I understand you need 5x108 +35mm through +42mm offset...What I don't understand is when I look at wheels that with the correct bolt pattern/offset on ebay, they say they won't fit the STR...What exactly am I looking for to determine if they'll fit?

For the record I'm looking at 20s, but it appears you can find 22s for the same price (obviously 22" tires will be more than 20" tires). Do 22s fit without any modifications?

 

DON'T DO 22's you will regret it. I had 20's and they fit perfect but they were such a pain in the as_ to maintain. I have seen a few sets of 22's and both sets had the fenders rolled.

 

You have to look at caliper clearance as well. That's something that "maybe" Brembo might have but I doubt they'd make an OEM tech drawing available to you.

I used the Brembo engineering drawings for their racing calipers when I had to get a new set of rims built for my race car and that was only the starting point. We still had to do a mock-up rim have it shipped to me so I could double check the clearance on the car. A good thing too. I had them do a bit more machining to get the job done right.

If they say it won't fit there may be a valid reason.

 

Figures...I'm just checking out ebay and see lots of chrome 20s around the $600-$800 shipped mark, but I'd hate to get them and they don't fit.

While I owned my 4.2 base from '07-'10 for all but the first few weeks of my 3 year ownership I had 20s, rolled the rear fenders and the rears still rubbed...I understand the STR's suspension is stiffer than the base but I know I could handle 22s...

I posted in '07: https://www.jaguarforums.com/forum/s...oes-tint-2524/

 

It's all about getting the CORRECT offset! I had 20's and didn’t roll my fenders. They never rubbed even w/passengers in the car. Oh, and getting it CORRECT isn’t cheap!

I would never put anything besides factory wheels on an STR. Most people purchase an STR for performance and increasing rotating mass is the exact opposite direction of the cars intended purpose.

 

I agree on the larger wheels being the wrong direction for this car. It's a shame enkie rpf1's don't come in the correct size. A set of those in hyperblack would look fantastic!

That being said to each his own so if you want 20's and you aren't worried about that BMW M5 pulling up next to you then get what you want but the rotor clearance will be your speedbump in that quest.

 

I understand your guys mind sets, but if you haven't already guessed, I like bling/flash...I don't think the STR is really that fast of a car; I bought a Jag, for the same money I could bought a much faster car...Maybe a 3lb pulley or spraying would change that...

 

It's not a mind set that 20s will reduce performance is it?

 

Depends what you consider performance, I break it down to four categories, braking, handling, launch acceleration and post launch acceleration...Assuming the 20s are actually heavier (odds are they will be) you'll actually get better braking, better launches and overall better handling (not in every aspect of handling but the majority due to less sidewall flex). So the only thing it really affects is acceleration after the launch.

On the other-hand, let's say you could find some fairly lightweight 20x7.5 put on a skinny 235 XX R20 tire; odds are that setup would weigh less that stock and thus increase post launch acceleration.

A separate debate would be the pig of the rotors the STR has, if one is wanting better acceleration, convert the STR brakes to a base S-Type's setup...Brakeperformance lists their premium rotors for the STR as 25.5lbs for the front and 17lbs for the rear. Weights for the base, 17.25lbs for the fronts and 12.5lbs for the rears. Converting to the base's brakes yields a staggering 26.5lbs of unsprung weight...Keep the stock rims and put on the skinnier tires and along with the rotors shave 40-50lbs total pounds of unsprung weight, your car will feel like it on nitrous, but that's only if you value pulling on a M5 or acceleration more than braking...

 

^in all my experience of autocrossing it is always the lighter wheels provide better braking, better handling, and better acceleration. A heavier wheels doesn't mean more weight will stop the car faster. It actually will mean more mass means it's got more momentem and will be longer to stop, harder to corner, and slower to accelerate.

You would not want to reduce weight in the brakes. They are there for a purpose so that theory is bad advice. It's safer to get lighter wheels.

 

"Lighter" wheels isn't God when it comes to better braking, rather it's a complex formula of the distribution of mass, rotational inertia, tire compound and contact patch of the tire...

If you're wanted to pull on a M5 from a roll, going to base brakes (saving 25lbs) makes sense...How is it bad advice? They're there to compete with the M5; the base brakes stop a base S-Type without incident. If you want to WIN first place in AutoX, don't buy a STR...

 

Wishful thinking but I think incorrect. (But it's your car so do as you like.)

 

I always love it when arm chair engineers think they're going to re-engineer with a few bolt on bits what Jaguar & Ford spent tens if not hundreds of millions on.

The light wheels is always wonderful for acceleration and I notice it right away when I have my original light weight magnesium rims on the the race car versus the forged 3 piece racing rims. The trouble is that the magnesium rims are not nearly as durable and at this point in time they are irreplaceable for that car.

But if you're shopping 20-22" rims on EBay I don't think you're really making weight a priority.

I was at a Jag show yesterday and I was parked next to a couple of 2005 XKRs one the limited edition car. Those have the 20" rims and the BBS wheels are nice with that accent ring . But I also noticed plenty of rubs and scraps on one (mine is even worse at the moment, 3 out of 4 are rashed). Event worse was that one of the tires had a huge bulge in the sidewall. Yikes! The guy just detailed the car including tire slop and he's driving on that?

It's tough enough with the rims I have and 35 series tires. Those would be 30s! I think they'd look good on the STR and hasn't someone already done this?

The brake hardware looks a bit smallish though.

If you want lighter brake hardware you could always do-your-own carbon fiber setup. I saw the brakes on a Bentley Soper Sports model a few weeks ago. No one could make them fade at the track after 2 days and those are really, really big brakes.

 

Thanks, I've pointed I'm willing to take a hit in some categories of performance to get 20s...I'm debating the folks who think keeping it stock provides the best performance...

 

Maybe the XKR 20" rims then. Path of least resistance. I can't see how clunky/chunky/heavy chrome plated rims is going to improve performance.

Go to the bottom of the page
2005 Jaguar XKR Wheels / Rims / Covers | Shop Online Discount Store

 

It really depends on the chroming process, how many layers of chrome/nickle/etc but usually on big wheels, 18-20s only a quarter pound is gained...If unsprung weight is important to you, save nearly 27lbs and covert to base S-Type brakes...

Wow, not a bad price at all...Thanks

 

We've had a lot links with prices like that and when you call they have no stock ... It was meant more as an example of what those wheels look like.

 

Fair enough. I (and others) were basically pointing out that various "upgrades" to performance are in fact downgrades. Wheels commonly fall into that category.

Many things you change on a performance car are a trade-off.........