Rear Motorcycle Tire Flat In the Middle | Causes and Fixes

11,000 accidents occur due to bad tires every year, and rear flat tires in the middle of motorcycles are a top contributor to it. The rim gets damaged, braking performance is sacrificed, and you significantly lose control. 

What causes the rear motorcycle tire to be flat in the middle? The issue can occur to both tube and tubeless tires because of the following reasons:

• Leak between the tire and rim
• Puncture in the tire or inner tire tube
• Leaking spokes rim
• Valve stem failure 
• Sealant failure in tubeless tires

Read with full attention, and you will be able to fix the issues yourself. With some help, you can save the cost of seeing a mechanic.

Causes and Solution of Rear Motorcycle Tire Flat in the Middle

There is no universal solution to all the problems of flat tires. For each problem, you need to perform a unique action to solve it. 

Leak between Tire and Rim

Source: Liveabout

A leak between the tire and rim is a common cause for flat rear tires. It occurs due to improper mounting, damaged rim, or debris stuck there. It lets air escape directly from the inside of the tire, and the pressure drops. The tire loses its roundness and gets flattened. 

Signs and Solution

To confirm that the flat tire is due to a tire/rim leak, look for the following signs:

• Soft tire
• Slow deflation of the tire due to losing air pressure
• Hissing sound during the ride
• Apply soapy water and observe if bubbles are coming up. This not only confirms the leak but also helps identify the exact spot. 

Once confirmed, follow these instructions to solve the problem. 

• First, deflate the tire by removing all the air from it.
• Use a flathead screwdriver and gently pry the tire down to see the accumulated dirt and debris on the rim. 
• Clean the debris with a small rag and inflate the tire. Run a leaking test again with soapy water for certainty. Watch this video for a visual aid.

Puncture in Tire or Inner Tire Tube

Whether you are running tube or tubeless tires, puncture can happen to both. This occurs mostly due to sharp objects like nails, screws, or debris kicked up by the front tire. The tire loses its air and gets flat in the middle. 

Signs and Solution

Diagnosing the problem requires you to inspect the tire properly. Pay attention if there is a hissing sound, the presence of stuck sharp objects, the visual flatness of the tire, or if the tire feels soft. 

Using plugs is an easy and quick solution for punctures not bigger than ¼”. Prepare the plug in the following manner:

Source: Ridermagazine

• Take a sticky plug and use an applicator tool with a needle-like hole in front.
• Put the sticky plug through the applicator’s eyelet and make sure it’s half it. 
• Take the sharp object out of the tire and make a quick measurement. If it is bigger than ¼”, then you had better take it to the customer service center. 
• Now, insert the plug with the help of the application. You may have to put a lot of force into it. Stop pushing when only half an inch of the plug remains outside the tire. 
• Bring out the applicator and cut the excess of the plug. The puncture is solved. Pay attention if there is any hissing sound. 

Valve Stem Failure

Source: Shutterstock

Valve stem is the hole in the wheel of a tubeless tire to allow inflammation and deflation. For tube tires, it is a separate component that screws into the rim. A crack, a loose core, or a faulty seal can lead to valve stem failure. 

It allows air to leak out and cause a flat spot in the center of the rear motorcycle tire. It happens due to wear, damage from impacts, or faulty components during manufacturing.

Signs and Solution

You can easily identify the cause of the flat tire if it is because of valve stem issues. There will be visible damage, like cracks or loose cores allowing air to flow out. 

Fixing the problem can be a little tricky, and you may need several tools to change the stem. Manage tire spoons, rags, valve core remover tools, clamps, tire pressure gauge, soapy water solution, a new stem valve, etc. 

• Unscrew the valve core to air out the tire completely.
• Use tire clamps to remove the tire slightly enough to expose the valve stem.
• Cut the valve stem from the inside to remove it from the rim. 
• Put some thread locker on the new stem so it stays tightly on the rim without getting damaged. Tight the valve strongly with the screw. Now, you can remove the clamps. 
• Refill the tire with air and keep an eye on the air pressure gauge to prevent over or under-inflation, as it can lead to heavy steering. Put the valve core back, and your bike will be ready to ride again. 

Spoke or Valve Seal Failure

Spoke seal failure happens in tube tires, while valve seal failure occurs in tubeless tires. Both failures cause air leaks and flatten the tire in the middle. 

Signs and Solution

The signs of flat tires will be the same as those of the earlier ones. 

• The one particular sign that hints towards bad seals is that the hissing sound will come near the spoke nipples or stem valve on the rim. 
• Also, apply some foam water and see if bubbles form to confirm the bad seals.

Using tire sealant can solve the issue for leaking spoke rims or valve seal failure. Remove the stem valve to let all the air out in tubeless tires. Attach the sealant bottle to the stem and let all the sealant pour inside it. Put the valve back in and inflate the tire with air. Your rear tire will be good to go. 

For tube tires, use tire spoons to detach the tire from the rim. Check spoke nipples for worn or missing spoke seals. Replace all seals with new ones. And you are good to go. 

FAQs

Knowing the answers to the following questions will be helpful when dealing with rear motorcycle tires.