Treadmills are back in many homes, and the running belt is the part that works hardest. There is constant friction between the belt and the deck: without lubrication it rises, the motor is overloaded, the belt jerks and you get noise and a smell of hot rubber.
A neglected treadmill is a safety risk: a misaligned or dried-out belt can suddenly drag under your foot. Here is a simple plan: clean, inspect, set the tension and lubricate with silicone, which cuts friction and is kind to rubber and plastic.
What you will need
- damp cloth, optionally with a disinfectant
- vacuum cleaner or dust brush
- hex key (usually supplied with the treadmill)
- flat and cross-head screwdrivers
- WD-40 Specialist Silicone
- dry cotton cloth
- the manufacturer's manual
Important: Switch the treadmill off and unplug it before any work. Lubricant must only go under the belt onto the deck: if it gets on the top running surface, the belt becomes slippery and dangerous.
Step 1
Clean off sweat and dust
After every workout, wipe the handrails, console, pulse sensors and bottle or phone holders with a damp cloth, in short everything your sweaty skin touches. Sweat attracts dirt and bacteria and eventually causes rust on metal parts.
Every week or two, vacuum under the belt, around the motor and around the machine. Dust and pet hair drawn under the belt act like an abrasive.
Step 2
Inspect the parts
Check that all screws are in place and that handrails and brackets are not loose. Tighten fasteners if needed. Make sure the belt runs straight in the centre and does not drift to one side, and look for cracks or frayed edges.
Jerking and odd noises usually mean either a lack of lubrication or a misaligned belt, so check the tracking first.
Step 3
Adjust the tension and tracking
Too much tension can split the belt and strains the roller bearings, while too little makes the front roller slip. The adjusting bolts are at the rear, left and right. Turn them with the hex key at the same time and by the same amount, a quarter turn at a time.
If the belt drifts left, tighten the left bolt; if it drifts right, tighten the right one. Test at low speed and take exact values from the manufacturer's manual.
Step 4
Apply silicone under the belt
With the treadmill unplugged, slacken the belt as described in the manual so you can lift it off the deck. Shake the can of WD-40 Specialist Silicone, lift one side of the belt and spray evenly onto the deck towards the centre. Repeat on the other side.
If the manufacturer specifies a particular belt lubricant, follow their requirement.
Step 5
Spread the lubricant and remove excess
Restore the belt tension, switch on and let the treadmill run for a few minutes at the lowest speed with nobody on it. The lubricant will spread across the whole friction surface.
Wipe any excess from the side edges and frame with a dry cloth. Check the top of the belt: it must be clean and dry.
Step 6
Lubricate small moving parts
Treat the folding hinges, incline locks and threaded adjusters with WD-40 Smart Straw using the thin straw. This stops squeaks and makes folding easier. Do not spray it on the belt or deck.
Tip: In winter, central heating makes indoor air very dry and the belt dries out faster. If the treadmill lives on a balcony or in an unheated room, let it warm up to room temperature before running and lubricate more often.
What next
Wipe the treadmill after every run, vacuum weekly and lubricate the belt roughly every three months, or more often with heavy use. Your machine will then run quietly for years.
These uses come from the experience of WD-40 users in many countries. Always follow the instructions and warnings on the product label.
More guides in «How to use».