[TR] TR4A IRS Suspension Question

[dave]

+1 on the Goodparts adjustable camber brackets

-----Original Message-----
From: Triumphs <triumphs-bounces at autox.team.net> On Behalf Of Jerry Van
Vlack
Sent: Wednesday, March 24, 2021 10:33 AM
To: Jim Henningsen <trguy75 at gmail.com>; triumphs at autox.team.net
Subject: Re: [TR] TR4A IRS Suspension Question

Jim, I did the same modification (or nearly the same) on my 4A a few years
ago. 1" lower all around but HD lever shocks and Goodparts rear trailing arm
adjustable frame brackets.

Lowering the 1' will cause issues with your alignment shop as it relates to
getting some negative camber for the front and perhaps the rear too since
you did not install the adjustable brackets in the rear which are adjustable
for camber.

The front is a bit more difficult in that you'll need the ability to adjust
the upper A arms since (at least in my case) removing all of the shims on
the lower A arms still did not pull the bottom in enough to get the negative
camber I wanted. I was after 1/2 to 1 degree of negative camber. You don't
want positive camber. There are consumer available parts to make the upper
arms adjustable from a few of the British suppliers in England. I suspect
you'll need to source those. Not sure why the big 3 here in the states don't
offer something for the uppers.

As to ride height differences in the front it may take some driving to
settle the front. The rear may or may not be affected by the tube shocks if
they bottom out at rest (very unlikely and not wanted) The Goodparts
brackets can adjust ride height while maintaining a good camber setting so
I'd recommend installing those as well as some form of front upper A arm
adjusters before spending cash with an alignment shop.

Others may have differing opinions but this was my experience and solution
when lowering the 1" all around.

JVV

-----Original Message-----
From: Jim Henningsen
Sent: Tuesday, March 23, 2021 8:06 PM
To: triumphs at autox.team.net
Subject: [TR] TR4A IRS Suspension Question

Ok, just finished redoing front and rear suspension on my 67 4A IRS.
Complete disassembly, clean, repaint, new urethane bushings, tie rod ends,
trunnions, etc.  New comp springs ( 1 inch lower) all corners, new stock
tubes shocks up front and new KYB gas shocks on the tube shock conversion
brackets for the IRS.  Reinstalled all alignment shims as installed as the
car drove pretty straight.  Urethane packings on springs.

After completing, I noticed that all four corners have a slightly different
ride height when measured from garage floor to bottom on fender lip at
center of each wheel.  Left front: 26 3/4 inches, Right front: 26 1/4, Left
rear: 27 3/8, right rear: 27 7/8.  I think the higher rear height is coming
from the tube shock conversion as it was lower with the levers.    So about
a half inch off each side.   I don't recall having this issue when I redid
my TR6, but that was a while ago.   Rears also have stock trailing arm
brackets (one and two notch brackets on each side - believe these are
original from new given history of the car).

Looking for help on next steps before bringing it in for an alignment.  Will
alignment correct height difference or do I need to add 1/2 inch spacers on
lower sides.  I am going to put uprated valved levers back on rear to
eliminate the extra height in rear.

Any help appreciated.

Thanks
Jim Henningsen
Ocala FL
Too many TRs to maintain!
61 3A
62 4
67 4A
75 6
81 8

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