I just got a pair of used 245/75 R16 tires from a friend. So I mounted them up on my old aluminum mags and mount the 245's on rear axle of the truck. 

 

 

They are a bit shorter in height. The gains are great!

 

Engine load is reduced by 5% to 10% roughly. 

EGT's are about 50*F lower.

Acceleration is way better and faster. 

Cruising RPM's are right about 1,960 RPM at 65 MPH.

 

I've got to reset my cruise timing limit on the Quadzilla I need to drop from my current 25% to 20% it was holding cruise timing climbing about 2-3% grade. 

 

I'm going to document MPG usage as well in the coming days. 

Edited July 2, 20186 yr by Mopar1973Man

Double check to see if it a 3 wire sensor or 1 wire sensor.

 

2 minutes ago, Mopar1973Man said:

Double check to see if it a 3 wire sensor or 1 wire sensor.

 

Yea it's a three wire, 2001.5 .  Schematic shows that the Oil pressure and it share the 5 volt reference voltage.  My pulling on it to connect must have finished off the connection that it had.  So now I am forced to fix it, and the Oil Pressure sending unit power.

Edited November 21, 20186 yr by int3man

4 hours ago, int3man said:

Yea it's a three wire, 2001.5 .  Schematic shows that the Oil pressure and it share the 5 volt reference voltage.  My pulling on it to connect must have finished off the connection that it had.  So now I am forced to fix it, and the Oil Pressure sending unit power.

Just to add this, the 2002 wiring diagram show 3 wires to the the oil pressure "sensor", but my 02 only has one. The 5v reference only goes to my map sensor. This change happened somewhere in 01 and 02. So if you are basing 3 wires on the schematic, you should check to be sure.  Mine is a switch only and an early 02, bought it in October of 01.

I'm starting to worry something is about to crap out on the 01 since it is getting abnormally great fuel mileage.

 

My fuel usage running roughly 75-78 mph from Grants, NM to Pueblo, CO then 45-60 mph due to continuous road construction projects from Pueblo, CO to the Iliff exit on I-225 in Aurora and 2 days of running around Denver for job interviews for a total of 665 miles on 26.83 gallons of fuel. 

 

I'm running #2 diesel with Walmart 2 stroke oil and a Smarty S03 on SW# 5 with RV275 injectors with roughly 80,000 miles on them. Power and smoke output seems normal.

7 minutes ago, 04Mach1 said:

I'm running #2 diesel with Walmart 2 stroke oil and a Smarty S03 on SW# 5 with RV275 injectors

 

Interesting.  I am running stock injectors (for 303,000 miles), no two stroke oil (but 5% bio-diesel mandated in Oregon), and a Smarty SO3 on SW# 5 as well.  I am just getting ready to install new RV275 injectors and I am very curious as to how well they will perform.  I hope to do as well as your setup.

 

- John

58 minutes ago, 04Mach1 said:

for a total of 665 miles on 26.83 gallons of fuel. 

Nice,... I got 17.5 on last fill up, I guess I have nothing to worry about ha ha, except my ABS light  _______

1 hour ago, Tractorman said:

 

Interesting.  I am running stock injectors (for 303,000 miles), no two stroke oil (but 5% bio-diesel mandated in Oregon), and a Smarty SO3 on SW# 5 as well.  I am just getting ready to install new RV275 injectors and I am very curious as to how well they will perform.  I hope to do as well as your setup.

 

- John

I ran my stockers for 250k or so and put in some 275s. You will like it. The combination of new injectors and bigger on top that will be noticeable. Ought to pick up a little mpg too. At least I did in mine. I had a Banks tuner and not Smarty.  But I also did not see the mileage that @04Mach1 is seeing. I also like the bio diesel. 5% bio blend is rated better than the 2 stroke. It is not mandated out my way so you dont know whether you get it or not. 5% or less does not have to be labeled.

Novembers records...

23 hours ago, 04Mach1 said:

I'm starting to worry something is about to crap out on the 01 since it is getting abnormally great fuel mileage.

 

My fuel usage running roughly 75-78 mph from Grants, NM to Pueblo, CO then 45-60 mph due to continuous road construction projects from Pueblo, CO to the Iliff exit on I-225 in Aurora and 2 days of running around Denver for job interviews for a total of 665 miles on 26.83 gallons of fuel. 

 

 

I’ve seen some of my best mpg above 20 mpg, on that stretch of road from Denver to S/W Co. running empty with my Dodge, my best was hand calculated at 21.5 mpg. not bad for a 4x4 47re truck with 3:54 gears and 285/70/16.  I really don’t think I would come close to that with the winter blend fuel though, 

Roads around home here in the winter is usually average around 15 to 17 depending what I’m pulling or using 4x4 

Speaking of pizza cutters...I'll be changing the 285/75R16s on my first gen back to 255/85R16s when I have some spare time next month; in the brands I have, they're both right at 32.8". I'm right at 1800rpm unloaded on a flat at 70mph with converter locked.

