On the face of it, it would seem that your trailer tyres should last pretty much forever. But in practice, most trailer tyres should be replaced every four or five years regardless of mileage. Why? Because ozone in the air and exposure to UV radiation (read sunlight) can easily cause an innocent looking trailer tyre, that looks fine and still holds air, to suddenly fail at highway speeds. Nearly half of all road-service calls for towing or trailering problems involve flat tyres or blowouts.
Inflation is another cause for concern. Some tyres can lose a pound or more of air per week. And an under-inflated tyre can cause fishtailing and/or a quick build up of heat resulting in a blowout. Either of these instances occuring could end up causing you to have a very nasty accident. A quick pre-trip inflation check can help you avoid these common mishaps.
One thing to consider when buying new tyres for your trailer is that larger tyres rotate more slowly and generate less heat. And likewise, smaller tyres rotate faster, generating more heat and increasing the chances of failure. So all things being equal, it makes sense to choose the largest wheel/tyre size that your trailer manufacturer specifies. Also keep in mind that even higher-end ST rated tyres (Special Trailering), which have stiffer sidewalls to help with cornering, are still only speed rated to 65mph.
It is important that you consult your owner’s manual to find out the towing capacity of your vehicle. Keep in mind that the original equipment tyres that came with your vehicle are rated to handle the specified tow weight. That is of course, if they are in good shape. Towing places all sorts of additional stresses on a tyre. To perform safely, your tyres should have good tread depth. To check this use the head of an unused match and insert it into the tyre’s tread. If the tread is at any point below 3/4 of the head, the tyre should be replaced. US and European tyres have ‘wear bars’, or “Tread Wear Indicators” (TWI) moulded into the grooves of the tyre. When these become flush with the tops of the remaining tread, the tyre is at the legal limit of normal safety and must be replaced.
If your trailer does require new tyres, a trusted tyre retailer such as fastfitexpress.co.uk will help you find replacements that measure up to the original equipment tyres. Keep in mind that there is no need to jump up to a more aggressive tyre class, as long as the replacement tyres are of the same quality and size as the original equipment tyres, you’re fine. Switching to another class of tyres may not just cost more but could compromise ride and handling characteristics.
Towing is a very demanding activity and proper tyres play a big part in being able to perform it safely. For most of us, the best bet is to visit a trusted tyre retailer, who will have all the tyre replacement and tyre towing capacity figures. They will recommend the best replacement tyre (often several), which will meet your trailer and budget requirements. Towing is not the time to cheap out on your tyres, but it also doesn’t have to be an excuse to overspend, either.