Comparing Trailer Tire Sizes 20.5x8-10 and 145/80-12 for a Snowmobile Trailer

Updated 03/07/2016 | Published 03/06/2016

Products Featured in This Question

Kenda Karrier S-Trail ST145/R12 Radial Tire w/ 12" Galvanized Spoke Wheel - 5 on 4-1/2 - LR D

(364)

$132.94

Kenda Karrier S-Trail ST145/R12 Radial Trailer Tire - Load Range D

(566)

$92.26

Kenda Karrier S-Trail ST145/R12 Radial Trailer Tire - Load Range E

(566)

$73.63

Question:

I just purchased a used enclosed snowmobile trailer and it has 145-12 radial tires on it. All my other trailers have 20.5-8-10 tires on them bias ply. I believe both size tires will fit and I always go with load range d or e. While the 145-12s look a little weird are they a better tire for my trailer than the wider bias ply tires ?

asked by: Victor S

Expert Reply:

First, you want to use the tire size and load range specified by the trailer manufacturer as it has been deemed the best option for that particular trailer. Sometimes you can go to a different tire size provided there is enough space around the existing tire for a larger size or if the capacity of a smaller size is sufficient for the gross trailer weight capacity.

The 20.5x8-10 is an older tire size designation that isn't really seen on trailers anymore. It has been replaced with the 205/65-10 tire size.

Regarding the load range you have to be careful because the higher the load range on any tire size, the more psi is required to reach that capacity. The wheels may not be rated as high and if you run lower pressure then the thick trailer tire sidewall will generate excessive heat and lead to tire failure.

I recommend sticking with 145/12 tires if that is what the trailer manufacturer recommends. We have this size available in a load range D, # AM10130, rated for 1,220 pounds at 65 psi, and a load range E, # AM10140, rated for 1,520 pounds at 80 psi. I have linked video reviews of both tires and a link to our help article on trailer tires for you.

expert reply by: Michael H