17" vs 18" stock tire sizes - difference noticeable ?

[csuder99]

So yesterday I traded my 1500 Tradesman V6 for a similar vintage (2013) 2500 Tradesman 5.7 because I upped my travel trailer last year. The original tire size on the ST/Tradesman 2500 was 245/70R17 and the PO had put on later model year 18" wheels. The tires were a little too optimistically sized and rubbed at the control arms and to lower the drive train load when towing I'm looking at going to a stock size.

In 2014 275/70R18 became an option on 2500 models. However looking at the tire dimensions the 245/70R17 are nominally 30.5" tall while 275/70R18 list at 33.2". That's a big difference, about 8%.

Does anybody have experience with both 17" and 18" wheel sizes, either by switching on the same truck or going to a newer truck with the same gearing ? I'm interested in seat of the pants, MPG or towing feel differences. 17" stock wheels are cheap around here and I might go that route as practicality takes precedence over looks (still will have aggressive tread tires).

Thanks !

 

[NewBlackDak]

So yesterday I traded my 1500 Tradesman V6 for a similar vintage (2013) 2500 Tradesman 5.7 because I upped my travel trailer last year. The original tire size on the ST/Tradesman 2500 was 245/70R17 and the PO had put on later model year 18" wheels. The tires were a little too optimistically sized and rubbed at the control arms and to lower the drive train load when towing I'm looking at going to a stock size.

In 2014 275/70R18 became an option on 2500 models. However looking at the tire dimensions the 245/70R17 are nominally 30.5" tall while 275/70R18 list at 33.2". That's a big difference, about 8%.

Does anybody have experience with both 17" and 18" wheel sizes, either by switching on the same truck or going to a newer truck with the same gearing ? I'm interested in seat of the pants, MPG or towing feel differences. 17" stock wheels are cheap around here and I might go that route as practicality takes precedence over looks (still will have aggressive tread tires).

Thanks !

I didn’t change size, but my truck came equipped with HTs, and going to ATs lost a solid 1mpg. I didn’t really have a choice. Where we camp I was having trouble getting g out with the highway tread.


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[jaflowers]

My truck came with the 20" rims, I really want to go down to the Larime 18" eventually.

 

[csuder99]

Update: Scored a set of 265/70-17 tires on chrome steel wheels *with* the TPMS sensors for $50 on craigslist. Did I mention wheels/tires are cheap around here ? I didn't do any scientific instrumented before/after tests but subjectively the engine seems happier with the smaller tires. The lie-o-meter also shows numbers I haven't seen before, even when adjusting the old numbers for the low reading odometer.
The litmus test is going to be in three weeks when I'm dragging my travel trailer up into the mountains. Stay tuned....