QuestionQUESTION: I have a 1973 Aristocrat Landstar travel trailer that needs tires. The markings on the tires say: 6.50 - 13ST Special Trailer, Goodyear, Nylon Cord 4-ply, Load Range C, MFEC NH1252. Can you tell me what the conversion sizes are that will fit this travel trailer?
what
ANSWER: Tom,
First, I hope you are aware that ST type tires are different than regular passenger car tires. Typically they carry more load at a higher inflation pressure than passenger car tires - meaning you shouldn't use regular passenger car tires in place of ST type tires.
Second, there are 6.50-13ST tires available. You have to search on web sites devoted to trailers.
And thirdly, a 6.50-13 Load Range C is 6.6" wide on a 4.50" rim, with a diameter of 24.6" and a load carrying capacity of 1325# at 50 psi.
The closets fit in another sizing system is an ST175/80R13 Load Range C and it is 7.0" wide on a 5.00 rim (6.8" on a 4.50" rim) with a diameter of 24.0" and a load carrying capacity 1360# at 50 psi. This will work provided there is some side clearance and the loss of a little ride height isn't a problem.
---------- FOLLOW-UP ----------
QUESTION: I'm having a hard time finding 6.50-13ST tires. I did contact a website that sells trailer tires and was told a replacement for the 6.50 would be an ST175/80D13. I'm more confused now not knowing the difference between an ST175/80R13 and a ST175/80D13. How am I to know which tire will actually replace the 6.50-13ST and fit the trailer? I appreciate all your help. Thank you.
AnswerTom,
The difference between the 2 tires you mentioned is that one is a radial (the letter "R") and one is a bias tire (the letter "D" for diagonal)
Many folks feel the bias tire is less sensitive to wind and road input, but others feel that radials do a better job of tracking. It's confusing and I'm not sure either is really true.
Otherwise, these tires are identical.
