I was at the dealer yesterday and they mentioned the ride quality of the 18inch wheels vs 19/20 inch ones is noticeable. Much harsher on the 19/20 than the 18s. The car looks cooler with the bigger wheels but is the harsh ride worth it? They didn't have a type in 18 inch wheels for me to try so I had to take their word for it.

 

I think the ride is great with the 19" wheels on the V6S convertible. The base V6 (without active dampers) may be harsher, although owners here say it's fine. The coupe may be different.

 

I'm fine with my 20" on the V8S but then I was not expecting a softer ride and I did not drive anything else.
If it's a concern I would make sure they found one for you to compare. Perhaps a different dealer.

 

I have a 2002 XKR with 18" wheels, a 2010 XKR with 20" wheels, and I had an F-type V8S with 20" wheels for four days last week (in which I drove about a 1000 miles). Unquestionably, as a cruiser my 2002 is the smoothest on the highway and far and away the quietest. But, I found the F-type to be a bit softer and more compliant than my 2010 XKR coupe, and found it very comfortable. The one thing that I didn't particularly like was the amount of road noise translated from the low profile tires on the 20" rims into the cabin. This is obviously more apparent on freeway, higher speed driving, and not on trips through the neighborhood. The F-type's newer suspension (and probably lower rear spring rates) is a superior one, and while the ride is firm, it's not harsh by any means. I didn't even know there was an 18" option on the F-type.

 

I am in a bit of a unique position because I have had both on my base car which came w/ 18" Velas. After about 2K miles on those, I found a very good deal on a set of 20" Gyrodynes, which came off of an F-Type R Coupe and mounted those. I now have about about 2K miles on the 20".

My perception is that there is almost no difference in terms of "harshness" as long as the pavement is in reasonably good condition. On more broken pavement, the 20" are a bit more harsh, but not as much as one might expect. However, hitting a pot-hole likely could be very bad news with the 20" wheels. I will likely remount the 18" soon because I do intend to drive through the winter (pot-hole) season.

In terms of handling, I do think my car is noticeably better on the 20" wheels but that is not so much due to the wheels as it is a much bigger contact patch on the substantially wider tires. The car feels more "planted", and I enjoy driving it more because of that.

F-Typical on this forum did exactly the same thing on his base coupe, so perhaps he'll check in and give his view.

 

I too was worried reading about the harsh ride from the 19-20" wheels but the stock 18" Vela's weren't going to cut it design-wise so I bit the bullet and went with the 19's and I can tell you,it's like what Foosh said...almost zero difference on good roads so unless you drive on really bad roads,I wouldn't even worry about it.

That being said,I did opt for the wheel/tire protection warranty...just in case.

 

The answer can be found in the recommended tire pressure rating. On the 20" it's 36 I think. What is it for the 18"?

Speaking of which, the Jaguar XJS tires had incredibly smooth ride quality. Basically they were two huge balloons. You only had to inflate them to like 24 psi. You couldn't feel anything from the road.

 

Exactly the same, 36 psi. That's what's listed on the tire pressure door placard on my base car for the 18's.

 

In general, this is always true given the exact same tire. With smaller diameter wheels, you'll have more tire sidewall which will absorb more of the road noise.

I mentioned comparing using the same tire brand/type as different brand/type tires will have a different side wall stiffness. The more performance oriented the tire, the stiffer the sidewall (and rougher ride).

 

Hmm...

On the test drive I tried a base V6 on 19", and an R on 20". The low speed ride of the R in the softer setting was better than the base V6.

I bought a base V6 coupe fitted with 18" Velas, but also bought a set of 20" Gyrodynes before I took delivery. The Velas are now stored in the garage, as after trying the car with the Gyrodynes I found the ride pretty much the same, if not better.

Counter-intuitive I know, but not the first time I've experienced it. It's as if the "spring rate" and "damping" of the tyre is better matched to the suspension, meaning that when you hit a bump the whole lot moves together. Catseyes in the road and small potholes are less of an issue too.

 

I think the only apples-to-apples comparison one can make is the the difference between the two sizes on our base cars given our experience. On that, I agree with what you said with regard to no difference (or slightly better on the 20's) on most pavement and that the larger sizes may be a better set-up on the base car. With the adjustable suspension on the R model, that alone could account for the differences you felt on the test drive.

There are some pretty broken up roads in our nation's capital, which I travel most weekdays. On really bad pavement, the 20" set-up is definitely a bit harsher, but as I said before, not as much as I expected.

 

I have 20's on my R and the ride is good.. At the recommended 36 psi you can feel the pavement cracks a wee bit.. if you drop it a few pounds less so.
For the type of car, it rides well.
Stock Pirelli tires are o.k.. they tend to get noisy (hum) after 10 - 15 thousand or so miles (depending on how hard you drive it) and the cure is to upgrade to Michelin PSS tires.
Lawrence

 

Pss' s going on tomorrow! Picked up some "rain debris" today and lost all air out of pass-rear. Been wanting to switch over, and now I have the excuse. Will let this forum know over the next week how different the ride is.

 

Looking forward to hearing your experience as I'm planning to do the same. My OEM P Zeros are wearing very well but I think they're a pretty mediocre tire and I'm probably going to just proactively switch to the PSS. Out of interest, which local tire shop are you using for the switch?

 

Curious if you guys are thinking of going up a size wider on the rear when you switch to the PSS tire? Some folks on this site have said they are going to or maybe already have.
On my XKR the Pirelli tires got noisy (at first I thought it was a bad wheel bearing) after maybe 15,000. miles or so. When I switched to the PSS tire the grip was better than the Pirelli tires (new) and when I sold it I had about 18,000. miles on them with no noise.
I plan to switch the ftype r over once the Pirelli tires get noisy.
Lawrence.

 

I'll have to ask my XKR-owning colleague what he's using.

He did say the service bill came to over £1k* last Friday just addressing the should, rather than the could items.

*half of this was new rear tyres.

 

Yes, I'm thinking about trying a 305 rather than the stock 295 if it works out. When I did this on my 911 which has 295s as stock I went with 305s on the rears and felt it made a difference. The switch from the Porsche N1 spec to Michelins delivered a noticeable improvement and for me was worth every penny, then again I've also switched out brand new tires in the past (I ditched the awful run flats on my BMW 550i shortly after picking up the car) so I've got form for impatience with stock factory OEM tires. I will say I'm impressed with the wear on my P Zeros, after close to 9000 miles the wear is light and even, but I'm happy to trade that for less hard-wearing but grippier tires even though that results in more frequent replacement.

 

PSS On, very little time on them so far - but I will start a new thread to record performance over the next few days. The rear p-zeros were basically gone, 8500miles and 5 track days... not great. Of course, the right rear lived up to its name and had 0psi this morning, and would not hold air. Drove the mile or so to the shop - no problem. (Basically, Wow! on the run flats - never had them before, saved me a ton of hassle).

I had Goodyear in Los Gatos do the work - they've done all my tire work for all my cars, and will always beat tire rack prices. I will also have them mount two of the tires to my old rims (being repaired now) so I have a front a rear spare in the garage.

first impressions on the new shoes? Awesome! on my old tires, when the tires were cold it was almost impossible to not spin the rear pulling out into traffic. Tonight, on the drive home I could not get the tires to let go at all - on rain soaked LG roads!

Quite, and a noticible difference in feel.

More to come....

 

Great report, Spinningbull! Thanks for posting. You're making me want to get this switch done ASAP!

 

Run flats? Am I missing something?