Front anti roll bar diameters

Does anyone have available the irrefutable diameters of the front anti roll bars please?
I gather that the softer comfort springs demanded an increase in diameter for the front anti roll bar but from what to what?
What I need to find out is what has been fitted to my car. It could be standard for year (2002/3)
If I measure the OD including the protective coating (probably a PU coating) I get 20mm.  

I believe the really thick one was 25mm. But what was the diameter of the bar fitted to the car as it left the factory with standard springs?
Can anyone help with that please?

Come on chaps someone must know the answer to this please!
 

I for one don't know.......have you checked the specifications section of the workshop manual? Maybe the enlightenment you seek is buried in there or check Rimmers catalog they may have the info listed with part numbers.

Yes, I have checked.
The potential confusion is that at least one respected source suggests that there was an increase in diameter for the softer suspension, and that at the end (85th) that the bar was thicker still. That same source suggests that there was a 2mm difference between one bar and the next.
It is fairly certain that the thickest was 25mm.
One dimension (recorded in the manual) is noted to be 20mm, but that doesn’t say whether that is the thinner or the thicker two.

I need to renew the struts or at least the springs to resolve the ride height that is way too low.
It is my belief that the PO fitted the comfort pack springs (or some with a similar rate but not necessarily the same free length or possibly same rate but shorter).
Clearly the PO changed the springs - that is obvious- what is not known is what was done to the anti roll bar.
A rough check over the PU coating suggests that diameter is 20mm. That suggests the actual bar might be marginally thinner than 20mm or the bar is a nominal 20mm.
Common sense suggests that if the original springs are re fitted then the first (smaller diameter) bar needs to be fitted otherwise it will be too stiff. Hence the need for clarity.

I think you are correct with your 25mm, obviously this is going to increase the torsional stiffness & tame any wayward roll.
I looked into changing my standard bar to the uprated offering but couldn’t find one which was wallet compatible.
I had a collection of rose jointed rod end, enough to assemble a set of drop links, these gave me a range of adjustments for the standard bar, upwards. I adjusted them buy the same degree, enough to make it obvious there was more tension in the system & subsequently forgot about them.
As expected there was a little less body roll (or was it psychosomatic),
It was quite a long time ago.
I look in on them when I’m in their area & they are still well & quite shiny.
M

They can be as clean as they like. I’m still eager to know what the diameter is for the two thinner ones.
Ideally someone with known provenance for a 2002/2003 car to measure the diameter of their ARB.
Any chance please?

I have a 2002 Tf 135...std original car. I will measure it tomorrow. 
It looks like new so no pitting and should be accurate using callipers.

On this subject, Gaydon are currently transferring all the paper mg rover drawings to digital format.
Of course, this could take a very long time, but contacting Gaydon may be in order regardless.

Hi,
I have a 2002 TF with the original front ARB which measures 20.39 diameter over tye PU coating, so I would take this as 20mm.

Ive just fitted a soft ride kit and the front springs have a yellow paint flash which appears to be an increase on the standard blue spring rate. Yellow =420lbs Blue = 375 lbs.

Rear springs incidentially are Red 600lbs as original, dampers are gas pressurised Monroe.

Welcome to the T Bar. And with a very useful first post!🫡

I would second that, thank you.
A note on my shiny drop links; unless I’m having a “rough & tumble” with Cobber, my intentions on here is to provide inform that may help overcome a members problem, possibly by using an alternative route.
I assumed you were looking for an outcome & adjustable drop links, to increase tension in the network, might have overcome your difficulty.
I, like you, wished to fit an uprated anti-roll bar, which I couldn’t find at a price I was prepared to pay, the rose jointed link idea was my way forward.
Once all the projected alterations on my car are complete, I will address the suspension setup, maybe I’ll have to find an uprated bar to achieve a satisfactory results.
M

Laurence J wrote:

Hi,
I have a 2002 TF with the original front ARB which measures 20.39 diameter over tye PU coating, so I would take this as 20mm.

Ive just fitted a soft ride kit and the front springs have a yellow paint flash which appears to be an increase on the standard blue spring rate. Yellow =420lbs Blue = 375 lbs.

Rear springs incidentially are Red 600lbs as original, dampers are gas pressurised Monroe.

This is an interesting post for me. My stock TF has a jiggly ride that I can't live with. I haven't totally convinced myself which is the culprit...the dampers or the springs. The fact that they uprated the front springs in the soft ride kit is interesting.
You can have a firm sporty ride without the jingle if it's done right.
My MX5 has Bilsteins all round with matched lowering springs, is a firmer ride but is far more comfortable.
The ride is the only thing I dislike with the car!
It's on a to do list.