Suspension Aligment on TR4A

[Reinaldo]

Hello,

After a frame off restoration on my TR4A (without any possibility on changing chassis geometry) , I tried to align the car but couldn't reach the specs.

The best I got was:

FRONT:

caster: left 1 deg 11' right 58'

camber: left 1 deg 38' right 1 deg 02'

toe-in: left minus 2.1 right minus 1.9

 

REAR

camber: left 2 deg 05' right 1 deg 31'

toe-in: left 0.3 right minus 0.4

 

For the rear I could buy the adjustable trailing arm.

Any help?

Thanks in advance,

 

Reinaldo

[tthomson]

Hello,

After a frame off restoration on my TR4A (without any possibility on changing chassis geometry) , I tried to align the car but couldn't reach the specs.

The best I got was:

FRONT:

caster: left 1 deg 11' right 58'

camber: left 1 deg 38' right 1 deg 02'

toe-in: left minus 2.1 right minus 1.9

 

REAR

camber: left 2 deg 05' right 1 deg 31'

toe-in: left 0.3 right minus 0.4

 

For the rear I could buy the adjustable trailing arm.

Any help?

Thanks in advance,

 

Reinaldo

 

 

 

Hi Reinaldo,

 

The trailing arm brackets are location specific, they have different numbers of notches in them. If you recently removed and refitted these, you may have them in the wrong places. I don't recall exactly what notch arrangement is correct, but I'm sure someone will let you know.

 

If the brackets are in the wrong places I doubt you will never be able to adjust them into spec.

 

TT

[88V8]

REAR

camber: left 2 deg 05' right 1 deg 31'

toe-in: left 0.3 right minus 0.4

 

For the rear I could buy the adjustable trailing arm.

Welcome.

 

For the rear, it should be possible to set the toe-with the shims? Adding/removing a shim on the inner mount makes a small difference, adding/removing on the outer mount makes a bigger difference.

 

As regards camber and ride height - that's an awful lot of positive camber you have there - the adjustable brackets (I have them on my TR6) are excellent, and save a lot of messing about with the notch brackets. It may be cheaper for you to get them direct from Richard Good.

 

At the front, I cannot help you as I have only adjusted the toe-in.

 

What is the ride height at each corner, measured to the underside of the wheel arch?

And what size tyres do you have?

 

Ivor

[littlejim]

Reinaldo,

 

Puzzled by a couple of items:

caster- I thought it was fixed at 3deg by the trunnions. Is this the measurements from a computer alignment machine? (I wouldn't know how to measure it.) Maybe someone with expertise can comment on whether you have the right trunnions.

 

Toe in. Why is there a problem in getting it to near 0deg. Are the adjustment nuts at the end of the threaded portion?

The rear toe in would keep me happy - didn't realise you could measure it that finely.

 

Camber. Was it done with weight in the car? Have you got the right springs? (mine had the wrong rear springs, which altered things a bit.) Shims got my front camber to 0deg which is what I was after. The correct length springs and a bit of shimming got me from positive to 0deg camber at the back, (used the original brackets). I don't know whether it will necessarily work for you but no harm in trying.

(The car behaved much better in corners going from 0 to negative camber. When it was going from positive to negative, beforehand , cornering was a bit exciting as it 'snapped' from understeer to overersteer and vice versa.)

 

I didn't do my alignment on a machine. I found all the original shims were about 1.2mm thick and therefore suspect that adjustments such as '0deg 02minutes' were never envisaged by Mr Triumph when he made the thing. (you can of course make your own shims out of thinner steel sheet if you want to.)

 

Maybe the forum members who race the 4A can tell us all the details of getting it right.

Edited February 11, 2009 by littlejim

[Reinaldo]

Tony,

 

Thank you for your reply.

You raise a very good point. In fact I took into account the notches but I just kept the way it was before and that might be wrong.

Outer are 2 notches and inner are one notch. Can someone confirm that? See picture attached (taken by the time of dismantling)

Regards,

 

Reinaldo

 

Hi Reinaldo,

 

The trailing arm brackets are location specific, they have different numbers of notches in them. If you recently removed and refitted these, you may have them in the wrong places. I don't recall exactly what notch arrangement is correct, but I'm sure someone will let you know.

 

If the brackets are in the wrong places I doubt you will never be able to adjust them into spec.

 

TT

[Reinaldo]

Ivor,

 

Thank you for your reply.

Yes, I guess it should be possible to set the toe with the shims. I will try.

I will also measure the ride height at each corner and get back to you.

