Interesting measurements. I'm going to do some extensive testing and
measuring on Peyote this winter and play with the front and rear
suspension to try to get rid of some of the understeer.
Just a note, when I first did my suspension mods on my TR3 the people who
drove behind me said that the car was "twitchy". They had no idea. I
thought it was too little toe in, or too little caster, or too much
coffee. I fiddled with every alignment parameter and it made no difference
except when I got really carried away with the toe in and the car
developed a kind of autopilot (THINK about turning in and it's already
done). Turned out it was a combination or travel and bump steer. Even when
I didn't sense a bump, the steering was doing crazy stuff as the
suspension moved up and down. I reduced the travel and lowered the car,
and moved the itdler and steering arms up (yes, that was hard to do and
certainly not legal) and it started working really well. By the time I had
everything else tweaked in I had a TR3 that had almost no body roll and
didn't push like a cow.
-----Original Message-----
From: Jack W. Drews [mailto:vinttr4@geneseo.net]
Sent: Friday, October 12, 2001 10:21 AM
To: Justin
Cc: Jim Elbe; 'fot@autox.team.net'
Subject: Re: TR 4 NEGATIVE CAMBER
See below
Justin wrote:
> I just skimmed through research materials and found the following.
(Some
> doesn't apply to your specific request, but it still might be of
interest to
> others.)
> --Justin Wagner
>
> A handy note for TR 4A owners...
> "A good way to get 1/4 degree more negative camber it to reverse the
upper
> fulcrum shaft, on which the upper A-arms mount, as it is offset. This
shaft
> usually rides with its bulging part to the outside. Reverse it so the
bulge is
> inside and you'll increase negative camber" Grassroots Motorsports
article by
> Tim Suddard
>
> Jim Elbe wrote:
>
> > What's the best way to get some on a TR 4 ??
> > RMVR will not let you change mounting points or use non-standard
> > components. I've read the book about heating and bending the uprights.
Is
> > this still the preferred way to go ?? If so can someone recommend a
place
> > that knows what they are doing ? Can the uprights only be sent to be
done ?
> > Thanks in advance.
> > Jim Elbe
> > TR 4 #223
What Tim Suddard said in GRM must have been true with the springs and
spacer setup
he had at the time but is was different on the chassis I measured. I
thought the TR
community might be interested is a set of actual measurements, made last
winter
during the rebuild of Ol' Blue into New Blue.
Conditions: bare chassis, front crossmember 3-3/4" off the ground to
simulate no
spacer and competition springs. Measurements will be somewhat different
with
everything assembled and the front suspension loaded, and accuracy is
within what I
could attain, not having an alignment machine:
A-arm length bulge in bulge out
stock +.6 +1.6
.375 short -2.1 -1.0
.500 short -3.0 -2.1
So, with this combination of competition springs and no spacer, reversing
the bulge
direction of the upper trunnion changes the camber by about 1 deg. And,
although
one would expect the changes to be linear, they are not because of the
angles
involved.
I find that with everything loaded, things change by 1/2 deg (don't ask me
why -- I
don't know -- must be deflection somewhere or everywhere).
Your mileage may vary. These chassis are pretty old and have usually seen
lots of
abuse in their 40 year life. One friend of mine installed upper a-arms
shortened
.375 and had to turn one bulge in and one bulge out to get the front
wheels about
right.
Maybe the best way to do all this is to use the system discussed last
winter
regarding the setup on Irv Korey's car. I'll let someone else explain
that.
--
uncle jack - red, white, and New Blue
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