OK, so I am searching for tires for my dually. I thought I knew a little bit about tires, but have learned recently I didn't know anything! Tire sizing is crazy! One good thing that has come from it is that I have created a great little calculator with Excel to show me what all these sizes really mean.

So currently I am running 235/85/16 which equates to a 31.75". The truck only has a 2" levelling kit. I want to go with something that will give me more height as I have 4.11 gears. I also want something that will allow me to go off-road occasionally. Being in the desert snow & mud aren't a major concern. I plan on occasionally towing with this rig.

My current thoughts are to go with a 17" wheels.

Since I am currently running on 235's the best I have found in this width is a 235/80/17 which gives me 31.80" in height. This doesn't really buy me much other than I have less sidewall to worry about.

So, now I have to wonder how wide can I go on a 98 dually before needing spacers? Are spacers really a bad thing? How do I determine space size to tire size? How big of a tire can I put on this truck without lifting it further than it already is? I don't want to go so big that I am going to be creating more steering problems for me...

The "smallest" bigger tire that I am finding is a 295/70/17 which would be 33.25" in height increasing my overall tire height by 1.5". Which begs another questions, how high do I have to go to have a noticable reduction in RPM on the freeway?

 

Sorry, I just realized that I posted this in the wrong forum and there ain't no way for me to move it... Sorry MODs...

 

I don't know much about spacers for duallies, so I can't help there. But you will notice a difference in RPM on the highway with the change in sizes you mentioned. What's important there is the circumference of the tire, not the height. This calculator http://www.dakota-truck.net/TIRECALC/tirecalc.html will return the effective gear ratio change when comparing tire sizes.

 

i went from a 265/75/16 to a 315/75/16 and it was exactly 10 percent lower.


heres something for you that helps

http://www.intercotire.com/site62.php

 

i run 285/70/16s on my dually, i use a 2" spacer to fit them in the rear.it is one of the best mods i have done. i am running the yokohama geolanders. there are some pix in my gallery

 

Viper, I just replied to a thread last week on this subject, but searching is not my best thing on here. You can run 265-75-R16's on factory rims with a washer on each lug or a spacer plate like I made for mine in my gallery. Your other option is to buy spacers. You can run up to 315's with 2.5 inch spacers or up to maybe 305's with a 2 inch spacer. I have a set of 2.5 inch spacers I am currently trying to trade for 2 inch ones. No one is biting. I were leary of the spacers holding the weight. Not any more. I grossed over #30,000 hauling too much dirt in a dump trailer the other day. I have since took the spacers off and inspected every inch of them. There is no deformation, cracks, stress marks, nothing. PM me if you have any more questions. I have been researching this for almost a year now. I want to run 285's on my 2001 DRW. I just haven't saved up the money yet. I think that is the large tire as far as width goes that I can put on my factory rims.

 

The 285/70/16 would actually lower the height of my tire by some small fraction of an inch. Although I do like them bettern than the setup I currently have.

 

Unless I am missing something 265/75/16 would put be smaller than my current setup of 235/85/16. My biggest concern is getting more tire height to help reduce the RPMs. I would like something wider than what I currently have for the looks of it. I will PM you about the spacer.

 

You probably want 255/85R16. About a 33" tire

But narrow enough for duallys, I think

 

since I know modding this truck is why you bought it....look into lighter wheels (alcoas/ eagles) if you want to improve to the ride slightly....or go big with 19.5's or 22's.....Towing a gooseneck or 5th isn t this trucks main purpose so bed hieght is not a real issue. Getting the 4.10's to be like 3.55's.....thats around 12% ....so you would need a 10-12% change in tire as well....I would not be too concerned with width....but height/ circum . I d look at 33 inch tires...and try to get them on the truck, 16's or larger wheels.

I have a pretty good hook up at a tire store....pm me if you want to go down there....I bought around 30 tires last year.