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budwich's avatar
budwich
Explorer
Aug 07, 2014

tires again... two sizes, unusual but does it matter?

Well, I was taking closer look at tires on a 210RB Terry Dakota after doing our recent 10K mile trip around the "world". We bought the 2007, this spring specifically to get out and about. Tires are doing well but upon a bit closer look, one side (curb side), the tandem axles have on ST 205 75 r14 while the other side have on ST 215 75 r14. Now, on a 4W drive vehicle this would probably be an significant issue for the drive train but since a trailer is only being pulled and the wheels are independent, does it really matter with the slight difference? I guess the previous owner had an issue with one tire which was then replaced with the "closest" available size. I guess the question would be should the tires be the same size for a given axle? The tires are pretty new both tread wise and build (2011, 2012 stamps if I am reading them correctly).

Thanks for any guidance / comments.

14 Replies

  • Put the trailer on flat level ground. Measure height to the frame between the axles for each side.

    I would put the same size tire on a side and then depending on the height measurement which side to put the taller tires.

    As for handling etc I doubt it will make much difference with the tires as close as they are.
  • Diameter inches (mm)
    26.11 (663.1) 26.7 (678.1) 0.59 (15) 2.3%

    Width inches (mm)
    8.07 (205) 8.46 (215) 0.39 (10) 4.9%

    Circum. inches (mm)
    82.02 (2083.19) 83.87 (2130.31) 1.86 (47.12) 2.3%

    Sidewall Height inches (mm)
    6.05 (153.75) 6.35 (161.25) 0.3 (7.5) 4.9%

    Revolutions per mile (km)
    772.54 (480.03) 755.45 (469.41) -17.09 (-10.62)

    The first numbers are for the 205 tires and the second set are the 215 tires the third is the difference.
    My opinion would be to have the 205's & 215's on the same axle.
  • I wonder what the thinking was? Taller tires on the curb side to counteract the road crown?

    You are right, for a vehicle with a differential or transfer case it would be a bad thing, For a trailer it won't have any effect.
  • Personally I want all the tires to be the same size. Tire issues are one of the most frequent problems most RVers have to deal with. If finanically possible, I would also switch to 15 inch rims with "E" rated tires. For me, I would rather have a little over kill margin of safety as opposed to using tires that are at their maximum capacity of weight load.