| Tire stretch diameter. - Click HERE for Original Thread |
| blue_monkey_man |
Hey sorry if this is kinda a newb question. But anyways I have a set of staggered rims 16x7(front) and 16x8(rear). The fronts have a pair of brand new 205/45R16 tires on them and I need to get new ones for the rear. A guy I work with said I might need to stretch a tire with a bigger sidewall to get the same diameter. So my question is does anyone know what tire I can use so the rim and tire will have the same outside diameter? The outside diameter of the tire must be the same as the front once on the rim, but it is okay if there is a bigger contact patch. Hopefully you can understand what im trying to say. lol
-Thanx :) |
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| Invalid Zero |
Unless you stretch a 205/45-16 on the rears you won't get it exact. Your ideal tire size to match the front diameter would be 235/40-16, nobody makes that size as far as I can tell though.
You could go with a 225/45-16 but they would be slightly taller.
16" wheels limit your tire choices. |
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| JustinL |
Ok, let me just double check to make sure I understand what you are asking. You want to keep font and rear diameter the same, and you are worried that the stretch of a 205 on an 8" rim will lower the diameter of the tread because of the angle of the sidewall. Interesting question. First of all, it is not necessary to have the same F/R diameter unless you have 4wd with a locking center diff. Still I'll do some math for you because I hadn't thought of this issue before.
We need to find the height difference in the sidewall of a 205/45/16 from vertical (7" rim) to angled (8"). Sidewall height is 92.25mm. Adding .5" (12.5mm) to the base of the triangle gives a new height of 91.4mm. The difference multiplied by 2 is a 1.7mm outer diameter difference between 7" and 8" rims. If you are comfortable putting 205s on your 8" rims it will only be off by a marginal amount. It's .5" outside the recommended rim width, but you can read about opinions on tire stretch in other threads.
I'll second the 225/45/16 recommendation if I was doing this on my car. |
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| zhao |
what car is this for anyway? odds are your stock tire for it isn't a 205/45/16 anyway, so thats probably not same diameter of the stock tires and thus isn't a good point to be matching other diameters up to.
it sounds like ur using civic/corolla sizing, and those had a stock diameter usually of just under 23in's (i think civics were usually 22.7-22.8ish on 14in tires). ur 205/45/16s are roughly 23.3 inches. going to a 225/45/16 would push it to 23.7ish which may be a entire inch more for diameter depending what car its going on
something like a 215/40/16 would be roughly 22.7 so should may be a better option then the 225/45/16s depending on the car, and would fit on both 7in and 8in rims.
in a 16in you have almost no tire choices so you can't just go up a fraction of a size, its usually a increase by leaps and bounds. |
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| blue_monkey_man |
| Thank you for all the good helpful responses. It is for a 1992 Eagle Talon TSi, it is AWD so that is why I am concerned about the diameter matching front and rear. the size on the rear now is 225/45R16. So do you think that it is okay the way it is? I was just concerned because the rear appeared to be taller but mabey that is just me being crazy lol. |
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| zhao |
u should be using a 25in diameter for that car from what i remember. the tires you have on there right now are too small for that car by over a inch. you probably have a lot of wheel gap because of that, and the car is actually sitting lower to the ground by over half a inch.
also, do not run a staggered setup on that car, that is going to mess with the awd something fierce because you will never get the sizing close enough. |
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| blue_monkey_man |
| So do you think I can just get bigger tires or is my bet bet just to buy new rims? |
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| zhao |
bigger tires and new rims, staggered rims are never goign to work right on that car.
a 205/55/16 is stock. 225/50/16 is a good size too, not sure how wide you can go on the first gen talons but those 2 sizes should work fine unless you have some stupid offset rims |
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| blue_monkey_man |
| Ok I think I am going to be going to a tire size like with new rims or mabey a 17" rim. Thanks everyone for your help |
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