how would you pick a tire for a 17 or 18" rim that would keep the stock dimensions as a 245/50/r16

or in otherwords the same ride height.

 

i think that for every inch bigger rim, you go down one series.

Example, 17" rim would be 245/40/r17
18" rim 245/30/r18

i think

 

just go to a tire manufacturer's website and look them up. ie, check out BFGs site, and look at the info they have...they list the diameter's etc. for all their tire sizes.

or, just do this...

for a 245/50R16 tire...

take the width (the "245") and divide it by 25.4, then multiply it by the aspect ratio (the "50") divided by 10. that gives you the sidewall height...

245 / 25.4 = 9.646"

9.6456 x (50 / 10) = 4.823"

now, multiply that by 2 (because there are 2 sidewalls), then add the diameter of the tire (the "16")

4.823 x 2 = 9.646

9.646 + 16 = 25.646"

so, the total diameter is 25.646"

try it with others and you can always figure out the tire heights...

-b

 

to damn smart for your own good.

only one problem....the 9 * the (50/10)= a higher number than 4.?

 

yeah...its 4.823....

-b

 

That looks VERY familiar.

You should type yours up on "Paint" then save it as a .jpeg file. That way you don't have to type it everytime someone wants to know. That's what I did.

 

actually i was going to say 48.23 since 9 * 5 is 45.


but i knew what you meant.

 

ahhhh ok...sorry...its late...

-b

 

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

 

This Calculator is pretty nifty as it show all tiresizes for different size rims equal to your stock tire size


Ken

 

thanks everyone!

 

yeh i just bought some cragars but they still 16's does that mean that i get the same tire size or does it matter that they are 16x7. u know me im the typical dumb high school football player. so could somebody give me the dimensions on a tire with 16x7?

 

You can still use the same size tire. The only diff is the bead (where the tire seals to the rim) will sit in a little farther. It will actually make it look like you have fatter tires on there than you actually do.

 

Here ya go I think this is what you are looking for? http://www.c5-corvette.com/tirecalc.htm

 

thanks for that vette link! that's nice....

 

Try this link

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

 

that was really good too!

nice to get a rough idea of the tire sizes with a picture like that.

thanks alot!

 

so if i got 18X8.5" rims
do you think either one of these 2 tires would be good enough
275/35/18?
285/35/18?
and what about back spacing?
thanks in advance

 

your putting a large tire on a narrow rim..........i wouldn't do it. i'd look to more of a 245 or a 255 at most probably.

i'm looking to put a 275 on a 9.5 wheel and your trying to do it on a smaller diameter like a 8.5?

i'm sure it's been done, although i don't think i would want to try it.

good luck.

 

i thought it might have been to wide of a tire
these rims also come in 9.5, but i don't think i would want that because i don't want the tire to stick out of the fender wall at all
does anybody have a picture of 9.5" rims from behind the car??

 

you have to understand that the width of the rim doesn't necessarily mean they will stick out....it's all in the spacing.

you can get 8.5 rims although most companies that sell these versions i don't trust.

the 17 firehawk wheel is 9.5 so it must work. it better work...

 

http://www.dakota-truck.net/TIRECALC/tirecalc.html

 

For 18's you want a 40 series tire. Its not the exact same overall size as the 50 series on a 16" wheel, but its the closest you're gonna get. My 18's are 18x8.5 front and 18x9.5 rear and I'll be using 245/40/zr18 rubber in front and 275/40/zr18 rubber in the rear. I could go with with wider tires but I want to be able to tuck the wheels in the fenderwells when I adjust the suspension to the lowest setting (for shows).

 

You guys are making that waaayyy harder than it needs to be..ok...so u know what the numbers mean..you really dont need all that math..i used to work at a tire store; here's the easy way to do it (if you dont believe me, go ask someone at a tire store to see two diff. tire sizes after you calculated them..it'll be damn close)

If you were to stay in the same rim size (16), if you wanted to put a wider tire on it, its called plus zero. Basically you increase the width ten, and decrease the aspect ratio by 5. Thus, you'd get 245/50/16 (what im runnin now), which is basically the same height as a 235/55/16

To change rim size, you plus 1. Basically what you would do is for every rim size you increase, you would increase the width by 10 like before, but this time decrease the aspect ratio by 10. So if you were going to a 17 inch rim, you'd go to a 245/45/17 (change from the origional size of 235/55/16. To an 18 you'd be lookin at 255/35/18. Now i know for a fact taht there is no such thing as a 255/35/18, so therefore you can go back to plus zero the opposite way in the same rimsize (decrease the width 10, increase the aspect ratio 5), resulting in a 245/40/18 and so on. I hope that helped. (that way as well the speedo shouldnt be affected, or if it is not nethin noticable)

 

according to all the math........it's getting a little crazy in here.....they all say that in order to keep the same idea as my stock 245/50/r16's i will need a 275/35/zy18 in the front and a 295/35/zy18 in the rear.

anyone agree to this?

 

not i

 

why not explain why...........all the number add up to this being the optimal solution.

show me a better way then rather then leaving me hanging. i wouldn't post this question if i wasn't looking for help you know.

 

?what do ya mean..i did explain it up like 2 or 3 posts

 

Use the tire calc from the C5 website. Compare the sizes you mentioned. You will find that 40 series sidewall on an 18 is the closest you can get to 50 series sidewall on a 16. The 35 series sidewall on the 18 would make you're speedo off by 3% (while the 40 series makes it off by .3% or something).

 

umm dude your math and numbers method contridicts read back over what you said........

 

all of this is getting to be too much.

could some one tell me what will work.

i am running a 275/18 tire on the front. can i get away with a 40 series with a slight lowering or is a 35 the only way to go.


that's all i want to know.