When I bought my X350 many years ago it originally came with 20" Callistos.
Within a week I destroyed a tyre on a pothole, discovered that one of them had been welded, and learned how expensive Callistos are to replace.
So I freaked out and sold off the Callistos and put 18" Venus rims on it.

The thing is, I have always loved the look of 19" Customs on the X350. To me they are the "XJR look".
Customs still seem relatively cheap, and some quick math tells me that they give me 87% of the widewall height on the 18"s.

I suppose that the biggest question I have is robustness. The roads in London are really bad, and, I have hit some really, really bad potholes with the Venus rims and they seem utterly indestructible. How are the 19" customs in this regard?

My suspicion is that ride comfort will not be affected that much going from 18 to 19". Am I wrong?

 

I don't know how bad the roads in London are in comaprison to the roads here in Germany, so I cannot comment on the robustness, but I have not had any issues in that sense.

Regarding the ride comfort I do not feel a big difference.
When I bought the car it sat on 18" aftermarket rims that I replaced with 19" Customs, as, same as you, I love the look on the car, and I did not feel a difference.
In the meantime, I have also bought a set of 18" luxury rims that I use with winter tires, and even with summer tires in 19" form and winter tires in 18" form the difference is negligible, IMO.

 

I'll have to say, the 19s worried me when I got the car, my previous Jag had 16s and that seemed about right. But, so far they have held up to the abuse of the constant local construction that surrounds me, and the hammering on the interstate. It came with fresh Michelin tires, and I'd imagine with that little sidewall, premium tires will be a must.

 

I have also pondered over this matter a lot.
Stayed with 18s and am content.

 

I've driven an x350 with 18" and 19" rims back-to-back. There is a difference in ride you can notice, but it's not monumental. My opinion is there is slightly more road feel. I personally bought a car that had 18" rims because I wanted less road feel. You do give up a slight bit of handling.

 

17" rims might offer you the most robust, & cushy, ride for really bad roads.

 

When I bought my 2005 Super V8 with its original "custom" wheels, ALL of them were bent but they were repairable. I have to be very careful in NY metro area to avoid sharp bumps and potholes but I KNOW it's only a matter of time before one of them gets bent again. IMO every inch you add to the wheel diameter is trading DOWN on ride quality and durability.... in favor of appearance.

I wish they made the Custom style in an 18" rim.

Best Regards
Jeff

 

If the high performance front brake option is fitted (355mm front discs) there may not be enough clearance to fit 18" or 17" wheels.
I have 20" Callisto wheels, and 19" were also an option for the car, but I don't think I could fit 18" wheels.

Pete M

 

I have 20" Callisto wheels on my 2006 SV8 Portfolio.
I decided to keep the "upgraded" 255/40 R20 tires that the previous owner had installed (so a 40 profile instead of the 35 normal profile, providing a higher sidewall; that 40 profile also corresponds to the 40 profile of 255/40 R19 tires required for 19" Custom wheels). The purpose was to protect the rims and to provide better comfort.
Up to now, 60.000 km with such tires/wheels, I had no issue of bending or cracking.

I can also confirm that 18" rims fit with the 355 mm front discs of the car as I use 18" wheels with winter tires during winter.

 

Up to MY2006, when both the Super V8 and the XJR had the Brembo brakes, 18" wheels definitely fit, although, at 365mm, the front disks are slightly larger than the later performance front brakes.

At that time, at least here in Europe, the Super V8 came with 18" Prestige wheels as factory standard, whereas the the XJR had 19" wheels.
As stated before, I run my MY2004 SV8 with 19" wheels in summer and 18" in winter.

From MY2006, with the new performance brakes, the disks where 10mm smaller in diameter, but it may be that 18" wheels do not fit anymore because the caliper might be bigger then the Brembo one due to the larger diameter of the piston.

Best regards,

Thomas

 

My SV8 is a Portfolio 2006, so with the ATE 355 mm discs/calipers.
My winter Coventry wheels fit with no issue