2008 was the one year that the non-R model got the same 18" Vulcan wheels that the earlier STR had, except on the non-R, they used the 8" wide wheels both front and rear. I have a 2008 4.2 non-R to which I want to fit the STR 9.5" wide Vulcans on the rear.


My question is will the STR wheel/tire setup fit on the non-R rear with no clearance issues? Has anyone done this rear 9.5"-wide Vulcan wheel upgrade on their non-R?


Looking at my current setup, the 8" wide wheels with the 245/40-18 tires on the rear have about a 1" clearance with the rear inner wheel well's vertical structures. The tightest point seems to be where the brake line fitting is secured to the inner well, so I wonder what this clearance might shrink to with the 9.5" wheels with the 275/35-18 tires? Or did the STR have parts differences to gain clearance?


If an STR owner with Vulcans wants to be a real angel, would you reach over the rear tread with your palm and drop/sweep your fingers around the inner edge of the tire from around the 10-o'clock to the 4-o'clock positions, and see if the back of your hand brushes against anything in the wheel well? If not, then there is at least an average hand's thickness clearance in the STR. My dirty hand thanks your dirty hand (sorry)!

 

They will fit w/out any issues. I have the STR wheels on my 4.2.

 

Thanks for the quick reply. I wonder if the later Vulcan wheels are the same dimensionally as the earlier STR wheels on your car? Do you run 275/35-18 tires on your rear? Thanks!

 

Yes, they are the same size. I was going to use Vulcan wheels but couldn't find any for sale. Yes, I have 275/35-18 tires on the rear. I have the same size all around as the STR.

 

Just to close out this thread in case someone wanders through here in the future: yes, the STR Vulcan rear-tire setup does fit on the non-R 4.2, but it is rather a tight fit. The reason I started this thread was that the first service facility I tried, refused to install the tires because of liability concerns. They said that there was too little clearance, and they were concerned that if the car were heavily loaded, there would be no clearance.

The second place I tried installed the STR rears (Vulcans with Conti Extreme Contact DWS 275/35-ZR18) with no comment. I drove home listening intently and heard no rubbing sounds. At home, I drove one rear wheel up on a 3" high wood block to load up one side of the car. Even thus loaded, there was still no contact between the tire and the body.

The most probable tire rubbing point is with the rear inner plastic wheel well liner, at about the 11 O'clock position on the right side and the 1 O'clock position on the left side. This is where the plastic liner bulges a bit in curvature. In the unloaded state, there is about a 1/2" clearance between the liner and the inner sidewall. In the loaded state, for the loaded side only, this reduces to about 1/4" clearance. So it looks like it might be tight, but there should be no clearance issues (unless you put a ton in the boot?).

I'm still curious as to what sort of tire clearance the STR has in this area. Is it as tight as I have observed on my 4.2 non-R? Or is a different part number wheel well liner specified on the STR? Or is the rear suspension geometry a bit different to yield more clearance? Any STR owner care to add to the database?

 

They are all the same. Same rear suspension for all years. Even the Lincoln LS/Ford Thunderbird are the same but they have a slightly different rear wheel well.

Many LS guys are running all sorts of Jaguar wheels. They even have a thread with pictures of all the different wheels. Lincoln did not have very many wheel styles but Jaguar sure does and they change them almost every year too!

If you want to read it it's 8 pages long and has 246 entries. I believe they have beat that subject completely into the ground!!

Jaguar Wheels Fitment Database

The plastic rear wheel liners are the same for the STR and the non-STR. Exactly the same clearance as a non-R car.

It is a bit tight but still fits OK.
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Good grief - I had not realized that there was such a big parallel market for Jaguar wheels on the LS.

Not to
but I wonder if when an STR is heavily laden, the computer controlled (???) rear suspension hikes up the skirts so that the clearances remain constant, while our dumb springs just compress?

 

No. The CATS suspension just changes the damping rates. There is a suspension level sensor to give feedback to the cats but no ride height adjustments like the XJ’s can do with the air suspension. The STR is still using regular coil springs (But they are different from the non-SC cars.) and guys have installed lowering springs in their STR's too.

The XJ guys have methods to fool the air suspension into lowering the car.
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Just to close out this thread properly - I now have gone 900+ miles on my NOS 9-1/2" wide Vulcan wheels with 275/35-18 Conti DWS tires on the rear of my 4.2 (that is, the STR set-up). There has been no sign of any tire fouling of the wheel wells, even though the fit is m-i-g-h-t-y tight in a couple of spots. So all the above responses were spot on - no problems upgrading the atmos S to the STR tire sizing.