Ooops...added missing link to post above

This again tells me it's not a damper or spring issue. Road surface imperfections, including large bumps, reflect the nature of a damper's high velocity valving, and would be jarring over bumps of all sizes if too stiff.

Your symptoms could even be caused by stiff suspension bushings, and the 2013 improvement could simply be a softer bushing, and that makes a lot more sense than a spring/damper/program change. Comparing part numbers of '12 and '13 suspension component part numbers would be useful. And if that is the case the dealer might be willing to do the upgrade at little or no cost.

Bruce

 

Bruce

Thank you very much for spending time researching tires even though you do not have a personal interest in it. (Bruce owns a gorgeous 5.0 XKR that he tracks regularly). I'm making a list of questions to ask my friend, Roger, next week, regarding the tire options. Since I will have my car there, I'll have them look at wheel/tire options as well. See what they think would fit over the brakes.

As to ultra performance tires vs. grand touring; interesting for their potential differences. I'll be sure to ask about the construction differences. Still, the "grand touring" Turanza has a "W" speed rating (168MPH) vs. the top "ultra performance" tires with ratings of "Y" (186MPH), vs. my stock Pirelli Zero Nero rating of "H" which is "only" for 130MPH. I would actually expect the lowest speed rated tire (my Pirellis) to have the most flex in their sidewalls. Sidewall flex is what generates undesired heat and would have to be reduced at higher speeds.

Needless to say that I always disliked when factories installed lower speed rated tires (H) on a car that was capable of much higher speeds. I always saw that as a cost saving issue but, now I may look at it as a ride issue. American manufacturers did so frequently and I am surprised that Jaguar would do so. I would expect the 5.0, 385HP XJL to be good for close to 160MPH top speeds but, now is speed governed to 120MPH because of the stock tires. Not a real issue for America but, I'd be surprised if Jaguar implemented the same speed/tire limitations for Germany.

Your observation seems correct about the damper valving. Being unfamiliar with the valving arrangement of my Jag dampers, I have not drawn the same parallel but, what you say makes general sense.

Bushings can definitely be an issue with ride harshness. I have not considered that because I have never seen a car where the factory bushings would have been too stiff for me. I often had replaced the stock ones with stiffer ones. But, again, they could be, no reason to eliminate them from the suspect list. I'd very much hope that to be the issue as it would be easy and inexpensive to change them. Comparing parts numbers for bushings and dampers is also an excellent suggestions, much easier than asking the dealer about the 2013 changes. It is not likely that they would have the correct answers.

Thanks again,

Albert

 

I suspect that is more often the case, but other factors play into it as well.

The more I study info on Tirerack's site the more I realize your new tire pick is going to be a bit of a gamble. Where you're fairly happy with the Ventus, their ride doesn't rate all that well against others. The "Survey" ratings and ranking are based on consumer responses which are too subjective to be useful, and very much affected by expectations that may or may not have been met as opposed to objective testing. The "Test" results performed by Tirerack staff for each tire are more insightful, but still subjective for ride characteristics, and only useful when comparing against the other three tires in the group test. The chances of them having tested the 2 or 3 tires together that you may be interested seems rather remote. And then how much of a difference is there really between their top pick and one in the middle? You don't care nearly as much about some performance aspects, but slight differences in ride quality will be key.

How about approaching it like this...

Determine if the poor ride is just your specific car by driving another 2012 XJL with a much more recent manufacture date. If it rides the same then it's not just your car and you can rule out bad tires and suspension issues on your car.

If it's just your car then the dealer can focus on resolving the problem, whether it's a problem with your particular suspension or tires, and the cost of fixing is obviously theirs.

If they suspect tires they can swap on a mounted set off the other car quickly and the improvement will be obvious immediately. If it isn't then the problem must be in the suspension and they can start looking at that harder.

But if it isn't your specific car then you can look at improvements that you can do, and driving a 2013 to experience reported ride improvements would be first, and if adequate for your needs you can determine what they changed, and whether it's possible to retrofit to your car. You can also consider whether simply changing the tires might make enough of an improvement on its own, or whether combining that with the '13 retrofit might be what you need. Your dealer might cover part of the tire or retrofit costs to see you totally satisfied.

