As many of you know, I just got a 98 Cobra. It has 17X8 factory Cobra R type wheels on it.
I want to go with a wider tire in the rear. Some of tire websites like discountdirect.com and tirerack.com use to have a chart showing maximum width tire vs. the wheel width, but I can't find it now.
I know for sure a 255 will fit the 8" wide cobra wheel. But what about 275? I didn't think it would, but on the tirerack.com website, they show 255 x 40 x 17 frt, 275 x 35 x 17 rear, as a tire option package for my car/factory wheels in their application guide. 275 seems a bit wide for a 8" wide wheel, but I'm not an expert on it. And I don't want to buy wheels just yet.
I don't want the tires rolling off the rim at 100mph plus.
Anyone with any experience in tires?
Glen
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-1998 Black Cobra, Kenne Bell 2.1L Supercharged
-2005 Mustang GT, Premium, 5spd, Redfire, Mac Catback
-2007 Roush Nitemare Stage 3 Supercharged #48 of 100
275 will fit on a 8.5. I dont think you can fit more than 265 on an 8.
I went to a tire store and they were telling me that I could put a 275 40 17 on my 17x8. I also asked if it was safe, they told me yes. That's what I wanna do . I need some more tire.
If you go that wide the tire is going to roll over the edge and stick out. Typically it looks retarded when you do that, and it's not safe (no matter what they are telling you, they are just trying to get a sale). When you go that wide you have a good chance of the tire breaking the bead when taking corners with any decent rate of speed.
I have been told over the years, is that just because the tire is wider doesn't mean that the "contact patch", (the width of the tire actually touching the ground will be any wider). Because when a wider tire is forced on a rim that is too narrow it makes the outside of the tire "curl up"( for lack of a better word) and will not lay flat on the pavement.The edges will completely miss the pavement, so actually that extra width you gained with the 275, in this case, will not even be touching the ground. So your in the same boat you were before with the 255. Your best bet is to get the widest tire that will fit on your rim width, where you will have full contact of the tire on the pavement. You will have better traction this way anyways.
I have 275s on my stock 17x8s and they look and perform great, never had a problem. They definately do not stick out funny on the edges. They are 275 40 zr17s, so they are not the lowest profile tires in the world, but they are nice and flush. I don't like that rubber band look anyway.
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Rio Red 98 GT Convertible
Full Densecharger cold air intake
Steeda Intake spacer
Steeda underdrive pullies
Flowmaster cat-back
Dropzone sport springs (2'' drop on all four corners)
B&M Quick-Shift Electronic Shift Kit
In Summary, all of the cheapest performance mods I could find.
At least it looks and sounds fast...
I have been told over the years, is that just because the tire is wider doesn't mean that the "contact patch", (the width of the tire actually touching the ground will be any wider). Because when a wider tire is forced on a rim that is too narrow it makes the outside of the tire "curl up"( for lack of a better word) and will not lay flat on the pavement.The edges will completely miss the pavement, so actually that extra width you gained with the 275, in this case, will not even be touching the ground. So your in the same boat you were before with the 255. Your best bet is to get the widest tire that will fit on your rim width, where you will have full contact of the tire on the pavement. You will have better traction this way anyways.
Yup.
I have 245/45/17 up front and a 275/40 out back, but I am gonna throw a 255/40 on the back this summer. Then again I have over 2,000 tires to choose from in our shop.
If you go that wide the tire is going to roll over the edge and stick out. Typically it looks retarded when you do that, and it's not safe (no matter what they are telling you, they are just trying to get a sale). When you go that wide you have a good chance of the tire breaking the bead when taking corners with any decent rate of speed.
ilblissli:
I understand what you are saying about them wanting to get the sale, but these are two pretty large tire stores (nationwide) and with the whole Firestone/Ford expolorer deal, I believe they are now a little more careful about what they tell you. It doesn't mean they are 100% correct, but I do believe they might be in this case. I also think that if they just wanted to sell stuff, they would have realized that it would be more worth them also recommending new wheels and not just the tires.
What I mentioned about the tire rolling off the rim, is exactly what you said. Breaking the bead. I do run at high speeds for extended periods and worry more about it happening at those speeds. Thats why I am asking.
Quote:
I have been told over the years, is that just because the tire is wider doesn't mean that the "contact patch", (the width of the tire actually touching the ground will be any wider). Because when a wider tire is forced on a rim that is too narrow it makes the outside of the tire "curl up"( for lack of a better word) and will not lay flat on the pavement.The edges will completely miss the pavement, so actually that extra width you gained with the 275, in this case, will not even be touching the ground. So your in the same boat you were before with the 255. Your best bet is to get the widest tire that will fit on your rim width, where you will have full contact of the tire on the pavement. You will have better traction this way anyways.
95blueoval:
When I melt these babies, all of the tire will be touching the ground . Just kidding. I am not doing it just to do it. If they won't fit properly, then I won't put them on. But if they are the proper size and fit, then they will work and get maximum patch to the ground, thats what I'm after.
Quote:
I have 275s on my stock 17x8s and they look and perform great, never had a problem. They definately do not stick out funny on the edges. They are 275 40 zr17s, so they are not the lowest profile tires in the world, but they are nice and flush. I don't like that rubber band look anyway.
98GTdrop-top:
I can't see the tires in your gallary
Quote:
I have 245/45/17 up front and a 275/40 out back, but I am gonna throw a 255/40 on the back this summer. Then again I have over 2,000 tires to choose from in our shop.
blackfang:
Which car in your gallary? You got so many :thumbup
Why are you going with 255?
Everyone:
Thanks for all the input. It would seem the general concensus here is that a 275 will fit. BUT, I have noticed that those of you who are running the a 40 profile. The tire sizing guide says that a 275/35/17 is the same diameter as the 245/45/17? Hmmmm? Basically, you have gone with a slightly larger diameter tire, which means more gear.
__________________
-1998 Black Cobra, Kenne Bell 2.1L Supercharged
-2005 Mustang GT, Premium, 5spd, Redfire, Mac Catback
-2007 Roush Nitemare Stage 3 Supercharged #48 of 100
My current car the 97 cobra. I am going with a 255 because it has a better contact patch over the 275 and they actually look wider on a 17x8 rim than a 275.
How wide of a tire on 17x8" Cobra Wheel? 
. I need some more tire.
. Just kidding. I am not doing it just to do it. If they won't fit properly, then I won't put them on. But if they are the proper size and fit, then they will work and get maximum patch to the ground, thats what I'm after.