 

Stock tires were 235/85R16.

 

There's torque galore to overcome any minor differences in diameter from 30-33", and I can't seem to keep rubber on the rear tires regardless of how wide/skinny they are 

 

 

3 hours ago, ofelas said:

Speaking of pizza cutters...I'll be changing the 285/75R16s on my first gen back to 255/85R16s when I have some spare time next month; in the brands I have, they're both right at 32.8". I'm right at 1800rpm unloaded on a flat at 70mph with converter locked.

 

I run a 255/80R17 in the winter and love them. They aren't huge, but have more axle clearance than 245's or 265's. Since they aren't very wide they also have less unsprung weight than other 33" tires.  

 

I had 4 chains on breaking trail yesterday thru 10" of fresh snow and only drug the diff a couple times, I am pretty sure it would have been nearly constant with 245's or 265's. 

 

There is that fine line between compromise and necessity, for me that's 255/80R17 in the winter and 245/70R19.5 in the summer. 

 

I've contemplated a gear swap to 4.10's for years, but the only place I'd really get a big benefit is at 65 with a trailer in 6th which I don't do all that often but when I do it's normally for hours so I start thinking about gears again. It's also only with the added drag of a camper trailer. 

 

Then again I did 750 miles in a day two weeks ago with a horse trailer and 4.10's would have been annoying in 6th at those speeds. So my money won't be going to gears... 

Comparing... 255/80 R17 to 265/75 R16 basically the same width of tread. 255's are a 33 inch tire. From the ground up to the axle centers.

 

285/75 R16 - 16.4 inches. (+0.1 inches)

255/80 R17 - 16.5 inches.

235/85 R16 - 15.85 inches (-0.65 inches)

265/75 R16 - 15.8 inches. (-0.7 inches)

245/75 R16 - 15.25 inches. (-1.25 inches)

215/85 R16 - 15.20 inches (-1.3 inches)

 

Not a huge difference till you get to the 245's which is an inch difference from axle center line down to the ground. Basically, you can travel in a whole 1.25 inches more snow than I can. Not a huge loss in my book.

 

 

Edited November 25, 20186 yr by Mopar1973Man

10 minutes ago, Mopar1973Man said:

Comparing... 255/80 R17 to 265/75 R16 basically the same width of tread. 255's are a 33 inch tire. From the ground up to the axle centers.

 

285/75 R16 - 16.4 inches. (+0.1 inches)

255/80 R17 - 16.5 inches.

235/85 R16 - 15.85 inches (-0.65 inches)

265/75 R16 - 15.8 inches. (-0.7 inches)

245/75 R16 - 15.25 inches. (-1.25 inches)

 

Not a huge difference till you get to the 245's which is an inch difference from axle center line down to the ground. Basically, you can travel in a whole 1.25 inches more snow than I can. Not a huge loss in my book.

 

 

I’m sure you meant 255/85R16 (sidewall being 85% of tread width), rather than the “80”. 

40 minutes ago, AH64ID said:

I run a 255/80R17 in the winter and love them.

What @AH64ID post is above...

32 minutes ago, Mopar1973Man said:

Comparing... 255/80 R17 to 265/75 R16 basically the same width of tread. 255's are a 33 inch tire. From the ground up to the axle centers.

 

285/75 R16 - 16.4 inches. (+0.1 inches)

255/80 R17 - 16.5 inches.

235/85 R16 - 15.85 inches (-0.65 inches)

265/75 R16 - 15.8 inches. (-0.7 inches)

245/75 R16 - 15.25 inches. (-1.25 inches)

 

Not a huge difference till you get to the 245's which is an inch difference from axle center line down to the ground. Basically, you can travel in a whole 1.25 inches more snow than I can. Not a huge loss in my book.

 

 

 

When the center of the axle is only 7.5” off the ground I’ll take 1.25” of extra clearance, same goes for rocks and such. 

 

When the axle tube starts to drag then issues start to arise and 1.25” is a lot, IMHO. 

 

Its all about what trade offs we want to make. We’d all get better mileage in a 2wd truck, but for many of us that would be worth it the few times a year we use 4wd. For me the taller tire means more clearance and it’s worth the slight hit I’ll take the rest of the time. 

 

19 minutes ago, AH64ID said:

When the center of the axle is only 7.5” off the ground I’ll take 1.25” of extra clearance, same goes for rocks and such.

