Apologies as I know this has just been covered in another thread but I just can’t find it. My 89 convertible doesn’t have a rear anti roll bar. Is this correct? From the above mentioned thread I think it maybe but want to be sure . Sorry again for repeating this and thank you for your help.

 

The rear bars were an on again/off again affair with Jaguar.

Just look under the car and, if you have one, you'll see it.

https://www.jaguarclassicparts.com/u...tre-sportspack

All the pre-HE XJSs had the rear bar. But then Jaguar stopped using it for a few years. Then (as I recall) it reappeared on the 6-cylinder cars circa 1985. The reappeared on on some V12 cars with "Sportspack" suspension....but I don't think all Sportspack cars had it.

I dunno about facelift cars. I think only the 4.0 coupes had the rear car....but I can't swear to it.

Cheers
DD

 

My 94 V12 has a rear bar.

 

brinny
Doug is dead on (as to be expected!). If the rear ARB is not there, Jaguar did not fit it. FWIW, I have driven XJSs wiith and without, and IMO, provided the ride height is right, they ride, corner and handle better without the rear ARB.

 

I agree Greg. My XJRS does not have a rear bar but does have the relevant spring rates, bilstein dampers and tweeked steering rack and can not be faulted in how it handles. One would have to assume Jaguar and Walkinshaw did not omit the rear bar on their flagships for no reason.

 

Agree from down here also.

My 1985 XJS Coupe V12 had the bar, I removed it, and fitted it to Wifies S2 V12 Sedan, oh boy, that sorted that little beast very nicely thank you.

I noted the same as Greg and others, the XJS was better without it and the Sedan was better WITH it.

Prior to that, the S2 Dainler 4.2 I6, HAD the bar, and I assumed factory, and since this was pre computer and Forum days, had very little reference to indicate otherwise, but I did sort it later in the ownership, and it had been fitted from a 1977 XJS by the previous owner.

 

My XJS didn't have a rear bar so I dded one....and IMO the feel of the car thru corners was remarkably improved. Flatter stance, steering felt tighter, less under steer.

Adding one to my Series III gave the same results.

I've added a rear bar to every car I've owned that didn't already have one. I really can't think of a down-side....except perhaps the decreased under steer might catch some drivers off-guard if driving very aggressively.



Cheers
DD

 

How so?

I'm asking, not arguing

Cheers
DD

 

And one wonders if Jaguar eventually regretted the decision....as the rear bars were standard fit for several years, then disappeared, then reappeared in later years.

Everything is a compromise. It's safe to assume that various things are taken into consideration when making such a change....including costs. Trying to understand *why* Jaguar did certain things has left me scratching my head a few times over the last 20 years.

Under certain conditions the V12 XJS is already a bit tail-happy without a rear bar, and more so with the rear bar, so my guess is the rear bar was deleted to make the car more user-friendly. Jaguar thus saved a few dollars and might've rationalized, probably correctly, that the 'Luxury GT' buyer would never miss it or ask for it...or even think about it.

Cheers
DD

 

The question "Which cars came with a rear bar?" has come up quite a few times over the years. It might be interesting to poll owners. My guess is a pattern would be revealed....if the response rate was high enough and broad enough.

Cheers
DD

 

In my experience, a rear bar or stiffer rear bar combined with a performance damper increases overall handling at the limits by reducing the delta of weight transfer during abrupt maneuvers.

During normal daily and even spirited driving a stiffer rear bar relative to the front can noticeably decrease steering feel, pitch and feed back. This is a condition some drivers would not prefer. Since the XJS is fairly nose heavy in both I6 and V12 forms the 4 rear shock absorbers do a good enough job for most situations. Another facet is that as the rear leans over (pitch), one trailing arm shortens and one lengthens slightly given a rear steering effect that some drivers like. Personally, I dont like any rear steering effect, I found it interesting at first but un-settling on the 300ZXTT I once owned and on my XJ coupe. XJ coupes are more like a sedan and more top heavy than an XJS so the pitching motion is exaggerated so perhaps a rear sway bar is more useful on a sedan.

 

Doug, I would not think otherwise in your case!


As I mentioned all has to be correct in the axle fulcrums, and it also needs at least 0.5 degree of negative camber; assuming this ride height is crucial I found. Without an ARB, the rear will stay flat on a corner, and you can feel the rear pushing sideways, rather than rolling. If the RH is even a touch too high, you get the feeling it is rolling about the diff axis.


I found this by chance when I fitted a set of rear shocks that had the spring perch poorly positioned and the thing rolled, even though by eye the RH looked OK. I adjusted the perch and bingo, back to normal.


The car I had with the ARB, I found cornered worse, the ability of the axle to follow the contours of the road in a corner was poorer, the ride felt more like a live axle's, adjustability on the throttle was far less sensitive.


Just my experience. I took one off a friend's V 12 car, and he felt the same about the change. I do accept though, on a saloon with its higher CoG, and ARB might well be beneficial. I have nothing against them in principle, just my feeling about this particular axle and car.
Greg

 

Thanks gents that’s answered that question very comprehensively indeed. I wanted to be sure it wasn’t there for a reason and not been deleted and possibly compromising safety by a past custodian. I will leave it off. I have noticed that the large heat shield over the rear axle has moulded bumps in it to go over the studs in the body where it is probably fixed. Or not as the case may be.

 

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i agree, and so much for outside information from some so called race guys, at Daytona ,around 1995.

i guess i'm getting a rear anti roll bar , stupid to throw old one into scrap junk.

good part is the body mounts are still there!

 

My 89 does not have a rear ARB, it does have the body mounts but no radius arm mounts.

I have stock front springs and heavy duty rear springs with Bilstein dampers that have TWR valving NOT Jaguar, the car handles very well, although you can feel the rear walking around on enthusiastic cornering.