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Discussion Starter #1
Hey guys I'm getting rid of my 18" rims and got a new set of 17" rims

I'm not good with tire sizes, So I'm wondering what size tire should I get, I want something that will fill in the wheel well as much as possible, but I don't want to have any issues with rubbing.

my car is lowered on sportlines, so there might be some rubbing issues if i go too big.

I was thinking 205-50-17

or would I be better off with 205-45-17? I see that size more than anything

So somebody with 17's and a drop help me please
 

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Discussion Starter #3
those look good. I might just go with the 45's instead of the 50's, but if anyone out there is lowered on 50's and 17" rims let me know, I'm trying to find a price on my tires, because the sooner I get my tires the sooner I can get my new rims on.
 

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205/40/17 is what i have... any thing bigger than a 40 is TOO FAT IMO... id rather have a rubberband wrapped around my rims than a big thick tire...
 

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Discussion Starter #8
well I priced the 205-45-17's and I can get them for about $390 mounted and balanced for a set, the 205-50-17's are the same price pretty much lol.

I tried googling cobalts with 205-50-17's and nothing lol.
 

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Here's my new rims BTW



those have 205-40-17 but the tires are too skinny and would look funny on my car.
hmm... im still thinkin 45s... 50s are tooo fat..they'd make those rims look like 15s. my sister's s10 xtreme has 205/50/16s or w/e they are & they look good on the truck... but for a car... 45s... i dont think youd have a wheel gap all that big, would ya?


EDIT: i like those! lol
 

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Discussion Starter #13
yeah you're right I see more 45's than anything and it looks good on a lowered car, I'd be happy to compensate for my 18's which are 215-40-18's So I'm terrible at math, but I wouldn't mind if the outside tire diameter of the 17's matched the tire diameter on my 18's
 

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ok so 215 x .40 = 86. that's your side wall height in mm
1 inch = 25.4mm so 18 x 25.4 = 457.2 now add your side wall height 457.2 + 86 = 543.2

so from tread to tread the wheel in theory is 543.2mm in diameter (there may be a slight stretch if the width of the tire is not the exact width of the wheel lowering the side wall)

now on a 17 we're going to change 457.2 to 17 x 25.4 = 431.8 add the 215/40 to it and now we have a wheel that's 517.8mm

let's try a 215/45 on the 17 now. 215 x .45 = 96.75 + 431.8 = 528.55

ok so...we're getting warmer. now let's try a 215/50.
215 x .5 = 107.5 + 431.8 = 539.3

pretty darn close if you ask me. the wheel is slightly smaller now and the speedo will read a tad higher than actual speed. maybe by 1mph cause you're only off by 4.1mm

hope this helps
 

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Discussion Starter #15
yes that helped alot, So it wouldn't matter that my 18's now are 215, and the 17's will be 205 will it?

also can't I put a 215 on my 17" rims eventhough there's 205's on it now?

I thought I heard something like that.


I feel like a complete tard when it comes to tires lol.
 

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it will matter, because the aspect ratio of a tire 215/40r18 is the percentage of the tire width 215/40/r18 (measured from wall to wall) so a 205/40/r18 will have a thinner wall than a 215/40/r18. catch my ff_drift? :toung:

putting a 215 on a wheel that calls for a 205 will make the side wall bulge and you might have rubbing problems. you may want to re-calculate for that and put an even larger wall on the 205. people do put fat tires on their mustang wheels and stuff all the time though. there's guys doing 335's on their 8 inch wide wheels. it does bulge but since it's only on the rears and those guys don't really care about being low and all they don't have to worry about rubbing.
 

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543.2mm is your 18's overall diameter tread to tread.
a 205/50/r17 will be 534.3mm
205/55/r17 will bring you to 544.55

it depends now, a 50 wall tire will bring your speedo up a little bit but you'll have a thinner wall which to most people is a more appealing look.

a 55 wall is going to be optimal size, but it's going to be pretty fat and may not look so great.
 

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Discussion Starter #19
ok thanks I think I'm going to go with the 50 then, doesn't matter if the speed-o is a little off, I never do the speed limit anyway lol

thank you so much for your help, hopefully in the next few days I'll have the tires mountes and put the new rims on my car
 
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