Free checklist
LiveBike safety inspection checklist: the M-check
The M-check every bike should get at intake, written down in order. Torque checks, wear limits and the items new mechanics skip.
Standard tune-up
Template v4 · WO-2291 · Sam
- *Chain wear under 0.5%PassFail
- *Rotor above stamped minimumPassFail
- *Brake pad compound (mm)1.8
- *Thru-axles to specPassFail
- *Tire sidewalls — cuts or bulgesPassFail
- Photo: drivetrain after clean1 photo
- Customer signature
Why write down the M-check
Every mechanic learns the M-check, and every mechanic does it slightly differently. Start at the front hub, go up the fork to the bars, back along to the saddle, down to the bottom bracket, and out to the rear wheel. Trace it on the frame and you get the letter M. The order matters because it stops you skipping things.
Written down, it becomes the standard intake inspection for every bike that crosses your counter, whether it came in for a flat or a full overhaul. That catches the cracked chainstay before you true the wheel, the worn rotor before you bleed the brake, and the loose thru-axle before the rider leaves. It also tells the customer, in writing, what you checked and what you found.
Wear limits and torque values here are common figures. The part manufacturer always has the final word, and many parts carry their limit or torque printed on them. Use that number when it exists.
The M-check, in order
Front hub, up the fork, bars, saddle, down to the bottom bracket and out to the rear.
1. Front wheel and hub8
- Quick release closed with firm cam tension, lever tucked, safety tabs intact; or thru-axle fully threaded and torqued to the fork maker spec
- Hub: grab the rim and rock sideways for bearing play; spin for roughness
- Rim: spin and watch for wobble, hop, dents and cracks at spoke holes
- Rim brakes: check the rim wear indicator or measure wall thickness
- Spokes: squeeze pairs for loose or broken spokes
- Tire: tread wear, cuts, embedded glass, sidewall cuts, bulges and exposed casing threads, bead seated evenly
- Tire pressure within the range on the sidewall and rim
- Rotor: measure thickness with a caliper against the minimum stamped on the rotor; check for bends, glazing and loose rotor bolts or lockring
2. Fork and headset5
- Fork blades, crown and dropouts: cracks, bends, paint crazing on carbon
- Suspension fork: stanchion scratches, oil at the seals, sag and rebound feel
- Headset: front brake on, rock the bike to feel for play; turn the bars to feel for bind or notching
- Front caliper or brake mount bolts tight
- Front brake pads: replace at about 0.5 mm of compound or at the maker wear indicator
3. Bars, stem and controls7
- Stem steerer and faceplate bolts to the torque printed on the stem
- Bars: cracks, bends, especially near the stem clamp and on carbon
- Stand over the front wheel and twist the bars against it; nothing moves
- Brake levers tight and at a sensible angle; lever travel stops well short of the bar
- Hydraulic: firm lever, no leaks at the lever, hose or caliper
- Shifters tight; cables and housing not frayed, kinked or cracked
- Grips secure, bar-end plugs fitted; bar tape intact
4. Saddle and seatpost5
- Seatpost at or above the minimum insertion mark
- Seatpost clamp and saddle clamp bolts to the torque printed on the part
- Saddle rails: bends or cracks
- Dropper post: full travel, returns, no play; remote cable or hose intact
- Top tube and seat tube: cracks at the seat clamp and the head tube junction
5. Bottom bracket and cranks6
- Crank arms: rock both arms to feel for bottom bracket play
- Spin the cranks with the chain off for roughness
- Crank bolts or preload cap tight; chainring bolts tight
- Pedals threaded fully in (the left pedal is a left-hand thread); pedal bearings smooth
- Chainrings: worn, bent or missing teeth
- Frame around the BB, chainstays and down tube: cracks and dents
6. Rear wheel and drivetrain8
- Rear axle secure: quick release or thru-axle as for the front
- Hub, rim, spokes, tire and rotor as for the front wheel
- Chain elongation: replace at 0.5% on 11- and 12-speed drivetrains, 0.75% on 10-speed and below
- Cassette and chainrings: hooked or shark-finned teeth
- Derailleur hanger straight; derailleur and pulleys secure
- Shift through every gear; no skipping or chain drop
- Rear brake: pads, caliper bolts, rotor, lever feel
- Chainstays, seatstays and dropouts: cracks
7. Finish4
- Lights and reflectors fitted and working where required
- Bell or horn where required
- Test ride: brakes, shifting under load, steering, noises
- Record every finding and every item outside the job the bike came in for
Print this page (⌘/Ctrl + P) for a clean paper copy, or build it as a template in Service.
