How to soften ride of 2017 First Edition
 

I leased the MY2017 XE First Edition in May, 2016 (I'm in USA). It has the 35t V6 engine, with 225/40R19 front, 255/35R19 rear tires, which are Pirelli Cinturato P7 A/S Plus. The lease is nearly ended and I think I will buy it. I have previously leased a 2004 XJ, 2007 XJ, 2010 XF, and 2013 XF, and I think the XE fits my needs the best. However, I would like the ride to be a bit softer (I don’t track the car or participate in any other competitions with it). The press pack indicated that the car "is based off the XE Prestige", but I don't know exactly which type of suspension that it has.

If I change to 225/45R18 all around (an option in the Owner’s Handbook), will that significantly decrease the annoying road surface feedback that I would like to lessen? Or will I have to make changes to the suspension to notice an improvement in ride comfort? Will this require changing out suspension components, or just new adjustments/setting to the current hardware?
TIA,
Bill

Hi. I thought that the ride from the prestige was very smooth, I wonder whether it is your tyres that are the problem. We have Dunlops on our XE R sport, the ride (on 19's) is amazingly good though I suppose that is compared to my F Type on 21's. I also found in the F Type that going to a flow forged wheel with Michelins improved the ride out of sight. The ride on 21s with Michelins is as good as the ride on the OEM 19s with Pirelli P Zeros. See if you can take a loaner with a different tyre and whether it makes a difference.

I went to the dealer last week and drove a Premium on 225/45R18 Pirelli Cinturato P7 A/S Plus tires all around, and the ride was noticeably softer, and to my liking. So that was good to see (feel). I am still uneasy about the suspension, which, to change may be a significant cost. I am certain that my car does not have the adaptive dynamics. The dealer says that, whatever the suspension setup is, they can’t change it. I looked at a link from another post re a workshop manual for the XE with ingenium engine. In it there is a page which shows the specs for vehicle ride height, castor, and camber, for both comfort and sport, and the specs are different for comfort vs. sport. So I’m confused, but maybe this doesn’t apply to my First Edition. Or maybe the shocks, stabilizer, or whatever are also different for the different XE models – don’t know.So while different tires might move the ride in the correct direction, it might be insignificant in the First Edition unless I commit to other changes. If it entails replacing parts, it might be more pricey than I want. Wondering if anyone has experience in this area.

I changed the suspension on my XF but luckily Spires sold an aftermarket comfort suspension kit for the X250. I also changed the wheels and tires, going from 245/40r19s to 235/50r18s which gave me another 3/4" of sidewall. I believe I got just about as much improvement out of the wheel and tire change as the suspension change, but together it made a world of difference. Its still not a luxury car by any stretch of the imagination, nowhere near the magic carpet ride of the old X308, but its now reasonably tolerable as a daily driver on the asphalt cattle trails that Fort Worth calls streets. I definitely suggest to try changing your wheels and tires to increase sidewall first and see if you get enough improvement to your liking as suspension modification could get very expensive.

The Spires kit gets its improvement by reducing the spring rate by 15% softer and they supply custom Bilstein B6 dampers that they have specially revalved to match the new spring rate. I'm guessing there is NOT a similar kit for the x760, but if you wanted to go to the extreme, it may be possible. You'd need to look for a shop that deals in custom suspension setups for race cars or hot rods and has a machine called a shock dyno and somebody who knows what they are doing. I talked to a couple such shops as coming off an X308 I wanted to explore going further than 15% and they were eager to do it, but the cost was going to be considerably higher than the Spires kit. You can figure about $200-$300 per corner for custom wound springs and $750 to $1,000 per corner for custom dampers. Installation was another $1,000. AND, they warned that sometimes the process of revalving dampers is iterative, i.e., you might not like their first stab at the valving and wish to pull them off and revalve them again. So you'd have to budget about $100 per corner for revalving plus r & r again. And you really need to replace the foam spring isolators with any new spring and I think they were $30 each. So I was looking at anywhere from about $5,000 to $8,000 and probably more toward the higher end for a complete customized suspension setup compared to a little under $3,000 installed for the Spires kit. Unfortunately, the XF is not a much more common car, otherwise there might have been aftermarket coilover suspension kits available with a wide range of spring rate choices and externally adjustable dampers.

And another thought I had explored, but discounted, the earlier XFs and 4 cylinder models came with smaller brake rotors that allowed a 17" wheel. I could not fit anything less than an 18" wheel over my 5.0 v8 XF's caliper. But seems like I remember reading that the base XE did also come with a 17" wheel at least in some markets. The smaller the wheel diameter you can fit, the more sidewall you can have and thus the greater comfort.

I haven't checked around yet for shops that do these kinds of mods in this area, but looks like I should begin the search. If the First Edition suspension parts are the same as the 2019 Premium, then a change in tires might be sufficient. I'd still like to know what parts my car has re comfort and sport configurations, and if the only dif is adjusting ride height, castor, and camber, which shouldn't be a big deal.

18's for sure will give a softer ride. I don't find the ride to be harsh with the 19's, but that's me... The Cintuarato's are awful tires though. I have gone through 6 of them in 30K miles due to bubbles and tears. The ride nice though...

