19.5" wheels - '03 3500 SWR

[Jeremiah]

Originally posted by nickleinonen

nope. the 245's are 245mm tread width and the 265's are 265mm tread width. so the difference is 20mm, but the overall height of the tires are different. the 245/70/19. 5 tire is ±33" tall, while the 265/70/17 is ±32" tall. now if you put a 285/70/17 tire on the stock rims, you would have a tire that is the same height as the 245/70/19. 5 being ±33" tall, but being 40mm wider



just a refresher for anyone who has forgoten [or never learned] what the numbers in a tire size are. example below...



Thanks for the education. I knew part of this stuff, obviously, but never learned the other because it wasn't necessary. No need to clog the brain with information it doesn't need. Now that there is a need to know, I can learn it.



I want a taller tire - preferably in a commercial size - to drop the rpms 200-300, but do NOT want a wider tire. Wider tires throw more mud and snow on the vehicle and aren't as efficient because they pack snow instead of digging down to where there is traction.



Of course, DC could have solved this issue for us if they'd left the 3. 55 rear end ratio as an option for owners who do lots of highway driving.





205/75/15



the red 205 is the tread width in millimeters [mm]

the green 75 is the aspect ratio. the tire's sidewall on this example is 75% of the tread width which works out to 153. 75mm [per side]

the blue 15 is the rim size in inches



there is other stuff that is on tire sidewalls like P and LT which are ratings for passenger and light truck. the ply rating is there too [c=6, d=8, e=10... ] and speed ratings [a-z more or less in alpha order -lower letter, lower speed, higher letter, higher speed rating ->y or w being fastest (z is below them )] and there is also temprature and traction ratings, with AA being top and C being lowest [AA, A, B, C]

 

[jimnance]

From my experience with the 315 BFG's which have about the same number of wheel rev's as the Ricksons I'd urge caution.



I like my 315's, but sixth gear is useless when pulling a big load except for totally flat ground. I thought fuel mileage might improve since RPM's are down, but the opposite has been true. Both towing and regular driving fuel economy is down about 1 MPG. It could be that now I'm going a little faster hence the lower MPG, but even if I slowed a bit my fuel economy wouldn't be better.



The one good thing is that towing my particular rig up BIG hills was impossible in fifth and turned 2900 RPM to get 52 MPH on the hills. Now I'm turning the same 2900 RPM's and getting 57 MPH on the hills.



Out pulled a BOMBED Ferd on the hills and I like it!

 

[Jeremiah]

Originally posted by jimnance

From my experience with the 315 BFG's which have about the same number of wheel rev's as the Ricksons I'd urge caution.



I like my 315's, but sixth gear is useless when pulling a big load except for totally flat ground. I thought fuel mileage might improve since RPM's are down, but the opposite has been true. Both towing and regular driving fuel economy is down about 1 MPG. It could be that now I'm going a little faster hence the lower MPG, but even if I slowed a bit my fuel economy wouldn't be better.



The one good thing is that towing my particular rig up BIG hills was impossible in fifth and turned 2900 RPM to get 52 MPH on the hills. Now I'm turning the same 2900 RPM's and getting 57 MPH on the hills.



H-m-m-m. Sounds like DC may have known what they were doing when they dropped the 3. 55/4. 10 in favor of a 3. 73/4. 10. You're stock w/315s and still beat a bombed Ford while pulling your 16,000 lb trailer?



Wait a minute! You're pulling 16,000 lbs in a truck that weighs close to 7,000? You don't have a truck, you've got a monster! That's roughly 23,000 lbls on my HP12-C!!! No wonder it won't pull hills in 6th gear!

 

[jimnance]

Jeremiah,



He was pulling a fifth wheel of aproximately the same weight.



I was still happy. I'm grossing about 22K fully loaded. 57 MPH up the big hills STOCK isn't too bad.

 

[Jeremiah]

Originally posted by jimnance

Jeremiah,



He was pulling a fifth wheel of aproximately the same weight.



I was still happy. I'm grossing about 22K fully loaded. 57 MPH up the big hills STOCK isn't too bad.

I'd say it's WONDERFUL, given the factory book of 16,000 lbs truck, trailer, wife, dogs, onboard water and everything else.