TrIpOd

hey guys, i have 4.10s and i need some new tires. what tire size do I need to keep my gear ratio the same as stock? i have been looking at nitto 555s. are they any good?

jrm1900

I don’t really understand you question, when you installed the 4.10 the computer should’ve been reprogrammed for the new gear ratio so the speedo, TC, and other engine functions work properly.
In order to get a new tire to feel as with stock gear (3:55) you’d need a much larger diameter tire that just won’t fit.
Nittos are a very popular choice for Mustangs but I use Michelin Pilot Sport

TrIpOd

let me try this again, what size tire do I need to keep my gear ratio where is it now? can I have a wider tire as long as I keep the diameter close to stock? i no that if i get a larger diameter tire its going to change the ratio. So what size tire do I need? If I can I would like to get 255s

jrm1900

Ok, then the answer is yes, you can put wider tires and keep the original diameter but you also need to keep in mind clearence problems, I run 255 in the front and 285 in the rear.
I don’t know your wheel size, so the easier way for you to find out what fits is to visit www.tirerack.com input your car details and it will tell you what fits.
If I remember correctly the interpretation of a tire size is as follows
For example 255/40 R18 means:
255 tire width in cm = 25.5cm = 10.04”.
40= size of sidewall expressed as a percentage of tire width, in this case 255 * 0.40 = 10.2cm = 4.015”
R18 means 18” wheel.
Then your tire diameter will be 18” + 4.015”x2 = 26.03”

moosestang

If you have the stock 17's then you could get a 255/50/17 and it would be almost the same. The difference in diameter is so small that it shouldn't matter.

Here's a good tire size calculator where you can put in your stock tire size and see what the difference would be with other tires.

http://www.miata.net/garage/tirecalcold.html

lldsandsll

the width of the tire wont make a difference. it's the height of the tire and/or wheel that you would have to program for if they changed substantially.

TrIpOd

i wanted the 18" shelby razors but they dont fit the 255/50/17. what should i do? find different rims or can i get a tire that will fit the rim but not change my gear ratio?

jrm1900

If you want the 18" razorsyou'll need new tires 255/45 R18 or similar all around, or 255/45/18 in the front and 285/40/18 in the rear.Gear unchanged.

TrIpOd

im not saying your wrong but how do you know that? the ratio would still be 4.10?

jrm1900

Because the tire height of a 255/50/17, 255/45/18 or 285/40/18 is the same, meaning you'll cover the same distance x tire revolution thus you are not altering the final ratio, your speedo will read the same, your MPG will be the same etc.