As it turns out, the X150 XK, X202 S-Type & X350 XJ all use the same Anti Roll Bars

Anyone who's looked for aftermarket Anti Roll Bars for our cars, will know that there is nothing available...however there might be some improvements possible using the OEM options.

Here is an overview of the ARB's fitted to our cars from the factory



You can see that the bars have the same thickness (except for the XKR-S rear bar) so one can only assume that they are made from different materials to alter the stiffness.

The front 32mm is hollow. The rear bars 17mm & 19mm are solid.

Obviously the C2C4318 is the bar to have on the rear from an OEM point of view. The question is what about the front bar?

The last iteration of the S-Type R got the same rear bar as the XKR-S. But the front on the last STR's is the same as the Diesel S-Type & XJ.

Whereas the XKR & XJR has a different bar to the last STR's. Which one is stiffer? How can we tell?

Funny that the XKR-S has the same front bar as the standard XK's, but needed something different for the rear.

I would think that the front & rear bar options on the last STR's would be the stiffer ones, the rear is for sure. But the front?

I bought an XKR-S rear bar to go on the XJR, but haven't put it on yet as it's a massive job to swap it out. Pretty much the whole rear axle needs to be dropped... The front doesn't look to be any easier to change either. So without knowing which is the stiffer front one, i'm reluctant to spend the time/money, to possibly go backwards...

If we can find a vendor who makes custom Anti Roll Bars, then this would be a reasonable prospect, given that they would suit multiple vehicles, the sales potential would be fairly high, not just for one model.

Chris @ Mina, where are you? I've got a product suggestion!

What I don't know, is if the latest version of the XKR-S (the 5.0L model) has different bars again, if they are even stiffer, & if they fit the XJ & S-Type.

 

So just to add some more to this, there seems to be some crossover with the 5.0L XKR as well as the X351 XJ (XJR and Sentinel)

The rear bar C2C4318 was also fitted to the 5.0L Supercharged X351 XJ, up until VIN V27933, when it changed p/n to C2P23536, that new p/n is fitted to the Sentinel and the XJR. No idea if it would be backwards compatible to the earlier cars but it seems likely, the ARB bushes are listed as S-Type parts, and the ARB links are the same regardless of model.

Is the new p/n stiffer? Who knows...maybe...the C2P23536 is also listed for the XFR-S and the XKR-S from VIN B47118, so it might well be that the rear bar is compatible between the X150, X202, X250, X350 and X351

Also worth noting that the XKR-S GT has a different rear bar again, C2P25191

BUT the F-Type is listed as having a rear bar p/n XR835524 i.e. same as the V6 S-Type & X350, same as the non R-S XK's...

So the F-Type rear also compatible with the other models

The F-Type front bar is C2P23535, same as the X150 XKR, which was a replacement for the XR837161, that also fit the S-Type, and X350...

You see where this is going?

The front bars are interesting....

The XKR-S GT front bar is p/n C2Z3523, same part number as per the XF 4.2 N/A, 3.0L N/A and 2.0L Turbo... what? how does the big-gun GT road-racer have the same front bar as the soft model XF's?

Did they make the XKR-S GT softer at the front than the regular XKR or XKR-S? or are these bars actually stiffer (you would think they are stiffer)

I can't see any crossover between the X351 XJ and the other models for the front bar...which is a pity since you'd think the XJR front bar would be the stiffest...at least one would expect it...(btw the Sentinel runs the regular XJ 5.0 S/C front bar)

It's all very confusing, and brings me no closer to finding out which front swaybar to suit my car is the stiffest available....but we're getting there...

 

It's something I looked at too but beyond what was fitted to the XKR-S 4.2 which is presumably stiffer than the X350 one but I'm not sure how the stiffness could be determined without actually testing each one...

 

The front bar from the 4.2 XKR-S is the same as what's in my XJR now, and it can't be the stiffest one available, no way...

I'm thinking that the XFR-S front bar C2Z21477 would be the stiffest, from an application point of view. Interesting that in the JEPC there is a note about this bar being for "600Nm". With the XKR-S GT is using the same bar as the low-powered XF's, did they put stiffer bars in the N/A cars to make them feel more exciting.

But yep, the only way to be sure would be to test them. I think a fairly simple test rig could be set up;

Build a rigid steel frame to mount the bar replicating the mounting in the vehicle, at the two mounting points with the original bushes and hardware. And mount one side with a droplink so it's fixed.

The other end is then free to move, you could connect it to a hydraulic jack (like what's used in a press) and then measure the deflection in mm at increasing pressures (also need a pressure gauge on the jack).

The bar that deflects the least across the various pressures would be the stiffest...

It's really a matter of collecting the different bars that you want to test (and identifying them correctly, most importantly).

Taking them all to a company that makes swaybars (there are a couple here in Oz) and getting them to do the tests would be costly unless they are going to make new sway bars for us. Which will also be costly, considering the front bar C2Z3523 is only £160.47+VAT in the UK, you could not get one custom made any cheaper...

Which front bars to test?

C2P23535 ; F-Type, 5.0L XKR (£138.89) [replaces the XR837161] weight 3.07kg
C2Z3523 ; XKR-S GT & N/A XF's (£160.47) weight 2.64kg
C2Z21477 ; XFR-S (£138.89) weight 3.07 kg

Could pull the front bar off mine to test (XR837161) but who knows if the mileage has affected the stiffness?

Based on the prices you'd think the C2Z3523 would have more metal in it, but it's actually lighter according to David Manners...

If you had to just guess, the XFR-S front bar would be the pick, assuming that it fits the S-Type and X350, which it would appear to, based on the other bars mixing & matching between models..

 

Rejoice! Aftermarket swaybars are now available

https://www.jaguarforums.com/forum/xf-xfr-x250-44/xf-swaybar-upgrade-141963

 

I've ordered a set. Should arrive this week. Will post up what difference they make. Wish I'd seen this 6 years ago.

 

 

Hey jahummer, how does it handle now?

 

No idea, still on the lift for other modifications. Was supposed to be done November but that’s how it goes. I’ll certainly post up once I get it on the street and after it’s first track session.