Tires sizes that fit the stock rims?

[HotSnatch]

I have what is probably a dumb question, but can someone clarify if there are different tire sizes that can be mounted on the stock mazdaspeed wheels? I was thinking about something in the 225 width range. Thanks.

[ymic]

225/40/18 is the same as stock

I'm running 225/45/18 on the stock wheels... little more sidewall than the 40's

[AWDthis]

225/40/18 is the same as stock

I'm running 225/45/18 on the stock wheels... little more sidewall than the 40's

+1

[HotSnatch]

225/40/18 is the same as stock

I'm running 225/45/18 on the stock wheels... little more sidewall than the 40's

Thank you sir.

[funksilver07]

225/40/18 is the same as stock

I'm running 225/45/18 on the stock wheels... little more sidewall than the 40's
What tire, any rubbing issue?

[funksilver07]

225/40/18 is the same as stock

I'm running 225/45/18 on the stock wheels... little more sidewall than the 40's

225-40-18 same as stock? Could you explain that, please> stock tire size is 215-45-18. I'm also soon to be getting some new tires and think I'm going to try the 225-45 on the oem wheels...

[GoFast]

225-40-18 same as stock? Could you explain that, please> stock tire size is 215-45-18. I'm also soon to be getting some new tires and think I'm going to try the 225-45 on the oem wheels...

"same as stock" means that the diameter of the tire is as close to stock diameter as possible. While it is not exactly it is the closest alternative. if you google tire calculator it will bring up several useful calculators to tell you what each size tire is and will affect when compared to stock

[funksilver07]

exactly...a 225-40-18 compared to stock is 2.1% too fast, where the 225-45 is 1.4% to slow. The diameter for the 225-40=25.1" to the 225-45=26" compared to stock size which is 25.6." I've actually done this before, just didn't understand the statement that a 225-40 is the same as stock, it's not... both 40 & 45 series in a 225/18 will be close to stock size, not the same as. Just trying to clarify... http://www.miata.net/garage/tirecalc.html

[GoFast]

exactly...a 225-40-18 compared to stock is 2.1% too fast, where the 225-45 is 1.4% to slow. The diameter for the 225-40=25.1" to the 225-45=26" compared to stock size which is 25.6." I've actually done this before, just didn't understand the statement that a 225-40 is the same as stock, it's not... both 40 & 45 series in a 225/18 will be close to stock size, not the same as. Just trying to clarify... http://www.miata.net/garage/tirecalc.html

exactly. I dont think that a lot of people realize this. They think that a few tenths of an inch don't make a difference, but they do.

[ymic]

What tire, any rubbing issue?

Kumho Ecsta ASX 225/45/18, decent all seasons... I only rubbed once in the rear hitting a small dip on the hwy going well over 100....

[ymic]

exactly. I dont think that a lot of people realize this. They think that a few tenths of an inch don't make a difference, but they do.

I didn't mean they were EXACTLY the same, but they are the closest you can get to stock without worrying about the rubbing you get in the rear with a 225/45 cause it's meatier.

[GoFast]

I didn't mean they were EXACTLY the same, but they are the closest you can get to stock without worrying about the rubbing you get in the rear with a 225/45 cause it's meatier.

i know. I wasnt referring to anyone specifically.

[ymic]

i know. I wasnt referring to anyone specifically.

It's cool ;)

[Wastegate13]

235/40 is the closest to the stock size of 215/45 but its a bit much on the stock 7" wide wheel.

[funksilver07]

I'll probably go with a 225-45 on the stock wheel, I do have the concern of rubbing, a few millimeters make a difference for sure. I'm not to sure about running a 40 series on a 7" wide rim, not really recommended by anyone in the tire service industry. I know guys on here and other forums claim to run on them with no issues, just think using a 225-40 on a 7" rim is pushing it. I'd hate to roll off a rim autoxing my car. The stock size really does suck for this car, very limited choices for sure...

[Wastegate13]

I'll probably go with a 225-45 on the stock wheel, I do have the concern of rubbing, a few millimeters make a difference for sure. I'm not to sure about running a 40 series on a 7" wide rim, not really recommended by anyone in the tire service industry. I know guys on here and other forums claim to run on them with no issues, just think using a 225-40 on a 7" rim is pushing it. I'd hate to roll off a rim autoxing my car. The stock size really does suck for this car, very limited choices for sure...

What does sidewall height have to do with rim width?

[funksilver07]

When you combine the width/aspect ratio you get the bead of a cross-ply tire. It consists of bundles of bronze coated high tensile strength steel wire strands which are insulated with rubber. A cross-ply tire designed for off-road use typically has two or three bundles. A radial on-road tire normally only has one. The bead is considered the foundation of the tire. It anchors the bead on the rim. That's why you just can't look at the numbers individually, they need to be looked at together to determine the appropriate size wheel. Look at the link and plug in the 225-40-18, minimum width rim is 7.5", now plug in the 225-45 minimum is 7". I know people run this 225-40 I for one won't take a chance on that size on the stock wheel. My tires are the first thing between me and the road...nobody in the tire service industry will recommend a 225-40-18 on a 7" wide wheel, there's a reason for that...

http://www.tirerack.com/tires/Spec.jsp?make=Bridgestone&model=Potenza+RE050A&partnum=24YR8RE050AXL&vehicleSearch=false&fromCompare1=yes&place=8

[meicalnissyen]

exactly...a 225-40-18 compared to stock is 2.1% too fast, where the 225-45 is 1.4% to slow. The diameter for the 225-40=25.1" to the 225-45=26" compared to stock size which is 25.6." I've actually done this before, just didn't understand the statement that a 225-40 is the same as stock, it's not... both 40 & 45 series in a 225/18 will be close to stock size, not the same as. Just trying to clarify... http://www.miata.net/garage/tirecalc.html
(drinks)
another useful tool is the tirerack spec page, it will give the revolutions per mile number.

of course as any tire wears, the speedo will creepup above actual speed