Bruce

 

Bruce

Precisely my feelings regarding the TireRack comparisons. An other factor is their tested tire sizes and vehicles. If they test a tire at size 225x45x18, on a small BMW 3 it will not necessarily duplicate the ride and performance of a 274x40x20 from the same manufacturer/model on the big Jag. So, you are correct the posted tests has to be seen as "suggestions", at best.

I got an appointment for tomorrow at my selling dealer about this issue. Might postpone it as they call for 100% rain and I don't think that running the car on wet pavements will produce the same ride results. They are promising me a Jag XF as a loaner. I asked for an XJ, exactly for what you suggested; to be able to dive it multi-days and conclusively tell if the issue is only with my car or not. Unfortunately, they do not have XJ loaners. About a year ago I really lucked out to end up for an XJ SC for a day as a loaner at the other dealership. Then, I posted on the XK forum about the fact that I found the 20" wheel's ride "a bit harsh" for the XJ.

I did indicate my desire to the Sevice guy to be able to do some comparison driving but, he did not bite. I'll see when I'm there, face to face, and ask for a longer test drive. We parted with the crew of this dealership on excellent terms, all feeling very happy with the deal we got so, they may want to offer that drive to me, as to a good customer. We'll see.

In the meantime, I was wondering about the bolt patterns and offsets for my XJL vs. my 2005XK8 that came with 18" wheels. If, by chance, the bolt pattern would fit I could possibly manipulate the offset with the H&R spacers, like on the '08XK. That could be the most reasonable tire/wheel change option, if it comes to that. I need to dig into that possibility.

Albert

 

I enjoy the handling and ride of XJ. I prefer a steering which translates every pebble or ant on the road. I feel Jaguar should keep the current suspension/wheel setup for S/C and SS models and soften the settings on the base models.
Even Car and Drive loved the steering of XJ S/C but they did complain about ride quality and noise. But I rather have mildly harsh ride with “alive” steering than soft ride with numb steering.

2011 Jaguar XJL Supercharged

 

The thing is that you CAN have a precise steering AND a good ride. We had them before for decades, before the low profile tires. Just go back and try BMW of a late 80's or early 90's version. I also posted that I loved the precision of the steering as well as the handling in general. But, the ride is far too harsh. I found that again last night when I made my regular 3 hours drive over less than perfect freeway surfaces. For the first hour I said to myself that it was not too bad, I could even live with it. For the last hour I just wanted to get the hell out of the car, having been beaten by the cumulative effects of millions of minor road surface imperfections and the resultant harsh ride and unacceptable noise levels.

The ride is the single issue that I have, I love everything else about the car. Unfortunately, the ride is a significant issue for me, given the distances I drive. If I only did the average commute, possibly I would not be so put off by it.

Albert

 

Albert,

What is your current tire pressure? My tire inflation sticker says 39psi for all tires.

-Tom

 

I can't offer a solution, but I thought it was an interesting thread. I bought an older XJ308 recently specifically because I suffer from chronic pain and I found the ride quality to be tolerable. I previously had a 99 Lexus LS400 with the air suspension system that was totaled in an accident, but after a test drive, I decided the old Jag rides even a little better and the seats are far superior (Lexus seats are made for fat people). Both ride on 16" wheels with meaty sidewalls. I recently rode in a friend's 1964 Cadillac with probably 14 or 15 inch wheels and while I'm sure the braking and steering were lousy, you could NOT feel 12 inch potholes at all. I was tempted to buy it from him.

I'm not sure what I'm going to get when this old Jag wears out because the trend among all auto manufacturers has certainly been to sacrifice ride quality for bigger brakes and probably mostly, bigger bling. Sounds like I might not be able to upgrade to a newer Jag when time comes. I may have to be looking for something else or I may just be stuck driving old cars forever. At least I am close to work. I could not tolerate a 3 hour commute even in a hovercraft so I feel for you. Good luck.

 

Seems like what goes around comes around.

For years, people were going out after purchase and buying aftermarket tire/wheel combos in ever increasing diameters and lower profiles.

Now that they come equipped that way from the factory, it's going in the other direction.

You may find that even the 18 inch diameter wheel and a 40 series profile to be harsh. It is harsh on a X308 SC. The tires are inflated to 36 psi.