 

Very true. If your really offroad a bunch 35" or 37" would do much better for clearance. 

 

19 minutes ago, AH64ID said:

Its all about what trade offs we want to make. We’d all get better mileage in a 2wd truck, but for many of us that would be worth it the few times a year we use 4wd. For me the taller tire means more clearance and it’s worth the slight hit I’ll take the rest of the time. 

 

Again for some that do travel offroad a bunch yeah bigger tires have their merits. I can see trying to clear rocks and such being a needed thing. Be even with stock tire sizes so close at 0.65 or 0.7 inch difference that not a heart breaker. I can see where a 285's just way too much rotational mass where your 255/80 do just a bit better. All the years of running 235's not fair from your mark. 

 

Now for someone like myself, that is now committed to being a pavement pounder that -1.25 inch is a bonus with less wind drag under the truck. If was to be able to change the role of my travels I might consider going back to 235's again being that extra bit of clearance. Merits can be had in both directions just depending on what you plan on doing with the truck.

Even in my day of back country travels and firewood hauling never really had any issues. Now being I run that BigTex trailer for firewood that even lower to the ground clearance wise. If the trailer will clear it the truck has no problem.

 

I can also see the difference in the travels were you might be true offroad (I mean off the forestry roads all together cross country). That would require that kind of extra clearance. 

Edited November 25, 20186 yr by Mopar1973Man

I've been reading these posts with interest but nothing to this point has made me think I would change tires and size I have been using at least 3 or more years on this '02 and my previous '01 which got totaled.  NItto Duragrapplers 285/75x17 on 3rd Gen wheels.  Load range E, weight rating of 3970 and a very stiff sidewall which is one major feature I was after. 

 

They tow very well and I could not tell much difference in mileage between the previous 265's original on the '01.  '01 had 3.55 open diff while the '02 is 4.10 suregrip.  I did pain quite a bit over getting a straight tread tire as opposed to something with some type of traction tread.  So far no complaint and that is several times in snow and have yet to hang iron.  First time I took the '01 to Campers hideaway and if anyone knows the road there you know how steep that is in a couple places.  I never thought I would make it barefoot but climbed right through the worst part with little difficulty.  Our place is the very first at top of the hill so did not have to deal with anything too steep inside.  Coming back down the rig did try to swap ends but I managed to finagle it OK.

 

While there have been more, this last winter I really got caught by surprise.  I was on my fav steelhead fishing river and by myself as my pard had only spent one night.   Last weather report was one he came with and it was pretty fair one 2 days old.  I had nearly left day before but decided to wait until next morning to miss most of PDX suck traffic and drivers. 

 

Imagine my surprise to wake up to about 2" of snow!  As I recall it was also the first Saturday of spring break.  I figured probably not that bad on towards PDX which turned out true but not until after the coast hills.  Traffic was everywhere and some spun out including

semis and a number of TT and MH either spun out or pulled off to the side.  Any on my side I managed to drive right around.  I pulled off at rest stop east of Elderberry Inn and when I stepped out the snow was at least 18" deep.

 

Never thought I would get going again but did and never had to hang iron.  Not too much trouble at any one spot.  That was a new set of tires both of those occasions so may be different with less tread on them.  Nevertheless I am extremely pleased and I would estimate no less then 60,000 miles out of a set, probably more.

 

That's my story and I'm stickin' to it!! 

Those are a good tire. Dad runs them on his 06 when the camper is loaded up. They are one of the last few 17’s with more than 3195lbs of load capacity. 

1 hour ago, AH64ID said:

Those are a good tire. Dad runs them on his 06 when the camper is loaded up. They are one of the last few 17’s with more than 3195lbs of load capacity. 

 

They are a good tire.  I had about 40,000 on the first set when I got hit and totaled the '01.  Lost a tire with no damage to rim but couldn't find a matching one so ended up finding another set of right priced 3rd Gen rims and bought 4 new.  I have 7 mounted and 1 loose rim now.  IIRC the first set still had about 7/32 tread but will measure one tomorrow just so I know for sure.  Discount tire says Nitto won't have those for much longer because they don't make enough $$$ on them.  Why is it when you find something you really like it seems like it eventually disappears???  BTW, forgot to mention in my previous post I was towing my toy hauler on hwy 26 in the snow.  While it is larger than my previous one it is also lighter but still over 15,000 gross.

6 hours ago, Russ Roth said:

Discount tire says Nitto won't have those for much longer because they don't make enough $$$ on them. 

 

Kind of like a Big O tire I fell in love with years ago and the quit making them.

Edited November 26, 20186 yr by Mopar1973Man