[HPR]

I have an M Sport staggered tire/wheel setup on my 2015 35i X3. 245/45 R19 front and 275/40 R19 rear. I'm looking to go to a square configuration. Has anyone done the larger setup using the 275/40 R19s on the 9.5" wheels all around? If so, what are your impressions as to improved or degraded handling? Are there fitment issues with front tires rubbing the fender liner?

[Riick]

275 is too wide. They'll run colder, use more fuel, and heavier on the suspension hurting handling and ride quality like slower/lazy turn in, etc. There's no benefit to a tire that big on the X3.

245/45-19 is perfect for the X3 on all 4 corners. Getting rid of the staggered will help with understeer as well. Throw on a set of nice summer performance non-runflat tires and it'll drive like a totally different machine.

[x3sm]

Originally Posted by Riick

275 is too wide. They'll run colder, use more fuel, and heavier on the suspension hurting handling and ride quality like slower/lazy turn in, etc. There's no benefit to a tire that big on the X3.

245/45-19 is perfect for the X3 on all 4 corners. Getting rid of the staggered will help with understeer as well. Throw on a set of nice summer performance non-runflat tires and it'll drive like a totally different machine.

You should say "in my opinion" next time. Assuming michelins summer tires (for sake of comparison) 245/45-19 weighs 26 lbs, 275/40-19 weighs 28 lbs per tire rack. I'll say its worth the 2 lbs for much improved handling. The 275 tire is not too wide at all. Research. Also I would say getting lighter wheel than OEM is a HUGE improvement or forged OEM like style 343 from the M5.

[scostu]

Originally Posted by HPR

I have an M Sport staggered tire/wheel setup on my 2015 35i X3. 245/45 R19 front and 275/40 R19 rear. I'm looking to go to a square configuration. Has anyone done the larger setup using the 275/40 R19s on the 9.5" wheels all around? If so, what are your impressions as to improved or degraded handling? Are there fitment issues with front tires rubbing the fender liner?

https://x3.xbimmers.com/forums/showthread.php?t=1421266

[doodlebro]

OP, what handling goals are you trying to achieve with squaring the tires out? Getting fatter fronts is only going to make this car understeer more, so I'm not sure it's going to accomplish what you're setting out to achieve.

[HPR]

Originally Posted by doodlebro

OP, what handling goals are you trying to achieve with squaring the tires out? Getting fatter fronts is only going to make this car understeer more, so I'm not sure it's going to accomplish what you're setting out to achieve.

Not being able to rotate tires is chewing up the fronts at a faster pace than the rears (Berthoud Pass is tough on them). I'd like to go to a square setup to enable rotation. I have a set of non-run flat snow tires/wheels in a square 245/45/19 configuration and experience a bit of under steer. Don't know if that's a result of tires only, square configuration, or both. Hence my question concerning the bigger meats. I recognize that a performance tire and more un-sprung weight will affect handling characteristics, so I'm just trying to get the benefit of other folks experience.

[x3sm]

Originally Posted by doodlebro

OP, what handling goals are you trying to achieve with squaring the tires out? Getting fatter fronts is only going to make this car understeer more, so I'm not sure it's going to accomplish what you're setting out to achieve.

That is incorrect... square set-up will definitely reduce understeer in xDrive scenario. In-return a square set-up will create a neutral handling car.

[doodlebro]

Originally Posted by HPR

Not being able to rotate tires is chewing up the fronts at a faster pace than the rears (Berthoud Pass is tough on them). I'd like to go to a square setup to enable rotation. I have a set of non-run flat snow tires/wheels in a square 245/45/19 configuration and experience a bit of under steer. Don't know if that's a result of tires only, square configuration, or both. Hence my question concerning the bigger meats. I recognize that a performance tire and more un-sprung weight will affect handling characteristics, so I'm just trying to get the benefit of other folks experience.

I think you should just square up at 245/45R19 since I've never had an issue putting power down with that. These cars are designed to understeer with the square setup as to make the handling more predictable, but I am certain it can be tuned out by stiffening the rear gradually.

Basically, you'll pay out the ass to square up fat tires, so stick with the stock 19 size and then work out the understeer from there. I can't see it being easier to tune this stuff out when you have fat rubber everywhere.

By the way, do you have uneven inner/outer tire wear due to the slight camber that these cars have? I'm trying to figure out how to deal with that properly.

[Riick]

Originally Posted by x3sm

That is incorrect... square set-up will definitely reduce understeer.

This is correct.

[Victoracer]

Originally Posted by Riick

275 is too wide. They'll run colder, use more fuel, and heavier on the suspension hurting handling and ride quality like slower/lazy turn in, etc. There's no benefit to a tire that big on the X3.

245/45-19 is perfect for the X3 on all 4 corners. Getting rid of the staggered will help with understeer as well. Throw on a set of nice summer performance non-runflat tires and it'll drive like a totally different machine.

Whyyy the misinformation. It should be in my opinion blah blah blah.

this is a 4000lb vehicle, it can absolutely handle a 275 size tire. I have no idea how you would burn more fuel. More grip does not equal heavier steering ... blah blah. I lost 20lbs a corner going with 19s in a 275 tire from the 20" stockers

I personally have run a 295/30 on 18x11" wheels on my 2600lb race car for years. Why ? It's called wider contact patch or scrub radius.

I prefer rotating tires, so huge benefit there for me. ( I drive 30-40k miles a year) I agree it will feel like a better drive as well as understeer refuction.

