Hi Tom,
Why a TR4A suspension conversion? Why not TR4 and install Revington TR's
special top fulcrums that allow camber to be adjusted where you want it?
Using this sort of TR4 (post-CT6931) setup would be a much easier and
more direct conversion with less cost, far less welding, same or better
results,
and a generally more durable setup than TR4A. With respect to durability, I
suspect when you say TR4A suspension, you mean a modified version of that with
all the strengthening gussets, extra mounting bolts, more like what was done on
TR6 from '72 on. That is closer to TR4 in terms of durability. But, it's
involves a lot of high quality welding.
With any of the setups you should get 3 degrees of caster (adjustable
with the Revington TR fulcrum, not with stock TR4 or 4A).
Camber on TR2/3/4 originally was set to +2 to +3 degrees, more
appropriate for bias ply tires. It can be reset anywhere from 0 to -1 degrees,
for
improved handling and wear with modern radial tires.
These camber changes can make TR3 steering a bit twitchy at speed, but
usually not so much that you can't get used to it. Camber changes can make
TR4/4A rack & pinion steering a little heavy at slow speeds.
For regular road use, 0 to -3/4 degrees of camber is probably about
right. Lesser negative camber would minimize twitchiness or low-speed heaviness
(which depends upon the steering system being used). For more aggressive
driving
and competition, -1 to -1.5 degrees might be appropriate.
If you'd like to see the RevingtonTR fulcrum setup on a TR4, I've got some
photos posted at http://www.triumphowners.com/640
Note: very early TR4 front suspension (to CT6390) was basically the same as
TR3A. Of course, R&P steering was used on the TR4.
Cheers!
Alan Myers
San Jose, Calif.
'62 TR4 CT17602L
Date: Fri, 26 Aug 2005 03:51:16 -0700
From: "T. S. White" <tswrace@pacbell.net>
Subject: Front suspension?
I plan to do the TR4A sus pension conversion to my TR3A this winter. I
understand that will add some positive caster to my suspension.
Has anyone ever addressed the subject of camber for the TR3A sus pension?
- --
Best Regards,
Tom
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