[YetiM3]

I know BMW shows 245 as recommended width. Anyone running 255/50r19?

Trying to put Michelin Premier LTXs on, and they are hard to come by in 245s.


Recommendations on max width for all 4 corners.


Thanks

[Scandic24]

Originally Posted by YetiM3

I know BMW shows 245 as recommended width. Anyone running 255/50r19?

Trying to put Michelin Premier LTXs on, and they are hard to come by in 245s.

Recommendations on max width for all 4 corners.

Thanks

I wouldn't recommend 255/50 19".

You can use this calculator to find compatible sizes. (OEM size is 245/45 19" or 275/40 19" rear on staggered setup,
as you probably know )
https://tiresize.com/comparison/

[Pinewood]

As above, you will change the overall diameter of the fronts. If you have a square setup then a cautious yes, but on a staggered setup, a big no no.
You would ruin your transfer box

Edit: just re read that you have a square setup. It would work if your swapping all 4 tyres, but it will change the overall gearing/speedo etc

[Scandic24]

I did a quick comparison between a 245/45 and the 255/50:

[Pinewood]

Which site is that calculator on? Very informative :-)
As long as all tyres are same size = same diameter, and the tread depth is within 2mm of each other, BMW say your transmission will be fine.
I would go for it, if you can't get the tyres in the original size

[Scandic24]

Originally Posted by Pinewood

Which site is that calculator on? Very informative :-)

See my first post in the thread....

[YetiM3]

All,

Thanks for the help. It will be a square set up, with same tire sizes (brand new) and 4 19x8.5 wheels.

just trying to decide between 255/50r19s or 245/55r19s, or even 245/50/r19, to find right balance with a good sidewall height, good contact patch, and good handling feel.

For instance, will 255/50s feel sloppy compared to 245/55s? will 245/55s feel less grippy than the wider 255/50s? Subjective question i know, but since the 8.5 inch width of the wheel optimally matches up with a 245, just figured i'd get some others' perspectives.

thanks

[Lotus99]

Originally Posted by YetiM3

I know BMW shows 245 as recommended width. Anyone running 255/50r19?

Trying to put Michelin Premier LTXs on, and they are hard to come by in 245s.

Recommendations on max width for all 4 corners.

Thanks

How the heck did you come up with 255/50 based on an OEM size of 245/45/19? When you go up a wheel size / tire width, the profile ALWAYS has to drop, to maintain the same overall diameter of wheel and tire.

[Tjalle]

For best performance, you should buy tires that are STD on X4 M40i - they are 19" RFT.

However "everybody" choose optional 20" with Michelin Pilot Super Sport non-RFT:s - which are very good, but costs a packet, especially with rims.

[Greg2010]

Originally Posted by YetiM3

I know BMW shows 245 as recommended width. Anyone running 255/50r19?

Trying to put Michelin Premier LTXs on, and they are hard to come by in 245s.


Recommendations on max width for all 4 corners.


Thanks

Op, the 255/50r19's (X5 OEM tires) would definitely fit on X3 OEM 19x8.5 wheels...and also appear to fit when mounted on the X3 based on info below (however, you'll want to check your specific wheel type, as the fit comparison below is for BMW X3 369M wheels).

As you said, this provides additional tire size/brand options for the X3!

[YetiM3]

Where'd you get that screen grab from?

[Greg2010]

Ha! I pulled info using the "size comparer" tool on www.rimsntires.com (and then copied/reformatted data in Excel).

[Lotus99]

Originally Posted by Greg2010

Op, the 255/50r19's (X5 OEM tires) would definitely fit on X3 OEM 19x8.5 wheels...and also appear to fit when mounted on the X3 based on info below (however, you'll want to check your specific wheel type, as the fit comparison below is for BMW X3 369M wheels).

As you said, this provides additional tire size/brand options for the X3!

5% off is pretty bad. I'm shocked you've got a casual attitude about giving that advice to someone else. I'd never drive my car like that. Your ABS sensors are going to be off, which depend on speed readings. Most calculators I've seen state that pretty clearly.

"When changing tire sizes, we recommend staying within 3% of the diameter/height of the original tire. Any more than this and you face the risk of brake failure."

http://www.1010tires.com/Tools/Tire-Size-Calculator

[Greg2010]

Originally Posted by Lotus99

5% off is pretty bad. I'm shocked you've got a casual attitude about giving that advice to someone else. I'd never drive my car like that. Your ABS sensors are going to be off, which depend on speed readings. Most calculators I've seen state that pretty clearly.

