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Discussion Starter · #1 ·
I think it is common knowledge that the X350 cars lost the boulevard ride the previous steel saloons were famous for from 1968 onwards. My previous X350 started off with 20" Sepangs and the ride was just AWFUL ! So I got them swapped for 18" for nothing, as dealer presumably could sell them on for a good price. My current X358 Sovereign came with 19" Polaris, which I have run since I purchased the car in Oct last year, but the front tyres were coming up for replacement. I wasn't really happy with the ride quality, but it was tolerable with the pressures at the "Comfort" settings. Anyway, I decided to downsize the wheels to get a "fatter" tyre, and was able to buy some very nice condition 17" "Elegant" wheels complete with tyres on eBay. These 17" wheels were originally the standard wheels on the SE saloons from 2003, but over the years this size was dropped and it was all 18, 19 or 20 inch wheels. There is also another advantage of the 17" wheels, as the tyres that go on them have much more of a bulge-out from the rim, so are far less prone to kerbing, With the 19" you only have to look at the kerb when parking and you've kerbed the wheels ! These 17" wheels must be several years old yet have no kerbing marks and seem to be original, not refurbished.

Well, yesterday the wheels were fitted, and to my eye, look good. Of course, having once owned an XJ6 Series 3 I am used to 15" wheels. The tyres on these cars were 205/70/VR15. However, whilst two of the wheels had 2016 Kumhos on with plenty of tread, the two others had older tyres, one a 2007 Kumho, and the other a 2003 Pirelli. This latter wheel is in mint condition so I suspect it was the spare and only used fairly recently. I chatted with Louis, my mechanic friend who fitted the wheels, about the age of these two tyres. He told me he never takes risks with tyres, being a keen motorcyclist, and said that tyres are cheaper than having an accident. So today, I replaced these older tyres with a couple of Toyo Proxes. All seems well so far, and the ride is a lot more compliant. The wheel with the older Kumho has gone in the boot as a spare. I should mention that I also bought a wheel without tyre for a good price also on eBay to make up the five as I don't like space savers.
 

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Interesting, I did the complete opposite on my old 3.0 and swapped the 17’s for 19” Customs. Transformed the car for the better for me. I think that 19-20” wheels are the sweet spot visually personally, I guess it is a age thing.

Regarding kerb marks, taking extra care when parking keeps the wheels damage free, of course accidents can happen. A family member recently drove my car and managed to damage a wheel, until then were pristine.
 

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I agree Alec

My 20"s ride absolutely fine, not a crashing ride at all. Don't get me wrong hit one of these crater size potholes and you'll feel it, but probably not THAT much more

On that topic, I try, wherever possible to avoid potholes, it can be challenging at times and have hit some fairly sizeable ones with a large BANG.......The car is stopped as soon as possible and I get out fearing / dreading the worst and nothing!!

As for kerbing marks?
I don't care what anyone says, that's just down to carelessness and operator error pure and simple. My A6 wheels were mint after many years, although I did get too close to a kerb at least once, but totally my fault.
The alloys on my XJ have zero kerbing marks because I am careful AND my wife doesn't drive my car

Once more, it's not down to 15" or 16" or 17" against 20" alloys it is down to operator error!!

Jim
 

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I love my 20" Sepangs! I'm just having all five refurbed!
 

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Fraser interesting thread. By going to 17 inch you say the ride is a lot more compliant. Pls Could you be a bit more explanatory about the differences you noted and the degree of ride improvement. I like the look of my custom 19,s but ride quality is one of my top priorities. Do you particularly notice the difference on motorways, particular surfaces, when going over sunken covers, speed humps. Is the difference really worth it?
 

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I am with you Fraser, happy with my 18" and no intention of changing them, had 20" on my Sportbrake and wasn't really happy with them, car felt better on the 19" Arturas and winter tyres i used for 6 months of the year.

I don't really get the obsession with low profiles, especially on SUV's, not a good choice for off road at all, although i suppose not many ever make it off a tarmac road.

Seems odd that the more you pay, the less rubber you get for your money!
 

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its a bit of a fallacy that bigger wheels are better. In actual fact, they reduce the performance of the car quite dramatically

What they do do, and why the trade has always favoured them is to give a progression from basic spec through to a number of options that they can sell as upgrades. This is all based on the flawed theory that looking like a race-car is good.

The biggest two down-sides are in handling and comfort.

Handling is defined as the ability for the car to do what you want it to from the steering wheel. And the amount of tyre lateral deflection is probably the biggest tool towards achieving that. reducing the height of the sidewall, merely reduces the available deflection to work with, thus reducing the handling. Its no secret that the best handling cars of all time generally had narrow tyres - think Lotus Elan, generally considered the best ever on 145/82 tyres. I remember doing a test some years ago for GM, where without exception all of the drivers felt that the Omega handled the best on 14" wheels with 195-section tyres when compared to 15, 16, 17 and 18 inch equivalents.

Comfort also follows suit. Tyre vertical deflection is the key to providing comfort

Admittecly, there is an outright dry-weather grip increase with wider tyres, but this is all relative - a car of this size and weight needs nothing more than 225-section tyres to develop adequate grip in any case, even for a superchraged one.
 

