245/275 is still within tire manufacturer recommended spec for rim size.

Mich Super Sport : 8-9.5"
9-10"

 

The size out of spec I am referring to is the 285/30/19. It calls for minimum rim size of 9.5 at least in the S0-4. The 275/35/19 meets the 9.0 fitment for the 2011 rim

 

i'm running 285/30 on my 08 9.0 rim. Pirelli pzero corsa r compound.

 

http://www.bridgestonetire.com/tire/...-pole-position

 

^^^^We are all aware of what the manufacturer's call out for the recommended wheels widths vs. tire cross section. Many of us here, me included, are running 285/30/19 in the rear on our stock 9" wheels with no negatives. If you looked at the link I posted, you would see that I am extremely happy with my 245/35/19 - 285/30/19 S-04 combo. Great handling and very important, to me, is that it kept the stock OD very close to stock. As I said in my earlier post, IMHO, there are negatives to using 275/35/19 in the back, especially if you are using 245/35/19 in the front.

1. You are increasing the OD in the rear by .6" of an inch.

2. You are introducing a. 8" rake in a vehicle not designed for a rake.

It will probably work out OK for you, but IMHO, the negatives introduced my your choice of tire size far outweigh any positives of keeping the tire section width in line with the manufacturer's recommendations.

In my youth, I managed a tire store for a short time, and I guess I have been a tire nut since them.

I wish you well with your choice.

Lou

 

@ Lou- I really appreciate the advice and presenting the option of running another set up. The clearance is my main concern that you all have helped me with identifying and I appreciate the information. I will post picture and identify if any negative side effects of 275/35/19-245/35/19. I know it's a number game in keeping close to factory settings but in that case I would just stay stock. I was running 285/35/18 on my R34 GTR with 9.5 TE37's and I preferred the 275's RE-01 I originally put on that rim before replacing with the 285. Yes different car but personal preference.

 

It's been a week since I installed the 275/35/19 and 245/35/19. Thank you to everyone here for your recommendations, they fit with no problems and the ride feels great. Other than the great ride expected after replacing worn down tires, the steering is what I noticed the most (good). The diameter seem to have no affect on daily spirited driving and no cons to report at this time in using a 275/35/19 in the rear.

 

I demand pics!

 

just wanted to do my part and post some pictures of a similar setup. super sports 245/35/19 fronts 275/35/19 rears on stock 2011 suspension and wheels.

they fit fine with plenty of clearance and dont appear to bulge. lexus shouldve put 245/275 rubber on the f from factory.

i went with 275/35/19 even after all the rave reviews on cl for 275/30/19. thought i'd be a guinea pig with tires being relatively inexpensive to replace. after plenty of late night reading on cl, i was concerned the diameter differential and the resulting rake would throw the feel of the car off, but i haven't really noticed a difference. will be sure to report back as i log more time on the new tires.

i thought the stock size ps2s where pretty good, but wow the wider super sports are bloody fantastic.

now some pics!

side shot:


front angle:


front:


rear angle:


rear:


i just wanted to thank everyone who contributes to these forums for taking the time and sharing their experiences. just finished reading the diy pad and rotor threads and i got an itch to install these bad boys myself haha. thanks again cl f community!

 

if sticking with stock wheels, i'd always stick with stock tires. lexus engineers spent $$$$$$$ fine tuning this thing.

 

Disagree, cost savings always play role.

Even Porsche puts wider tires on higher trim 911s vs the base car.

 

/\ If you havent changed to the wider upsized tires I believe you do not know what you are talking about. From personal experience moving up to Michelin PSS 245/35/19 and 275/30/19 from factory tires gave me more grip, less slip, less road noise and what is def more control in turns at higher speeds. The car previously use be feel quite bumpy and on edge during high speed turn ins whereas now I feel more confident. Perhaps its the compound on the PSS but I think the width played just as important a role in the improvement.

 

yea, but you do realize that say for the GT3, porsche also put tons time, energy, blood, sweat, tears to match it to the sport cups, right? and it's not just tires. it's engine, transmission, suspension components, complete overhaul.

 

and you tested this in your local strip mall, right? or did you have full open access to the nurburgring or suzuka with a fleet of highly paid, highly skilled, highly trained automotive engineers?

 

thanks for your opinion. while i agree with you that engineers choose a specific part for a reason, i'd be naive to think that reason is always performance. engineers are smart people that solve problems. in this case the problem is:
powerful v8
+ is chassis
+ lexus qualities (luxury, reliability, styling etc.)
+ fuel efficiency / emissions (the is-f is best in class and lexus is the luxury hybrid company afterall)
+ internal budget (the f program was born from mr. yaguchi and team's passion on their own time)
+ msrp targets (undercut the m3 and c63amg)
the engineers chose the parts that best solved this problem.

this is precisely why members on these very forums have improved performance via various mods - suspension, exhaust, intake, headers, wheels, downforce and tires. no they haven't done a thousand laps of testing on the nurburgring, fuji speedway or suzuka curcuit, but they have felt and seen improvements on drag / lap times on courses all over north america. these forums have been a great place to get knowledge and first hand experience with the is-f. i always felt the 225 / 255 ps2s were too narrow and other member's experiences cemented this feeling.

even lexus runs fatter rubber, the is-f pikes peak racer (albeit on the front only, 245s on 18 inchers) and the trd concept wore 245 / 265 on those sweet magnesium wheels.

the cdn $150k porsche gt3 + sport cup tires is an unfair comparison. gt3 engineers turned a race car into a road car. the is-f engineers made a road car race-ier, for the the lack of a better word.

the fr-s / brz twins also illustrate my point. there is absolutely no way those narrow, prius spec tires are the best fit. it is clear a low msrp and low rolling resistance (fuel efficiency) influenced this decision.