A Supra Mk III Turbo with 16 inch diameter wheels and 50 series tires is much more comfortable and does not lack in steering precision or cornering power. And that's with the tires habitually inflated to 42psi.

 

Thank you. Exactly my feelings. No real justification for the big wheels. We could get equal or better braking power with smaller disks simply by putting-on upgraded calipers. My full-blown GT2 & 3 class race car ran on 15" wheels, tall sidewalled slicks and, boy, did it have plenty of stopping power from those racing calipers!

The surprise is NOT that you got a much better ride out of the MKIII, the surprise is that it was that good at 42 psi. At least we had the option back those years. We could drop the pressures to a street value of near 30 psi to get the good ride and raise it for racing or sustained high speed driving (over 100MPH) to reduce sidewall flex.

I'm running 32 psi all around, which is recommended on my door jamb for my Pirellis. I even tried lowering them to 26 psi and it really did not make any substantive difference. Wonder what tires sizes you have to come with such high pressure recommendations?

Today I dropped off my XJL with the ride issue. I went back to the selling dealer. They showed a great deal of willingness to address the issue and were not against the idea of replacing my tires if no other issue is found. To show good faith I offered to split the cost with Jaguar for new tires. As I mentioned in an other post, my tires were already 14 months old on the car when I purchased the car brand-new. In effect the thread depth was new but, the compound was certainly not, and if the car had spend most of its time under the hot CA sun, it could have made the "new" tires old and brittle.

Interestingly, a man pulled in just before me with a previous gen XJL. I looked at his wheels/tires and he was using 19" wheels and nearly the same tire sizes I had. Difference was his 255R vs 275R for me. Now what was a surprise to see that he had the Ventus V12 tires on, the same tires that I have on my '08XK. I am content with the ride of my XK. So, I asked him about his ride. He stated that he had just replaced his Pirellis with the Ventus and he realized a significant improvement with the ride. So, I am tempted by my own and his experience to just go with the known quality of the Ventus V12.

My loaner car is a Jaguar XF with ContiPRoContact 18" tires. Plums, you are correct that even an 18" tire could be too stiff. I drove the XF for 1.5 hours from the dealer back to my hotel. It was stiffer than what I would prefer, the dampening was altogether very similar to my XJL's. However, the difference was clear after this drive. The XF was stiff, perhaps too stiff but, it was lacking the "harshness" that my XJL has. After 1.5 hours I was not beaten-up the same way as I get in my XJL.

BTW-kudos to the XF suspension. I call the XJL handling great and the XF is also great. It is (XF) actually more agile than the XJL and more responsive in transitions. This is not seen as a negative towards the XJL but, as a REAL positive to the XF. The same handling difference that would be seen between a BMW 5 series and a 7 series. Which brings me to the point; the XF is the real sport sedan for Jaguar. The XJ(L) is their flagship saloon or limousine. As such it should be held to a different ride standard than the XF or the XK. For its to ride to be as stiff or even harsher than either is, IMO, a mistake from Jaguar.

I'll report back when some results come-in from the dealer visit.

Albert

 

Ummm... the Supra was right up to last year

How about 13x165 70 series mud and snow belted tires on a Datsun 510 at a sustained 100mph+ for a couple of hours at a crack in the summer. That required the old moonshiners' trick of running on the white lines to use the coolest part of the blacktop. Very amusing

 

Funny you should mention Supra. I've owned a mk3 with the sawblades and I'd have to say the mk3 is more comfortable than any modern car I've been in lately, but I haven't been in one since before I got hurt. I love Supras, have owned a few of them and still hold onto a 1985 mk2 Supra that was the first car I bought after grad school. Even on stock 14" wheels, it handled beautifully and had a fairly compliant ride. Back then I dropped it on lowering springs, installed custom 16" wheels and did a few seasons of autocross. It's a bit rough for me now so I only drive it to a car show a couple of times each summer and that's about it.

 

Phil

Supras were King back in the turbo years. I remember writing an article for the American Lamborghini magazine and I suggested that Lamborghini needed something radical at the time in order to differentiate itself from far less expensive cars, like the TT Supra, that provided quite similar performance compared to the Lambo. I suggested the use of light weight, expensive materials, such as carbon fibre chassis and this was back, oh, 20 years ago. Finally these days they are applying carbon fibre to their cars.