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Discussion Starter · #9 ·
Fraser interesting thread. By going to 17 inch you say the ride is a lot more compliant. Pls Could you be a bit more explanatory about the differences you noted and the degree of ride improvement. I like the look of my custom 19,s but ride quality is one of my top priorities. Do you particularly notice the difference on motorways, particular surfaces, when going over sunken covers, speed humps. Is the difference really worth it?
It is far better when passing over sharp ridges or sunken/raised man-hole covers, or anything fairly low but sharp. Also cuts out the high frequency vibration you get on bad or old tarmac. I see the large wheel brigade have responded, well, I am happy. If they want a crashy ride then OK. Maybe the roads are maintained better where they live, but here in Cheshire we have had decades of neglect, and it really shows. On German roads the 19" were perfectly OK, but the Germans seem to be able to roll surfaces like billiard tables. I never see any of the dreadful surface dressing over there, either. I've been going to Germany for holidays since 2008, and always wonder at how they can do something our highways engineers seem to find too difficult.
 

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It is far better when passing over sharp ridges or sunken/raised man-hole covers, or anything fairly low but sharp. Also cuts out the high frequency vibration you get on bad or old tarmac. I see the large wheel brigade have responded, well, I am happy. If they want a crashy ride then OK. Maybe the roads are maintained better where they live, but here in Cheshire we have had decades of neglect, and it really shows. On German roads the 19" were perfectly OK, but the Germans seem to be able to roll surfaces like billiard tables. I never see any of the dreadful surface dressing over there, either. I've been going to Germany for holidays since 2008, and always wonder at how they can do something our highways engineers seem to find too difficult.
Speaking as an engineer, I resent being associated with those who are 'repairing' our tarmac :-D.

The only comparison I have to this debate is going back to my Triumph 2.5P.I.
I used to swap my lovely alloys with low profiles for standard steel rims with skinnier tyres for winter months.

Hardly comparing apples with apples, but the ride was superior with the steel rims.
Handling wasn't an issue because the roads were more slippery anyway.....

For my money, huge wheels and 35 or 40 A/R tyres are purely a fashion statement.
As for the pot-holes - well, even my old-fashioned 18" rims still fail to secure my teeth some days.

Phil.
 

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On German roads the 19" were perfectly OK, but the Germans seem to be able to roll surfaces like billiard tables. I never see any of the dreadful surface dressing over there, either. I've been going to Germany for holidays since 2008, and always wonder at how they can do something our highways engineers seem to find too difficult.
It depends! Sometimes it feels that in the UK roads are resurfaced only to be dug up the next month to repair piping or something else hidden underneath! The repair usually being a patch done by non-road builders.

Germany has also gone through 8 years of Wolfgang Schäuble's austerity and many roads and bridges have become pretty ropey. Finally the purse strings seem to have been loosened and there are major roadworks everywhere. The patches and potholes are being sorted. However, the Germans do seem to have the skill and the equipment to mitre in repairs into existing surfaces which are only perceptible due to a differing colour. It is good to see that road-surface normality will be resumed here in due course.

On the other hand though, the Germans seem to make roads that don't drain as well nor do they use cats eyes much. Driving at night is usually a bit trickier here than back at home. And their sign-posting logic takes some getting used to.

Btw, I see you are from near my home town - Alsager :)
 

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I'm with you on this one - although I would prefer 18" as the compromise size.

My other pet hate is all these modern wheel styles leave the brake caliper and disc on show. I much prefer all the rude mechanicals hidden behind the wheel. There is a Daimler option that does just that and looks magnificent.

Having the rude mechanicals of my X358 on show always makes me think of a Duchess with her petticoat showing.
 

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I'm with you on this one - although I would prefer 18" as the compromise size.

My other pet hate is all these modern wheel styles leave the brake caliper and disc on show. I much prefer all the rude mechanicals hidden behind the wheel. There is a Daimler option that does just that and looks magnificent.

Having the rude mechanicals of my X358 on show always makes me think of a Duchess with her petticoat showing.
I think you are probably referring to the 18" Prestige Wheels. As you say; magnificent 8)
 

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Discussion Starter · #14 ·
To Neilr
You're absolutely spot-on about the excellent German patching repairs. This year we were driving north-east of Berlin on a minor local road, and came to a straight of about 1km. Ahead as far as the eye could see were a series of rectangular patches, (about 30 I reckon). So I slowed down, expecting a bumpy ride, only to find the road was like a billiard table with each patch expertly rolled to be absolutely level with the old tarmac. You are, however, sadly right on signposting, but I find this is the same all over Europe. This must be the one thing we do which is better. Having autobahn exit signs only a kilometre in advance has caught me out a few times, as there are so many trucks you can miss it, only to see the "Ausfahrt" sign when you're tanking along at 80 mph !!
 

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... on signposting, but I find this is the same all over Europe. This must be the one thing we do which is better. Having autobahn exit signs only a kilometre in advance has caught me out a few times, as there are so many trucks you can miss it, only to see the "Ausfahrt" sign when you're tanking along at 80 mph !!
I rarely miss exits these day as the wife watches the navigator and informs me of my pending mistake! However, when I came out here, navigators were rare and I was always missing junctions and exits :( I get the feeling that she thinks that I'm still not keeping an eye on the guidance :)
 

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I was over in Germany last month with the XJ on the autobahn, made fantastic progress at 6am on a Sunday. Regarding exits, I decided to stop at a service station from 260km/h, the brakes were stinking hot when I got out :)
 

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Discussion Starter · #17 ·
I was over in Germany last month with the XJ on the autobahn, made fantastic progress at 6am on a Sunday. Regarding exits, I decided to stop at a service station from 260km/h, the brakes were stinking hot when I got out :)
260kph = 162 mph. Hope your tyres are up to snuff as well !
 

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My first X350 came with 19" customs - I bought a set of 17" Elegance for winter and found they gave a nicer ride and better economy.
 
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