by Dennis Webb
How old are your tires? How safe are they?
If you have ever looked at your car/truck new tire warranty, you will notice that generally they are good for 5 – 6 years. Why is that? – Because as the tire ages, it loses its elasticity and material degradation. See the Safety Research & Strategies Tire Aging Animation at http://www.safetyresearch.net/safety-issues/tires/ (part way down that page).
Think of a rubber band that has been sitting in a drawer for quite some time, when you go to use it, it breaks. Why, because over time the rubber band develops cracks in it. The same thing is happening to your motorcycle tires.
Temperature also plays a role in material degradation. NHTSA research has found that tires age more quickly in warmer climates. NHTSA also found that environmental conditions like exposure to sunlight and coastal climates can hasten the aging process. People who live in warm weather and coastal states should keep this in mind when deciding whether they should retire a tire.
Storage can also have a role in material degradation. If a tire has been inflated and mounted on a wheel, it is technically “in service” – even if it’s never been used. I store my FLHRSEI2 in one side of my 2 car garage; The 4 x 4 gets the boot to the driveway. The garage has an ambient temp in the 40s all winter. I place plywood on the concrete and cheap carpet over the plywood. This allows my tire not to be exposed to the cold concrete floor all winter. I also periodically move my FLHRSEI2 so that the bike does not rest on the same tire contact points all winter.
Service also plays a role in material degradation. How frequently you ride, what loads you generally carry, the type of roads you ride frequently and at what speeds you generally ride. It isn’t very hard to understand that riding at interstate speeds on those ground down grooved surfaces are no friend to your tires. Never mind the added attention one needs to pay to riding on it.
Tire Pressure – Proper Tire Inflation is Critical to Tire Performance and Tire Life Under-inflation or overloading can cause sluggish handling, heavy steering, and internal damage due to over-flexing, and can cause the tire to separate from the rim. Over inflation can reduce the contact area (and therefore available traction), and can make the motorcycle react harshly to bumps. Check the tire pressure when the tires are cold (at least three hours since the last ride),
Regularly inspect the tire tread depth to ensure that adequate tread remains. Tires have small wear bars molded into the tread grooves. When the tread is worn down to the level of the wear bars (indicating 1/32 inches of tread remaining), the wear bars become exposed and the tire should be replaced. Some manufacturers recommend replacing the tire when there is 2/32 or 3/32 inches of tread remaining
I use the HD Combo Air pressure/Wear Gauge. It is compact and easy enough to carry in a saddlebag or tour pack. I believe the wear gauge shows red numbers at 2/32 inches remaining. Hint – Time to change the tire.
You can also use a penny in a pinch to check tire wear. Stick the penny into the tire tread with Lincoln’s head down and perpendicular to the tire surface. If you can see ALL of Lincoln’s hair, change the tire. If a portion of Lincoln’s hair is “NOT” showing, then you have some, unspecified, tread wear remaining.
I also go by just how comfortable my visual inspection of the tire makes me. My “Peace of Mind” is worth far more to me than the cost of a new tire.
So, how old are your tires?
Look for a Rectangle on one side or the other of your tire. Tires made after 2000 have a four-digit DOT code. The first two numbers represent the week in which the tire was made. The second two represent the year. A tire with a DOT code of 1109 was made in the 11th week of 2009.
It is entirely possible for you to purchase and install new tires off the shelf that were manufactured a year or more ago. That time still counts in the age of the tire.
At the January Chapter Meeting, Safety Officer, Walter asked how many members check their tires before each ride. I was hoping to see more hands raised, at least a visual inspection before each ride. One never knows when you may have picked up debris in your tire and sustained a cut.
Happy Riding DR
Note: I used the following sources for my information
1) – http://www.edmunds.com/car-care/how-old-and-dangerous-are-your-tires.html
2) – http://www.msf-usa.org/downloads/MIC_Tire_Guide_2012V1.pdf – I highly recommend reading this one, even saving the pdf file for reference.