275's vs. 325's Tires on SRW F-350

Flyfisher

Member
New to the forum and working on switching from bumper tow to 5th wheel. I found a used F-350 I like but the owner swapped the tires and rims from stock 275's to 325's. I suspect the taller sidewalls would lend itself to some sway but not sure...and also curious if the added height could be a problem since I see the F-350 sits a couple inches higher already than an F-250 or even the F-350 DRW. I am just starting the learning curve with 5th wheel so I appreciate any help. Thanks!
 

brianharrison

Well-known member
The first number in the tire size is the tread width in millimeters - the second number is the aspect ratio and it helps determine the sidewall height. My stock F350 are 275 70 18 - Sidewall is 275*0.7=192.5mm.

In any case - the load rating of the tire is the most important - Load range E I would suspect - 3,640lbs at 80psi. Are the aftermarket similar rating?

Yes the added height MAY be a problem - the trailer must be level when hooked up to the truck. My 4x4 F350 with a Reese signature series hitch, and the Landmark pinbox on its second lowest height makes my trailer level - just barely.

Hope this helps.
Brian
 

Bob&Patty

Founders of SoCal Chapter
X2 on what Brian said. One more thing that is important...is rear end gear ratio. I suspect that the 325's are a taller tire. Soooo...you have a higher gear ratio which will do 2 things. Make the engine work harder when pulling and make the engine burn more fuel. The other issue will be the speedo with will read slower than you really are going. Just food for thought.
 

caissiel

Senior Member
I would get proper wheels and sell the 325s.
I set mine with 275/70/18 for $400.
The 325 are most likely not load range E.

Sent from my LG-LS720 using Tapatalk
 

Donhutch1800

Active Member
I have a f350 king ranch with 295/70/20 aftermarket wheels and tires.the side walls will be a little softer that the stock tires.as long as there E range tires and I'm sure they are you will be fine.I run 85 psi in my tires to stiffen them up a little.i pull a landmark San Antonio and have no problems at all.
 
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