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Secrets to Blow-Out-Free Trailering
We live and we learn—especially now that there are enough of our trailers out there that we can start to see patterns and investigate them. It’s clear, for example, from a few blowouts and a lot of background research, that infrequent use is the number one enemy of trailer tires and heat is the enemy number two. The good news is that, according to all reports, Ironhorse trailers continue to behave well even during catastrophic tire failure. Keep reading and you’ll learn how to keep tire failure damage to a minimum. Read a little further and you’ll learn how to avoid tire failure altogether.
When a tire fails–Typically the first thing you’ll notice is a fast, regular, low pitched drumming noise coming from the rear of your tow vehicle. A quick glance in the rear will verify that one side of the trailer is bumping up and down with the same frequency as the noise you are hearing. Once you’ve done that, you’ve got maybe 20 seconds to slow down as the tire carcass has cracked and allowed an air bubble to form between the tread and the carcass of the tire. If you don’t slow down, stop and change the tire, the tread will separate from the tire carcass, flop around and tear the fender on that side of the trailer, regardless of whether it is fiberglass or metal.
How to avoid tire failure–Tires with a severe case of dry rot are prone to blow outs, even used gently. To make bad matters worse, some dry rot is visible—very narrow random cracks in the surface of your tires. But that’s just the tip of the iceberg as you can’t very well tell how deep the cracks are, and hence, how dangerous they are. Remember it’s a crack in the carcass that allows an air bubble to form between the tire carcass and the tire tread. So dry rot is really something you want to avoid.
While most people understand that unused tires eventually develop a severe case of dry rot, not everybody understands that infrequently used tires can also dry rot pretty quickly. Raising your tires off the ground or putting wood blocks between your tires and asphalt or concrete may low down dry rot but it won’t prevent it entirely.
Why sound tires sometimes fail–The bottom line is that as tires and the air inside them gets hotter and hotter, the harder that air searches for a weak spot. So what makes tires get hotter? Black asphalt and 100 plus degree temperatures are a good start. Add trailers loaded near or beyond the design weight, rough roads and under-inflated tires and you’ve got a pretty good recipe for trouble.
What’s so bad about under-inflation? When tires roll, the sidewalls flex and the flimsier the sidewall, the more they flex. That’s why special trailer (STXXX) tires are recommended for trailers instead of passenger tires (PXXX).
The special trailer tires have much stronger sidewalls–that’s why they are so expensive. Regardless of which tires you use, the heavier the load at a given level of inflation, the more the sidewalls flex. Likewise, the heavier the load, the rougher the road and the faster you drive with the same initial inflation and outside temperature, the more the tires flex and the hotter they get—until one of those weak spots gives way.
Likewise the lighter the load and the slower you drive, the less the tires flex and the cooler they run for a given level of initial inflation and pavement temperature. That’s important, because according to tire manufacturers, trailers with ST tires should not be towed faster than 65 mph. However, our experience suggests that load trumps speed. Specifically, even though we install tires with a combined carrying capacity of 3500 lbs on both our one bike and two bike trailers, no one has yet reported a blowout with one of our one bike trailers. The bottom line is that while the owners of the two bike trailers often carry more than a ton of bikes and “stuff”, the owners of one bike trailers rarely carry more than half that.
Clearly, towing a fully loaded two bike trailer with less than its 50 lbs maximum rated cold (initial) inflation at 85 mph across South Dakota on a 105 plus degree day is a prescription for catastrophic tire failure.
Seven Steps to Blow-Out-Free Trailering
- If your tires are over three years old and your trailer stays parked for weeks at a time,replace them no matter how good they look, how much tread they have or how few miles you’ve put on them. It’s TIME, not miles, that count.
- If you park your trailer for more than 30 days, put wood blocks between the tires and the concrete or asphalt.
- If your trailer has been parked for more than a month, check the tire pressure before towing it more than five miles.
- Adjust your initial inflation pressure to match your load and the outside temperature. 35lbs for an empty one bike trailer on a cool day to 45 lbs when its fully loaded on a hotday. For a two bike trailer, 40 to 50 lbs for the two extremes makes more sense.
- Adjust your speed to match the load in your trailer—at least 10-15 mph slower for twobig Harleys than one dirt bike.
- Adjust your speed to match the roughness of the road and the outside temperature–slowdown if the road is rough or if it is extremely hot. Slow down even more if it is both.
- Every time you stop, feel the treads of your trailer tires and your tow vehicle tires; if yourtrailer tires are hotter than your tow vehicle tires, slow down.
