Harley Davidson: How to Check Tire Tread
Checking your tire tread is quick and simple, and should be an essential part of every riders pre-ride routine maintenance.
This article applies to the Harley Davidson Softail, Touring, Dyna Glide and Sportster.
Good tires on a motorcycle are essential for proper handling and safety, especially in the wetter winter months. Because there are only two of them, and they are much smaller, the tires contact patch is more important for a motorcycle than an automobile for obvious reason. Checking your tires for proper inflation and good tread depth should be an essential part of your pre-ride checklist.
Materials Needed
- Tire tread gauge
- A penny or quarter
Most tires have what are known as wear bars molded into the tire tread. This is a small raised bar that is in a deeper part of the tread and extends across the whole tire; when the raised parts are worn to that point, it indicates it is time to change the tire. The wear bars usually are designed to be exposed around 1/32 of an inch, which is a little less than a millimeter. Many experts suggest replacing a tire with anything less than 2/32 of an inch of tread is remaining, even before it hits the wear bars.
Step 1 – Prepare the motorcycle for inspection
Park the bike on a smooth level surface in an area that has adequate lighting. Make sure the motorcycle is resting firmly on the kickstand and that it is stable when performing the task. Also, make sure that you have plenty of room on all sides of the bike to conduct the inspection.
Figure 1. A good parking spot. 
Figure 2. Tire tread gauge.
Pro Tip
Make sure the motorcycle is firmly rested on the kickstand to avoid it falling over, damaging you or the bike.
Step 2 – Check the tread
Tread gauges usually come in one of two different basic types: analog and digital. The analog gauge works very similar to a tire pressure gauge and digital is pretty self-explanatory.
- Take the protruding rod from the gauge and place it in a low spot on the tread of the tire.
- Read the depth on the gauge.
- If it reads less than 2/32, replace the tire as soon as possible.
Figure 3. Tire with more than 4/32" tread depth. 
Figure 4. Tire worn to wear bar. 
Figure 5. Tire worn to the structural cords.
Another way to check the tread wear of your tire that is accepted among enthusiast is known as the "penny test." This simple test involves taking a penny, or a quarter, and inserting it in the tread, head first. As long as the president's head is inside the tread, you should be good to go.
Step 3 – Check for other wear/damage
Just because your tires have plenty of tread does not mean they are ready to ride, and don't need replacement. While you are checking them, make sure they are fully inflated to what the factory stick recommends. Also, check for cuts in the tread or sidewall, which can happen from debris on the road. Check for bulges and bubbles, which happen for no reason often at the worst time due to manufacturing defects or pothole damage. Look over the bead where it seats on the rim and make sure it is even all the way around, or you can get a speed wobble. Lastly, look for cracks, drying out and weather damage, which can make a tire unpredictable and dangerous.
Figure 7. Cracked sidewall. 
Figure 8. Sidewall bulge.
As a general rule of thumb, I replace my tires every five years no matter how much tread they have left on them, because the dry California air drys them out and makes them rock hard. I hope this helps to keep you safe while on the road.
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