2015 Coupe Base..no adaptive suspension. Stock rims are 18" Velas with Continental Sport Contact 2. Switched to 20" Gyrodynes with OEM Pirellis 1000 miles ago.

WITH THE 18s:
The extra sidewall definitely helps with ride quality as it helps absorbs any bumps in the road. The drawback is that they numb the steering feedback just a little bit. The Continentals are extremely forgiving, have high grip, predictable breakaways and will announce when you are approaching their handling limits. Turning Dynamic on firms up the steering just a little.

WITH THE 20s:
OEM Pirellis are garbage. Unpredictable with trace amounts of understeer. Despite having extra "traction" from the upgraded size 275-295..I can't mash the throttle from a stop without losing traction. The Continentals hooked up with little to no drama. The thinner sidewalls brought back the instant steering feedback I was missing.

The additional unsprung weight and rotational mass added by the upgraded size definitely impacted the cars ability to accelerate and brake.

Pros:
-Looks more proportionate to the car
-Brings back the steering feel that was missing with 18s
-Ride quality is much firmer (can be a pro or con)
-BIGGEST PRO- EASIER TO CLEAN!!

Cons:
-Ride quality is much firmer (can be a pro or con)
-Car feels nervous and skiddish (I attribute that to the Pirellis)
-Acceleration/braking impacted
-The spoke design of the Gyrodynes extend beyond the tire wall so you can curb the face of the rim.

Was the upgrade worth it? I'm indifferent about it. Visually it looks great. From a performance aspect..eh. Again I attribute it to the OEM Pirellis. Once I get a different rubber on there, my opinion might change...but I think 19's would be the ultimate way to upgrade without compromising too much.

Before:



After:

 

The issue is with the Pirellis, not the Gyrodynes. I picked up my PSS/Gyrodyne wheel set today and noticed a 3/8" tall bead around the rim lip. Won't avoid damage with a solid rub, but will give notice before you are into the metal.

 

That's odd as my aftermarket wheels have pretty extreme raised spokes, and the Pirellis have plenty of bead (rim guard) as you can see in the pics below. Not sure why the same wouldn't apply for the Gyrodynes, except that mine are 19" vs 20" tires. Perhaps it is a mounting issue?

 

Having done exactly the same thing to a base car, I agree with some of your observations, but don't suffer your ambivalence. I had 2K miles on the Contis/Velas, and now 5K on the Pirelli/Gyrodynes.

I didn't think the Conti's had more grip than the Pirellis in warm pavement temps but never drove the Contis in colder temps. I feel more grip with the Pirellis in the summer conditions they were designed for. I don't perceive any obvious differences in braking and acceleration, but there's no arguing the difference in unsprung weight, so that's probably true to a minor degree.

I perceive the ride-quality difference as very minimal, but it is slightly firmer which I like. As you said the steering feel is vastly superior, and I think turn-in is much crisper. The latter is inconsistent with the understeer you mentioned, which I don't perceive at all. To me the car feels much more planted and sure-footed. Adding it all up, I vastly prefer the 20" set-up.

 

Thanks for the comparison. My F type came with 20's from the factory so I have nothing to compare with but I will say that I went with 18's on my other ride a Infiniti G35 due to concerns on adding too much weight.

 

The 20" wheels transform the car in the appearance department!

 

Function over form, here. Call me nuts, but I would never pay money to add unsprung weight. To put it another way, the only way I'd have left 18s on the car would be if 17s wouldn't fit. As far as the cosmetics of the swap, the spoke design of those 20s is definitely prettier than that of the 18s, but my eye has as much trouble with huge wheels as my head does. I may be alone in this, but I think the 18s look more proportionally correct on the car than the 20s. 18s that were styled like the 20s would be optimal. JMO, of course...

 

Interesting. I bought the Gyrodynes/Pirellis used (stickers still on the tyres) before I took delivery, and fitted them after about a month.

Ride: The Velas/Contis would iron out a rough surface compared to the Gyrodynes/Pirellis, but seemed to result in a double-bounce on anything undulating/bumpy enough to get the bodyshell moving. As a general comment my car has always felt like it had a higher spring rate than the low frequency damping could cope with, but dismissed cats eyes and potholes with ease.

Acceleration/Braking. I can unstick the Pirellis in the first 3 gears on warm (20c air temperature and sunny), dry, Tarmac. This suggests that the rotational inertia of the larger wheels and tyres is not having a pronounced effect on acceleration. Braking is as violent as I could ever want, but perhaps not as eyeball-popping as 305mm discs and Brembo 4-pots were on 1200kg of VW. That said it's a 1700kg car. They do not stop on a sixpence.

I originally test drove a base 'vert on 19s, and a R coupe on 20s. The low speed ride of the R when not in Dynamic was better than that of the 'vert.

 

I would have gotten 19's on my R if I could have, but I'm fine with the 20s. The forged blades with CF isn't too bad on weight, and they do look pretty amazing in person.

 

These are up for grabs!

$1875!!

https://www.jaguarforums.com/forum/p...odynes-152058/