Bpower

My opinion is based on facts. Cant argue with math.


If something "fits" without rubbing then it doesn't mean its good. If you are running stock 8" and 9" rims with those tire sizes then you are WRONG based on the tire manufacturer rim width range.

But hey its just your opinion after all.

flowrider

iTrader: (9)

^^^^No, it's more than my opinion. I have had my 245/285 combo for one year and 6K miles. There are NO negatives. The car handles better (in both dry and wet conditions) than it did with the stock PS2s. They lay down a flat footprint that runs from edge to edge. The tires are also quieter and they soak up bumps better than the PS2s. As I said, from experience, the 245/285 Continental DW setup is, IMHO, the way to go on stock wheels on the F.

Now, when you made your post you did post IMO, which the last time I looked meant "in my opinion." I really don't want to argue with you but, the recommendations you gave are too tall and will throw the electronics off.

Again, my recommendation comes from one years experience and from having worked in the tire industry when I was much younger.

Lou

Bpower

According to manufacturing specifications for the tire in question the rim width range for DW tire size 285/30/19 is 9.5-10.5 with a 10 inch wheel being an optimal. As for the front size 245/35/19 also according to manufacturer rim width range is 8-9.5 with optimal 8.5 inch rim. As you know your front is 8 and rear is a 9 which makes the 245 be acceptable but not optimal for the front and 285 not acceptable for the rear and that is the fact.

Brian@Vossen

The E-class coupe in Europe, a base diesel E200/220/250 with very thin tires (not sure of the size sadly) has the lowest CD of any production car now, .24....this rises to .27 with the V-8 model with much wider tires. Mercedes of course does not mention this detail, they just like to say "the E-class coupe has the lowest CD" but its just one model that is designed for efficiency which has the skinniest tires.

The E 200/250 diesel has 235 tires all around. The optional tires are 235/255 in the rear. They do offer a 245/265 option as well.

lobuxracer

iTrader: (2)

Tires are one of the worst offenders for coefficient of drag. Keep in mind, the top of the tire is moving at 2x forward speed, so the impact on the aerodynamics is pretty severe. For all the aero stuff they do in F-1, the cars would be alarmingly faster if they were able to fit a close fender around the tires.

Most of us won't notice a difference in fuel mileage with what we're calling wider tires. If you really went radical and put 335s on all four corners, you'd see a big difference, but at the sizes we're typically talking about, you'll not see a dramatic change.

melbitoast

iTrader: (1)

The thought I came up with this morning is that I'll just write down what my current average is and then compare that a few months down the road after I put the new tires on.
Since it will be some time before I am able to modify the car the way I would like to, I doubt my driving habits will change very much. That should allow me to witness a fair display of any mileage differential.

DaveGS4

iTrader: (2)

Bpower, Lou - take it to PM please (some OT posts removed)

lobuxracer

iTrader: (2)

Necro-thread revival.

I put 245s on the OEM rims and 255s in the rear to better balance out the car's inherent understeer. Ever since then, my highway mileage on long trips has dropped from 27 - 28 to 24 - 25. Two or three mpg doesn't sound like a lot until you realize it's a 10% loss. It has been very consistent too. Trip to Ft. Lauderdale, trip to Charlotte, and trip to Jekyll Island all showed the same efficiency loss.

I checked pressures and set them to the factory numbers with my Longacre digital pressure gauge, so I'm certain the tire pressures are correct. I also discovered traveling at indicated 80 mph gets me about 23 mpg, and traveling indicated 74 or less gets me 25.6 mpg. That's a big difference for a small speed change.

Just thought I'd post up some real world experience on the impact of wider Michelin PSS on the front. It seemed really bizarre and very disappointing considering I'd like to go even wider all around.

I8ABMR

In theory increasing the difference from and rear tire width will only create more under steer at 10/10 ths but at a higher speed. That's why the 275 made more sense in terms of overall dynamics to me. I guess the understeer that may be induced would be at too high of a speed to notice plus the rear F sport sway bar in the rear will dial some of it out making it more neutral. Not sure what size Im going to in the rear but I am absolutely going wider . I think since I want to maintain the same tire size difference as set by the manufacturer, want to use Michelin tires ( I am a big fan ), and want to dial out as much understeer as I possibly can for track use I may start with a 275 and then see how she feels on track. If she is oversteering on corner exit I will go 285

Lou I know you are a big proponent of the 285/30 rear ( and kind of the forum pioneer into that size ) and I wanted to ask if you track your ISF, and if you do how did she feel when pushing hard mid corner and corner exit. Thanks buddy. BTW there is a track day at Wild Horse Pass on 4/5. Bring her out and lets have some fun !!


In terms of the OPs question. Yes it will affect mpgs but not by much. Unlike my LS460 where I went from 235s all the way around to 255s front and 295s in the rear. . I noticed a 10% drop in mpg in my LS going that much wider. With the up'd sizes on the ISF I would estimate a 1mpg drop... if even. Most of the drop with the wider tires probably comes from simply pushing harder LOL

ISFpat

iTrader: (10)

I'm running 305's in the rear and I almost never reach 20mpg. I'm averaging 18-19mpg with 60/40 street/highway

Rossi

iTrader: (4)

I guys make me LOL,
I don't think you are driving the right car if you are concerned about MPG.

I have 245/275 PSS and love it, maybe slightly smaller in diameter, well, that makes the car sit lower.
I swaped for the Fsport sway bar in the rear, slapped on 15mm spacers to widen the track, also lowered the front with Eibachs making the car less bouncy, and the turn-ins are noticably way sharper. I would never go back to stock.
I have a hill on my way I go up every day, long strait with a wide S following, I can really feel the difference when I put the power down.

If you are concerned about the looks, I just park your car next to mine, the OEM setup looks somewhat wimpy next to mine. It looks really nice, when you fill up the fender wells.

Last thing about Lexus engineers spending all that time on researching the proper tires bla bla bla, just take a look at Porsche engineers widening the tires on the 911s, the tires get only wider with the better 911s.

JKweezy

I went with Lou's rec and went with 245/285 S04's since Dec 2013 and i noticed about 1-2 mpg drop... i do 80/20 highway/street and she's my daily commuter... i could get about 350 miles w/ stock tires out of the tank w/ usually a gallon to spare... now i get about 325 (read on the trip meter) out of the tank w/ a gallon to spare... i keep a gas log and corrected the mileage difference of 1.1% in my calculations w/ the new tire setup... i used to avg about 22-23 mpg w/ stock tires, now it's dropped to about 20 mpg... the most i pushed the tank w/ stock tires was 380 miles on the trip meter and filled up 16.408 and we know that our tanks are 16.9...

My TCS still goes off from a dig, but does feel more stable (more straight) as before the tail would slide out towards the passenger side, and around simple turns out of my neighborhood it would slide but not as much so to me didn't feel much difference in grip... I have an 08 so no mechanical LSD... But i have had the tires during the winter and spring season so that may change when the summer texas heat comes along as these tires are summer tires... so i will probably go back to stock size but stick with s04, as i wasn't happy with my PSS i had before in stock size, to save on mpg since gas prices aren't going to be dropping anymore...

lobuxracer

iTrader: (2)

If this were true, I would have bought the C63 AMG. It gets horrible mileage but will smoke the F in a straight line right off the showroom floor. With a few mods, it won't matter what you do to your F short of a 200 shot of N2O and the MB will disappear in front of the F.

I bought the F because it has balance - no gas guzzler tax, decent (but not stellar) reliability, and four doors.

Rossi

iTrader: (4)

Couple photos for you I8ABMR

Rossi

iTrader: (4)

Here is the front......