[TR] 4A upper A arms

[DAVE HOGYE]

TR4s after CT6344 VIN, used 3 degree trunnions and the upper arms that you have.  This tilts the upright reward for 3 degrees of caster.  So the long arm or the one with more of an arc is the front arm.  The shorter/straighter arm is the rear arm.  This must be stated in a repair manual somewhere.  But, if you mock up the suspension with the 3 degree trunnion, upright, ball joint and the spring pan in place, the arm placement should be obvious, because the upright with the upper ball joint attached will not slip in place between the arms.  The suspension should be set up without the coil spring or shock to make sure there is smooth, no binding operation while moving up and down and turning.  
TR4s built before 6344 used the TR3 front suspension.  TR4As and TR6s used the same upper arms, but different design lower arms, trunnions and upright.  
You can use TR4A-TR6 brake calipers and rotors (slightly smaller diameter) if you change the caliper bracket on the earlier uprights.  The calipers are much lighter weight and much less expensive and more readily available, and more choices of brake pads. 
 
Dave H.

> On 05/17/2026 6:06 PM PDT Cliff Hansen <cliff_hansen at outlook.com> wrote:
>  
>  
> The longer arms are the rears.
>  
> I think the letters are on the shorter (front) arms.
>  
> The letter faces up. L up on the left side, R up on the right side.
>  
> Cliff
>  
>  
> 
> ---------------------------------------------
> From: Triumphs <triumphs-bounces at autox.team.net> on behalf of dave northrup <dave at ranteer.com>
> Sent: Sunday, May 17, 2026 4:27 PM
> To: list Triumph <triumphs at autox.team.net>
> Subject: [TR] 4A upper A arms
>  
> I am converting my 3A to 4A front suspension using 4A upper A arms.  I bought them from a breaker, and as i clean them up i notice that 2 of the 4 arms have L on one side and R on the other. Yes, left and right, but beyond that I don't understand.   And the other 2 A arms have no marking
>  
> How do i install these A arms?
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