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Are Your 275/40-18 at all corners still working well?


ingram4868

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I remember several years ago that members opted to go with 275/40-18 tires rather than the staggered size. I think Micheline were the favorite tires at that time.

 

Anyway, I have to get tires for my newly acquired 18 x 9.5 inch KR rims. I would like to use one size tire so that I can put a spare tire in the trunk of the same size. I won't be racing with these rims and tires, just cruising to car shows.

 

For those of you that went this route, is it continuing to work out for you, did you drop the practice and which tire do you prefer?

 

Thank You

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I am running Michelin Pilot Supersports 285/35-18 on all four. PSS is an excellent dual purpose (street/track) tire. Definite handling improvement over the staggered setup, particularly in reducing understeer. 285's would be a very tight fit with stock suspension (between inside sidewall & front spring), but I have upgraded front strut/coilovers, 275's will fit & I would go that route with OEM setup if you are considering it. Also 275 is same diameter as stock so they won't throw off your speedo.

Most tire shops will allow a test mount for fitment & exchange if they don't fit as long as you don't drive on them.

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I have used the 275/40-18 on the 18 x 9.5 wheels for a long time and I have the same as my spare . I run the Michelin Pilot Sport PS2's - have 12,000 miles plus on them and still have tread - and use them on the track for open track days . It's nice to be able to rotate ( including the spare ) . Very happy with the setup !! Wish I had a set of those KR wheels .

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I just put on a set of 4 275/40-18 BFG Sport Comp-2s and love them. A great street tire in the dry and wet. I'll be using them at the track this weekend, they're supposed to be a decent track tire as well. They're going to be going on my street rims next Spring.

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Thanks for the recommendations thus far (keep them coming). While I give this more thought I think it would be smart for me to select an A/S tire for the KR rims when I go on trips. My stock rims were widended and have NITTO NT05 rear tires with INVO's on the front. That's the setup for around town, just incase someone wants to play or I feel the need :)

 

The BFG's look like a bargain compared to the Michelins.

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I just put on a set of 4 275/40-18 BFG Sport Comp-2s and love them. A great street tire in the dry and wet. I'll be using them at the track this weekend, they're supposed to be a decent track tire as well. They're going to be going on my street rims next Spring.

I have BF Goodrich Sport Comp-2s 255/45/18 on all four corners and my KR rims are going on tomorrow. I used the 255s at the track in Jan on stock rims and they were great!! I bought 2 new BFGs 275/40/18 to put on the rear and use up the 255/45/18 on front only at the track when I go back again in Jan with same group. When I use up both sets of front 255s, I will replace with the same BFGs 275/40/18 on front so that the same tire will be on all four corners again, just in the larger size on KR rims!!

 

Andy

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Thanks for the recommendations thus far (keep them coming). While I give this more thought I think it would be smart for me to select an A/S tire for the KR rims when I go on trips. My stock rims were widended and have NITTO NT05 rear tires with INVO's on the front. That's the setup for around town, just incase someone wants to play or I feel the need :)

 

The BFG's look like a bargain compared to the Michelins.

My Ford dealer got me a great deal on my 255/45s, so I went back for the 275/40s...again a great deal for Atlanta...$185 per tire and free Nitrogen fill. Mount and balance was $65 for all 4. Nothing else....

 

Andy

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Andy,

 

I've found that I need to check and sometimes add air to my tires about 3 months. I live at 5000 feet and in the fall /winter the outside temps can swing drastically.

 

When you have nitrogen in the tires what do you do when you need to add air? Do you mix regular air or take it to a facility with nitrogen?

 

Last question do your HAWK HPS pads cut down on brake dust or did you buy them for performance value?

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Andy,

 

I've found that I need to check and sometimes add air to my tires about 3 months. I live at 5000 feet and in the fall /winter the outside temps can swing drastically.

 

When you have nitrogen in the tires what do you do when you need to add air? Do you mix regular air or take it to a facility with nitrogen?

 

Last question do your HAWK HPS pads cut down on brake dust or did you buy them for performance value?

Supposedly the nitrogen varies less than the oxygen as temps change. You can top off with oxygen as needed or I just swing by the dealership if I need to add any air. If you mix the two, you will start to diminish the nitrogen benefits. You will never have 100% nitrogen since some oxygen will be present in the tires when they are mounted on the rims...there is no vacuum created to remove the air as nitrogen is introduced into the tires.

 

The HPS Hawk pads were primarily for performance since i went to a track event in Jan, but I thought I heard that they are better on the brake dust issue than the OEM pads, but I can't confirm that since I added the SGT Front Brake Cooling kit so ALL my brake dust gets blown out on to the outside of my front rims in very quick fashion!!! At least they work as advertised (Thanks Jer!!)

