Kind of new to the stretched tire thing.... help me pick my tire sizes

[ddgsxr504]

As some of you may know I recently came upon a set of FN01RC's for dirt cheap (17X9F/17X10R) and they have 3 different tires on them, meaning the front tires are the same but the backs are different from the front and each other.

So.... I searched and I pretty much have my choices narrowed down. I don't really care about speedo accuracy ( I ran all the number and no matter which set up I go with my speedo will never be off more than 2 mph).

Right now there are 235/40/17's on the front and 255/40/17's on the rear. To me the side wall on the fronts seem a little too small, meaning I want to fill in some more fender gap but I really don't want to lower my car any more (already at a 3 in drop from stock). I am definately going with 235/45's up front so basically I guess I just need help with picking out my rear tires.

Should I go with 245/40's or 245/45's in the rear???

Specs:

[naed240sx]

You definately are not at a 3" drop over stock.

I say lower it more and go with 235/40 front and 245/40 rear.

245/45 is a pretty large diameter compared to stock. Not sure why you would even consider running that in the rear.

Then again, in the end it all comes down to tire selection. Picking sizes first and then buying tires is the wrong way to do it. Decide what kind of tires you would like to run first, then check out the available sizes. I would say get some Falken Azenis 615, but they don't come in the 245 size, so my reccomendation would become 235/40 front and 255/40 rear.

I don't know why you think the 235/40 sidewalls are too small. 205/40 is pretty bad, but 235/40 is plenty, and fits great on a 17x9 (I have RS2s all around on my FN's)

Edit: Just read your note about speedo accuracy. 245/45 is will actually change your speedo by 3.16%. (Still not enough to matter much, but enough to note. In my personal case my speedo is way off because I'm running a 4.36:1 rear diff. Doesn't bother me)

[ddgsxr504]

Ok I am unsure about the drop, it's def around 2.2-2.5 inch range.

I really don't want to lower it more because I already scrape my front chin spoiler on everything I look at. The chin spoiler only sits about 4.5 inches off the ground.

245/45 is actually .1 inch smaller tire diameter compared to stock, but then again I don't know what you used for my stock set up. For me it was originally 205/55/16.

Yes I do need to sit down and figure out what tire I want to get though.

a 3.16% change in speedo accuracy equates to about 1.8-2.0 mph off which you are correct in concluding that it's not much to even worry about.

Since I am already running 235's up front I guess I will stay with that and try our the 245 set up in the rear.

Thanks,

Jason

[naed240sx]

245/45 is actually .1 inch smaller tire diameter compared to stock, but then again I don't know what you used for my stock set up. For me it was originally 205/55/16.

Not true. You are doing your calculations wrong. I used 205/55/16. 245/45/17 is taller than stock.

a 3.16% change in speedo accuracy equates to about 1.8-2.0 mph off which you are correct in concluding that it's not much to even worry about.

Haha no offence, but how the hell did you equate a percentage to a number without using a second number to take a percentage of.

A correct statement would be: "That only equates to 3.16mph at 100 mph, which is not much to worry about."

Different diameter tires will make the speedo a percent off from the factory, meaning if it is off 5mph at 50, it will be off 10mph at 100. It's not gonna be off a constant number throughout all speeds.

Good luck with your tire choices by the way. Finding tires you like in staggered sizes is never an easy task.

[ddgsxr504]

Not true. You are doing your calculations wrong. I used 205/55/16. 245/45/17 is taller than stock.

Oops, I used 245/40 not 45 in my figures which is actually .2 less from stock, sorry I've been at work all day and I'm ready to choke some people out so I'm kind of scatter brained right now.

Different diameter tires will make the speedo a percent off from the factory, meaning if it is off 5mph at 50, it will be off 10mph at 100. It's not gonna be off a constant number throughout all speeds.

Yeah I get that, I used 245/45 as well but I came up with 3.2% exactly, also I was basing my calculations off of 60 mph which gave me a 1.9 mph difference. At 100 mph I dont't think it matters how much my speedo is off.

Anyway I think we are on the same page just different paragraphs. lol

Thanks again sorry if I got confuesd and irritating.

[naed240sx]

Oops, I used 245/40 not 45 in my figures which is actually .2 less from stock, sorry I've been at work all day and I'm ready to choke some people out so I'm kind of scatter brained right now.

If you aren't already, you should use this page:

http://www.1010tires.com/tiresizecalculator.asp

It is amazing. Allows you to compare stock size to 4 other tire sizes at once. Incredibly useful.

[ddgsxr504]

Thanks, I was using some inferior calculator I found on google. I tried to use this one ^ at work but the server chooses not to let me see certain things.

[Juujai]

go with 45 series. s14 deserves 18s thats why.

[naed240sx]

go with 45 series. s14 deserves 18s thats why.

Wait, what?

You are saying that he should get 45 series sidewalls for his 17s because s14s should have 18" wheels?

This makes absolutely no sense.

[ddgsxr504]

go with 45 series. s14 deserves 18s thats why.