255/50's vs 275/40's on stock rims?

[mpentico]

Which is better?

255/50's or 275/40's on stock 17inch rims?

I will be installing a set of Ford Racing springs regardless of the choice.
My current 255/45's have quite a bit of wheel well gap.

I am most concerned with handling. I like to turn fast and sharp.

Will a higher sidewall effect torque to the wheels?
What about gas milage? Which gets better and why?
Will the extra inch of width on the 275's really give me anything?

 

[Mrgreen94gt]

The 275/40's will make the wheel gap worse, and you will probably scrap like hell on virtually anything once lowered. Go for the 255/50's. Nitto offers the 555 in that size now.

 

[anthony05gt]

The 255/50/17 will be 27.3'' tall which is the same height a factory stock. The 275/40/17 will be 25.66'' tall...............way too short. The extra width will give you a better look because they are wider, but I personally like a wide tire. PM me if you want to learn tire math.......it's easy. That way you can figure out what you really want, then check to see if it's available. There are absolutely no drag radials available for the new stangs that actually have the proper height which is 27''. One of these days the tire companies will make a 27''-28'' tall drag radial in 17's or 18's. Right now all they have is a little less than 27'' tall and almost 28'' tall (too tall) in 17''-18'' drag radials. I know you're not looking for drag radials, but I am.

 

[JTGrant]

google tire width calculator or rim width calculator

 

[mpentico]

Well I got the Ford Racing springs today.
Hope to install them next weekend, weather permitting.

Now let me get this.....

The factory 235/55 Pirelli tires are 27.1" tall.

My current 255/45 Toyo tires are 25.9" tall. (or 1.2" shorter than factory)

The car now looks like it has tiny wheels inside a big wheel well.

If Ford Racing springs will drop the car 1.5" inches, wont the Toyo tires fill the wheel well just like the factory tires?????

The 275/40 Kumho tires I am considering are 25.7" tall. (or 1.4" shorter)

Am I missing something here?
When I'm finished this should look just fine... right?

Does anyone have the 17's with 40/45 & spring set up????
Photos????

 

[LeftOvers]

How well do the 275's fit on our stock 17 inch rims? is there alot of overhang or is it pretty good?

 

[351CJ]

Well I got the Ford Racing springs today.
Am I missing something here?
When I'm finished this should look just fine... right?

Yes, you're missing something.
The smaller diameter tires will never fill the wheel wells and they will never look right.
You should go with tires that are the same diameter eg. 255/50.

 

[bluecar]

I have an 07 and my tire shop advised 255/50 tires on my stock 17x8 machined rims. There is a bit more overhang than I want so I am changing to 17x9. They're going to OE Concepts GT500 replicas in a 17x9. My tire shop told me this would be an improvement. 275/40 IMO will look fat and bloated in addition to being too short on stock 17x8 rims.

 

[vansterdam]

This tire calculator recommends staying within 3% of stock tire height. The calculator says that the 275/40R17 would be over 5% shorter than stock which is not recommended.

 

[07 GT/CS]

Just to piggyback on this conversation, what about the 18" rim situation that some of us are in? Anybody upsize their stock tires for a larger set on an 18" rim? Or should I start a new thread instead of hijacking? Did a search on tires and didn't come up with that much on the 18" rim topic.

 

[mpentico]

Well I got the Ford Racing springs today.
Hope to install them next weekend, weather permitting.

Now let me get this.....

The factory 235/55 Pirelli tires are 27.1" tall.

My current 255/45 Toyo tires are 25.9" tall. (or 1.2" shorter than factory)

The car now looks like it has tiny wheels inside a big wheel well.

If Ford Racing springs will drop the car 1.5" inches, wont the Toyo tires fill the wheel well just like the factory tires?????

The 275/40 Kumho tires I am considering are 25.7" tall. (or 1.4" shorter)

Am I missing something here?
When I'm finished this should look just fine... right?

Does anyone have the 17's with 40/45 & spring set up????
Photos????

Well I installed the Ford Racing springs.
It helped with the wheel well gap, but did not cure it.
I do enjoy the ride, and will go with the 255/50 series tires in May.
The added height will also add a little clearance.

The springs also seem to have solved? my hood lift problem at speeds above 100MPH. Guess less air is getting in under the car/hood. ?????

Thanks all for your input.

 

[RhinoGT]

Just to piggyback on this conversation, what about the 18" rim situation that some of us are in? Anybody upsize their stock tires for a larger set on an 18" rim? Or should I start a new thread instead of hijacking? Did a search on tires and didn't come up with that much on the 18" rim topic.

I've been running kumho 275/40 18's on my factory bullitts for about 11k miles now. The tires themselves suck for traction, but they do fit. I am looking into either some bfg gforce kdw2s or bfg drag radials soon.