When To Replace Trailer Tires

Don’t mess around with your safety or unexpected trip interruptions.  The Best Reason to replace old or worn trailer tires is personal sanity, because who wants to deal with it on the side of the road? In the Rain?  In the Cold?  No thanks.  We recommend heading the warnings early.

Since you are in (almost) complete control of this, choose to avoid having that really frustrating trip.  Yes, it’s a statement of the obvious (or at least it seams like it).  Nobody wants to deal with a flat tire in the middle of a trip.  And yet, like the trailer in some of these photos, the warnings came many miles ago.

Learning From A Worn Trailer Tire Disaster

Replace Worn Trailer TiresThe images here are a worn trailer tire failure on the side of the road.  You can see the tire in shreds — I’m guessing because it was driven a little after the initial failure.

Unfortunately, I don’t have any info on the situation.  It was just there on the side of the road.  I didn’t even think to check the tire manufacture date.  Sorry, that would be interesting info.

What do we see?  The tire was worn out a long time before the failure.  Significant wear, in the center, so I wonder if it spent it’s life over-inflated?  Maybe an axle alignment issue?

The reminder is the same we all know:  Replace worn trailer tires before they force it.

The Best Worst Case

OK, we’ve all been there.  We know something needs our attention, but it’s not urgent, so we put it off.  It may nag at us, but for the moment it’s still working, so we let it slide.  So it goes when it comes time to replace worn trailer tires.  It’s so easy to look at them and say “Well, they’re not completely gone.”  Or “Hey, they’ve got another 1000 miles.”  Or “I’ll be careful this one more trip.”

Yes, I’ve been there too.  I’ve purchased used tires to save some money for a trailer I don’t use that often.  That’s all well and good, until it’s not.  The unfortunate part is we don’t get to decide when it’s not.  That’s when Murphy’s Law steps into the picture and finds the best worst time to leave us hobbled — seeking to replace a popped, trailer tire.  That can turn a good trip into a very frustrating day.  Hopefully you have a good Spare Tire.

Aged TireWorn or damaged trailer tires are not the only reason for a flat.  It happens, sometimes you just run over something.  That makes a bad day too, for sure.  Yet, for this article our focus is on the avoidable problems.

Since we’re talking tires, please remember that the real worst case is when that tire failure causes expensive damage, or injury.  That’s not the usual, but it does happen.

When Must You Replace Trailer Tires?

As tires wear, they don’t just hit a point where this mile they’re great, and the next mile they’re worn out.  It’s gradual, and there’s a lot of gray area.  Furthermore, most tires will survive long past the time to replace them.  So when do you really “Need” to replace the trailer tires?

Some tire stores will give you the 3/32″ rule, while others will say 2/32″ (1/16″).  This is talking about tread depth.  Most tires also have “wear bars” that show when the manufacturer thinks the tire is worn out.  See the wear bar photo.  If the tire tread, in it’s most worn spot is below this number, then replace it.

Wear Bars Showing - Replace Trailer TiresOK, that works pretty well for car tires, but when have you ever “worn out” a trailer tire?

For trailers, wear-out happens most often when there are other circumstances.  Things like misalignment, or bad brake balance.  I haven’t actually “worn out” a trailer tire.  Yes, I’ve had to change them because of age, dry rot, or road hazard damage, but not just for wear.

Another rule a tire store may tell:  Replace trailer tires every 3 years regardless of wear.  (I’ve heard everything from 3 years to 6 years, so I reject timelines as an absolute.)  I agree, time is an important factor, but it’s not an absolute.  And yet, it reminds me to ask myself Who to Believe?  I don’t buy into the 3 years stuff.  If the tires can’t last more than 3 years, they’re the wrong trailer tires, if you ask me.


For what it’s worth, here are my recommendations on when to replace trailer tires.  Please note that I’m not a tire expert, so consider this as advise from experience, not from expertise.

  1. If there is significant wear on any one portion of the tire (perhaps the edges more than the center).  Note:  This usually means there is a bigger problem.  Maybe it’s simple like too much or too little air pressure.  Or, maybe it’s more serious like a bent axle, bent rim, or axle alignment.  It could be a spring hanger that’s come loose.  (I saw that once.)
  2. If the tread wear really does reach the wear bars or 3/32″ rule.
  3. If there is damage on the tire (like a slice, or a bulging sidewall, or a chunk of tread missing).  These can come from hitting curbs or debris.
  4. If you find significant dry rot.  Dry rot is the little cracks that appear over time in the rubber.  We expect some tiny cracking when we look really close, but if it becomes significant, replace the worn trailer tires.  Dry rot is natural with rubber over time, made worse in the sun.  Ask a tire store if you’re in doubt.
  5. Consider time.  If the trailer lives outdoors, tires will not last as long.  If you don’t cover the tires in storage, they won’t last as long.  I don’t put a “years” deadline on it, because it depends on many factors.  Just keep an eye on it and make sure they don’t go past 6 years because tire stores won’t help you with them (like to fix a flat, except to replace them) after 6 years.  Note:  6 years from the manufacture date, not 6 years on your trailer.
Trailer Tire Failure
Replace Worn Trailer Tires Before The Disaster. The Warning Signs Of Wear And Impending Doom Are There.

How Can You Make Tires Last Longer?

Although most trailer tires don’t spend enough time on the road (typically) to wear out, there are several things we can do to keep them from premature death.  From item 5 above, a generalize expire time is 5 or 6, maybe 7 years, so let’s get them there without other big problems.Covered Spare Tire

  1. Don’t store them in the sun.  That’s the worst for dry-rot, which is the leading cause of death for trailer tires.  Cover them.
  2.  Keep them inflated properly for the conditions.  While there are times for low inflation, make sure it is always at a level that’s right for the load.
  3. If the trailer stores with a significant load for a long time — like an RV or tiny house — put it on blocks.  This takes the load off the tires.  All tires leak down a little over a long time.  It’s better for the tires with no stress from bulging out as the pressure goes low.
  4. Make sure the axles align properly to themselves, and with the tow vehicle.  Watch the tires, and if they start to have wear patterns, fix the problems to make sure they serve you well.

That’s it.  Do the above, then unless you travel with the trailer a lot, you won’t need to worry about failures from worn trailer tires.   Take good care of your trailer tires, replace them when needed, and they’ll take good care of you.


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