2010 XF Supercharged. So the stock rear tires are 285's. Has anyone tried 295's? I have even heard of some people putting 305's on . Looking for better grip and less slip to improve launches. Thanks.

 

My 2014 XJR has 295 stock. My rear rims are 10" wide. I think yours are too?
I don't know about 305's? Seems to be plenty of room around my 295's.
.
.
.

 

Yeah, I am going 295's for rear tires when it's time.

 

Yep, the 295s should fit fine. They should also improve the ride and reduce the fender gap fractionally.
Funny thing is when I bought new tyres for the XFR a few years ago I ordered and paid for 295s on the rear then when I saw them being fitted I spotted that they were 285s. I was not impressed but rather than waste half a day and insist on what I ordered I allowed them to continue fitting the 285s and demanded a refund of the price difference (about $100 IIRC) which I got.

 

OZ I see you have the euro toys lower pulley and tune. How happy are you with it? I just called mike last week and ordered it finally for my xfr. I had the resonators removed and put in a magnaflow x pipe. I have a mina intake and filters Mike seems to think 520 to the wheels, seems like a reach?

 

I am very happy with the pulley and tune.
Zero problems, big boost in power and torque, pulls like a train through to 7,000 rpm plus the added bonus of a lot more SC whine under load.
But be aware that although I have the Eurotoys lower/crank pulley the tune is a VAP tune not a Eurotoys tune.

 

The difference between 285 and 295 isn't going to do much for you compared to choosing a stickier tire that compromises wear and cold/wet weather driving. There's your big gain in traction.

 

The stock rim sizes for the XFR and 5.0 Supercharged are 20x8.5 ET49 and 20x9.5 ET66. This applies to both the Nevis and Draco design wheels. You can run 295s, but it's technically not optimal for a 9.5 inch rim.

I agree with this, running a well rated Max or Extreme Summer Performance tire (Michelin PS4S or PSC2) will net you noticeable results.

 

I changed mine for the Michelin pilot sport 4S last season and they are truly impressive. I would strongly recommend that. I have a 2010 XF SC with the staggered setup (same as XFR) with rear wheel drive and it handles so much better
I stuck with 285 wide

 

295 fits fine. no appreciable performance gain. probably makes car slightly slower as it's a taller tire..

the stock 285 width tire on the 30 ratio is actually a fair bit shorter in overall height than the front 255/30 so that bugged me and i went with 295 rear.

on the stock wheel there was no rubbing with the 295 rear, but with aftermarket wheels or with stock and spacers, you may rub - i did and i rolled the rear fender lip to solve the issue.

as others have posted, tire compound is key to traction - extra width just makes car press down a bit less on each part of the contract patch. tire is a foot wide either way

295's for matching over all tire height front and back and also for goals of filling out the wheel wells for aesthetics

 

The 295's are going to be taller and heavier, both of which will have a negative impact on acceleration.