Tyre Size Question For Mazda 3 Skyactiv

[Alex Kurdian]

Hi guys
I have a question about tyre sizes for the mazda 3 skyactiv....
My car currently has 16x6.5 wheels 50 ofset

I'm upgrading to 17x8 40 offset...and the Tire dealer says I need 235 45 17 tires....is this correct? or do I need 225 45 17? I wanna make sure nothing rubs or causes issues with the odometer ...etc...

can anyone chime in and help me please...thanx guys

[aris]

225/45-17 is the correct size

[Alex Kurdian]

225/45-17 is the correct size

thanx mate

[Alex Kurdian]

Question though : what if I use 235 45 17...will that cause any problems on a non lowered Mazda?

[Aitch]

Main problem is the bigger tires will cause your speedo to read slightly slow while driving; also effectively increases your gearing and makes acceleration slightly slower.

[Alex Kurdian]

Main problem is the bigger tires will cause your speedo to read slightly slow while driving; also effectively increases your gearing and makes acceleration slightly slower.

I'm not following you mate? the rolling diameter hasn't changed ..its just a wider tire? how will that effect the speedo?

[Aitch]

The "45" portion is the sidewall, but is measured in percentage of the width (the 225 or 235 number). So if you increase the width of the tire by 10mm, but the aspect ratio (45%) stays the same, then the sidewall is getting taller. End result - the diameter increases.

[Alex Kurdian]

The "45" portion is the sidewall, but is measured in percentage of the width (the 225 or 235 number). So if you increase the width of the tire by 10mm, but the aspect ratio (45%) stays the same, then the sidewall is getting taller. End result - the diameter increases.

ahh ok..clearer...so for eg.....if I ran a 235 45 17 17x8 40 offset wheel...on a non lowered 3 skyactiv...is this going to rub fenders or inners...or effect suspension ride etc??

[Kiyomi]

you should run 235/40/17's on a 17x8 :D. even if there is a slight diff in the odo. its only gonna be like 1 or 2 kms.

you wont rub at all, unless you weigh the car down severely. no fat chicks bro! :D

[aris]

Here is the link to the tire size chart
http://www.miata.net/garage/tirecalc.html

Tire Size Comparison

Specification Sidewall Radius Diameter Circumference Revs/Mile Difference205/55-16 4.4in 12.4in 24.9in 78.2in 811 0.0%225/45-17 4.0in 12.5in 25.0in 78.5in 808 0.4%

Specification Sidewall Radius Diameter Circumference Revs/Mile Difference205/55-16 4.4in 12.4in 24.9in 78.2in 811 0.0%235/45-17 4.2in 12.7in 25.3in 79.6in 796 1.8%

[Alex Kurdian]

you should run 235/40/17's on a 17x8 :D. even if there is a slight diff in the odo. its only gonna be like 1 or 2 kms.

you wont rub at all, unless you weigh the car down severely. no fat chicks bro! :D

hahahaha DEF no FAT CHICKS...I will be running 235 45 17's though....

[Kiyomi]

hahahaha DEF no FAT CHICKS...I will be running 235 45 17's though....

lolz.

just lettin you know, that once you get 45's, you will want the 40's next time round. just saying :D

[Alex Kurdian]

lolz.

just lettin you know, that once you get 45's, you will want the 40's next time round. just saying :D

whyz that mate?

[zzz3]

whyz that mate?

That sidewall is too big. More rolling resistance (slower acceleration), sidewall flex (more body roll), decreased fuel economy...

[Alex Kurdian]

That sidewall is too big. More rolling resistance (slower acceleration), sidewall flex (more body roll), decreased fuel economy...

Ok cool I'm now getting 225 45 17! on a 17x8

[Pereira11]

205 50 17

[Alex Kurdian]

question?? if my OEM Wheel is a 50 offset and the new wheel is a 40 offset with this be an issue with the stud thread? is there enough thread for the lug nuts?

[Aitch]

Offset won't affect how deep the lug holes are. You'll be fine.

[Alex Kurdian]

thanx guys ohh these are the wheels I'm putting on next week

TSW Vortex
http://www.bgworldwheels.co.nz/images_gallery/390_l.jpg
http://i194.photobucket.com/albums/z54/sufan144/cid__0529101032a.jpg

[Alex Kurdian]

and one more
http://i49.tinypic.com/1zzswgz.jpg