[PirelliCondoms]

Hello all, I recently replaced my 2001 Chevy 2500 with a BMW X7 40i for both daily use and towing use. That being said, I have been towing my boat and my race car trailer with my E46 inside ~6500 lbs for both( my x7 has the factory towing package ). That being said the runflats are driving me crazy with how loud they are while towing. I understand the factory tires are about 31" tall. Is it possible to replace the wheel with a 20" wheel and a Falken AT4W in 285/55/20 (33in tall)? AT3w's have been some of the best tires I have ever used for highway towing, boat ramp towing, and muddy pits at tracks.

[AvGeek]

Why not 275/50/20? It's actually a stock size so theoretically shouldn't have any clearance issues assuming your wheels are also close to OEM.

That being said, 285/55/20 is closer to 32" than 33" so it might also be alright, but I'd still stick closer to the stock 31" if at all possible.

[PirelliCondoms]

Originally Posted by BG X7

Why not 275/50/20? It's actually a stock size so theoretically shouldn't have any clearance issues assuming your wheels are also close to OEM.

That being said, 285/55/20 is closer to 32" than 33" so it might also be alright, but I'd still stick closer to the stock 31" if at all possible.

Well with the 285/55/20 I get load range E tires which are generally much better for towing.

[AvGeek]

Originally Posted by PirelliCondoms

Well with the 285/55/20 I get load range E tires which are generally much better for towing.

You could do 275/55/20 which would bring it right to about ~3.5% difference from stock which is closer to the 3% mark than the ~4.8% you get from a 285/55/20. I see the A/T4W does come in a load range D in that size.

[JJacksonIII]

Check this out
https://tiresize.com/calculator/

275/50/20 are super close

[PirelliCondoms]

Originally Posted by JJacksonIII

Check this out
https://tiresize.com/calculator/

275/50/20 are super close

I understand that, but I do not know if there are any load range E tires in 275/50/20, I'm pretty sure they're all D but I could be wrong.

[JJacksonIII]

Originally Posted by PirelliCondoms

I understand that, but I do not know if there are any load range E tires in 275/50/20, I'm pretty sure they're all D but I could be wrong.

Well, you also don't want to mangle the transfer case. What wheels do you have on the X7? Did you get the 21" wheels or the 22"?

[JJacksonIII]

Originally Posted by PirelliCondoms

I understand that, but I do not know if there are any load range E tires in 275/50/20, I'm pretty sure they're all D but I could be wrong.

Yeah, I think you're screwed if you want a load range E tire.
This chart is pretty helpful.

https://tiresize.com/chart/

[tkelley86]

Originally Posted by PirelliCondoms

Hello all, I recently replaced my 2001 Chevy 2500 with a BMW X7 40i for both daily use and towing use. That being said, I have been towing my boat and my race car trailer with my E46 inside ~6500 lbs for both( my x7 has the factory towing package ). That being said the runflats are driving me crazy with how loud they are while towing. I understand the factory tires are about 31" tall. Is it possible to replace the wheel with a 20" wheel and a Falken AT4W in 285/55/20 (33in tall)? AT3w's have been some of the best tires I have ever used for highway towing, boat ramp towing, and muddy pits at tracks.

Casually replaces 20+ year old Chevy truck with X7

[PirelliCondoms]

Originally Posted by JJacksonIII

Well, you also don't want to mangle the transfer case. What wheels do you have on the X7? Did you get the 21" wheels or the 22"?

My car came with the 21's

[PirelliCondoms]

Originally Posted by tkelley86

Casually replaces 20+ year old Chevy truck with X7

Lol, yeah it was time to get a vehicle that was nice to tow and my wife can drive around.

[PirelliCondoms]

Maybe I'm just not understanding but the Bridgestone Alenza A/S is 31.1 inches tall. The 285/55/20 AT4W has an overall diameter of 32.4". Seeing as that is about 4% taller all the way around, the effects would be nearly negligible as the stresses would be extremely similar, the tire is only .65 taller on each side of the wheel. If the offset is maintained, there should be no fitment issues. I think the load range is worth the potential slightly lower fuel economy of taller wheels.

[AvGeek]

To be frank, do you actually need Load Range E (or D for that matter) tires? Say you're towing ~6500lbs with 600lbs on the tongue (which is max tongue weight), and for simplicity let's say that additional weight is evenly distributed at 150 additional pounds per wheel/tire. That really shouldn't be a problem for even XL rated tires.

[crackerjack15]

A taller tire is going to effectively reduce your rear end ratio and acceleration will be slower. Also, there isn't much clearance on the front control arm to the top of the tire for much larger tires.