I spent a lot of time searching this and other forums and am surprised I haven't found this info, so I'm posting here and apologize if there's already a post with my answer.

My questions are regarding tire and wheel sizes for a 2014 V8S.

1) I'm wondering what the widest tire I can get on the OEM rear wheels is?

2) I'm also wondering what the absolute widest tire I can get on the rear with an aftermarket set of wheels without any rubbing?

I'm asking because I personally think the F Type would look better with fatter rear tires for a wider looking stance.

Thanks in advance for your help!

Matt

 

The widest tire recommended for a 10.5" wide rim is 305. 335 is about as wide as you can go without removing fender liners if you use the right offset, but that makes the diameter of the wheel too large without using going to a 25 aspect ratio. An ideal tire size would be a 355/25-20 if the fender liner is modified to add an additional centimeter (and that's only available in a P-Zero Corsa for $800+ each). The widest available and readily fit tire is the 305. Additionally, you can add 15mm spacers and use H&R lowering springs (as I have) to widen the look of the stance.

 

Wow, 355's are what the Viper has on it. Those are some MASSIVE tires. I'd love to go that wide but would be happy with a 335 or 325. Do you know what the proper offset would be for these tires?

 

That depends on the wheel you use. Since no one has done it before, it would likely require measurements to calculated. I doubt anyone knows off the top of their heads.

As a note, if you're looking to increase grip to prevent wheelspin, wider isn't always better. Taller is how you want to go. But it sounds like you are doing it mostly for looks.

 

I'm doing it for grip and looks. Has anyone you're aware of got 325's on their car?

 

Wider tires will help lateral grip, but may hurt wheel spin resistance. Just a heads up there. I'm not aware of anyone past a 305.

 

Exactly, it will only be for "looks," because it would slow the car down. Adding wider wheels and tires means even more weight, and the car is already fat.

 

I own and race a 92 Spec Miata, so I get the whole rolling resistance thing and understand it. For the street though, a bit more grip in the F Type's rear end with the added wider looking stance would be perfect for me.

Any ideas on a vendor I might talk to regarding offsets and actual wheel/tire sizes?

 

+1. I'll get to that and respond to the OP a bit later.

IMO, too many people on this forum focused on the quarter mile. If that were my focus, I would have bought a rail. Lateral Gs is where it's at.

 

The real issue is whether you've found a 325 tire that has a good compound. The Michelin PSS at 305 may have superior grip to an off brand at 325.

 

OP, I was just like you at one time, thinking wider tires give more grip, but they only spread the tire's "footprint" wider and thinner, and add no traction.

 

...in the forward/aft direction. Laterally, a wider tire creates a wider patch under lateral load. "The right tool for the right job". OP, you going road racing or drag racing?

 

Agreed with most all of Mr. Unhingd said. I don't follow the "you want a taller" tire thing - all that's doing is changing the effective final drive ratio, car won't leave / accelerate as hard...so yeah, less traction issues. Besides, if you throw an abnormally tall tire on this car, the ECU has an absolute fit and lights up every warning light it can come up with

My 2 cents. It's all about compound.

Are you drag racing or only care about going straight even on the road? An MT drag radial is the winner - no brand of regular street tire will even be close. Put a 355 street tire against a 275 drag radial and the DR will walk it.

As Unhingd said, a proper PS2 will do wonders (IMO) over the factor P-zero's and alot of other tires.

However, I do think we can calc out a proper wheel size and offset to use. Why would the offset depend on the type of wheel he uses????

OEM is 20x10.5 28 offset. If we want to add .5" to the outside, essentially getting it flushed up with the fender, we could use a 20x11 with 22 offset. Inside stays the same and outside is pushed by 12mm.

Throw a 305/30/20 or 315/30/20 on it and call it a day

Anything bigger than 315 and I think *ideally* you'd need a wider wheel which seemingly starts to get a bit interesting

 

I'll weigh in here a bit. I have a base V6 which came with the 18" Vela wheels. I really didn't love those wheels, so I was able to purchase from a former forum member a set of 20" Storm wheels (the ones that come with the carbon ceramic brakes), fitted with 305/30 Michelin Pilot Sport Cup 2 tires. What I've come to discover is that with this car, it's a delicate balancing act. The Storm wheels are the lightest wheels Jaguar offers as they are forged. However, 305/30 stiff sidewall, soft compound tires pretty much negate that weight advantage. The PS Cup 2 tires are heavy.

On the plus side, on a warm day with the tires properly warmed up, it is nearly impossible to break them loose on launch with the base V6. I'm sure the V8 could break them, but they have tremendous launch grip. The wider stance also looks great on the car. These tires also offer an amazing amount of lateral grip. I haven't pushed them too much on public roads for obvious reasons, but they are noticeably more planted on some sweeping entrance ramps.

On the down side, the combination of width, sidewall stiffness and grip means that these tires really like to find the grooves in road surfaces. Driving on a rutted highway (most in the northeast) or other rough road can be quite an experience. The car will tramline unlike anything I've experienced before. You cannot drive inattentively on these types of roads. Also, that weight, focused toward the outer diameter, means that this combination has an incredible amount of rotational inertia at high speeds. If you get off the go pedal to abruptly at high speeds, that inertia can be felt. The back end definitely gets a bit loose in those situations, and it is compounded if the road surface is a bit uneven for the reasons I already highlighted.

Just some things to consider. From what I've learned, if you are going to run it only on a track or pristine road surfaces, then wide sticky tires are great. Deviate from that a bit into the real world, and the combination requires some vigilance. Though I love the grip and the look, I will not be replacing the PS Cup 2's when they wear out. I will get the PSS's in the standard 295/30 size.

 

I believe Stohlen really meant taller sidewall. At lower pressures, that enables the tire to flex into a huge patch. If you want drag traction, go with a 14 inch rim and an aspect ratio sufficient to get you back to the stock diameter. You'll have to delete the calipers, but that's what the chute is for.

 

I'm not dragging or tracking the car, just making it look cooler. I have much experience with PSS's at 325 width. Great tires. What width 20" wheel do I need for those tires? Will they fit in the wheel well without rubbing?

 

You're correct.

 

An 11" wide wheel would do it, and you'd need to have them custom made with the proper offsets (+22), center bore (63.4mm), and bolt pattern (5 X 108) Your answer was also provided in post #13 above:

OEM is 20x10.5 28 offset. If we want to add .5" to the outside, essentially getting it flushed up with the fender, we could use a 20x11 with 22 offset. Inside stays the same and outside is pushed by 12mm.

 

I believe the OEM is a 38mm offset. For a 15mm extension, you'd want a 32 mm offset on an 11 inch rim and 325 tire. (Foosh's calculations were correct) However, the rear tire would then be about 2.5% larger in diameter than the front. This may create issues if you have an AWD.

 

Ideal Rim Size for a 325/30ZR20 Pilot Sport Cup 2 tire is 11.5"
Width Range is 11-12". If one is going to have custom rims made to fit both the car and tire, is there a reason - aside from the additional weight - you would not have the rim made to the ideal size for the tire.