 

Hope that helps!

Andy.

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I remember several years ago that members opted to go with 275/40-18 tires rather than the staggered size. I think Micheline were the favorite tires at that time.

 

Anyway, I have to get tires for my newly acquired 18 x 9.5 inch KR rims. I would like to use one size tire so that I can put a spare tire in the trunk of the same size. I won't be racing with these rims and tires, just cruising to car shows.

 

For those of you that went this route, is it continuing to work out for you, did you drop the practice and which tire do you prefer?

 

Thank You

 

 

I'm running the same size on all 4 corners with Hankook Ventus Evo K12's....love it!

 

And I track mine, and drive it in the rain....no trailer/garage queen here

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  • 2 months later...

Do any of you have lowered suspensions with this wheel/tire setup? I'm wondering if there are issues with the lowered FRPP kit and 275/40/18 all around.

I have the FRPP suspension off of my SGT on my 2009 Mustang GT convert with 275/40-18s on KR wheels and have NO PROBLEMS !

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  • 3 weeks later...

I'm planning on 275/40-18s all around on a 2012 GTS. Need to recalibrate speedometer/odometer?

It depends on what you are switching from....

 

I went from factory rims and tires at 235/50/18 to new tires only at 255/45/18 on all four corners and needed substantial change to speedo programming. Then, I switched the 255s to new 275/40/18 on new Alcoa KR 18" rims on all four corners. This time, the speedo is only a slight bit off....it reads 50 and actual speed is about 49.6, so I'm ok with that amount of accuracy.

 

I figure if I'm doing 55 in a 45 zone, then my actual speed may only be 54.5, so the police may not mess with me. I still tap the brakes and slow down, but I figure I'm better off being 1/2 mph slower than actual speed...it may just save me a ticket one day.

 

Differences can vary from one manufacturer to another in the posted number of revolutions for the same size tires. I even found that the posted tire revolutions were still not accurate for my new tires and had to adjust by trial and error until I was comfortable with the accuracy for my specific car..

 

Hope that helps.

Andy.

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Yep! It told me that I needed to use a value of something like 745 rotations for my tires, but I actually wound up using something like 795 or 800 to get the speed to be accurate. I used 3 different speed detection radars that they have posted around my general area near school zones. They are mounted just above the speed limit signs and show your speed...very accurate too. I used my Expedition and my wife's car to verify the reading was accurate before I began.

 

I didn't want to rely on one reading so I test it against three different ones where it was easy and safe to do. Two were on the same street on either side of the school zone. I just waited until about 10pm when school was closed, traffic was super light, and then brought the speed up to 45 (in 35 zone just before the 25 mph school zone starts). Once I got the correct value programmed into my SCT X3 tuner, then I ran it past the same 2 again, but this time at 50 to make sure there were no major variations. At 45, I was in 4th gear, but then at 50 I was using 4th gear on one set of passes, then O/D on a different set to make sure there were no issues.

 

I also have a GPS watch that I use for running, and that can do the same thing, but it is harder to look at the watch and the speedo especially when dark. I found it was much easier to use the Speed Limit Radar signs and glance back and forth several times while driving to make sure everything was holding steady.

 

When I mounted the 275's on the new rims a few months ago and re-tested again, I found that one of the readings would flip back and forth multiple times from 49 to 50, so that is why I think it may read slightly lower than actual now, and technically the circumference of the new tires should be just a hair shorter than the set of 255's. To me it was not worth making any changes, and again, I'd rather read 0.5 faster that I'm really traveling when a Officer is on the other end of the speed detection!!

 

When I go to the track in January, I'll take my Garmin GPS watch and test it once or twice on the straight at 100 to see what it reads...that's the real test for accuracy!

 

Good luck!

 

Andy.

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  • 2 weeks later...

For what it is worth, I'm now running 275/40/18 on all 4 corners....Albino500 talked me into the balanced set for the track and sell the 255/45/18 tires to a used tire shop. I added the Fays2 Watts link and really loving how my SGT handles and corners!!! The 275/40/18s are awesome.

 

Andy

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  • 1 month later...

Update....

 

I took the car to the track last weekend and the 275/40/18s worked very well. I even swapped the front to rear on the last day of the weekend event...that's the beauty of having 275/40 on all four corners.

 

No problem with how the car tracks going down the road...it doesn't suddenly seek the other lane or something.

 

Enjoy!

 

Andy

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I'm glad to hear the update. Thanks! I only recently heard of "tramlining." More snow here in MA tomorrow reminds me that I need to remain patient.

 

I recently noticed that the Shelby GTS prototype had 275/35-18 tires on all 4 at one point. But those were BFG g-Force R1 track tires. The GTS wheel/tire package currently uses 255/45-18 & 285/40-18 Goodyears.

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