Need quick help with trailer tire size question

[Bigprairie1]

Anyone know what a 6.35 x 14 tire size in new terminology? (I get the 14" diameter stuff...but I'm curious about the rest of the rim/tire width possiblities)
I have this on an older trailer I just got and I'm going to get a new spare for it.
Many Thanks!!
BP

 

[Bob_VT]

Re: Need quick help with trailer tire size question

Trailer tires are still denoted the old way and you should have no problem matching it providing you have the right size

 

[H20Rat]

Re: Need quick help with trailer tire size question

Trailer tires are still denoted the old way and you should have no problem matching it providing you have the right size

At least from what I've seen, most trailer tires have moved towards the NEW way, especially with radials. The only ones still using the old style are for the really tiny tires that aren't available in radial, bias only.

http://www.carlisletire.com/products/trailer/radial_trail/index.html


http://www.maxxis.com/Repository/Files/m8008load.pdf



At least for the OP, the best might be just to break out your tape measure. Per this chart (http://www.tirerack.com/tires/tiretech/45_conversionchart.html) 175/70R14 or 185/65R14 will get you close, with the 185 being wider and possibly more expensive. (not always true though) Using the miata tire size calculator, the 175 will come in at 6.8 inches wide, and a diameter of 22.7 inches.

 

[Bigprairie1]

Re: Need quick help with trailer tire size question

Guys, quick update. I got down on my hands and knees (vs. the spec sheet in the trailer) and the tires currently on the trailer are: P195-75R14....ok, no problem.
I've located a couple of 'possible' high quality spares and I have a couple more questions you guys might be able to help me with.
How close a fit would the following be to the current 195-75R14?
-195-70R14
-185-75R14
-205-60R14
Now bare in mind this is for a spare tire only. To my recollection the first number is a width indicator....what about the next number? (ie: 60 or 70 or 75 series)....do these have to match the originals? As for the first number...any reason one of these wouldn't fit the same 14" rim?
All good and again, many thanks.
BP

 

[UncleWillie]

Re: Need quick help with trailer tire size question

As you indicated , the 14 is the "Nominal" Diameter of the rim.
The 185,195,205, etc. is the Width of the rim in Millimeters. (195 / 25.4 = 7.7 inches.)

The 60,70,75 is the profile of the tire in Percentage.
195/70-14 means the Profile is 70% of the 195mm width. 195 x .70 = 136.5 mm profile. 136.5 / 25.4 = 5.37 inches.

So a 195/70-14 tire is 7.7 inch wide with 5.37 inches of tire on each side of a 14 inch rim. 14 + 5.37 + 5.37 = 24.75 inch Diameter.

A 205/60-14 tire is 8.1 inches wide with 4.84 inches of tire on each side of a 14 inch rim for a 23.69 inch Diameter.
A 185/75-14 tire is 7.3 inches wide with 5.46 inches of tire on each side of a 14 inch rim for a 24.92 inch Diameter.

Your 195/75-14 tire is 7.7 inches wide with 5.75 inches of tire on each side of a 14 inch rim for a 25.52 inch Diameter.

Not so obvious the that the 205 is the smallest, diameter wise.

If both tires are not the same diameter the trailer will have a slight list.
If the width is significantly different. The tire bead may not seal on the rim.
There is usually a lot of wiggle room in the width.

The real issue will be the Load capacity of each tire.
Trailer tires are usually operated at very near 100% load, the isn't much wiggly room!