[ksa8907]

Originally Posted by lasitter

My truck currently has Kumho Solus KR21 235/75R15 tires, 108T XL 2183 lbs weight rating, 6.5" tread width and weighing 28-29 pounds. These are not LRR tires.

The General Tire Grabber HTS is the only (non-winter) LRR tire available in that wheel size, so I am considering buying that tire, and also tires for 16-18" wheel sizes, where there are many more options.

One question I'm trying to answer is this: Given that I'm already getting very good highway fuel economy (up to 32mpg @ 55mph under ideal conditions), what is the biggest bump in fuel economy that I might get as a result of tire selection?

Then: How much would I have to give up in terms of driving and performance characteristics, in order to achieve those benefits?

General Tire Grabber HTS LRR 235/75 R15 109T XL 2271 lbs./51psi 12.0/32" 32lbs 7.2"
Michelin Latitude Tour HP LRR 255/65 R16 109H SL 2271 lbs./51psi 10.5/32" 33lbs 8.5" (owners hated it)
General Tire Grabber UHP --- 255/65 R16 109H SL 2271 lbs./51psi 12.0/32" 34lbs 7.7"
Pirelli Scorpion Verde+ AS LRR P235/70 R16 106T SL 2094 lbs./44psi 11.0/32" 30lbs 8.0"
Pirelli Scorpion Verde AS LRR P235/70 R16 106H SL 2094 lbs./44psi 11.0/32" 31lbs 7.2" (2011 Production)
General Tire Grabber HTS LRR 235/70 R16 106T SL 2094 lbs./44psi 12.0/32" 33lbs 6.5"
General Tire Grabber HTS LRR 235/70 R16 106T SL 2094 lbs./44psi 12.0/32" 33lbs 7.0"
General Tire Grabber UHP --- 255/55ZR18 109W XL 2271 lbs./51psi 11.0/32" 32lbs 8.5"
Pirelli Scorpion Verde AS LRR 255/55 R18 109V XL 2271 lbs./50psi 11.0/12" 36lbs 9.0"
Continental CrossContact LX20 LRR 255/55 R18 109H XL 2271 lbs./51psi 12.0/32" 35lbs 8.6"

I'm very suspicious about tire manufacturer claims regarding LRR. No one is releasing CRR data for their products. That said, I'm generally aware of the claims made for LRR tires.

The tires above cover lots of different options and strengths. I'm going to have dedicated winter tires so that one tire does not have to accomplish everything.

Just looking at the tires above, and considering the weight, PSI inflation, rubber patch on the road, and approximate sidewall height, and forgetting price, which ones would likely show the greatest improvement in MPG?

The greatest difference in weight above is the Verde+ at the 16" wheel size with 30 lbs. and 8" of rubber on the road, and the 18" wheel with Verde with 36lbs and 9.0" of rubber on the road. That's a pickup of 2-8 pounds per corner for me. What does that cost me just in weight, or in terms of the six pound difference between the Pirelli's?

Compared to my current 6.5", it looks like I can have a lot more tire on the road if I want it, and that might represent a big improvement in stopping and handling. That's partially why you'll see the UHP summer tires in the list, in case MPG improvement isn't enough to matter.

It also looks like I can shave 2-3 pounds off the wheels. Still working on that.

If cooper makes the discoverer htp in that size you may want to consider it. We put those on my wife's car a couple years ago, 30k miles later they have about 50% or so tread left. I have been very happy with them.