It's one of those Jaguar mysteries

Interestingly, the E-type had a rear ARB for years....but Jaguar deleted it during the last couple years of production. A few years ago someone on another forum gave numerous examples of Jaguar's habit of gradually "reducing specification" on their cars. That is, removing equipment. If nothing else we can safely assume that no manufacturer objects to saving money. If xxx-feature is problematic, or it's felt that customers wouldn't object to its absence, why spend the money?

As for the XJS rear bar, some have said it was deleted because of noise complaints. Seems plausible.

Others say that Jaguar found the car to turn in faster track times without it. Also plausible, although it brings up the old adage about "what works well a track car might not work well on a street car".

With respect to re-introduction, Greg's remark about "fashion" is plausible as well. Everyone else was using a rear bar...and Jaguar didn't want to be caught with pants down on spec sheets (heck, rear ARBs have been ubiquitous for ages. Even my old Hondas have 'em) nor be accused of being too soft and wallowy by magazine editors....or potential customers.

My own speculation is that Jaguar decided that they could delete the rear bar, save a few dollars, and potential buyers simply wouldn't care. Later they re-thought their decision....which calls for more speculation

Personally I'm in the "pro" camp. The rear ARB gives a flatter cornering stance, reduces understeer, and gives the car a more responsive feel. I like all that. Faster on a measured track course? Higher lateral acceleration on a skid pad? I dunno...and don't care

I agree with Greg's remarks about ride quality although the difference, IMO, is barely perceptible with the small bars used by Jaguar. It's much more apparent on the large rear bars offered in the aftermarket....which can also bring on some undesirable driving qualities. I experimented with different sizes and can assure you that bigger is not always better.

Cheers
DD

 

Thanks for that gents. I shall chew it over some more.

 

As always, Doug has expressed it very well. I don't have the roads of the UK, but I have a mix of flat straight prairies and twisting mountain roads that get broken up from frost heaves. In many ways, the UK roads are a dream to drive, they are so smooth in comparison.

For me, I'll take the rear ARB every time, as it allows the car to be driven with confidence in the twisties and it it doesn't wallow and plow that way a car without it does. There is one particular corner on the Trans Canada highway through British Columbia that is a cut right through the mountain, then a pair downhill sweeping off camber reverse bends. I can go 30 km/h faster through that bend with the rear bar than without, simply due to the flatter stance of the car. I can't say as I've noticed a deterioration in the ride quality, but if there is one, I think the advantages quite outweigh the drawbacks.

Here is the corner. Excuse the poor quality of the photo, there was water on the windshield. Once through the cut it bends to the right. Note the run away lane on the right, that's for when people overheat their brakes and they fail when they don't know how to drive in the mountains. I see it every summer in the rental RVs, trailing a cloud of brake smoke on the way down as they ride the brakes.

 

ARB's. are there to control body roll. Maybe they were a tick the box option in some markets.

If fitted correctly ARB's have Zero effect when BOTH wheels move up/down simultaneously. So they will not reduce ride compliance.

Stiffening (ie adding a rear ARB) the rear will reduce understeer/increase oversteer.

A really stiff rear bar with low traction will cause the rear of the car to want to slide. This can be very disconcerting and dangerous in inexperienced hands.

This guy explains them

 

I believe that spot is just outside of Squamish - yes? I always dread that spot as many, many people don't have a clue how to handle that area - often gets closed due to fatal accidents in bad weather....

 

Golden, in the Kicking Horse Canyon.

 

ah, I was wrong then, I've been to Golden so would have driven down there.