Thanks for the tip on where buying the cheaper adjustable brackets. I will check if they ship international (I live in Brazil).

The tyres are Firestone 165 R15.

 

Regards,

 

Reinaldo

 

Welcome.

 

For the rear, it should be possible to set the toe-with the shims? Adding/removing a shim on the inner mount makes a small difference, adding/removing on the outer mount makes a bigger difference.

 

As regards camber and ride height - that's an awful lot of positive camber you have there - the adjustable brackets (I have them on my TR6) are excellent, and save a lot of messing about with the notch brackets. It may be cheaper for you to get them direct from Richard Good.

 

At the front, I cannot help you as I have only adjusted the toe-in.

 

What is the ride height at each corner, measured to the underside of the wheel arch?

And what size tyres do you have?

 

Ivor

[Reinaldo]

Jim,

 

I am fortunate to get such a good technical tips from you guys.

But I might not be knowledgeable enough to cover your points. Let me try:

 

CASTER - As per the attached drawing I did replace the bushes on the trunnion. As far I remember was only that. Yes the figures I gave came from a computer aligment machine. So somehow I am not getting the expected 3 degrees by the trunnions. I will investigate further.

 

TOE IN - I guess I should be happy with the rear as you said. The adjustment nuts at the end of the threaded portion you mention is at the trunnion?

 

CAMBER: No weight in the car (I mean no passenger and spare wheel not in place). I might have the wrong springs, possibly good for the TR6. One of the trailing arms also came from a TR6 (change done like 9 years ago) but in this case I am assuming it is interchangeable (I mean is exactly the same one either for TR4A or TR6)

 

Thanks,

 

Reinaldo

 

Reinaldo,

 

Puzzled by a couple of items:

caster- I thought it was fixed at 3deg by the trunnions. Is this the measurements from a computer alignment machine? (I wouldn't know how to measure it.) Maybe someone with expertise can comment on whether you have the right trunnions.

 

Toe in. Why is there a problem in getting it to near 0deg. Are the adjustment nuts at the end of the threaded portion?

The rear toe in would keep me happy - didn't realise you could measure it that finely.

 

Camber. Was it done with weight in the car? Have you got the right springs? (mine had the wrong rear springs, which altered things a bit.) Shims got my front camber to 0deg which is what I was after. The correct length springs and a bit of shimming got me from positive to 0deg camber at the back, (used the original brackets). I don't know whether it will necessarily work for you but no harm in trying.

(The car behaved much better in corners going from 0 to negative camber. When it was going from positive to negative, beforehand , cornering was a bit exciting as it 'snapped' from understeer to overersteer and vice versa.)

 

I didn't do my alignment on a machine. I found all the original shims were about 1.2mm thick and therefore suspect that adjustments such as '0deg 02minutes' were never envisaged by Mr Triumph when he made the thing. (you can of course make your own shims out of thinner steel sheet if you want to.)

 

Maybe the forum members who race the 4A can tell us all the details of getting it right.

[Dale Moore]

Reinaldo

Inner 1 notch, outer 2 notches. So it looks like yours are correct.

Regards

Dale

[littlejim]

Reinaldo,

 

for toe in at the front, the nuts are on the 'tie rods'. Have you got a manual to look at?

[Reinaldo]

Dale,

 

Good to have that confirmed! Thank you!

 

Reinaldo

 

 

Reinaldo

Inner 1 notch, outer 2 notches. So it looks like yours are correct.

Regards

Dale

[Reinaldo]

Jim,

Good, now is clear what you meant.

Yes I do have the manual, that one with the light blue cover. I will investigate that further.

Thanks again

Reinaldo

 

Reinaldo,

 

for toe in at the front, the nuts are on the 'tie rods'. Have you got a manual to look at?

[Reinaldo]

Ivor,

 

I did the height measurement today on the wheel arch:

Front Left 27 and 1/2 inches

Front Right 27 and1/2 inches

Rear left: 28 and 1/4 inches

Rear right: 28 and 3/4 inches

 

Regarding the 1/2 inches diference at the rear I need to investigate further on wether it comes from chassis or body to chassis pads.

Now for sure I am curios to know on how these figures compare with others cars.

 

Thanks,

 

Reinaldo

=========================================================

 

 

Ivor,

 

Thank you for your reply.

Yes, I guess it should be possible to set the toe with the shims. I will try.

I will also measure the ride height at each corner and get back to you.

Thanks for the tip on where buying the cheaper adjustable brackets. I will check if they ship international (I live in Brazil).

The tyres are Firestone 165 R15.