Despite the great performance of the Supra I decided to go with the 3rd gen TT RX-7 for its far lighter weight. Got the R1 model with the racing goodies and the teeth-rattling suspension. Of course, I modified it, raced it for many years before destroying it at Sears Point raceway. Got an other one that I still own today, modified to 500HP 2600 lbs with absolutely killer suspension. The only parallel that I can draw with my XJL that they both wear me out if I drive them over the same less-then-perfect roads for my 300 miles round-trip. Of course, I would not take my TT on that long commute but, use it only for local canyon carving. I was definitely hoping that the XJL would pamper me with with its luxurious surroundings AND with its ride. First condition passed with flying colors, second; FAIL.

Albert

 

Albert,

Hopefully the new tires work out for you. I am huge fan of Toyo/Sumitomo tires for the soft ride and the sticky rubber. I would highly recommend them.

I will be honest though, if you find the ride in the XF stiff, especially on the 18s, i don't think you are going to be satisfied with the ride in your XJL, regardless of the rubber.

Your commute is quite long and you would probably be happier in a S or even a E 550. They are both extremely comfortable to ride in. You will get very similar push from the V8 engines. They just won't be as agile.

 

Your recommendations regarding the tires is spot on. I have not used Toyo on my street cars but, used it a ton on my stock-class, street-tired racing cars. The Sumitomos, the HTR-Z III is what I have on my ultra performance canyon racer and they work beautifully. Certainly one to consider.

Having said that I agree with you that the tire differences alone will likely not deliver what I would like. At this point, if I can just get a similarly acceptable ride as my XK provides with its 19" tires, I'll settle for that.

I'm pretty much locked into a 3 years lease so, getting a different car is not much of an option. I still prefer everything else in the Jag so, I'd compromise if we could get the ride to improve incrementally.

Thanks for the recommendations,

Albert

 

I have a 012 XJL SC with the Sport and Speed Pack. I guess since the car is capable of a top speed of 174 the tire inflation recommendation of 39psi makes sense if you are running at top speed.

 

Yes, it does make sense if you are running sustained speeds over 100 MPH. Not many of us in the US can do that.

Usually tire manufacturers would list a lower inflation value for "normal" speeds and higher pressures for sustained high speeds. I would think that you should be able to drop to a more reasonable pressure of 32 and make a bit of difference in ride quality. Having said that I dropped my pressures from 32 to 27 and did not sense much improvement. With the softer sidewalls of higher aspect ratio tires the ride difference due to a 5 psi change could be substantial.

BTW - as a quick update on my car; the dealer did find a code in my car that indicated a failure in the left-rear damper solenoid. That solenoid controls the valve operation of the damper and if bad, it could account for the harsh ride. The solenoid opens and closes thousands of times per second, regulating the fluid flow through the valves, thus, changing the damper characteristics per the "adaptable" computer parameters.

Let's hope that it does make a difference when I get the car back. Should be a day, or so.

Albert

 

Update; The dealer found that the left rear damper (shock) solenoid triggered a failure code. He replaced the damper assembly. The ride is improved, without a doubt. Now, probably 80-90% of the pavements I drove over for nearly 2 hours were actually OK. Not excellent but, better with the new damper.

I stopped by my racing sponsor and we basically test drove his 2013 Lexus, his earlier (not sure of the year) BMW M5, my loaner XF and my new fixed XJL. Best ride hands down; Lexus. Worst: BMW. The XJL had actually felt slightly softer than the XF all around but, my XJL did display a bothersome vibration over short sections of pavement that did not produce anything like it from the XF, BMW or the Lexus when driven over the very same sections at the same speeds. I could just change lanes and the vibration would go away. I think that it is the Pirelli's thread design in combination with the type of road surface. Will find out as I ordered a new set of tires that should be mounted tomorrow for next week's long drive.

So, damper fixed, car better but, I would still like to get rid of that particular vibration over specific surfaces and like to have a tire with less road noise for those 3 hours-long non-stop drives. Hope I get it with the new set.

Albert

 

Great news!

 

Albert,

You might also consideration the Nitto Motivo for your new set of tires.

http://www.experiencemotivo.com/

-Tom