Looking for opinions about possibly downsizing my wheels/tires from 20" down to 17". I have a 2008 1500 4x4 with the OEM Chrome 20" wheels. When I bought the truck I wanted the dealer to switch the 20's out with factory 17's from another truck, but all he had were ugly steel wheels.

I commute in the truck 80 miles round trip. I am also looking at purchasing a 25 ft. travel trailer to pull on trips. One of the big reasons I bought a 4x4 this time was to have the ability to take mountain roads & trails to the trail heads so I could ride my ATV, instead of always renting a $200 a day jeep (Western Colorado).

Also, on the RV forums most people refer to 20's as power & mileage killers? Most recommend the 17" wheels.

Here is a pic of the 17" wheels I like.


Here is what the truck looked like on the first day.


Any thoughts or suggestions?

 

Do it, I would go with cragar soft eights.

 

If you would be interested in trading your 20"s for stock alum 17"s id do it depending on where you live. Id like the 20"s powdercoated and run em as my winter boots. The stock wheels i have only have 800 miles on em before i put aftermarkets on em.

 

Do it in a heartbeat. Better mileage on road and much better performance off it...

 

Yes do it! Better mpg!!

 

well it depends on what tire you put on those 17's. Put a 35" mud tire you'll loose mpg but put on the oem goodyear road tire you will gain mpg but you couldn't go offroading. Maybe look into getting a 33" bfg a/t tire.

 

Good point. My initial thoughts were to go with the OEM size 265/70 R17 in an AT or even M/S tread.

 

I would def go for it! i did and i wouldnt ever look back on my decision!!

 

I don't see how the rim size has anything to do with power & mileage. Sure, they weight a little more, but it'd be like 1 mpg and not 10.

The effective power / gearing is dependent on the overall diameter of the tire, not the wheel it's mounted on. 33's are going to be 33's whether they're on a 17 or 20 inch wheel.


Sure, 17's give you more flex but truthfully, I don't think I'd be willing to drive my truck anywhere my current tires couldn't take me. Maybe a beater, but not anything worth more than a few grand.

 

Here is my opinion


A larger circumference tire has more weight; my truck weighs 2400Kg (5300 lbs), what is an extra 120 lbs as a percentage maybe 2.2%. So yes this will reduce your gas mileage, but not significantly

The tire however takes a couple minutes to heat up while driving, until this heated point has been reached, your friction between the tire and the road will be greatest, thus much reduced gas mileage for this period. This can be mitigated by using Nitrogen in the tire as Nitrogen does not suffer the same heating and cooling effects as air, plus Nitrogen is better for rubber life.

Getting back to friction, if we go for a skinnier width tire, there is less friction, thus a fuel savings, but who wants a skinny tire on a truck, less carry capacity generally.

I would wager that most people do not go to their dealer to have the vehicle recalibrated after changing their tire size. I had $160 ticket when I changed the tire size on my Dakota to a tire that had a greater sidewall aspect ratio than recommended. I installed a GPS devise and the vehicle displayed speed was low by 10%. The dealer recalibrated this for me. So if someone changes the tire size from 20” to 17” and does not have their speedometer calibrated, toss their results out the window, these will be invalid.

Trailer hauling, I chose to keep the stock 20” on my Ram as the sidewall aspect ratio is relatively small. This would help elevate some sway from the trailer. The higher the aspect ratio, the higher the rim from the ground, the more flex the tire has.

Bottom line, yes marginal increase in fuel mileage, worth the cost of changing tires, not in my opinion as the smaller tire also turns more frequent, thus increasing the contact time to the ground and thusly wear