This is the original post from Brain Lanoway
<mailto:Brian_Lanoway@standardaero.ca> ...enjoy.
Peter Zaborski CF58310UO
> It's now taken me 2 years, but I finally think that I've got the camber
> on both my rear wheels right and I thought the list might benefit from
> some of the 'science' I've applied to the task. There's been some
> traffic on the list last spring about this subject, but I haven't seen a
> comprehensive approach to this yet. I hope this helps.
>
> First some background. Last year, I installed new trailing arm up-rated
> rubber bushings, springs and rubber spring packings, only to find that
> the rear camber was still excessive - with the driver's side sagging
> more than the other. This spring, I mixed and matched the trailing arm
> brackets - using the same mirror-image combination on both sides - the
> net result being the proper camber on the passenger side with some sag
> still remaining on the driver's side. Finally, I remixed the brackets
> on the driver's side alone to get that right. I now have both sides at
> the proper camber angle - primarily through using various trailing arm
> bracket combinations.
>
> Since there are 36 possible trailing arm bracket combinations with the
> one notch, two notch and three notch brackets - either in the 'up' or
> 'down' positions, I measured the bracket and trailing arm geometry,
> applied some trigonometry, and then created the following table to
> determine the range of camber adjustment possible using the 36
> combinations. Please note that the camber angle shown in the table is
> the RELATIVE angle between bracket combinations, the actual angle you'll
> end up with depends on the camber angle you're starting with. By the
> way, 3U means positioning the bracket with the three notches up, etc.
>
> Here's the table:
>
> outer bracket - inner bracket - relative camber angle (degrees)
> 3D - 3U - 0.00
> 3D - 2U - 0.98
> 2U - 3U - 1.50
> 3D - 1U - 2.11
> 1D - 3U - 2.42
> 2U - 2D - 2.49
> 1D - 2D - 3.40
> 3D - 1D - 3.49
> 2U - 1U - 3.61
> 1U - 3U - 3.80
> 3D - 2U - 4.40
> 1D - 1U - 4.53
> 1U - 2D - 4.78
> 2D - 3U - 4.93
> 2U - 1D - 4.99
> 3U - 3U - 5.91
> 2D - 2D - 5.91
> 1U - 1U - 5.91
> 1D - 1D - 5.91
> 2U - 2U - 5.91
> 3D - 3D - 5.91
> 1D - 2U - 6.83
> 3U - 2D - 6.89
> 2D - 1U - 7.04
> 1U - 1D - 7.29
> 2U - 3D - 7.42
> 3U - 1U - 8.02
> 1U - 2U - 8.21
> 1D - 3D - 8.33
> 2D - 1D - 8.42
> 2D - 2U - 9.33
> 3U - 1D - 9.40
> 1U - 3D - 9.71
> 3U - 2U - 10.32
> 2D - 3D - 10.84
> 3U - 3D - 11.82
>
> The actual angle you achieve may differ somewhat from that listed above
> because the rubber bushings distort when you force the bushing bolts
> through to meet the new bracket holes.
>
> I found that it's best to change only one bracket per trailing arm at a
> time. If you want to leave the ride height alone, change the inner
> bracket. If you want to raise (or lower) the ride height while changing
> the camber angle, change the outer one. To use the table, figure out
> which bracket you're going to leave as is and then find the next
> combination that allows you to do this while achieving the approximate
> camber angle change desired.
>
> In my particular case, the combination I ended up with was: passenger
> side; outer = 1D inner = 2U, driver's side; outer = 3D inner = 2U.
>
> I should point out that it is very possible to change out a bracket
> while leaving the rest of the rear suspension intact. To do this, place
> the rear of your TR on jack stands, jack up the trailing arm so that you
> can support it (and take the spring pressure) with a secure support
> under the trailing arm, place your jack under the arm where it joins the
> bracket, remove the bushing bolt, remove the nuts on the bracket to
> frame bolts, raise or lower the jack so you can get the frame bolts out,
> remove the bracket and install the new one. Make sure you replace the
> alignment shims as you found them. There is some grunt work involved in
> getting the trailing arm back into the new bracket and aligning the
> bushing bolt holes (I've found that a pipe clamp is a great help in
> forcing the trailing arm back into the bracket) but the whole job can be
> accomplished in about an hour and a half.
>
> Couple of cautions: make sure the trailing arm is securely supported
> while you do this; that rear spring can cause a severe injury if it lets
> go. Secondly, go this bracket change-out route only after you've
> renewed the trailing arm bushings, springs and rubber packings as
> required.
> -----Original Message-----
> From: Cirillo Ronald A NPRI
> [mailto:CirilloRA@Code80.NPT.NUWC.NAVY.MIL]
> Sent: Monday, March 15, 1999 10:39 AM
> To: triumphs@autox.team.net
> Subject: FW: negative camber
>
>
>
> Brian.
>
> Thanks to Jim Hill we know that someone has gone
> through the trouble
> of deciphering the notches and their effect on camber. I for
> one would be
> very interested in knowing all the permutations of the notch brackets.
>
> Ron
>
> > ----------
> > From: Jim Hill[SMTP:Jim_Hill@chsra.wisc.edu]
> > Reply To: Jim Hill
> > Sent: Sunday, March 14, 1999 10:59 PM
> > To: triumphs@autox.team.net
> > Subject: RE: negative camber
> >
> >
> > Harvey Cohen wrote:
> >
> > > Does anyone dnow how excessive negative camber is
> > > corrected in the rear wheel of a TR6?
> >
> > And Scott Suhring replied:
> >
> > > More than likely the trailing arm mounting brackets are
> > > put on incorrectly. The knotches must be facing up and
> > > the brakets with two knotches go on the outside while
> > > the brackets with one knotch go on the inside.
> >
> > That's may well be the stock configuration, but there are
> actually at
> > least
> > three different brackets (1, 2 and 3-notch), all with a
> slightly different
> > offset between the mounting holes and the holes for the trailing arm
> > bushings. In addition, the brackets can be installed upside down if
> > necessary to adjust the camber (which may require different
> combinations
> > on
> > the left than on the right).
> >
> > With a total of some 36 possible combinations of brackets
> and mounting
> > configurations, it's possible to make substantial
> alterations in camber.
> > Some time ago Brian Lanoway posted measurements of all the
> permutations -
> > perhaps he'll post it here again.
> >
> > Jim Hill
> > SpyderWeb Vintage Racing
> > Madison WI
> >
>
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