I tried searching to see if this was brought up before because I imagine it has been but I was unsucessful in finding it. My stock tires for my Mazda 3 2008 is the 205-55/R16. I want to go wider, I imagine you can go wider than 215's, but what size is the widest that you people have on your mazda for the 16 rim? Thanks in advance! Brandon

 

Iirc, that is a 6.5" wheel like the 17's, and the max recommended is a 215. That's what I'm running on my OE 17's.Some 225's will squeeze on there, but it is likely they will start to balloon a bit. That's not good for handling. i.e. the "more harm than good" scenario.
For less speedo and gearing error w/o going to a wider wheel, your best choice would be a 215/50. The error would be approx -1.72%. When your speedo would read 65mph your actual ground speed would be 63.9mph. You might notice a slight off-the-line improvement using these.
Or you could go to a 215/45 in which case the error is -5.34%. Speedo=65, actual, 61.71mph. That's a lot. A huge off-the-line improvement w/these. Worse mileage and a higher tire tempature.

Going the other way (larger diameter,) a 215/55's error would be +1.698%. Speedo=65, actual, 66.12mph.Less off-the-line, more mileage and fewer miles on the OD too.

Goto a 7" wheel and your best choice is the 225/50, the difference only being -0.082%. Speedo=65, actual, 64.95mph.

Any of these changes would have to be factored into, and adjusted to get accurate mileage figures, but as you can see, going to a 7" w/the 225's is closest to OE.

 

So if I went to a 215 it would actually not make the tire any wider? I wanted to make them as wide as possible. Thanks!

 

'Course it would, but only by 10mm (<1/4".) What you are trying to do (or should be) is keep the circumference as close to stock as possible for a street car. Dedicated track tires are a different story.
On a 6.5" wheel most reputable tirecompanies/stores will not mount anything bigger. Or they might but @ your own risk.

As I'd said, your absolute best choice is to go w/a 7"~7.5" wheel and 225's. Ya' can't really go too much wider on a 3 anyway w/o rubbing issues. 235 is the safe max for a non-lowered vehicle. Some have said they've been able to run them on a lowered vehicle too, but w/some issues.

What do you really hope to gain? Appearance? Handling? Grip? Braking?
Remember please that there's a limit to all of these things and sometimes too much is simply too much.
The bigger/wider a tire, the heavier it's going to be too. That increases unsprung weight which adversely affects both handling and braking, as well as slows acceleration and (can) reduces fuel economy. Rolling resistance is also an issueof a tire with a bigger contact patch potentially has more of that too... but that's not a hard/fast rule these days either.

See what I mean? There is a balance in cars as there are balances in life. If you want your car to perform on a daily driver basis, I would stick with some thing of a compromise between the width you want and what the car can safely handle.

 

pretty much, if your not going to lower the car, i tihnk the widest you can go (if your not lowered), is 235. but even that might be pusing it, as 16"s have more sidewall, and they will flex more.

 

are 17s are the biggest rims that will fit on it?

 

ive seen 19's fit on, and they were snug.

but honestly, i'd just go with a set of lightweight 17's or 18's at the most.
actually, just get a set of 17x7.5 or x8, and stick on a set of 235 (or 225) /45/17. that'll be a good combo for the track.

 

I just like the stock look better, so I guess I will go with the 215/50R16's...I appreciate all of the help peopel! Thank you very much!

 

You're welcome, MS118.I hope it wasn't too confusing and that it helped you make an informed decision?

 

yea, cant wait until I need new tires, I only have 500 miles on my 08 MS3. I just like to do research and get the right tire, I dont like the toyo proxies that it has now...I want something a little wider, thats why I think Ill go with the 215's...Thanks again!