TR4/4A Info on TR4A road springs required please.

[malbaby]

I am not sure if my springs are standard.... Compression rate is close to 300 lb/in.....Fronts are 245mm free height.....Rears are 283mm....Ride is too firm for me.
What should the standard free height and compression rate be for the front and the rear springs.
Are there any suppliers that offer a softer spring, say 220-250lb, with minor decrease in ride height.

 

[Foura]

I am not sure if my springs are standard.... Compression rate is close to 300 lb/in.....Fronts are 245mm free height.....Rears are 283mm....Ride is too firm for me.
What should the standard free height and compression rate be for the front and the rear springs.
Are there any suppliers that offer a softer spring, say 220-250lb, with minor decrease in ride height.

I would not be going to softer springs. The general consensus is that the original TR4A springs were too soft especially at the back. The TR5 and TR6 both had heavier rear springs in what is basically the same car. I am running TT4102 springs at the front which have a 420 lb/in rating, and Goodparts 470 lb/in in the rear. I had to use a spacer on the right back spring to get the car level. We drove the car to Noosa and back in 2013 and across the Nullarbor last year. No complaints from my wife about the ride. Softer springs at the front would lead to increased pitch under braking and unload the rear, possibly leading to lockup.

I would be checking the shocks especially at the back before you replace the springs. I am running Konis at the front and the rear has telescopic Monroes that were on the car when I bought it. I assume that you are replacing all the suspension bushes in the rebuild. This link gives a bit of info on springs and there have been numerous discussions on BCF if you do a search. https://www.tr-register.co.uk/forums/index.php?showtopic=29428

Good luck

 

[malbaby]

Thanks fourA.
Appears that I should get the compression rate and compressed length checked on all 4 of my springs.

 

[RJS]

My car is running stock springs. I have done a lot of research and confirmed the following:

Front Spring: Rate = 312 lbs/in. Fitted height = 6.75". Stock came with short or long springs (9 1/2" unfitted or 10 1/4" unfitted). Aluminum spacer/packing piece came thick or thin accordingly.
Rear Spring: Rate = 280 lbs/in. [FONT=&quot][/FONT]Fitted height = 9.00" Don't know unfitted height

As noted above, the TR6 went to a 350 lbs/in rear spring.

Bob

 

[malbaby]

Thanks RJS.
Are you running the 9 1/2" front, and how do you consider your ride quality.

 

[RJS]

The front has a 1" packing piece installed so I think that means it is the 9 1/2" spring but, I don't know for sure.

Ride quality is good for my needs - gentle to slightly spirited drives on weekends. Our roads here are two lane back country roads with lots of curves and 50mph speed limit.
The rear does squat pretty well though when pulling away hard from a stop.

I have urethane bushings but original springs and shocks. No idea how many miles on shocks but odometer reads 38, 000 miles. On the project list is new shocks for front (still deciding between stock or performance) but leave original springs. Rear will almost certainly be rebuilt performance lever shocks followed by TR6 rear springs if I think the rear needs further help.

Bob

 

[nicodiaz]

Foura,
My Tr 4a is also unleveled since I rebuilt it, although I never noticed it before.
Where do spacers fit exactly and are they home made.
Thanks

 

[Simon TR4a]

I would not be going to softer springs. The general consensus is that the original TR4A springs were too soft especially at the back. The TR5 and TR6 both had heavier rear springs in what is basically the same car. I am running TT4102 springs at the front which have a 420 lb/in rating, and Goodparts 470 lb/in in the rear. I had to use a spacer on the right back spring to get the car level. We drove the car to Noosa and back in 2013 and across the Nullarbor last year. No complaints from my wife about the ride. Softer springs at the front would lead to increased pitch under braking and unload the rear, possibly leading to lockup.

I would be checking the shocks especially at the back before you replace the springs. I am running Konis at the front and the rear has telescopic Monroes that were on the car when I bought it. I assume that you are replacing all the suspension bushes in the rebuild. This link gives a bit of info on springs and there have been numerous discussions on BCF if you do a search. https://www.tr-register.co.uk/forums/index.php?showtopic=29428

Good luck

My setup is similar to this, I also use the Triumphtune springs, I think the same part number, and I use Spax adjustable gas shocks front and back. The TT springs sit about a half inch lower than stock.
I was using a TR6 front sway bar but found it caused too much understeer so took it off.

The spacers I have seen have all been aluminum alloy castings.

 

[Foura]

Foura,
My Tr 4a is also unleveled since I rebuilt it, although I never noticed it before.
Where do spacers fit exactly and are they home made.
Thanks

The spacers are machined aluminium from Richard Good https://www.goodparts.com/shop/index.php?categoryID=15
My car was low at the right rear and high at the left front. I used one of Richard's 1/2" spacers on the right rear. It goes on the bottom of the spring and the insulator, which also came from Goodparts, goes between the spacer and the suspension arm. This levelled the car up nicely all round. I was able to remove and replace the spring by disconnecting the shock, but I have telescopics at the back. Depending on how long your springs are, you may need to disconnect the driveshaft from the diff to drop the trailing arm.

Seems like a lot of TRs need levelling. Mine had a good chassis, new urethane bushes and all new springs and still needed levelling. Anyone have any theories?

 

[nicodiaz]

Foura.

Thanks for the excellent and detailed information.

Robert
'66 Tr4a Irs
Oceanside, Ca.