maxpower220

iTrader: (1)

Explain why the metric tire formula for sizes uses the SAE inches for rim diameter. That's the only confusing part; the mix of metric and U.S. measurements.

If I were make a tire, I'd use metric for width, inches for sidewall, and a ratio of perceived coolness for rim diameter.

BassAckwards

Lol yeah I can't explain why they change it for the rim size but that's what they do.

DWTampa

I am very new tot his forum and happy to have found it. Your 2 posts I have just read did exactly what you said it would do and explained the tire sizes very clearly. Thanks for that. I have been reading and reading to try to see if my question has been addressed already somewhere... and also trying to figure the best board to ask it on.
I have a question about what size tires my stock rims will accept. And how to exactly know what width my stock rims are. I have a 2012 F150 XLT 4x4 super crew with a 5.0.
If you could shoot me any advice on my question or where I should post it I would appreciate.
Thanks
DW

BassAckwards

What diameter rim do you have now? The 20"s are generally 8.5" wide, 22"s are 9" wide, 18"s I think are 7.5" wide but I could easily check, and the 17"s are 7" or 7.5" I think again I could easily check so just let me know!

DWTampa

Thank you for the reply. I should have mentioned my factory rims are 17". I am trying to see if I can get a tire with a diameter of close to 35" and as wide as I can go and still keep my stock rims. I have a 2" leveling kit installed already and I really like the look of a wide tall tire with mucho side wall.
Thanks again for the reply,
DW

BassAckwards

Your wheel appears to be 7.5" wide and the biggest tire you can fit with a 2" level kit is 35x12.50R17 which is the same as a 315/70R17 for a 4x4 F150. Either one technically is recommended to only fit a minimum of 8.5" wide rim but it would still work on a 7.5" rim wide technically. I've seen a bunch of people do it. You can decide for yourself if you want to go that route.

mustangtrey

would 275/70/18 fit a stock 2010 fx2 or would 275/65 be better?

BassAckwards

275/65R18 is a stock size.

275/70R18 is an inch taller @33"

It's a close call a 33" might fit a 2wd but I'm not 100% positive.

WeRodeInTrucks

I need new tires and I've always wondered about the size and conversions and how they work. Because of you im at less of a loss. Thanks a ton!

AHmotorsports

Metric works in MM.

1ST Number- Width of tire (ex. 265=265mm wide)

2ND Number- % of Width (ex. 265/65R18, Sidewall equals 65% of 265mm)
*this is the part everyone gets confused by 265/70r18 being taller, 265/60r18 being shorter. All same width at 265mm. *Just because a tire has a LARGER first number, does not mean the tire is TALLER just WIDER.

3RD Number- Size of rim

Tip- tire-size-conversion.com/metric-tire-conversion/
*easy cheat tool