blazzer

So i am posting as a last resort, most of the info i am looking for i find, and in this case i have found tons of info, but am still very confused.
Tire and rim size has always confused me and need to start asking questions.

I have some buddy club rims 15x6.5. I have been looking at upping the rim size for wider/sticker tires.

i have asked around at some local tire shops and i am getting mixed answers that are confusing me and some of these answers also seem uneducated.

i DO NOT!!! want to stretch my tires, lots of info online says i can do this but i do not want to considering i track my car.

wider tires i am considering are 225/45/15 i have been told these will and will not fit my current rims (15x6.5) that i will need at least a 15x8 minimum. i find this confusing and as much as i have read about rims and tires sizes... i am feeling more confused.

i see articles and threads about people running 7" width rims with 205's and 215's and 225's size tires... info about them being stretch or not is unavailable.

if some explanation could be had i sure would appreciate some. i don't want to be spoon fed i want to learn but i am honestly just confused now. i dont understand how to apply proper tire sizes based on width to any kind of size width rim.

can i keep my current rims and have 225/45/15 installed? do i need to up my rim size or find wider 15 inch rims for a tires size like that? if so why? i cannot figure this out.


( f.y.i) i do understand clearance issues fender rolling, possible suspension geometry adjustments for better fitment/grip/traction etc. i just do not understand tire-rim fitment)

TunerN00b

Whether a tire is stretched or not depends on the specific size pf the tire. General statements only using section width aren't necessarily universal.

Example, a 205/50-15 is usually only rated by the manufacturers for a 5.5" to 7.5" wide wheel, while a 205/40-16 is generally approved for a 7" to 8" wide wheel.

If you want to know if that tire size is safe to use on you wheels, then you need to look up the specs provided by the manufacturer for the specific tire you intend to run. The approved wheel sizes could (but often don't) vary between brands and even models for a single size of tire.

blazzer

so to understand properly, it is not universally about size it is specific to the tire and to the rim based on brand/manufacture.

even so... i find that confusing. i must not be understanding something. for example Nitto's website. they show for the NT01's for a 15" rims 2 tires fit.
205/50/15 rim width>5.5/6.5/7.5
225/45/15 rim width>7.0/7.5/8.5

so the 205's and the 225 both fit rim width from 7-7.5" so does this mean more specially to my application; my buddy club rims of 15x6.5 the 225's will NOT fot the rim safely or at all versus the 205's fitting ideally?

whether it is specific to brand/manufacturer or not. i still do not understand how to find the proper fitment of tire that will fit for safest and best grip/traction. based on rims size/width to tire width. just because a company has fitments on there site does not generally mean it is the best for my size rim. for all i know those nittos sizes could mean under fit/ perfect fit/ stretched fit.

so what am i doing wrong?

0AJ@tirerack.com

Correct, this is not an industry standard thing, it is individual for the tire.

Lets look at a 205/50/15 Dunlop Direzza ZII Star Spec tire.

*see attachment*

Per the manufacture, the tire will fit on a rim that is between a 5.5"-7.5" wheel. You will see that there is a measured rim width spec as well. This means that the tire is optimum at this size. That is somewhat debatable, but is what the manufactures suggest.

So for your 6.5" wheel, the larger you go, the more stretched you will get. Going too large will make the tire be 'sucked in'. I would recommend a 205 size.

Not to confuse you any more, a few other specs to consider are the tread width and the section width when considering performance tires or fitting something to a modified vehicle. Section width is measured sidewall to sidewall and tread width is measured edge of tread to edge of tread. This is important when considering modified vehicles as while some tires may fit the rim width range, the tire itself will run a bit 'large' just as a pair of shoes may run large between brands.

Hope this helps.
-AJ

blazzer

Thnx AJ, that helped a lot. applying what you said and doing some searching and reading, cleared somethings up for me.
Thank you for mentioning the tread width and section width. Honestly never considered that.

really helped made understanding this a bit clearer. thank you for your response :D

0AJ@tirerack.com

Glad to help! If you have any other questions, don't hesitate to ask.