I currently have a 2015 coupe S with the 19" wheels and would like to close up the wheel gap. I would love to be able to lower my f-type, but that is not an option for me right now. I barely clear my own driveway, let alone most places I have been to down here. I am planning on getting 20" wheels and am thinking of getting tires that have the same side profile as the 19"s. I know about the speedometer being off but the difference is only 5% and I am willing to live with that. I was just wondering if anyone has done anything similar and if there were any other effects I'm not aware of. Thanks in advance.

 

You're not actually filling up the wheel gap at all if you go with the proper 20" profile size/width. Only increasing the amount of rim/decreasing the amount of tire profile.

19" vs. 20" Wheels + Tires:

Front: 20" are 7.9mm higher.
Rear: 20" are 9.9mm higher.

This is about 1% difference overall and will not noticeably affect anything. Speedo might be off 1/2 a mph at like 80.

Now if you go with the same size, its a different story. This is 25.4 mm higher tire size and you'd have much taller tires than any F Type comes stock. I'd imagine this has not been done before, because it raises the ride height of the vehicle and could (but probably will not) cause contact with the fender liner during suspension compression.

 

Thanks for the reply. Looking at tire sizes, a 295/35/20 is about 1 inch taller than a 295/35/19. Im not too concerned with hitting the fender as that's only 1/2" the tire is closer to the fender. It would pretty much be like lowering the car, or at least that what I think it would be like.

 

That's not the case, when you lower a car you're only taking suspension travel out of the vehicle. The top of the tire is still going through the same arc it would be at stock ride height. When you add 1/2 an inch to the tire profile, you're creating a new arc that is closer to the fender to start. For example: if you bottom out the suspension on a 100% stock vehicle, the tire would be 1/2" from the fender liner. If you bottom out a lowered car with the same tires, it would be 1/2" from the fender liner. But if you bottom out a vehicle with a 1" larger tire, you're now hitting the fender liner.

 

+1. That half inch radius increase will cause issues at full suspension compression.

 

Spacers!

 

Your speedo will under read by the 5% you mention. That appears to be more than the tolerance many U.S. Law Enforcement agencies use for handing out tickets. It may also be illegal in some states. Tell me again how you're willing to live with that as - regardless of how slowly you drive - it seems you're likely to be open to prosecution.

 

I think he's saying that he intends to increase overall tyre diameter by using the aspect ratio for a 19" tyre on a 20" rim. This will give the 5% figure he mentions. But, that's an under-reading speedo. Most places are +10%, -0% so that's a ticketable Offence before anyone starts to wave a radar gun...

 

From what I understand, most speedometers in the US have +/- tolerance of 5%. Right now, my car came from the factory with a 275/35/19 tire, while a 295/30/20 tire is available, also from the factory. At 65 mph, his speedometer is going to read about 2 miles per hour less than his actual speed. Going to a 295/35/20 tire, my speedometer will read about 3.5 miles per hour below my actual speed. That is something I can live with.

 

In the US, the constabulary doesn't really care how accurate your speedo is. It's up to you to interpret is adequately do avoid speeding. We can put any size tire we want on a car as long as it remains interior to the upper part of the fender flare. Cadillacs with lift kits and monster truck tires are legal. Just don't speed. The real issue for the OP is whether there is adequate wheel well clearance.

 

Would also affect the odometer, which may or may not be a legal issue. I would think it would also be like changing the gearing a bit.

 

Thanks. That's exactly what I need to know.

 

your ride height would also be higher, so don't do it. it'll look weird.

 

I would try first with the standard types for the 20" and see what you think. I reckon they give you the filled out appearance on their own without having to increase the tyre profile.

 

+1.

Having switched from 18's to 20's, that's true in both perception and reality. I measured both the fronts and rears on each size before putting the 20"s on the car. The 20"s are almost an inch taller in diameter even though the lower profile 20"s are supposed to equalize the difference.

Of course, that means only a half-inch or so in the wheel well, but my eye perceives the wheel well to be more filled out because of the much larger wheel.

 

On my old xkr I went from stock 285/30/20 to 295/35/20 and it looked great and aggressive. I like a bit larger diameter tire to close fender gap on my cars so when the time comes for new tires on the f type I'll go up roughly 1". I'm thinking 285/35/20, 295/35/20 or 305/30/20

 

the 305/30 is pretty much a no-brainer since it increases the diameter by only 6 mm over stock. However, the 295/35 increases the diameter by almost 30 mm. That will negatively impact your acceleration times. If you want to close the fender gap, you'd be better off changing springs. That would also give you a more aggressive look by lowering the car.

 

I don't care, I don't track the car or race it so I don't mind the larger tires. 😄

 

I did this exact thing on my VW Phaeton. I swapped 18" stock VW wheels for 19" wheels off a Bentley. The stock Bentley tires are about 3/4 inch "taller" than the VWs which closed some of the wheel to fender gap, raised the car a bit and adjusted the speedometer reading slightly, but not enough to affect the GPS. The was no rubbing on suspension parts or fender liners.

 

Why would wheel diameter affect the GPS? That's based on where the car is, not the rotation of the wheels.