Tire size help

[lamaro88]

I have owned my X5 for about a year now and just noticed that when the previous owner changed the wheels and tires he got different sizes then OEM. I am not sure what sizes my car had out of the factory. If someone can help me out finding out that would be cool.

The tire sizes are 275/45/20 all around. Maybe he did it to be able to rotate tires? I have never had errors or anything. Is this setup good or bad? I am needing tires soon, should I get a different size?

[hilld]

That tire setup will allow you to rotate tires without any issues and extend the life of your tires. The key is when / if you want to run a staggered setup that the diameter of the front and rear tires are the same. The 275/40/20 size is the front size of the staggered setup which runs 315/35/20 in the rear. The big advantage here will be for looks in the rear, the cars don't really have enough power to warrant that size tire in the rear.

Personally, I love the look of the meaty fat tire in the rear, but from a performance perspective it is overkill.

[X5 MAN]

Those are pretty huge tires, if not fat.

45/20 translates to a 2'' bigger tires then stock tires on a non-M , X5

[lamaro88]

Originally Posted by hilld

That tire setup will allow you to rotate tires without any issues and extend the life of your tires. The key is when / if you want to run a staggered setup that the diameter of the front and rear tires are the same. The 275/40/20 size is the front size of the staggered setup which runs 315/35/20 in the rear. The big advantage here will be for looks in the rear, the cars don't really have enough power to warrant that size tire in the rear.

Personally, I love the look of the meaty fat tire in the rear, but from a performance perspective it is overkill.

Thanks for the response. I would like the look of it also but I guess I should be fine with the 275s.

[lamaro88]

Originally Posted by X5 MAN

Those are pretty huge tires, if not fat.

45/20 translates to a 2'' bigger tires then stock tires on a non-M , X5

So maybe I should at least drop it to a 40/20 instead of 45/20??

[X5 MAN]

Originally Posted by lamaro88

So maybe I should at least drop it to a 40/20 instead of 45/20??

Yes
Do you have M-sport ?

The OEM tires an are :

255/55-18 Load Class: XL
255/50-19 Load Class: XL

Optional tire size is:

20" 275/40-20

[lamaro88]

Originally Posted by X5 MAN

Yes
Do you have M-sport ?

The OEM tires an are :

255/55-18 Load Class: XL
255/50-19 Load Class: XL

Optional tire size is:

20" 275/40-20

It is not the M-sport.

Maybe it came with the 18s in front and 19s in rear and the previous owner went to 20 all around. Not sure why he went with 45 but ill go down to 40 when it comes time to change. Thanks.

[lamaro88]

Finally getting around to putting some new tires on.

Back in April I had to replace my front passenger tire. Until then all four tires had the same tread left. The people at Americas tires told me recently that since one tire was replaced if I just change out three of the tires with one being used, it will mess up the transfer case? Or should I be fine replacing just the three?

[Duc Hunter]

Originally Posted by X5 MAN

Those are pretty huge tires, if not fat.

45/20 translates to a 2'' bigger tires then stock tires on a non-M , X5

Correction here, sort of. Stock diameter on my 35d (believe all E70n ran the same diameter tires) is 29". 275/45/20 is 29.7" diameter. No the circumference is 93.4, vs 91.2 for stock sizes. The difference is 2.4%.

That said, I ran 275/40-20 for a long time and just went to 275/45-20. I would say, if they don't rub, stay at that size. you are not hurting anything, and are prob slightly helping your MPG at cruise, because your RPM are slightly lower. The larger sideway makes it a little more cushy ride over harsh roads, and they fill out the wheel wells better for sure. Many guys with 35d's are running even 30" tires (some even are lifted slightly) without issue. I am lowered, and chose mine to fill out the wheel wells better. I have ben very happy with my choice.

https://tiresize.com/comparison/

[uncle_sam]

Just curious @Duc Hunter. With the taller 275/45 you used in front, you didn’t have any issues with the top of this tire rubbing onto the upper control arm?