Would there be an mpg improvement by going to something like a 265/70-19.5? This tire would effectively gear from 3.73 down to a 3.46. Miles per rev would be the same as a 315/70-17, but would have the milage advantage of being narrower (265 vs. 315) and ability to run at higher pressure (up to 120 psi if your kidneys can take it).

How difficult would it be to get 19.5 rims for a 3rd generation non-dually truck? How much would a set of tires & rims cost?

 

Ya your RPM level goes down but I am pretty sure milage is about a wash. Look at this website www.brentzwheels.com.

 

My milage is a wash w/ the 315s I got on it now, so I would have to believe that it would go up w/ the 19.5s.

 

I went from 16 to 20's.
No change for me at all.

 

I would also like to know if it has made a difference to anyone that has done it. I think it would increase mileage being how rolling resistance is a major factor in fuel economy. On most vehicles raising the PSI in the tires will net you a 10% increase over an under inflated tire. A narrow profile should help and I like the looks of the larger big truck type tires on 3rd gens. I mainly drive on pavement and gravel driveways so the agressive wide tires are not doing anything for me except for looks. And the wider/bigger tires & wheels tend to put a bit more load on suspension componants which will accelerate wear.

 

I have the 4:10 rear and went from OEM to 19.5's. MPG improved slightly as RPM's are about 100 rpm lower for the same speed. Takes a bit more to get going, but once I'm crusing I have no problems with hills while sitting at 1700rpm, 55mph or so. Speedo is off by about 7%, but I can eyeball the difference. This summer I'll get out the GPS and get the wife to take a reading to check accuracy.

 

Vision type 81 wheels... Les Schwab sells them for about 2400 with 245/70r19.5 tires so there might be a small diference in price.. The vision wheels are for a SRW truck..

 

The results of doing a cost benefit analysis on a new $2000+ set of tires/wheels for fuel mileage reasons doesn't justify the purchase; but for more weight carrying ability/safety/tire wear - it would be justified.

Mark, do a search on 19.5's in the towing section - there are lots of threads on the subject.

 

Why so much for just tires & rims? Is there a cheaper source for the this type of setup - I'm not looking for anything exotic.

 

You wanna play? You gotta pay.

Give these folks a call and ask them: http://www.ricksontruck.com/

These are commercial tires - working tires. If you're making money with it, everyone wants a piece of the action.

 

I bought a set of aluminum 19.5's with 245's for my 2wd duelly, won't get them on for a month or so but will post results when i have some. I calculate every tank of fuel that goes into that monster

 

For a steel wheel, check Diamond Racing Wheels. Apparently they are slow, still waiting on mine.

Better check that tread width, the numbers can be decieving. A 265 19.5 tire is not a narrow tire.

 

You mean that a 265 would not have a tread width of 265 mm on a 19.5" rim?