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[jpk]

I'm trying to solve for Houston's bad roads on my 335is.

I'm currently using 19inch 313's with PS4S 225/35/19 and 275/30/19s. Slightly lowered on KW Street Comfort coilovers.

My tires wear well with no rubbing anywhere. I'm going to need new tires soon. In my history, I have bent a front wheel and busted a tire on bad roads. The wheel has been repaired and the tires replaced.

I'm thinking I might buy 18" 313s for the front and keep the 19" 313 rears when I replace the PS4S tires. I imagine the front will be less prone to road damage with 225/40/18's. Maybe it would ride a little better too. I don't track the car at all.

Any input would be appreciated.

[AWD Addict]

No

[vester86]

Originally Posted by AWD Addict

No

A bit of explanation would be helpful

For jpk

Although this is certainly possible, you should be aware that the rear wheel (in your suggestion) will have a thinner sidewall then the front wheels. This will affect vehicle dynamics but it is uncertain to what extend, no one knows. The point of stock tyre sizes is that circumfence (and thus sidewall height) is equal front & rear (regardless of the tire width, that’s where the different aspect ratio comes into play

225/40-18 has a 3,5 inch sidewall, 255/35-18 also has a 3,5 inch sidewall, whereas 255/35-19 stock 19” size) has a 3” sidewall. Your suggested tyresize of 275/30-19 has a 3,2” sidewall.

[Runnin'Rich]

https://www.willtheyfit.com

Dial in your circumferences with that website. Not sure how close you’re gonna get.
Maybe you want to be as close as possible if RWD for the DSC and tire pressure monitor not to freak out??
If you’re xdrive you want to be very close to matching.

It’s gonna look a bit more noticeable than on the g80 becuase they are running 19’s and 20’s
Black painted wheel will hide the difference a bit better than silver

[jpk]

thanks folks. Much appreciated. I'm feeling like the risk of breaking something with 225/35/19 on those stock 313s is too high. I may just spring for 18's all the way around. I have some work to do.

[jpk]

Using the tire size calculator it seems that 235/40/18 and 275/30/19 have closer dimensions than the stock 225/35/19 and 255/30/19. I'll figure this out.

To your point, it is hard to notice the differences in wheel size on the G80. I was not aware they were different.

Thanks again for the information.

[335i54n]

usually goes 225/255, 235/265, 245/275. if youre set on 19 i would do 245/35 and 275/30 otherwise moving to 18 245/40 275/35 gives a very good ride ,impact resistance, lower tire cost

[whyzee125]

The fact that you bent a front wheel is random, it could have just as easily been a rear so you really would only have mismatched wheels but only be avoiding the problem half way. IMO get a nice set of 18s all around or stay on the 19s and avoid potholes. Keep in mind 18s are by no means immune to potholes either but do wear a little more protection due to the slightly larger sidewalls.

[jpk]

Fair points for sure. I'm leaning toward getting 18's all around. Even as careful as I drive avoiding all the road faults in Houston is above my skill and luck level. I do think the fronts are particularly vulnerable with 225/35/19.

I'm liking the idea of 235/40/18s on the front. Will that size get me both no rubbing and a decent stance with the slight camber M3 control arms provide? The KW coilovers are height adjustable.

I'm already happy with 275/30/19's on the back. Zero rubbing. I'm thinking 275/35/18 will fit just as well.