 

Regards,

 

Reinaldo

[88V8]

Yes, I guess it should be possible to set the toe with the shims. I will try.

I will also measure the ride height at each corner and get back to you.

 

The tyres are Firestone 165 R15.

Yes. The toe-in needs to be in, and not one in and one out as your first post indicates?

I asked about the tyres only because there is a linkage to the height.

 

CAMBER: No weight in the car (I mean no passenger and spare wheel not in place). I might have the wrong springs, possibly good for the TR6. One of the trailing arms also came from a TR6 (change done like 9 years ago) but in this case I am assuming it is interchangeable (I mean is exactly the same one either for TR4A or TR6)

The camber should be measured with the car complete, and 150lb (70kg) in each seat, and the spare wheel and half a tank of fuel.

 

The notch brackets - the brackets you have were correct when the car was new, but due to events in the last 40 years of the car's life - accident repairs or rust - they may not be correct now.

It is simple to buy the adjustables, then it is not important to fight with the notch brackets, but if you are interested to read more about the camber and how to adjust it, here is an excellent article. http://www.buckeyetriumphs.org/technical/S...AdjRS/AdjRS.htm

 

There are other articles on the same site that you may find useful.

 

The trailing arm.... from a TR6... is perhaps OK or perhaps not.

There are two reasons. First, one of the trailing arms may be bent, even though it is not apparent.

Second, during production of the TR6 there was a change in the trailing arm geometry.

So for either reason, your two arms may not be the same.

Keep this in mind in case you find that you cannot get the same rear camber each side.

 

To check, you would need to remove them from the car (again) and set them up like this picture so that the mountings are parallel. The mountings are fastened to metal tie-bars, you see them, the grey angle-iron.

Then with a ruler across the hub mounting faces you see that the angle is the same. Or is not.

If you have a bent arm, or two arms that do not have the same geometry, then even with the adjustable brackets you may not be able to correct the camber, or you may find that when the camber is correct, one corner of the car will be too high or too low.

 

I had this problem. I found that the notch brackets were no good because of old chassis repairs, and one of the arms was bent. But with another arm of the same age (same age = same geometry) and the notch brackets, now it is OK.

 

Regarding the height, thankyou for the measurements, I will leave someone else to comment as I only know the measurements for the TR6.

 

Ivor

 

Edited February 12, 2009 by 88V8

[Reinaldo]

Ivor,

 

Thanks again for your inputs. I need to investigate further the camber loading the car in the way I have indicated.

I am reading the article you refer in your message.

Excelent warn on the chage of geometry of trailing arms during TR6 production.

I am doing some additional measurements on chassis and rear suspension to better identify the problem (trailing arms or deformation on the chassis) and what I do next.

I intend to start a new separate post regarding caster.

 

Thanks,

 

Reinaldo

 

 

 

Yes. The toe-in needs to be in, and not one in and one out as your first post indicates?

I asked about the tyres only because there is a linkage to the height.

 

 

 

The camber should be measured with the car complete, and 150lb (70kg) in each seat, and the spare wheel and half a tank of fuel.

 

The notch brackets - the brackets you have were correct when the car was new, but due to events in the last 40 years of the car's life - accident repairs or rust - they may not be correct now.

It is simple to buy the adjustables, then it is not important to fight with the notch brackets, but if you are interested to read more about the camber and how to adjust it, here is an excellent article. http://www.buckeyetriumphs.org/technical/S...AdjRS/AdjRS.htm

 

There are other articles on the same site that you may find useful.

 

The trailing arm.... from a TR6... is perhaps OK or perhaps not.

There are two reasons. First, one of the trailing arms may be bent, even though it is not apparent.

Second, during production of the TR6 there was a change in the trailing arm geometry.

So for either reason, your two arms may not be the same.

Keep this in mind in case you find that you cannot get the same rear camber each side.

 

To check, you would need to remove them from the car (again) and set them up like this picture so that the mountings are parallel. The mountings are fastened to metal tie-bars, you see them, the grey angle-iron.

Then with a ruler across the hub mounting faces you see that the angle is the same. Or is not.

If you have a bent arm, or two arms that do not have the same geometry, then even with the adjustable brackets you may not be able to correct the camber, or you may find that when the camber is correct, one corner of the car will be too high or too low.

 

I had this problem. I found that the notch brackets were no good because of old chassis repairs, and one of the arms was bent. But with another arm of the same age (same age = same geometry) and the notch brackets, now it is OK.

 

Regarding the height, thankyou for the measurements, I will leave someone else to comment as I only know the measurements for the TR6.

 

Ivor