D"gmail_attr">On Wed, Jan 6, 2021 at 9:49 AM=

          Bluehealey &lt;<a href=3D"mailto:bluehealey@gmail.com"; target=3D"_=
blank">bluehealey@gmail.com</a>&gt; wrote:<br>
        </div>
        <blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;=
border-left:1px solid rgb(204,204,204);padding-left:1ex">
          <div dir=3D"auto">
            <div dir=3D"ltr">
              <div dir=3D"ltr">These are the ones.
                <div><a href=3D"https://www.ahspares.co.uk/austin-healey/big=
-healey/suspension-front/top-trunnion-bearing-kit-pair.aspx" target=3D"_blan=
k">https://www.ahspares.co.uk/austin-healey/big-healey/suspension-front/top-=
trunnion-bearing-kit-pair.aspx</a></div>
                <div>Well worth doing.</div>
                <div>The other often overlooked source of heavy steering
                  is the Steering Idler. It is rarely lubricated, has no
                  real reservoir for oil, and a poor seal at the bottom.
                  I suggest releasing the ball joints that connect to
                  the drop arm to check it for stiffness. Complete
                  removal of the idler isn=E2=80=99t a difficult job and is t=
he
                  best way to clean and lubricate.</div>
                <div>The caster is pretty good on these cars (the
                  initial design was good). Camber could go from
                  positive to negative to be more compatible with radial
                  tyres. Also check and minimise toe-in. This has a
                  radical impact on steering feel when wrong (in either
                  direction).</div>
                <div>If after all that you still have problems, then go
                  for the caster changes you have in mind and tell us
                  about your findings. The Team may learn something.</div>
                <div>The only other aspect that seems to vary from car
                  to car is bump steer. Some can be horrible on fast
                  bumpies and others are on rails.&nbsp; I=E2=80=99ve never s=
een a
                  decent treatise on dealing with this on our Big
                  Healeys.<br>
                  Have fun.<br>
                  <div dir=3D"ltr">Alan - from my iPad</div>
                  <div dir=3D"ltr"><br>
                    <blockquote type=3D"cite">On 6 Jan 2021, at 13:35,
                      Team.net &lt;<a href=3D"mailto:lawrence.swift@gmail.co=
m" target=3D"_blank">lawrence.swift@gmail.com</a>&gt;
                      wrote:<br>
                      <br>
                    </blockquote>
                  </div>
                  <blockquote type=3D"cite">
                    <div dir=3D"ltr">=EF=BB=BF<span>When I rebuilt the front=
 end
                        on my BT7, I had the trust bearings at the top
                        of the kingpin replaced with bearings - made a
                        huge difference in the ease of steering.</span><br>
                      <span></span><br>
                      <blockquote type=3D"cite"><span>On Jan 5, 2021, at
                          10:36 AM, Bob Spidell &lt;<a href=3D"mailto:bspide=
ll@comcast.net" target=3D"_blank">bspidell@comcast.net</a>&gt;
                          wrote:</span><br>
                      </blockquote>
                      <blockquote type=3D"cite"><span></span><br>
                      </blockquote>
                      <blockquote type=3D"cite"><span>re: "The other two
                          are factory fixed and too dangerous to play
                          with or maintain...even if Kilmartin makes the
                          parts"</span><br>
                      </blockquote>
                      <blockquote type=3D"cite"><span></span><br>
                      </blockquote>
                      <blockquote type=3D"cite"><span>How so?</span><br>
                      </blockquote>
                      <blockquote type=3D"cite"><span></span><br>
                      </blockquote>
                      <blockquote type=3D"cite"><span>On 1/4/2021 9:40 PM,
                          <a href=3D"mailto:gradea1@charter.net"; target=3D"_=
blank">gradea1@charter.net</a>
                          wrote:</span><br>
                      </blockquote>
                      <blockquote type=3D"cite">
                        <blockquote type=3D"cite"><span>I'm with the
                            philosophy "set the toe and let 'er blow"
                            The 1/16-1/8" toe-in is most important for
                            proper tire wear.&nbsp; The other two are factor=
y
                            fixed and too dangerous to play with or
                            maintain...even if Kilmartin makes the
                            parts. Hank</span><br>
                        </blockquote>
                      </blockquote>
                      <blockquote type=3D"cite">
                        <blockquote type=3D"cite"><span></span><br>
                        </blockquote>
                      </blockquote>
                      <blockquote type=3D"cite"><span></span><br>
                      </blockquote>
                    </div>
                  </blockquote>
                </div>
              </div>
            </div>
          </div>
        </blockquote>
      </div>
    </blockquote>
    <br>
  </div>

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