How to Adjust Rubber Track Tension
Track tension is the single most important maintenance task for your compact track loader or mini excavator. Too loose and the track slips, de-tracks, and wears unevenly. Too tight and you stress the undercarriage, accelerate wear, and risk early track failure.
Checking and adjusting tension takes 10 minutes. Here's how to do it right.
Why Tension Matters
Proper tension keeps the track engaged with the sprocket, rollers, and idler throughout the entire rotation. When tension is off:
- Too loose: Track slips on sprocket, can de-track during turns, accelerates wear on drive lugs
- Too tight: Excessive stress on idler and tensioner, premature stretching, increased undercarriage wear, higher fuel consumption
Most track failures and undercarriage problems trace back to improper tension. Check it weekly, or any time you notice changes in how the machine handles.
How to Check Track Tension
Step 1: Position the Machine
Park on level ground. Lower your bucket or blade to the ground. Shut off the engine. The track should be at rest with no load.
Step 2: Check Track Temperature
Always check tension when tracks are cold—ideally before the first start of the day. Heat causes rubber to expand, which gives false readings. A track that looks correct when hot may be too tight when cold.
Step 3: Locate the Measurement Point
Find the midpoint of the track span between the front idler and the rear sprocket. This is typically above the top carrier roller (if equipped) or at the center of the track's upper run.
Step 4: Measure the Sag
Press down on the top of the track at the midpoint. Using a straight edge across the top of the idler and sprocket, measure how far the track sags below that line.
Most machines specify 1-2 inches (25-50mm) of sag at the midpoint. Check your operator's manual for the exact specification—it varies by manufacturer and model.
- CAT CTLs: Typically 1-1.5 inches
- Bobcat CTLs: Typically 1-2 inches
- John Deere CTLs: Typically 1-1.5 inches
- Mini excavators: Often tighter, 0.5-1.5 inches
How to Adjust Track Tension
Locate the Grease Fitting
The track tensioner is typically located at the front of the undercarriage, near the idler. Look for a grease fitting (zerk) with a protective cover or plug.
Some machines have the tensioner accessible from inside the track frame. Others require removing a cover plate. Check your manual for the exact location.
To Tighten the Track (Add Tension)
- Remove the protective cover from the grease fitting
- Use a grease gun with standard chassis grease
- Pump grease slowly—the idler will move forward as hydraulic pressure builds
- Add grease in small increments, checking sag after each pump
- Stop when you reach the correct sag measurement
- Replace the protective cover
To Loosen the Track (Release Tension)
- Locate the relief valve adjacent to the grease fitting
- Slowly loosen the relief valve (usually 1-2 turns)
- Grease will release and the idler will retract
- Watch the sag as you release—stop when you reach the correct measurement
- Retighten the relief valve
- Replace any covers
Warning: The tensioner is under high pressure. Never fully remove the relief valve or grease fitting. Loosen slowly and stand clear of the release path.
Common Tension Mistakes
Over-Tightening
A track with zero sag looks "right" but causes serious problems. Over-tight tracks:
- Stretch prematurely
- Accelerate idler and roller bearing wear
- Increase fuel consumption
- Reduce sprocket life
Some contractors over-tighten to prevent de-tracking. A better fix is addressing the underlying cause (worn undercarriage, bent frame, wrong track width).
Running Too Loose
A loose track seems like it's reducing stress, but it causes its own problems:
- Drive lug wear from slipping
- De-tracking during aggressive turns
- Uneven wear patterns
- Reduced pushing/digging power
Checking When Hot
A track checked when hot will read tighter than it actually is. When it cools, it may be too loose. Always check tension cold.
When to Check Tension
- Weekly: Part of your regular maintenance routine
- After working in mud: Packed debris can throw off readings
- After new track installation: New tracks stretch slightly during break-in
- If you notice handling changes: Unusual slipping, vibration, or tracking issues
- Before long jobs: Start major projects with correct tension
New Track Break-In
New rubber tracks stretch slightly during the first 50-100 hours. After installing new tracks:
- Set initial tension to spec
- Check tension after 8-10 hours of operation
- Adjust as needed
- Check again at 25 hours and 50 hours
- After break-in, return to weekly checks
The Bottom Line
Correct track tension is 1-2 inches of sag at the midpoint (verify your machine's spec). Check weekly when tracks are cold. Adjust with the grease fitting to tighten or relief valve to loosen.
Ten minutes of checking saves hours of downtime and hundreds in premature wear. Make it part of your routine.