Quote:
Originally Posted by harveyrv
2006 Chevy Silverado, 4.8L V8, auto trans, 3.23 final drive.....towing a 2720.
We've only had the truck a short time and towed with it 230 miles last weekend. Slightly hilly terrain (no mountains) 4 passengers and lots of cargo (including a kayak). We got a shocking 17.7MPG. We filled up when we started out and when we returned, so that is 100% towing mileage. I have no idea what it gets non-towing yet.
We are going on a 800 mile trip next weekend with some mountains and will report back.
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OK.....time to report back after our 800 mile vacation.
Our true mileage (calculated at each fill-up and considering the entire trip) is
16.6 towing. Again, it must be stated that this was going up CA Hwy 1 with lots of hills (including grades up to 10%) and many-many stops. We were also loaded to the max and ran the AC all of the time. Top towing speed 60MPH.
This mileage stuff is far from a perfect science and it has been my experience that mileage can vary greatly with a lot of differing conditions. For instance, the 1st part of our trip north, we were bucking headwinds of 30MPH and our mileage (at fill-up in Monterey) was 15.2. The last part of our trip, we were cruising down CA Hwy101 (no wind) and got 17.9 on the last fill-up (arriving home).
I also found that I am quite happy with our 3.23 gear ratio (I didn't think that I would be). It seems very comfortable for this truck and the amount of trailer that we have. I was concerned about pulling grades but found that it pulled a 10% grade comfortably @ 35MPH @ 3500RPM at the hardest part (part of the time was in 2nd @ 45MPH). It pulls 6% grades @55MPH in 3rd gear(occasionaly down-shifting to 2nd but maintaining 55MPH).
The family that was with us, had a new Dodge RAM Maxi-Cab 5.7L V8 with 4:11 gears and had to go up the 10% grade in 2nd gear (1st gear @35MPH was 4600RPM) and could not keep up with us (slightly heavier travel trailer). When he was forced into 1st gear, he had to slow to 25MPH to keep from over-revving the engine. This scenario was the same going down the other side. I was able to keep it @ 35MPH in 1st gear with moderate braking. The Dodge had to stay @ 25MPH in 1st and didn't dare go down in 2nd for fear of over-heating the brakes.
Having said all that, if and when we move up to a larger trailer, I will change the gearing accordingly.