17x8 why do most run 245/45 when 235/45 is closer?

[alkemyst]

The 235/45R17 is the 'right' fit for a 8" wheel and also closest to the factory 205/55R16 in height.

Why do most run 245/45R17?

Thanks....trying to debate hunting down used Cobra R's with the stock tires for $500-600 shipped or just picking up a new set of 1998 Cobra's + 235/45 Yokohama AVS100ES's for $1066 from tire rack.

[Var]

245 is a more common tire size

[alkemyst]

Yeah I found out that 245/45 comes factory on alot of cars. Whereas normally the 'bigger' tire is a little more expensive the 235/45 is usually the same price as the 245/45.

Anyone know if the gain in cross section/rubber on the ground, is worth the loss of gearing and heavier tire the 245 is?

[edubb11]

245/40-17 would be the optimal tire size, it's rolling diameter is within 0.1" to 0.3" of the stock tire size, depending on the tire.

235/40-17 is approx. 0.5" smaller in diameter, 235/45-17 is approx. 0.5" larger in diameter. So, take your pick based on speedo errors and/or acceleration gains or losses.

[Inland180]

Ive had both sized on my tire and its hardly noticable difference to me.

[Phlip]

Why do either when 225 is even closer?
If math serves me correctly, 205 is the closest to the section width of that 8" wheel... Lets break it down:

205mm - 8.07"
225mm - 8.86"
235mm - 9.25
245mm - 9.65

40 (40% section width)
of 205 - 3.23"
of 225 - 3.54"
of 235 - 3.7"
of 245 - 3.86"

45 (45% section width)
of 205 - 3.63"
of 225 - 3.99"
of 235 - 4.16"
of 245 - 4.34"

17" rim diameter

205/40 17 = 23.46"
225/40 17 = 24.08"
235/40 17 = 24.40"
245/40 17 = 24.72"

205/45 17 = tire height of 24.26"
225/45 17 = tire height of 24.98"
235/45 17 = tire height of 25.32"
245/45 17 = tire height of 25.68"

... compare these to your factory tire size of what? 195/60 15:
195mm = 7.68"
45% = 3.46"
wheel diameter = 15"
total tire diameter = 21.92"

... I explained this shit a LONG time ago and refuse to search for or fully explain my math again. If you can't convert metric to standard, kiss both sides of my ass, use google and come back later.

[axiomatik]

umm, you correctly state that the stock size is 195/60-15, but then you calculate tire height using a section width of 45. it should be:

195mm = 7.68"
60% = 4.61"
wheel diameter = 15"
total tire diameter = 24.21"

[alkemyst]

245/40-17 would be the optimal tire size, it's rolling diameter is within 0.1" to 0.3" of the stock tire size, depending on the tire.

235/40-17 is approx. 0.5" smaller in diameter, 235/45-17 is approx. 0.5" larger in diameter. So, take your pick based on speedo errors and/or acceleration gains or losses.

the 40 series is going to be an odd size to find in those widths.

[orion::S14]

245/40-17 is a pretty common size...

You can get most the good "sport" tires in that size: BFG KDs, S-03s, Kumho MXs, Dunlop 9000s, Pilot Sport, AVS Sport, FM901, ES100, etc...

- Brian

[Dream240]

the 40 series is going to be an odd size to find in those widths.

Hey, just check out www.discounttiredirect.com for these tire sizes and availability. And yeah the 245/40 and 235/40 are pretty common now due to alot of aftermarket demand. Also the 245/45 and 235/45 are even more common due to Manufac. using these right off the assembly line.

[Colorado S14]

I have a 17x8, 17x9 staggered setup on my car and run 225/45 front, 245/40 rear. I like it alot but am switching to a 235/45, 255/40 setup for next year. I just wen KA-T and am really looking forward to the super grip of the 235/255 setup.

[Phlip]

umm, you correctly state that the stock size is 195/60-15, but then you calculate tire height using a section width of 45. it should be:

195mm = 7.68"
60% = 4.61"
wheel diameter = 15"
total tire diameter = 24.21"
Forgive me, I typed a LONG ASS post and I was drunk when I did it... One error in the math used, but the idea was right, correct?

[axiomatik]

No worries, I just added that in case someone didn't notice the error and was trying to figure out why you were making calculations for tires that were 2-4 inches taller than stock.

[ghostuss]

I heard it give mroe grip Haha. Just wondering if that's true since this autoX guy was asking for 245 width tires.

[Dream240]

I have a 17x8, 17x9 staggered setup on my car and run 225/45 front, 245/40 rear. I like it alot but am switching to a 235/45, 255/40 setup for next year. I just wen KA-T and am really looking forward to the super grip of the 235/255 setup.

I have the 235/255 set up with 17x8/17x9. And I can tell you it's the shizzle.
I can't even loose grip on purpose...in the rain!!! I'm running with Toyo FZ4s and FN01R-Cs. i'm sure it's not ideal for drifting but I'm not there yet so who cares?

[ghostuss]

I am wondering if 235/55/16 with 8in width (26 in) will fit under s14 rear and still don't have to roll it? I am running the 25.6 right now and it only barely rubs the mud guard on high speed sharp turns. I saw a good deal on the 235/55/16 and I am wondering if I should get this size and use them for my spare 16in rims.

[Dream240]

Well the overall diameter of the wheel would be 664.90mm or 26.18 inches which is well over the largest size mentioned earlier.

This most likely will rub. Why not go with a smaller sidewall? 235/45? Not a common tire size but doable.

[sykikchimp]

if you care about neutral handling, don't stagger your tire sizes.

[ghostuss]

Well the overall diameter of the wheel would be 664.90mm or 26.18 inches which is well over the largest size mentioned earlier.

This most likely will rub. Why not go with a smaller sidewall? 235/45? Not a common tire size but doable.

It's for economic reasons. Some cheap tires to use in drifting practices. Now I htink I will do 225/50 at the rear.

[msaskin]

if you care about neutral handling, don't stagger your tire sizes.

I understand the point you're getting to, but it has a lot to do with tire choice and suspension setup as well.

I run Azenis Sports on FN01R-C's.

225/45/17 front on 17x7
245/45/17 rear on 17x8

My car is neutral as all get-out. NEVER had any understeer to mention, oversteer is simply a matter of tossing the car properly. If I'm controlled in my steering regardless of throttle input the car stays right where I want it to.

~matt

[Dream240]

I think he means staggering the sizes vertically. 17s and 18s would screw with the handling. Not the widths of the rims. I run 17x8 front and 17x9 back and NO understeer and minimal oversteer, usually when I want it. Good setup.

[Red]

I dont think he's talking about 17" - 18" stagger...

The C6 corvette has 18" -19" stagger and its a beast in the turns.


I'm running 18x8.5/18x10 235/265 stagger... I have understear due to the fact I have hard rubber on the front and soft on the back.

But with my extra power I can just kick the back out if needed.

Once I'm not a cheep ass i'll get the same tires in front...