[Riick]

Originally Posted by Victoracer

Whyyy the misinformation. It should be in my opinion blah blah blah.

this is a 4000lb vehicle, it can absolutely handle a 275 size tire. I have no idea how you would burn more fuel. More grip does not equal heavier steering ... blah blah. I lost 20lbs a corner going with 19s in a 275 tire from the 20" stockers

I personally have run a 295/30 on 18x11" wheels on my 2600lb race car for years. Why ? It's called wider contact patch or scrub radius.

I prefer rotating tires, so huge benefit there for me. ( I drive 30-40k miles a year) I agree it will feel like a better drive as well as understeer refuction.

No.

[x3sm]

Originally Posted by Victoracer

Whyyy the misinformation. It should be in my opinion blah blah blah.

this is a 4000lb vehicle, it can absolutely handle a 275 size tire. I have no idea how you would burn more fuel. More grip does not equal heavier steering ... blah blah. I lost 20lbs a corner going with 19s in a 275 tire from the 20" stockers

I personally have run a 295/30 on 18x11" wheels on my 2600lb race car for years. Why ? It's called wider contact patch or scrub radius.

I prefer rotating tires, so huge benefit there for me. ( I drive 30-40k miles a year) I agree it will feel like a better drive as well as understeer refuction.

True. The only way you would burn more feel with a wheel set-up is if they are significantly heavier e.g. run flats. I went from 18 inch run-flats to 20 inch (which are not light by any means) and did not notice any significant increase in fuel usage and I run my own numbers every other fill up. I modify all of my cars and I like to have fun with them, if I wanted to save gas I'd get a Prius.

[subieworx]

Originally Posted by x3sm

True. The only way you would burn more feel with a wheel set-up is if they are significantly heavier e.g. run flats. I went from 18 inch run-flats to 20 inch (which are not light by any means) and did not notice any significant increase in fuel usage and I run my own numbers every other fill up. I modify all of my cars and I like to have fun with them, if I wanted to save gas I'd get a Prius.

You are correct. Most people don't realize that changing tire width while keeping diameter the same does not increase the size of the contact patch on the tire and hence will not increase rolling resistance.

However going wider in the front can cause issues with aerodynamics if the tire sticks too far outside of the body and will create more drag.

I too am thinking of going with 275's all around on my 14 Msport. I am thinking of doing 275 40 20 on 20x10 wheels. Thinking of a 35 offset, anyone know if that will fit?

[doodlebro]

How often are you guys breaking traction with 245 wide wheels on these cars? I don't understand the need for fatter tires unless you're struggling to put the power down. I'm on a stage 2 tune and I still hook on Toyo proxes.

[x3sm]

Originally Posted by subieworx

You are correct. Most people don't realize that changing tire width while keeping diameter the same does not increase the size of the contact patch on the tire and hence will not increase rolling resistance.

However going wider in the front can cause issues with aerodynamics if the tire sticks too far outside of the body and will create more drag.

I too am thinking of going with 275's all around on my 14 Msport. I am thinking of doing 275 40 20 on 20x10 wheels. Thinking of a 35 offset, anyone know if that will fit?

My OEM wheels were 18" with 245/50-18 ET43 that had an overall diameter of 702mm, my new set is square 285/40-19 ET33 that are 710mm diameter. If you go with 275/40-20 your overall diameter will be 728mm. 275/40-19 slightly rubs on full lock during reverse. 275/40 with 20x10 ET35 wheels will rub for sure.

[Victoracer]

Originally Posted by doodlebro

How often are you guys breaking traction with 245 wide wheels on these cars? I don't understand the need for fatter tires unless you're struggling to put the power down. I'm on a stage 2 tune and I still hook on Toyo proxes.

I mean, you need tires for braking as well as cornering? Upsizing doesn't have a singular effect. I personally went down .5" in the rear in width. It's just personal choices and I know exactly why I went the direction I did.

[Victoracer]

Originally Posted by x3sm

My OEM wheels were 18" with 245/50-18 ET43 that had an overall diameter of 702mm, my new set is square 285/40-19 ET33 that are 710mm diameter. If you go with 275/40-20 your overall diameter will be 728mm. 275/40-19 slightly rubs on full lock during reverse. 275/40 with 20x10 ET35 wheels will rub for sure.

I would echo this. I can't find the pick but on the Facebook page a member posted the exact setup you desire 20x10.5 +35, but a slightly lower profile height 275/35 20. If I can find the pic I'll add it, I will say it looked about perfect

[x3sm]

Found this one on F25 Facebook group

Tires: 285:45 20
Wheels: 20x10 ET unknown

[x3sm]

Found another guy

Tires: 265/40/20
Wheels: 20x10.5 ET35

[scostu]

I like this......

https://x3.xbimmers.com/forums/showp...&postcount=164

[HPR]

I've received many replies to my original post...thanks to all. And, along with some additional research, I've decided to go with the 245/45/19 square configuration when the current staggered set gives it up. The car isn't tracked but is driven on a spirited basis with some regularity. For that type of driving there seems to be no significant upside to going with the larger 275/40/19 square setup.

[Victoracer]

Originally Posted by HPR

I've received many replies to my original post...thanks to all. And, along with some additional research, I've decided to go with the 245/45/19 square configuration when the current staggered set gives it up. The car isn't tracked but is driven on a spirited basis with some regularity. For that type of driving there seems to be no significant upside to going with the larger 275/40/19 square setup.

The only other additional info I would add, is that with a 9.5" wheel(unless otherwise stated by manufacturer), the ideal width choices are 255-275. You may end up with a really stretched tire that has the rubber band look.
Here are 3 tires 245,255,265 all 40 profile. If you look at the specs, the ideal would be a 265 on a 9.5 to keep a nice square shoulder. If your going to have an 8.5" wheel then the 245 would be the better choice.