Do 265 35 18's actually help slalom spd or lateral g's? Also, an Offet question...

Farmerbob · Nov 1, 2009, 01:40 AM

Hey guys, I notice that a good number of people upgrade to 18" wheels which are wider than the 8.5" stock (say to 18 x 9.5 or 10") and then put on 265 35's at all 4 corners, usually lowered on springs or coilovers.

Has anyone actually tested a before and after with the stock 245's vs. wider and lower profile 265 35's tires? Do they help day to day cornering driving, twisty road driving, slalom speed or lateral g's? 265's seem much wider at all 4 corners than the stock 245's, so wondered what effect on daily driving was like.

Also, if you go with 18" x. 9.5" wheels, and 265 35 18 tires, and if car is lowered on springs or coilovers, would you need at greater than 22mm offset (22-35) so the fenders won't need to be rolled? I like the RPF1 18 Enkies, but I think they are only 15mm or 38mm offets, so 15mm would rub? Thansk.

rallyredX · Nov 1, 2009, 07:23 AM

enkei rpf1 18x9.5 +15 on 245s don't rub. ;-)

Farmerbob · Nov 1, 2009, 02:24 PM

Thanks RallyRedX.

So you have Swift lowering springs with the RPF1's in the pictures? Did the Swift's lower about 1" in front and rears?

With that +15 mm offset, do you think the tires would rub on the inside at full lock, right or left, if you went with wider 265's x 35 x 18's? And, these are pretty light at 18.6 lbs vs. the stock 22 lb GSR rims - did you notice any improvement in acceleration or quickeness off the line?

I'm still wondering myself whether going from 245's to 265's on lighter 18" rims would actually help or hurt the handling of a GSR? 265's are really wide tires, so you get more contact rubber at each corner, but it already corners well at almost 1g in stock form, so I wonder if that balance gets messed up with 265's? Anyone have feedback? Thanks.

goofygrin · Nov 1, 2009, 02:32 PM

It depends on the tire fit on the wheel.

Assuming all other things equal, the more tire you put to the ground, the greater the total grip available for big turns (sweepers, onramps, etc.).

However, if the tire doesn't fit well (bulging sidewall, etc.) then the lateral responsiveness will suffer (i.e. slaloms). The best case is a wide wheel with a slightly stretched tire on that wheel. This will give you lots of width for big corners and a stiffer, responsive sidewall for lateral responsiveness in slaloms and the like.

And can you tell the difference day to day? Depends on how you drive

rallyredX · Nov 1, 2009, 05:52 PM

I feel 265's may rub. As for the performance from the lighter rims, maybe better fuel mileage.

goofygrin · Nov 1, 2009, 06:27 PM

depends on the tire and offset as to what's going to rub... "fat" 265s like an AD08 or Star Spec might rub at full lock if you've got an aggressive offset. If you're running a normal or "skinny" 265 like a falken or nt05 on a +22 then you're likely not going to get any rubbing.

I get very little rubbing (and only at full lock) with 275/35/18 NT05s on 18x10.5+15 RPF1s.

MrBonus · Nov 1, 2009, 07:22 PM

My 265/35/18 R888s do not rub anywhere.

Farmerbob · Nov 1, 2009, 09:12 PM

Do you guys running at 265 or 275 wide tire find any noticeable improvement in handling, turn in, twisty road driver control, etc.

goofygrin · Nov 1, 2009, 09:15 PM

You're asking a dumb question. Assuming the same tire, a 265 or 275 will ALWAYS have greater grip than a 245 (unless you're in snow or rain, but we're talking dry traction here).

If you can't imagine why, then you need to turn off the computer and think about it a bit.

MrBonus · Nov 1, 2009, 09:23 PM

Quote:

Originally Posted by Farmerbob

Do you guys running at 265 or 275 wide tire find any noticeable improvement in handling, turn in, twisty road driver control, etc.

I run wider, stickier 265s on the track so of course I notice an improvement in corner and exit speeds. More contact patch, more grip.

morfhious3 · Nov 1, 2009, 10:37 PM

Quote:

Originally Posted by goofygrin

depends on the tire and offset as to what's going to rub... "fat" 265s like an AD08 or Star Spec might rub at full lock if you've got an aggressive offset. If you're running a normal or "skinny" 265 like a falken or nt05 on a +22 then you're likely not going to get any rubbing.

I get very little rubbing (and only at full lock) with 275/35/18 NT05s on 18x10.5+15 RPF1s.

are you on lowering spring or coilovers?and in what camber?i guess no fender rolling.can you put some pics.i really like that setup what you have but then theyre been telling me it will rub a lot compared to yours little rubbing at full lock.and forgot to mention lowered 1 inch with swift.what do you suggest should i get the 18x9.5 or 10.5 +15.i'll be getting the nto5s too 265 or 275?no fender rolling as possible for me

flyguycfi · Nov 1, 2009, 10:46 PM

Quote:

Originally Posted by morfhious3

are you on lowering spring or coilovers?and in what camber?i guess no fender rolling.can you put some pics.i really like that setup what you have but then theyre been telling me it will rub a lot compared to yours little rubbing at full lock.and forgot to mention lowered 1 inch with swift.what do you suggest should i get the 18x9.5 or 10.5 +15.i'll be getting the nto5s too 265 or 275?no fender rolling as possible for me

10.5 +15 will probabaly require some fender rolling.

goofygrin · Nov 2, 2009, 07:28 AM

"probably" is an understatement. You'll need to roll the rears and run more than stock camber.

There are lots of pictures on this forum of my car and others with the same setup.

mpboost · Nov 2, 2009, 07:56 AM

Quote:

Originally Posted by flyguycfi

10.5 +15 will probabaly require some fender rolling.

+1

I am 99% sure goofygrin has rolled rear fenders, I know he also runs a lot of camber (especially in the front) for autocrossing.

I have the 18x9.5" +15 RPF1's with 265 Star Specs, and rear fender rolling is definitely required. The only way around that would be to run stupid amounts of rear camber or stick to a 245 tire. The front fenders are not as ciritical, and typically you are going to want 2 or more degrees negative camber up front anyways which will tuck the wheels in slightly. My front tires rub ever so slightly at full lock, but I don't worry about it because the only time I ever am at full lock is when I am trying to back out of tight spots in parking lots etc.

goofygrin · Nov 2, 2009, 08:21 AM

I'm rolled/pulled in the rear (to fit 285 hoosiers, which are like 305's in normal tires). 3.2* up front, 1.4* in the rear.