You can cram them on there, but you will get a "bow" across the tread face that will actually impact your adhesion adversely. The 275 should go on a 9.5" wide rim. There is also a safety issue of increased risk of the rim rolling out of the seam, particularly in a high speed high lateral g sweeping corner. With the generally increased cost of a larger tire, it does not make economic sense to spend more money and get less performance, and increase risk to the driver and passenger. Be both smart and safe, consult with the tire professionals and get the right wheel rim.

 

EAGLE1 - I did consult the tire experts and they said it wouldn't be a problem, and these grip better than the 265's I was running before. And I only pay $65 per tire for any size of RA-1's, so price really doesn't come into play.

Sentry65 - my power levels are pretty punny like Kolia said - only 440 whp and 400 wtq.

 

The NT-01 is a very slippery tire in the wet.

The tread design has very large tread blocks, and wide sipes (which contributes to its characteristic loud humming sound). In the dry it is just awesome, and the strong sidewall modulus gives a quick response to turn in with less inertial roll, as well as a quick "kick back" as you exit a turn. I really like it in the dry. But in the wet it is like trying to walk across a hockey rink in leather soled wingtip shoes.

I was doing a couple of warm up laps at Thunderhill after a rain storm in the morning. No standing water, but the track surface was wet. Looped it twice in two laps out of three at very moderate speed. Once on turn exit, another on a totally flat, slightly uphill straight! Just chugging along in a straight line with steady and very gentle throttle squeeze and ..........swoop! Snapped around in a nanosecond, and counter steer was absolutely useless. After the second one, I just drove it carefully back to the paddock. Lesson learned. For a daily drive....I would not recommend it. Going through a little puddle would be enough to set you into a slide as well, as I recall going through Turn 3 at Laguna Seca one early morning session there was a little dribble of water going across the track, about three feet wide, pretty much on the apex point, enough to give a nice little reflective sheen. Each time I hit it, the car lost grip. And that is not a particulary friendly turn to a spin. Still, there is more space to recover than a typical turn on a city street lined with cars and curbs and sign poles and such.

The RA-1 is a much better wet tire, it is even used by some race teams that run slicks on their cars as their rain tire. But don't get carried away that because a race team uses it in the wet that it is ok for a daily driver in the wet. It is a fabulous tire too........but it is not designed for that kind of use.

The BF Goodrich g-force TA KDW NT is a great tire, and it is a street tire, and it is very reasonably priced to boot. That is a fine daily driver offering with excellent adhesion and wet weather characteristics.....I put it on my wife's car I think so highly of it for all around performance and safety. In fact, they use that tire on the little formula dodge cars at the Skip Barber racing schools. I have driven it those little babies in the wet, hard, and they grip very well.

They also slide but in those light formula cars it is both predictable and recoverable. In our heavy cars once they get going it takes a lot of gripping ability to overcome the inertial sliding force and regain control. The other thing that is clear is that the tread pattern expresses a lot of water, because in an open wheel car.....if you don't have a face shield you will drown!!! After an hour in that thing in the wet I looked like I had been dragged behind a truck through the muck in an oil field. Asphalt residue and water and oil and dirt.....from toes to nose. It gets down through your driving suit, from your collar, the zipper flaps, the ankles and socks, the gloves, and with air pressure up under helmet....amazing how water can find a way to get through.

 

Your decision. If you go to the Nitto site and look up the recommended rim sizes for both the 265 and 275 tread width tires, they spec the 9.5 inch rim and in any event nothing smaller than 9.0. http://www.nittotire.com/tires_555.asp
Same for the NT-01
And, same for the RA-1 http://www.toyo.com/docs/tires/produ...category=sport
That does not mean that it will not fit. But there is no question that it is not ideal. I can tuck my 189 lb frame into a 32 inch waist pant.....but that gives belly bulge over the belt too!

Works just great until I put somebody's eye out on the other side of the room when the button gives way.

The difference of course is that I am just embarassed with a wardrobe failure. Somebody really gets hurt, most likely you, if you separate the rim from the tire at speed.

 

That is pretty funny Eagle 1. But, I had the same concern as you about this same issue. Yet, both Tirerack and Toyo said that it would not fail with a 275 on an 8.5" wheel and they said that many racers do + size due to rules with wheels - so it is pretty common to go outside their recommended wheel. They also said that 8.5 with a 275 won't have a roll over issue, they did say that I should not try a 285 on a 8.5 wheel as I would than loose grip.

 

Carter Thompson regularly ran the 285/30-18 V710 on an 8.5" wide wheel.

 

well, my numbers are going up next week, but my last dyno wouldn't go past 10 psi because the belt would slip. I'm making 12 psi normally. And it's on a dyno dynamics with no correction so you gotta figure dynojets are put out higher numbers so I could just as easily be saying I'm making something like 390 tq, though that's still less than 400


I'm projecting that after next week, my car will be somewhere around 470whp and 390-395 tq on a dynojet. Still not massive amounts of torque, but if the gears are putting 10% more tq to the wheels, that's going to be harder for my tires to grip



and yeah this morning at 56 degrees, the tires just have no grip in the rear - had some tire spinning episodes.

Doesn't help that when tirerack sent me my pirelli corsas, they were 2 years old. Yeah I was pissed cause I didn't catch it until I mounted them and put 10 miles on them. They gave me a $100 refund though, but still doesn't make up for it.

 

Very interesting that they would affirmatively go outside their recommended published rim sizes on a phone call. But, if you are happy with it, fine. And if it is autocross, I would not be super concerned either. But on a a big track, I would stick with the more conservative tolerances and choose the wider rim. (it does appear that my belly roll over is a bigger risk from their reply!)

 

Each tire has different sidewall stability. For example, the Falken Azenis in any size will have a stiffer sidewall than the Kuhmo MX in the same size. Obviously, the height of the ire matters as well. Generally, the smaller the second number is, the less they flex as there's no room for it. So a 265/35/18 Azenis would have a stiffer sidewall than a 265/40/18, ect.

 

i finally got those 245's t1r's on the front to match the 255 t1r's in the rear and it fixed the oversteer. its basiclly back to stock handling again just with better grip all round.