TR3A Front and rear springs

[Kiwifrog]

I am rebuilding a TR3A and for various reasons I have a load of TR4 spares left from a job lot that I bought off Tony Seach a few years ago when I was restoring a TR4. In my spares I have a couple of brand new TR4 front Springs and a pair of New Deep Dish TR4 rear springs.

 

As the front suspension of the 3A and the early TR4 are the same can I use the TR4 Front springs as long as I use the Aliminium spacer 107682 ? This is the recommendation from Moss if using the uprated front springs tt4006 which is common to the TR2-4A? Apart from the spring free lengths being different would there be any other issues for handling, geometry etc. At this point I am leaving the 0° uprights unless I can find a cheap set of 3°top wishbone arms for both sides, I already have the 3° uprights and balljoints.

 

Second Question

 

I have a set of Brand New deep dish TR4 Rear springs, Could I fit these to the 3A again with the appropriate spacers 137634,5 ? What would the concequences on handling be ??

 

Cheers

 

Alan

[NickKerfoot]

Hi Allan!

I can't see any problem in principal with what you want to do at the front. However, when the later TR4 got its deep dish rear springs, the position of the front attachment pin was moved forward (by an inch IIRC). So fitting these would I think push your axel rearwards by this amount... not ideal I guess!

 

Hope this helps...

 

Regards

Nick

[vivdownunder]

Hi Alan,

 

Here's a bit of spring info that might be helpful -

 

 

FRONT

 

The early TR4 coil spring that will fit your 3A has 6.75 coils and a free length of 9.75".

 

TT4006 coil springs used with the spacer, have an increased spring rate from standard 310 in. lbs to competition 390 in. lbs. They also raise the front road clearance by about .25".

 

Late TR4's used a front spring just slightly over 11" free length, which was used without the top alloy spacer. I don't know if this can be used without a spacer in a 3A.

 

REAR

 

The TR4 rear leaf spring that can be used on TR3A's has an eye to eye measurement of 40.5".

 

Later TR4 deep dish springs used with a lowering block had an eye to eye of 39.5", and as Nick says, can't be used on TR3A's because of a chassis mount change.

 

It's very difficult to comment on handling outcomes as it depends not only on the springs, but on tyre selection, wheel alignment, shocker type, use of anti roll bars and so on.

 

Regards,

 

Viv.

[Kiwifrog]

Hi Alan,

 

Here's a bit of spring info that might be helpful -

 

 

FRONT

 

The early TR4 coil spring that will fit your 3A has 6.75 coils and a free length of 9.75".

 

 

Regards,

 

Viv.

 

 

 

Hi Viv

 

Thanks for the info. I have a pair of springs which match the 6.75 coils with a free length of 24.75cm (9.75") they have blue indicator paint markings would you know what rating this signifies ??

 

Thanks for your help

 

Cheers Alan

[vivdownunder]

Alan, TT4006 higher rate 390 in.lbs road front springs were colour coded blue. (Standard coil springs were grey)

 

I think these were developed to give better ground clearance for rally work, as all other TT coil springs lowered the front.

 

Regards,

 

Viv.

[Graham Robson]

Why not look in the appropriate Parts Manuals (sorry, I don't have these myself). Are the Part Numbers the same .... or different ?

 

GRAHAM ROBSON

[Kiwifrog]

Viv

 

Thanks very much for your help I will be using the springs I have for the Front and will get a new set of correct rear springs and leave the 4 deep dish springs for a future project.

 

Why not look in the appropriate Parts Manuals (sorry, I don't have these myself). Are the Part Numbers the same .... or different ?

 

GRAHAM ROBSON

 

Hi Graham

Thanks for your input I have parts books for the 4 and 4A but not as yet for the 3A. I tend to use the excellent moss catalogues as parts guides. As far as the part numbers go the part numbers are different for the Tr3 and TR4 but the competition front springs have the same part number so I was wondering about the differences/interchangability between them also the Moss catalogue does not note the colour coding on the springs. I have to admit that I wanted to check on the Technicalities CD first but I can not find it since I tidied up my study .

 

Thanks again everone for their help when you live in the middle of nowhere in Rural France the Forum becomes your "local group"

 

Cheers

 

Alan

[ianc]

In my opinion (and of others who have driven TR4s with both flat and dished springs), the dished springs were a ghastly mistake. The handling in corners is not as predictable, and that is more important than the claimed improvement in ride on flat surfaces - try and find a flat surface on any British road these days!

Other "improvements" dreamed-up by Triumph included removal of the petrol isolator tap (after the TR3A) and removal of the diff drain plug (IRS cars, I think, or was it just TR5 onwards?).

Ian Cornish