Will this fit? (width, offset and tire size Qs)

[RazorHawk]

Originally Posted by DaJo

The difference size in wheels may also affect your speedometer reading.

I'm waiting for the S7:F myself...but won't be getting it unless they bring the size down...

If you just get tires that match the stock total height of the wheel, your speedo will be fine. For instance, you will want to drop approx 10 sidewall series for every inch you go up in wheel size, and you will be close. Then from there, do some math to figure it out.

Sidewall series is percentage of tread width that the sidewall is, remember to multiply that times two for total height of the tire (as there is sidewall on the top and bottom of the tire)

Ex:
Stock tire/rim 215/45R17
225 / 25.4 = ~8.46 in. treadwidth (convert from mm to in, divide by 25.4)
8.46 x .45 = 3.81 in. sidewall height (treadwidth times sidewall series)
3.81 + 17 + 3.81 = 24.62 in. (total height of stocl rim and tire combo)

So, with anything we do, we want to aim for that last number there, to keep our speedo on track. If the final number is lower than 24.62 in, we will be going slower than it reads, if it is higher, faster than it reads
)Please note, per Tire rack's website *no affiliation, I just like to use them for reference) most 215/45 R17 are listed at 24.6 in height, although the stock michelins are listed at 24.7 in total height)

I got some winter tires on 16" rims to give me some more sidewall to protect against all the nasty spring potholes in my area. Heres the math on that:
205/55R16
205 / 25.4 = 8.07 in. treadwidth (a little narrower than stock, good for cutting through snow)
8.07 x .55 = 4.44 in. sidewall height (a little more cushion for potholes)
4.44 + 16 + 4.44 = 24.88 in total wheel and tire height. THis means that my tires are now .16 in taller than stock, about .02% so taller than stock. No noticeable difference in speedo reading.

For any wheel and tire combo, you can take the equation below, which is a simplification of the above steps (starting with the standard tire size way of displaying numbers eg. 205/45R17) and leave one variable out, and you can figure out what you want/need/. My recomendation is to leave out the treadwidth variable, bacause you should be able to get close on sidewall, and that will be the most fine tuneable.

(((T / 25.4) x S) x2) + R = H
T = Treadwidth (in mm)
S = Sidewall series (a percentage expressed as a deciamal in our equation)
R = Rim size in inches
H = Height of total package

For the 19 in option discussed above:
We want 19 in rims, 35 series rubber, and stock tire height, so equation looks like this:
(((T / 25.4) x .35) x2) + 19 = 24.62 solve for T
T = 203.92, 205/35R19 would be very close

For 30 series rubber:
(((T / 25.4) x .30) x2) + 19 = 24.62 solve for T
237.91, 235/30R19 also very close to stock.

So, I hope I have not fried your brain, but there are the numbers for you.

[pjb86]

Go here and type in the tire sizes your looking at and it will tell you the outside diameter without all the math.
http://www.csgnetwork.com/tiresizescalc.html

[RazorHawk]

Originally Posted by pjb86

Go here and type in the tire sizes your looking at and it will tell you the outside diameter without all the math.
http://www.csgnetwork.com/tiresizescalc.html

That will work as well! Thanks!

[jchall30]

I guess I just need to look around and see what everyone else on here are using on there 19's. I want it to just look good. . Anyone that has these rims please post what tire size you are using.

JC

[GT86-Ian]

Few cars here for you, but larger the wheel you get worse the ride will be.

http://www.ft86club.com/forums/showthread.php?t=14234

http://www.ft86club.com/forums/showthread.php?t=17039

[DaJo]

Originally Posted by jchall30

I'll email Five Axis and ask about the sizes.

Please let us know what 5:AD's reply is! If they have 18's then I would be very tempted... Better yet 17's

[jchall30]

I will post what they reply. I bet it won't be till Monday.

JC

[DC-FRS]

Would like to know if 18x8.75 +35 all the way around will fit with stock height, and also if it will fit with slight drop lowering springs (either Eibach or Tein).

Thanks!

[ill86]

Originally Posted by DC-FRS

Would like to know if 18x8.75 +35 all the way around will fit with stock height, and also if it will fit with slight drop lowering springs (either Eibach or Tein).

Thanks!

Yep, easy math:
(Compared to OEM)
9mm less inner clearance
35mm extended outward

Front tire may stick out passed fender w/o a little negative camber.

[funcheung]

our car gas little horsepower....18 is good enuf. If ur worried about speed diff, just make sure you use the size that has similar rolling diameter as the stock size. I mounted 225/40/18 and 255/35/18 in the rear. For the track i use 235/40/17.

[jchall30]

Just a lot of choices between wheel size and tire size considering I'm only looking at 3 different wheels from 5 Axis. I am seeing the positives to all sizes. Ugg.

JC

[ZN6_88]

Hey guys, would anyone know if the work vs-xx (18 x 9.5 +20) in O-disk would clear the stock calipers?

[stout90]

how could you miss this thread?

http://www.ft86club.com/forums/showthread.php?t=7535

[JoeBoxer]

Stock suspension I like 18x8.5 +40ish offset with 235/40 tires. Check my build thread I have had a few different setups u can look at.