Wear limits at a glance
Common limits. Always check the part maker figure first.
| Part | How to check | Replace when |
|---|---|---|
| Chain, 11- and 12-speed | Chain checker or ruler | 0.5% elongation |
| Chain, 10-speed and below | Chain checker or ruler | 0.75% elongation |
| Disc rotor | Caliper at several points | Below the minimum thickness stamped on the rotor |
| Disc pads | Look into the caliper or remove | About 0.5 mm of compound left, or at the wear indicator |
| Rim, rim brakes | Wear indicator or wall gauge | Indicator worn through or wall concave |
| Tire | Visual and by hand | Casing threads showing, sidewall cuts or bulges, tread gone |
| Cables | Visual at ends and exposed runs | Any fraying or rust |
On a ruler, 12 full links of a new chain measure 12 inches; about 1/16 inch over is 0.5%.
Build it as a template in BIKE.co Service
Service checklists are live today, and the M-check is the ideal first template. Make one section per stage above. Use checkbox questions for the pass items, a number question for chain elongation and one for each rotor thickness, and a dropdown for tire condition with options such as good, worn and replace. Add a photo question to each section so a mechanic can capture the crack or the worn rotor as they find it.
Mark the safety-critical items as required. The checklist cannot be submitted until they are answered, so a busy Saturday cannot quietly turn the M-check into a glance. Add a long-answer question at the end for findings outside the job, and a signature for the mechanic.
Each submission produces a PDF with the answers, photos and signatures. Give it to the customer at pickup. When a rider says 'you never told me about the rotor', you have it in writing, with a photo.
What Service gives you for this checklist today
Eight question types
Short answer, long answer, dropdown, checkbox, number, photos, date and signature.
Required answers
The checklist will not submit until every required item is answered.
Photos and signatures
Photos from the phone camera, and a signature drawn with a finger.
PDF for the customer
Each submission renders as a PDF with photos and signatures drawn in.
Checklists report
Every submission of a template, filtered by date and status, on screen or as CSV.
Required before the visit closes
Attach the M-check to every visit and make it required, and nobody can close the visit until it is submitted.
Santa Cruz Hightower
- Size
- L · 29"
- Serial
- SC2381174
- Color
- Gloss gold
- Owner
- J. Rivera
- Fork
- Fox 36 · 150mm
- Drivetrain
- SRAM GX AXS
Service history
- Mar 12
Standard tune-up
Sam
- Jun 03
Rear derailleur hanger
Priya
- Aug 21
Tubeless setup · 29×2.4
Luis
- Today
Pro tune-up · fork lowers
Sam
Fork lower service due — 50 h since last
Every inspection on the bike record
One bike with its serial and service history. Customer and bike records in Service are on the roadmap; the checklist and its PDF are live today.
Illustration · sample data
FAQ
Questions shop owners ask
What is the M-check on a bike?+
The M-check is a safety inspection that follows the shape of the letter M across the bike: front hub, up the fork to the bars, back to the saddle, down to the bottom bracket and out to the rear wheel. Following the same order every time stops mechanics skipping items.
When should a bike chain be replaced?+
Replace a chain at 0.5% elongation on 11- and 12-speed drivetrains and at 0.75% on 10-speed and below. Measure with a chain checker, or with a ruler: 12 full links of new chain measure 12 inches.
What is the minimum thickness for a disc brake rotor?+
The minimum thickness is usually stamped on the rotor itself, and that is the number to use. Measure with a caliper at several points around the braking surface and replace the rotor if any reading is below the minimum.
How do I check a quick release is closed properly?+
A properly closed quick release needs firm hand pressure to close and leaves an imprint in your palm, with the lever tucked against the frame or fork. Check that the dropout safety tabs are intact, and for thru-axles check the axle is fully threaded and torqued to the fork or frame maker spec.
Can my mechanics fill this in on a phone?+
Yes, service checklists in BIKE.co Service are live and fill in on a phone or tablet browser. Mechanics can take photos, answer required items and sign, and each submission produces a PDF for the customer.
Keep reading
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