I only have 11,000 on my car (almost 3 years), and I haven't had any problems with tire wear. In surfing the web, I see some reviews that rate the Michelin Premier A/S very high (higher than my Pirelli’s and the Michelin Sport 4), but do not see them in Jag forums – maybe not available in Europe?

Just had a few conversations with my dealer rep. He worked with a service tech to confirm that the First Edition suspension has the same parts as the Prestige by comparing P/Ns. They were also able to confirm that the specs for ride height, castor, and camber were the same for each, and that they matched the “comfort” settings shown in the specs from the Topix workshop manual reference that I mentioned above (I sent them a copy of the pertinent pages).
So, it looks like changing to 18” wheels should result in a noticeably softer and more comfortable ride!

The spec for my XE Portfolio registered in May 2017 lists "Comfort suspension" and the ride on 19" is as good as my old XJ I traded in for it. I think to get a more comfortable ride, you have to change the springs and the shocks. My car doesn't have adaptive damping which used to be called CATS (thank goodness !!). So I am happy with the car even though the tyres have a low profile the ride is good.

Just a note... while this isn't XE specific, yes increase the tire sidewall height (i.e. going from 19" to 18" wheels) will provide more damping for road noise. However, the type of tire also plays a role in this as well. More aggressive performance tires will have stiffer sidewalls. Stiffer sidewalls will transmit more road noise to the chassis where as softer sidewall will absorb the road noise and not transfer as much to the chassis (thus providing a smoother ride to the occupants).

In short, it's not only the wheel size but also the tire type as well which will dictate ride quality.

An excellent point. Unfortunately there's not a standard rating system for sidewall stiffness, but in general you might also research the load ratings and speed ratings of tires. Looking at lower speed "all season" touring tires as opposed to higher speed high performance tires, a lower load rating could be an indicator that it might ride softer. Then go on websites like tirerack and read reviews from owners of similar sized sedans to absorb some subjective opinions before you choose a tire.

Another thing you can do is choose a slightly larger diameter tire. I chose a tire that was just a little larger overall diameter than what came on my XF from the factory. Speedometer is off by 2.2% but it kind of looks better because it fills out the fender gap more as if the car were lowered. To make sure I wasn't going to have any issues with rubbing, I first went to one of those "used tire" places and for $30 had them mount one cheap used tire in the size that I was considering. I put it on each of the front corners (I already knew many people on this forum were running much larger sizes on the rear) and checked thoroughly for any signs that it might ever rub on anything and then took it on a test drive. All good, I went ahead and ordered a full set of new tires.

Good point about load/speed rating - hadn't been thinking much beyond sidewall ratio.

I’ve never really understood how/why the XE tire pressures are so high (43/47psi) but the ride is so nice. I guess the suspension is tuned for it.

When I considered the 19” wheels, I realized the standard 18” tires had the same sidewall as the 19” on my F-type, and there was no way I wanted lower profile than that on my winter car.

I just went out to look at what my pressures should be on my XE. For a normal load, it's 37 psi front and rear, but for a full load its as per your car. Can this be an attempt to stop rim damage from potholes ? These pressure are much higher than those for my old X350 XJ6.

There's always a sticker on the car somewhere with recommended pressures, but that's got to be the recommended pressures just for the original tires the car came with. Probably the most extreme example is when people started to switch from bias-ply tires to radial tires back in the 70s. Recommended pressures for bias-ply tires were in the low to mid-20s because any more and the soft tires would start to deform and wear unevenly. Radials came out and you could run five to ten pounds higher without deforming the tire or adverse wear and get better gas mileage due to lower rolling resistance. Back when I was doing SCCA autocross in the 90s, I always carried an air tank and would add nearly ten pounds just during the race as it was recommended with modern radials you could go up to the maximum pressure embossed on the sidewall before the tire would deform and it would help prevent sidewall rollover during extreme maneuvering. Theoretically you could also tweak the understeer and oversteer with tire pressure adjustments between front and rear, but I wasn't a skilled enough driver for that to seem to make any difference for me. I suspect that the recommended pressure is based a lot on the specific OEM tire and that's based on a bunch of engineers calculations and testing that came up with a compromise between fuel mileage, handling and comfort and that you really have pretty wide latitude to run it much lower if you want comfort or run it much higher if you prefer performance. With modern TPMS tho, you can't go more than a couple pounds lower than recommended without triggering the TMPS indicator.

I’m glad you mentioned this. Mine lists 43/47 as ‘normal’, up to the max gross weight. It lists ‘light load’ as 34/34, for up to 3 people and 1 piece of luggage. That’s a huge difference! (This is for 225/45R18.)

Shocked to see that the ‘max inflation pressure’ is 51psi on the OEM Contis, not far from the 47psi recommendation.

Have to say that I’ve been amazed at the great ride, running 43/47 consistently.

New thought - can my XE run with "45s" on the existing rims? Current tires are 225/40R19 93HXL (front) and 255/35R19 96HXL (rear). Anyone have "45s" on 19" rims on their XE? Any rubbing or other problems? This would save me ~$500/rim if (1) the car can handle it, and (2) this would make a noticeable improvement in riding comfort. As I mentioned above, the owner's handbook shows "45s" on 18" rims.

The tire diameter would be about 3% larger, which would affect speedometer, odometer, etc. No idea if it would fit. There’s a tire calculator at the top of the forum, under ‘Tools’, and there are a zillion of them on the web.