"When changing tire sizes, we recommend staying within 3% of the diameter/height of the original tire. Any more than this and you face the risk of brake failure."

http://www.1010tires.com/Tools/Tire-Size-Calculator

Good point. The comparison above is strictly fitment (as I so "casually" stated above). Others will have to make their own decision on wether to upsize their wheel/tires beyond OEM height (even though its done all the time, just take a look around at the millions of jeeps, trucks, SUV's on the road with higher aftermarket tires on their vehicles). That doesn't mean its 100% safe. Note too that the speedometer reading can be easily recalibrated by simply changing out the speedometer gear at almost any tire shop.

[Lotus99]

Originally Posted by Greg2010

Good point. The comparison above is strictly fitment (as I so "casually" stated above). Others will have to make their own decision on wether to upsize their wheel/tires beyond OEM height (even though its done all the time, just take a look around at the millions of jeeps, trucks, SUV's on the road with higher aftermarket tires on their vehicles). That doesn't mean its 100% safe. Note too that the speedometer reading can be easily recalibrated by simply changing out the speedometer gear at almost any tire shop.

These "millions" of cars (wonder why your examples are not passenger type vehicles?) with higher aftermarket tires, how do you know they're not within 3% of OEM specs? You're saying that there are that many at or above 5%?

Regardless, IMO you should have stated what I said at least since we're talking about a safety issue and potential damage to his car, if you're going to put your info out there to a noob who's looking for advice.

I'm sure some of the disclaimer is related to liability mitigation and if the risks are just damage to your own car, then do as you wish, but if it was to truly cause brake issues, and cause an accident, then that's another story.

[Greg2010]

Originally Posted by Lotus99

These "millions" of cars (wonder why your examples are not passenger type vehicles?) with higher aftermarket tires, how do you know they're not within 3% of OEM specs? You're saying that there are that many at or above 5%?

Regardless, IMO you should have stated what I said at least since we're talking about a safety issue and potential damage to his car, if you're going to put your info out there to a noob who's looking for advice.

I'm sure some of the disclaimer is related to liability mitigation and if the risks are just damage to your own car, then do as you wish, but if it was to truly cause brake issues, and cause an accident, then that's another story.

Well, maybe I should have said that depending on the brand, changing tires on 19" OEM rims from 245/45/19 to 255/50/19 only raises the vehicle 0.5" above stock height, which is minimal in my book (does that help)?

As I said, take a look around at number of jeeps/trucks/SUVs that are raised several inches over OEM height (yes, over 5%) with no change of suspension or change to the OEM braking system...and as far as I know, there are no NHTSA rules or laws against it...and they still seem to pass the annual State safety inspection (mine included).

Perhaps its different in Canada (or wherever you are from)?

[Lotus99]

Originally Posted by Greg2010

Well, maybe I should have said that depending on the brand, changing tires on 19" OEM rims from 245/45/19 to 255/50/19 only raises the vehicle 0.5" above stock height, which is minimal in my book (does that help)?

As I said, take a look around at number of jeeps/trucks/SUVs that are raised several inches over OEM height (yes, over 5%) with no change of suspension or change to the OEM braking system...and as far as I know, there are no NHTSA rules or laws against it...and they still seem to pass the annual State safety inspection (mine included).

Perhaps its different in Canada (or wherever you are from)?

You don't seem to understand the reason for the 3% rule of thumb. It's not how much you raise the car that is the problem, which you repeatedly keep referring to, but rather the diameter of the tire and wheel combination, which can mess up the sensors' readings and affect the braking system. THAT'S the issue...

I don't know how much clearer that warning from 1010tires can be... They keep referring to tire diameter. Not ride height...

[Greg2010]

Point taken (and trust me, I completely understand but not sure you do). You cite something on a website...while I provide examples of how a minor change is not something that I am really concerned about for reasons already mentioned, which is quite the opposite. Recalibrate the speedometer and reprogram the ECU so car now knows dimensions of new tires/wheels. Whoala, problem solved. Time to move on (Op, you owe me big time)!

[mge92]

Bmw offers 310 m wheels with 245/40 r 20 and 275/35 r 20 and even offers 21 iinch rims as well. It's all about the circumference of the fronts compared to the rear. You also have to compare how they match compared to stock.

[Lotus99]

Jesus people... It's the Diameter Variance that matters. It's pretty straightforward and doesn't require guesswork as to what fits.

Just go to Tire Rack, put in your X3, and it shows you literally all the various tires that are the OEM diameter plus/minus a bit. And by a bit, I mean like 0.25% off. Not 5% off like suggested above.

Below I've put a screen shot of it. And here's a link to the Tire Size calculator if you don't believe me, showing each one of those tires is pretty much identical to the OEM diameter, all the way up to the 21" size. I've taken the liberty to plug in the sizes for you even.

http://www.1010tires.com/Tools/Tire-...0R20/245-35R21

If you're going to vary from these sizes, just make sure you're within a few % of the OEM diameter. It's that simple.
.
.
.