im gunna lower my mazda 3 2" could i fit 18" rims on it

 

Mazda6, Mazda3, RX8 all use the same bolt pattern/spacing

 

It's not at a dealership. It's one of the Mazdaspeed Engineers. he was performing a clearance study on the wheel fit.

No offense, but I'll take his word (no hidden agenda) as to what fits over some guy trying to sell me some wheels.

Those wheels you mention would sit ~10.5mm (less than half an inch) further out toward the fender. With some slight rolling of the lip, you should be able to make them clear.

The only way to know for sure is to get one mounted and size it up.

 

hey SS, so if i wanted to get rims 17x7.5 with +40 offset on 215/45/17 it would rub, im tryin to get the ADR Phantoms but before i buy i dont wanna get stuck plus i wanna drop it with the eibach pro kit later on i dont totally understand offsets thats why im dummyfied, so the bigger the number offset(41,42,43,44,45+....) the less of the chance it wouldnt rub?

edit-also 225 compared to 215/45/17, does that mean that 225 is thinner or thicker than 215?

 

If you draw a line down the centerline of the wheel. The offset is defined as how far the mounting surface of the wheel is from the centerline of the wheel.

For example...If you had a 7" (178mm) wide wheel, and the mounting surface was 3.5" (89mm) from the inside/outside edges of the wheel, you would have a zero offset.

For this same 7" side wheel, if the offset was set at +60mm (using my stock Mazda6 wheels as the example), then the mounting surface should be 89mm+60mm (149mm or 5.9") from the inside edge of the wheel.)

A 17x7.5 w/40mm offset would line up like this....

((7.5"*25.4)/2)+40mm= 135.3mm (5.3")....so from the inside edge of the wheel to the mounting surface is 5.3", meaning that you have approximately 2.2" from the wheel flange to the outside edge of the wheel.

Take off one of your rear wheels and make sure your car is sitting level and flat. Using a plumb-bob (weight with a pointed end that you can find at any hardware store cheap), hang it off the inside rolled edge (where the steel ends on the inside of the wheelwell.) of your fender at the centerline of the wheel. You need to have at least 2.2" (56mm) of clearance between the hanging string and the surface that the wheel mounts to. The tire/wheel could hang up on that as the tire compresses (I'd recommend rolling the inside of the fender slightly just to make sure...If you're not sure what I'm talking about, best to have a body shop quote it.)

With the recommendation of 52.5mm offset on a 7.5" rim, the 40mm offset will cause the entire wheel to sit 12.5mm further out toward the fender. Try drawing up my example on graph paper....It will make more sense once you see it.

You should be able to run a 225 on a 7.5" rim. A 225 is wider than a 215 (225mm wide rather than 215mm wide)

If you want a 18" tire, you need a 225/40R18, if 17" then 225/45R17....They end up almost exactly the same diameter.

 

ok so what youre saying is, the lower the number, the rim is getting closer to the wheel well causing rub? Ok so then from what i gather from this info is that 52.5 offset and bigger number, will work with the M3. is there anyway i can make 40 offset work? i do want a 17 inch rim and lower it about 2 inches

edit-i've come across another site(msprotege.com) and i did a search. One guy has the same rim set up only he used 215 tire(he has 17x7 +40 offset 215/45/17) he said he has no rub, is he full of ****? also when i logged onto bwt.com they also have other rims that have +40 offset and it says it'll work, dont get me wrong i dont mean to look like im callin you out and say that you're wrong, it seems that you know your stuff, i jus dont wanna end up spending like $1000 for rims that is jus gonna bite me in my a@# and have to sell and lose profit im also makin sure i understand what you're saying

 

Krim...SSTLAURE doesn't know everything. No disrespect intended but nobody here knows everything. I have found that 42mm offset works so it doesn't have to be 50mm or higher to fit without rubbing.

 

I never said I know everything, but at least I am leaving reasoning behind my beliefs...A salesman will tell you anything to make a deal. I could care less if you go out and spend money on rims that don't fit, but I will try to help you understand wheel sizing (because if you understand wheel sizing, then you can figure out for yourself what REALLY fits.)

My recommendation is still (just as I stated a few days ago) to have a wheel and tire mounted up in the size you are looking at and VERIFY that it fits. Some people rub and don't know it. I was one of those. I swore that the Mazda6 wheels fit without rubbing on the Mazda3....well when I was working on my suspension the other day, there are some rub marks on the fenderwell liners.....so I do rub and didn't realize it. The other recommendors in this thread could also be in this same position....

My 17x7 Mazda6 wheels (60mm offset) rub some, but they rub on "friendly" surfaces and won't damage the tires when it happens (which is only at full lock steering, so it also only happens at low speed.) These rub on the inside edge of the tire.

The 52.5mm recommendation was based on the 7.5" wide rim you were asking about, a 7" wide rim is 12.5mm (0.5") narrower than a 7.5" rim.

A 7" wide rim with a 40mm offset would have ~49mm from the mounting surface of the wheel to the outer edge of the wheel., my 60mm offset 7" wide wheels have ~29mm, so those would sit 20mm (3/4") further out toward the fender than mine are now.

Don't try to take the easy way out by relying on some people's opinions on a Forum. Do the plumb-bob test I detailed above and you will know exactly how much clearance you have to fit a rim. If it is larger than the 49mm above, then it should fit (I'd leave a few mm for extra clearance.)

FYI.....The 7.5" wheel with 52.5 offset recommended by the Mazdaspeed guy has 43mm measured distance from the mounting surface to the outer edge of the wheel, and he stated that it rubbed (not an opinion, a fact....he verified the rubbing condition during an engineering clearance study to figure out which wheels do actually fit without rubbing, but what does he know......Apparently the tirerack guy has done a more thorough fitment study...)

The wheel you are looking at would sit 6mm (1/4") further out of the wheelwell. You make the decision as to whether or not that fits.
My OPINION is that the 40mm offset wheels will place the outer edge of the wheel too far out of the fenderwell. Feel free to prove me wrong. (42mm offset would sit 4mm further outward) 46mm would be perfect with a 7" wide rim based on the fitment study.

 

Thanx SS

 

no problem.

The weather has heated up a little around here so I may just plumb-bob my car to see where the outer edge sits. I'll see if I have time and I'll post the info here. (Mine only rubs on the inside edge front when turned.) As the spacing gets wider, you can run into problems with the wheel catching the lip of the rear fender.