Replacement ST205/75R14 Boat Trailer Tires and Storage Covers to Protect Them from UV Damage

Updated 08/06/2018 | Published 08/04/2018

Products Featured in This Question

Karrier KR18 ST235/85R16 Radial Trailer Tire - Load Range F

(2429)

$192.58

Classic Accessories Spare Tire Cover for 26-1/2" to 27-1/2" Diameter Tires - White - Qty 1

(524)

$34.27

Classic Accessories RV Tire Covers for 24" to 27" Tires - Single Axle - White - Qty 2

(773)

$46.96

Karrier ST205/75R14 Radial Trailer Tire with 14" Galvanized Wheel - 5 on 4-1/2 - Load Range C

(2511)

$171.08

CE Smith Offset Spare Tire Mount - Galvanized Steel - 4- and 5-Lug Wheels

(441)

$42.61

Question:

I currently have a sailboat that with gear, boat and trailer weighs in at about 3,000lbs. I have Goodyear Marathon ST 205/75 R14 LRC tires on the sinlge axle trailer, with 5 lug 4.5 steel fairly rusted wheels original with the 1979 trailer. I am seeing some hairline cracks apearing in the sidewalls of the tires and am conerned about dry rot. The tires were purchased in 2011. I want to add a spare, which I currently do not have, that could eventually become one of the main tires. I was looking at your Karrier tire in the same size with the galvanized wheel, and the trailer mounted spare carrier. I wanted to know 1 do these tires come balanced, 2 will they be compatiable with the Marathons, and 3 is there a good test to determine if my current tires are in good shape - they hold air pressure with no problem for months, and there is very little threadware, expept for the hairline cracks seem fine. I tried taking pictures but the hairline cracks do not show up - I probably need a better camera than my phone camera. Most of my trailering is done locally, under 20 miles round trip, at 35mph or less. However, I occasionally make an 60 mile trip on the interstate 120 miles round trip. On the interstate I stay at 65mph.

asked by: Ellis

Expert Reply:

Trailer tires should be replaced every 6 years regardless of mileage or apparent condition. Not all age-related deterioration of a tire will be as visible as we might like but since your tires are about this old and since they DO have visible cracks in the sidewall it is indeed time to replace them. And since your wheels are rusty too, you might as well get that squared away at the same time.

In terms of weight rating you want the two wheels/tires on the trailer to be rated for at least the total loaded trailer weight, but if they were to be rated for more weight that would be good since that extra capacity becomes safety margin. On a 3000-lb axle trailer each of two wheels/tires must be able to handle at least 1500-lbs but again more is better.

The Kenda Karrier galvanized wheel and radial tire # AM32156 combines a rust-resistant 5-on-4-1/2 wheel with a ST205/75R14 radial tire. This item has a load range C rating of 1870-lbs per wheel/tire so it will give you a good safety margin. It is also rated for speeds up to 81-mph which means that it will run much cooler at your typical 65-mph highway speed. These require a 60-psi cold inflation pressure.

I do not recommend mixing new and old tires. I suggest replacing both with the item noted above and using the better of the two originals as your spare unless you can swing the cost of three, which would naturally be a better idea. There is no test I know of that can predict if/when the tire will fail.

Our special trailer tires are not dynamically balanced the way passenger vehicle tires must be since this is not always needed on trailers. What is done to "balance" these is that the distributor mounts the tire's low spot to match the wheel's heavy spot. This provides a degree of balancing that is usually fine for trailers (but it would NOT be fine for vehicle wheels/tires which really do need a dynamic balancing on a machine).

The best way to protect your new tires is to cover them during storage periods to reduce some of the UV exposure that is their worst enemy. Tire covers are cheap compared to new tires and they will let you get the most out of the new tires. ST205/75R14 tires have an overall diameter of 26.3-inches so covers like those shown on the linked page would be ideal. Classic Accessories RV Wheel Covers # 052963762402 would be a cost-effective way to safeguard your new tires. For a spare tire cover you could use # 052963751307.

For a spare tire carrier that bolts on I suggest the CE Smith Offset # CE27310G.