changing tire and wheel size

[zip]

I recently took ownership of a 2013 E350 EB 42K miles with the SMB 4x4 conversion. I am very excited to go forward with the Ujoint Offroad Colorado Sportsmobile Ride Improvement Package. New springs, shocks, re-gear on diffs, and maybe a change in the brakes. I will be moving up in size to a 35-inch tire. Currently, I have 18-inch wheels with the 285 65 size tires. It has been recommended that I go with a 17-inch wheel. It has been patiently explained to me by a couple people that reducing the size of the wheel is the best option when increasing the tire size to a 35. I have zero knowledge in this area and still having a little difficulty grasping this. I think I am being told that the sidewall is higher on the wheel downsize, so the ride is better. Am I understanding this correctly?
I appreciate any and all constructive advice.
Thanks.
Blair

​

 

[Rovertrader]

If you have 18” wheels, take a look at some 285/75-18’s (35”), which is a very sweet spot sidewall/performance wise…

 

[rruff]

I think I am being told that the sidewall is higher on the wheel downsize, so the ride is better. Am I understanding this correctly?

There is a lot of "lore" around this topic. Basically you have more suspension travel in the tire itself before you bottom out on the rim... 1/2" more in a 17" vs 18". Since 35s are generally ~34.6" tall, the 17 would have ~8.8" of travel and the 18 would have ~8.3".

The ride will have a lot more to do with tire construction and pressure, though. And there are modest downsides to having a taller sidewall, like a bit less cornering precision, and higher rolling resistance.

One advantage that 18s have in the 35 inch range, is many options in metric sizes. 295/70, 285/75, 305/70, and 325/65 are all within 0.3" of the 34.6" norm for a 35. In 17" there is only 315/70. There are many offerings in both 17 and 18 for ~35" tires though, and I haven't looked at prices and load range differences. If I go to 37s I'd like 17" rims because there are more offerings, but I'm happy with 18" for 35s.

This will give you idea of what is available. 315/70/r7s and 295/70r18s will be listed as 34s because they are a little under 34.5".

35 Inch Tires

Find all 35 inch diameter tires for every wheel size, including the metric and inch equivalent tire sizes available for each tire.

tiresize.com

 

[zip]

There is a lot of "lore" around this topic. Basically you have more suspension travel in the tire itself before you bottom out on the rim... 1/2" more in a 17" vs 18". Since 35s are generally ~34.6" tall, the 17 would have ~8.8" of travel and the 18 would have ~8.3".

The ride will have a lot more to do with tire construction and pressure, though. And there are modest downsides to having a taller sidewall, like a bit less cornering precision, and higher rolling resistance.

One advantage that 18s have in the 35 inch range, is many options in metric sizes. 295/70, 285/75, 305/70, and 325/65 are all within 0.3" of the 34.6" norm for a 35. In 17" there is only 315/70. There are many offerings in both 17 and 18 for ~35" tires though, and I haven't looked at prices and load range differences. If I go to 37s I'd like 17" rims because there are more offerings, but I'm happy with 18" for 35s.

This will give you idea of what is available. 315/70/r7s and 295/70r18s will be listed as 34s because they are a little under 34.5".

35 Inch Tires

Find all 35 inch diameter tires for every wheel size, including the metric and inch equivalent tire sizes available for each tire.

tiresize.com

HOLY COW! So much to know. Thanks.

 

[zip]

I have had BFGK02s for years and considering Falken Wildpeak AT4W replacements. Has anyone here had experience with these tires?

 

[Rovertrader]

That’s what I run on my Expedition and love them!! I’ve used Falkens the past decade with no problems or issues. Only snow use is winter trips to the mountains , but again, no disappointments…

 

[zip]

That’s what I run on my Expedition and love them!! I’ve used Falkens the past decade with no problems or issues. Only snow use is winter trips to the mountains , but again, no disappointments…

UJOR CO speaks very highly of them.