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I had an idea that keeps bothering me and doesn't go away...
I hate the AWD people having no trouble putting power on the ground, and then I think of our cars, that even if they have a T/S, they have lousy 60ft because of the lousy traction. Come on, 235 tires for 400hp?
I've began my research, and currently I run 285/30 r20 Michelins on 9X20 Sepangs. But still traction is an issue, even if I only have only bolt-ons. Of course the open diff doesn't help, but what if we could do something to stop even one wheel from slipping?
The 9 inch rim with an ET of 49 has a bit of room on the outside, pretty close to the inside.
Here are my thoughts:
1. I recall a member putting XKR-S rims which are 10.5 wide with the same ET, the inner fender had to be trimmed.
2. I remember another member getting 9.5X19 Jupiter wheels on his X350, which have an ET of 31. By my calculations, that is a tad outward from the XKR-S wheels. And he didn't even have to roll the fenders.
That means we have room to jiggle.
If the first generation rims from the new XK are widened to 12 inches, they would only need a 35mm spacer to clear the inner fender. That would mean that a 345 tire would clear. One would need to roll & pull the fenders about 35mm... what do you think? Would that be doable? I think the XJR needs as much traction as possible, given its minuses. And even if drag radials offer a solution, one would not be able to use on the streets when the need arises (e.g. a rs7 at a stoplight).
I don't think a 345 is going to fit without major body modification. The 285 you run now are probably pretty close to the inner and outer fender. You could let the air out of your suspension and measure the gaps with the suspension fully compressed and then you'd know exactly how much room you have, something I'm very curious to know too.
Muddybear, that's exactly what I did, although with the old school pen and paper. That's why I found out that the lower ET XK rims don't need much do be added to them, like 2.5", and also the spacer wouldn't have to be unrealistically large, about 35mm would suffice. Also, the fender shouldn't be pulled more than 30mm on the outside.
I made a drawing that shows the common rims width sitting on the hub. And then compare them with the widened wheels (the two on top). Base requirement was that neither shoult portrude deeper than the 10.5" XKR-S rim. Cambo, that is the exact thread that gave me the idea, along with another one that said the ET31 9.5X19 fits.
I deduced that just about an inch of additional clearance would be needed. It would be hard to visually see the difference from OEM, and, as I've seen on the internet, there are easy ways to do it. Plus I suspect the Jag would look awesome with some really big meats in the rear. But the most important thing is traction. We would finally solve any troubles, 345/30r19s even have drag radial options, but for less than 700hp, I suspect even streed tires would stick.
Here is what I've drawn up a couple of days ago, I also wrote down which is the hub, outside, inside. Each square is a centimeter of wheel width. Take a gander, and tell me what you think!
sorry, I don't know how to rotate it
PS: does anybody know of a place that widens alloy wheels in the EU? All I can find is in the US (as usual...)
Last edited by Matei Dima; Sep 12, 2015 at 03:50 AM.
would be nice now if you can overlay a cross section of the inner and outer fenders to see exactly how much space there is.
But going by your diagram, both the 12" and 13" wide wheels might barely clear the inner fender, but the outside fender would definitely rub. The OEM 9" wide wheels give you maybe 1" to the outside fender. The 12" wide wheels will stick out 2" past OEM and the 13" wide wheels stick out 3" past the fender. That would require some major fender flares and cutting of the body to make room.
I think if you were to roll the fender out a little, you could fit an 11" rim without rubbing but any more than and your going to start having issues.
But I'm on the same page as you, give me as wide as I can get
Muddybear, I used the size of the XKR-S 10.5 wheel as a limit for how deep the widened rim could go. Then See how much would that stretch out.
12" would clearly not clear the fender. I used the Jupiter 9.5" ET31 as an outer limit which would require no fender massaging. The widened rim would go past that by ~32-35mm. So clearly Something would need to be done. Rolling the fenders would yield about 10mm.
How hard would it be to pull the fenders about an inch? Please don't flame me, but I've seen some clips about using a heat gun and a phone book, and the results weren't that bad. Perhaps there are other techniques as well, but I don't know about that, it's the first time ever I looked it up.
I don't think an inch would draw attention or look ricey, what say you guys?
345/30 r19 anyone? :)
