Rear Shock-in-coil converstion

[Geko]

People, after having gone through several unpleasant experiences i came to the conclusion that my IRS needs serious improvement so i'm toying with the idea of a RATCO shock-in-coil conversion ( https://www.sites.google.com/site/tonyratco/shock-in-coil).

The telescopic shock conversion is a no-no as the tub is simply not made to withstand the shocks but the same could arguably be said for the chassis crossmember and TAs... So i'm interested to know the views of those who have actually made this mod if any and what's the feedback.

 

As always....

 

PS: Conrad: yes, this explains that...

Edited May 1, 2018 by Geko

[cvtrian]

Revington supply this kit -

 

https://www.revingtontr.com/product/rtr3003spk/name/damper-conversion-kit-rear-tr4a-6

 

with adjustable telescopic dampers and poly bushes, although - a limited amount of welding is required to the chassis to add strengthening gussets and top support plates to the spring turret...............(maybe a good idea with either kit?)

 

The Ratco version seems to mount the shock absorber upside down?

 

Good luck
Ian

[RogerH]

Hi Stef,

I fitted the Revington kit to my car back in about 1999.

There is extensive engineering to do to ensure it all fits correctly - it is not straight forward.

If the body does not fit correctly on the chassis - equal overhang both sides (quite common to be offset) then you will have problems.

If it does fit properly then you may need to cut some opf the body flanges off above the bridge to allow the damper top nut room.

 

I found the ride quite uncomfy and had no improvement over the standard lever arms for normal driving/touring.

 

A benefit it does have is that it is out of the way of the tyres. If you have excessive Negative camber the usual Koni strut can scuff the tyre wall.

I would suggest that good quality lever arms are the way to go for normal driving.

[stuart]

I have seen badly cracked spring bridges from the use of these kits unless the spring bridge is properly re-engineered to suit along with tying it to the rear diff bridge, see below picture Like Roger has stated properly rebuilt slightly uprated lever arms is the better option.

Stuart.

[harrytr5]

+ 1 lever arms

Regards Harry

[Dave I O W]

+2 Lever arms

 

Cheers

 

Dave.

[Will]

Note that the RATCO kit can only be used with standard length springs.

[RogerH]

Hi Folks,

having just looked at the RATCO version it is rather crude compared to the Revington set-up.

What is all that junk hanging under the TA.

 

If anybody tries any of these set-ups then please do compare the performance against a correctly working lever arm assembly.

 

Too often glowing reports are published of XYZ when what it is being compared against is completely knackered.

 

Roger

[Rem18]

I am an old TR boy soon to be, having been around them since I was 9.

I came up in the spax era.

I never bent except having adjustable on the front.

I organised a 2,500kms, 50 alpine passes in five days jaunt starting in Austria and finishing in Nice three times always finishing.

I have done another 6 classic car race rallies in my old tub.

I also live at the base of the alps and have done Europes highest passes ( one at 2760m to the top) to have my sandwiches on many occasions.

Also two kids in the back on most days as its sunny here so I often do the school run in the 5.

The levers with a dash more oil and if you like slightly stronger springs and even not is all you need.

T

[Rem18]

I also bought a front anti roll bar 25 years ago which I swiftly removed after fitting (it made turns in the mountains worse)

[TriumphV8]

The telescopic shock conversion is a no-no as the tub is simply not made to withstand the shocks but the same could arguably be said for the chassis crossmember and TAs...

 

I can not agree to that.

 

What definitely is a fact like always when "improving" TRs is that

you can do things wrong and make it worse than before.

Triumph engineers did the best they could in those days and with limited money.

That can not be beaten with cheap Chinese products and bad engineering.

On the other hand wouldnt it be a shame if 50 years of engineering

would not have given some progress in damping wheels?

 

So what was my intention to swap to telescopic dampers?

I found the damping of the levers really bad.

On the normal road the damping was too soft and when it becomes

bumpy the shocks become stiff and hammer very hard into the chassis making bad road holding.

 

So the car was never good on the street under all conditions.

As it was bad and uncomfortably I did not fill thicker oil into the levers.

This would make things better on smooth streets but worse on bumpy roads.

The reason is the size of the valves. To keep spring sizes and forces under control

the orifices to let the oil pass are really small compared to modern dampers.

From a point where the springs open the oilways fully there can not pass oil quicker.

The lever arm gets stiff putting horrible loads on all included parts.

 

This is the point to talk about strength of the mounting points.

What was never my intention is to allow this heavy bumps hammering into the chassis.

A good telescopic damper must "tame" the wheels on normal streets but open

the valves to limit the stress on heavy bumps.

 

With that I went to Bilstein, a famous company for dampers in Germany

and let them manufacture a damper according to my needs.

They took a thicker motorsport damper to allow big valves that open up

widely under heavy bumps.

 

What I got was a total transformation of the car.

If you start driving you get the nasty feeling this might not end good.

You get a perfect response from the ground you are driving over and expect

uncomfortable driving and unacceptable jumping on bumps because you

transfer the experience from the levers to the new dampers.

But that does not happen:

The faster you go the more you learn that the car is more comfortable than before.

 

I had my highway for testing on the way to my Triumph club.

In the past I reduced speed below 100Km/h to manage a heavy bump

on a quite smooth highway.

It totally lifted me in the seat that I was close to look over the windscreen frame.

This was followed by a quite unsafe feeling because also steering gets light.

Often this bump caused a nice complain from my passengers, too.

According to the above this puts really heavy stress on all components in the lever area.

 

With the telescopic dampers I now go beyond 120 Km/h there without any uncomfortable

feeling. Yes, the bump is still there and you notice the dampers working but the car

stays clear and straight and you have no more bad influence on the steering and the

whole car goes straight on the highway without complains, just like a modern car.

 

Similar is with the anti roll bars.

To be honest Triumph chassis is not the best.

In motorsport there is the rule if you have bad chassis

reduce wheel travel. This was done with the front bar.

The price was that steering gets a little bit heavier and understeer becomes more.

It would be fully wrong to make things worse by fitting a stiffer bar!

Triumph engineers simply did not have the money to add a rear bar.

 

So the first remedy is to fit the rear bar and up to individual taste after that a

stiffer front bar might be used.

Both bars must play together and the driver must know that cars behaviour can be swapped totally with bars.

So it is a good idea for street use to add a light rear bar and do nothing at the front.

 

I use the thickest bar at the front and a heavier adustable bar at the rear

and both without rubber mountings but connections like uniball that allow absolutely no play.

Definitely not everybodys taste but I like that feeling a bit similar to a gocart.....