[Reydan3]

I know the general rule of thumb is +-3% of dia or circumference is OK, but I'm wondering just how accurate that number is for this car.

I've got a 2014 3i sport and want to upgrade the wheel/tire package for the summer. My current setup is the OEM 16" wheels with Conti PureContact 205/60's. I'm thinking of upsizing +1 to 17" and either going to 215/50 or 225/45. I know the first will work just fine. The 225/45 is going to be 2.87% less diameter. I don't care about the speedometer inaccuracy, I'm just worried if that much difference in wheel height will mess up the ABS, the traction control, or something else.


TIA for any help with this :|

 

[[email protected]]

I know the general rule of thumb is +-3% of dia or circumference is OK, but I'm wondering just how accurate that number is for this car.

I've got a 2014 3i sport and want to upgrade the wheel/tire package for the summer. My current setup is the OEM 16" wheels with Conti PureContact 205/60's. I'm thinking of upsizing +1 to 17" and either going to 215/50 or 225/45. I know the first will work just fine. The 225/45 is going to be 2.87% less diameter. I don't care about the speedometer inaccuracy, I'm just worried if that much difference in wheel height will mess up the ABS, the traction control, or something else.


TIA for any help with this :|

I have a 2014 touring sedan.
17s are good idea vs 18s. Less unsprung weight, better ride, cheaper. However I chose to go with 225/50s on 7.5 wide rims. Fills wheel wells better than factory 18s. This is a 1% increase in diameter and probably reduces factory speedo error somewhat. Why go with something that increases that ugly wheel well gap? Higher profile gives better rim protection, better ride, lower noise And of course no problem with TC or ABS. No clearance problems either with factory ride height.

 

[jaredtx]

I am not super familiar with how Mazda's system works on our cars yet but a general rule of thumb is that as long as you are in +-1.5% of the OEM outer diameter you will be just fine.

Things start to get wacky with cars that have a staggered set-up and changing those ratios f:r and overall diameter increases can really mess up some systems. But we have a square set-up (all 4 wheels and tires are the same size) to as long as you are moving up or down the same at all four corners the OEM systems won't sense any change. Think bro-dozers and how much larger their wheels/tires are from OEM.

 

[datkidfromTO]

My OEM wheels are 18x7 +50 with a 215/45/18 and my summer setup was 18x9 +28 with a 215/35/18. it was pretty stretched I think -7.5% or something like that compared to oem spec. the only real issues I faced was my odometer and speedometer being off. traction control and abs and everything still worked perfectly.

Edit: that being said, I'm not saying that its a good idea to have wheels that much off spec, but all im saying is that it didn't cause any issues with the car.

 

[Reydan3]

Thanks everyone for the responses!

My OEM wheels are 18x7 +50 with a 215/45/18 and my summer setup was 18x9 +28 with a 215/35/18. it was pretty stretched I think -7.5% or something like that compared to oem spec. the only real issues I faced was my odometer and speedometer being off. traction control and abs and everything still worked perfectly.

Edit: that being said, I'm not saying that its a good idea to have wheels that much off spec, but all im saying is that it didn't cause any issues with the car.

Really good to hear you had this experience with a gen 3 @datkidfromTO.

As @jaredtx said, keep the diameters the same on all corners and things will be fine. I guess the electronics measures wheel rpm difference. There isn't really much solid information out there on this that I could find, but this makes sense specially for ABS and TC.

How about the TPMS? I imagine you had to re-calibrate it after the wheel/tire change which seems to be the right thing to do after any tire change. You didn't mention it, so I guess it was fine for you, correct?

 

[datkidfromTO]

Thanks everyone for the responses!

My OEM wheels are 18x7 +50 with a 215/45/18 and my summer setup was 18x9 +28 with a 215/35/18. it was pretty stretched I think -7.5% or something like that compared to oem spec. the only real issues I faced was my odometer and speedometer being off. traction control and abs and everything still worked perfectly.

Edit: that being said, I'm not saying that its a good idea to have wheels that much off spec, but all im saying is that it didn't cause any issues with the car.

Really good to hear you had this experience with a gen 3 @datkidfromTO.

As @jaredtx said, keep the diameters the same on all corners and things will be fine. I guess the electronics measures wheel rpm difference. There isn't really much solid information out there on this that I could find, but this makes sense specially for ABS and TC.

How about the TPMS? I imagine you had to re-calibrate it after the wheel/tire change which seems to be the right thing to do after any tire change. You didn't mention it, so I guess it was fine for you, correct?

Yeah so as long as the diameters are the same you’re not going to be having any issues.

As for the TPMS, our cars don’t have tpms sensors. Everything is monitored through the wheel speed sensors so all you gotta do after putting on new wheels is press the little button beside the steering wheel and reset it.