2nd Gen Non-Engine/Transmission old f--- needs a little help

[jeepit]

VolsFan, with the 3,55's I am right at 2000 rpm. If I go to 285's I will drop about 150 RPM.

 

[Road Dog]

NOT to be argumentative, but the equivalent of the 33x12. 50x16. 5, is actually a 305/75R16... ... The 285/75R16 is spec'd to replace the 33x10. 50. A 255/85R16 is a 33x9. 00.....

You're right. I looked at the popular BFG TA KO and most of the 16" tires have a 75% aspect ratio EXCEPT the 305 which is 70%. So a 305/70R16 is a 33x12. 2 tire. That's close to what the OP wants.
(The LT285/75R16 is 33x11. 4)

 

[HHhuntitall]

You're right. I looked at the popular BFG TA KO and most of the 16" tires have a 75% aspect ratio EXCEPT the 305 which is 70%. So a 305/70R16 is a 33x12. 2 tire. That's close to what the OP wants.
(The LT285/75R16 is 33x11. 4)

But also remember, aspect ratio refers to the widest point on the tire, not necessarily the width of the tread, as some non-P-metric sizes used to refer. I sell 2-300 tires a year in my shop, mostly fitting oversized tires to Dodge and Ford trucks, often after installing a lift kit or wheels. I also run 315x75R16 or 255x85R16s dualled on a fleet of farm and ranch trucks, and have experimented with just about every brand, size, and tread offering out there, trying to find the best tire for the money to keep a dozen or so trucks rolling on the road and off.

And tread widths, overall widths, and even overall diameter can vary between treads from the same manufacturer, let alone between different brands. I find Goodyear tires are usually noticeably shorter and narrower than most other manufacturers... ... Perhaps they're saving that much rubber... .

I've never had an issue with gear ratio. As stated, I run the taller tires on just about everything, and most of my trucks have the 3. 54 ratio. Your speedometer is off, but that's to your advantage if they're in warranty. I run 255x85R16s on my 3500s and very seldom have any issues with launching when loaded. Another beautiful feature of a Cummins!!

 

[Bob4x4]

A lot depends on how you use the truck and of course how much power it puts down. I run 315's with 3. 54's and it suites me perfect. It has a bit more than stock power though at 1k torque it's easy to get away with more. I tend to tow at 65+ so it cruises nice. If you pull a big grade and feel the need to keep it at a legal speed kick it down a gear. With the correct governor you can pull the legal speed limit in direct.