An M check is a quick, but methodical, part of your regular bike maintenance. You should carry out an M check for safety before every ride, and a more thorough one once a week if you use your bike a lot.
It’s easy to remember all the things to check if you imagine your bike with an M superimposed on it. The M shape starts at the rear wheel of the bike, goes up to the saddle, down again to the pedals, up to the handlebars and back down again to the front wheel.
Although an M check is primarily a visual safety check, tools to have handy are:
- a tyre pressure gauge
- a bike pump
- a multitool for tightening the brake cables and any other loose screws or bolts.
Rear wheel
Check that the wheel is secure and that the quick release lever is closed or the bolts are tight.
Press down on the tyre with your thumb and pump it up if it’s soft. A general, all-purpose pressure is for the tyre to feel firm but give slightly to pressure from your thumb.
You might want to make sure tyre pressure is correct in accordance with the number you’ll find on the tyre near the rim.
Pluck the bike spokes between thumb and forefinger to check they aren’t loose and are of equal tension.
finally, give the wheel a slow spin to look for debris or damage. Check the derailleur for straightness and also for any signs for damage.
Saddle
The seat should be aligned and tight enough so that it can’t twist or move up and down. Grab it with both hands and apply some force to check, then tighten any bolts that need it.
Make sure the saddle post doesn’t exceed the recommended height.
Chain and pedals
Check the chain for dirt and oil it lightly if needed.
Spin the pedals and make sure they move smoothly and without creaking. If you can see the thread between the pedal and the crank, tighten them up.
Handlebars and stem
On your way up, ensure the bottle cage is secure. Then stand with the bike’s front wheel clamped between your knees and make sure the stem and wheel don’t move independently of each other.
The handlebars should be at right angles to the front wheel.
Don’t skip over the plugs at the end of the handlebars. If they’re missing, make a note to replace ASAP as they can prevent severe abdominal injuries in the event of a crash.
Frame, Fork and headset
Look for cracks or damage, especially where the forks meet the frame.
The headset, the part that holds the forks in place, needs to be able to rotate smoothly and silently without any clicking. Check this by holding the bike frame, lifting the front wheel off the ground and turning the handlebars left and right.
Brakes
Make sure the brake levers are tight and don’t wiggle.
When you squeeze the lever, rim brake pads should squeeze equally on both sides and lie flat on the rim. For disc brakes, the rotor shouldn’t rub the pads.
Front wheel
For the final part of the M, check in the front wheel in the same way as the rear.
Check out our video on M checking Caerwyn's own bike here
