Bike Assembly: More than the Sum of the Parts

by Justyna Frank
professional bike assembly

Bicycle assembly is a time-consuming and skill-intensive activity.

Many bike manufacturers, especially those who sell their bikes directly to consumers via the Internet, maintain that their bicycles come pre-assembled, and that bike assembly is a simple as a few turns of a metric allen wrench.

Unfortunately, in most cases these bikes come from an assembly line in a country on the other side of the world, whose quality control standards and emphasis on safety may be quite different from our own, and who face no culpability if those claims turn out to be untrue. The US “manufacturers” are nothing more than distribution houses who sell the bikes to retail shops, and don’t even open the boxed up “pre-assembled” bikes in their warehouses.

This is why you must insist that your local bike shop treats bike assembly very seriously. At Cosmic Bikes, we don’t consider it a waste of time to take a bike out of the box, and begin by taking it apart to ensure that when it is put back together, it has been done so correctly. We make sure that all of the following points have been addressed.

This complete and dependable bike assembly process makes your new bicycle run better, feel better, and last longer. And it goes a long way toward ensuring your safety.

So, What Goes Into Professional Bike Assembly?

  1. Out of the box bike is put in a stand, and visually inspected for any flaws, defects or shipping damage. This ensures you won’t end up with a defective bike right out of the box.
  2. Wheels are pre-stressed using our proprietary process, dished (centered on the hub), trued, spokes properly tensioned, and hub bearings adjusted to correct tension and secured. On the rear wheel, we remove the cassette (cogs), inspect the freehub, and securely reinstall the cassette. Hub bearings are adjusted to correct tension and secured. Wheels are aligned within the frame, and wheel retention devices securely tightened. This process ensures that the wheels will stand up to rigorous use, and that rim brakes (if present) can be properly adjusted.
  3. Handlebars and stem attached with brake & shifter cables correctly routed, and excess cable and housing trimmed as needed. Brake and shift levers are aligned and secured on the handlebar, handlebars and stem squared and securely tightened. This ensures that the handlebar will support you, and control levers won’t give out or cables become tangled under normal operation.
  4. The headset (internal bearing assembly that allows for steering) is adjusted to correct tension, and secured to prevent its loosening under normal use. This ensures dependable and controlled steering.
  5. Crank assembly is removed and reinstalled, ensuring they are torqued to the correct tightness. Pedal threads greased, and steel pedal washers added before threading in the pedals to prevent excessive wear on the crank arm. The cranks and pedals support most of your weight, and transfer your power to the wheels while you pedal, and this step ensures they won’t inadvertently come loose.
  6. Brakes are adjusted for dependable, noise-free stopping, and secure attachment of brake shoes and cables is checked. Cables are pre-stressed to prevent excessive cable stretch. These steps ensure you’ll be able to stop confidently.
  7. Shifting mechanisms are precisely adjusted. Front and rear derailleurs are set up and tuned so that the gears shift correctly, and the chain does not come off the cogs in the event of overshifting. Derailleur cables are also pre-stressed. This ensures you can shift intuitively without taking your eyes off the road.
  8. Seat clamp is adjusted to correct angle and secured. Seatpost retention bolt or lever is securely tightened. This ensures that your point of support is solid.
  9. All component and accessory fasteners and bolts are tightened and secured with Loctite thread locker as appropriate. Nothing should unexpectedly come loose while you’re riding, causing you to become distracted or lose control while you’re riding.
  10. Tires are properly seated and inflated to correct recommended pressure. This is the best way to prevent the most common cause of flat tires.

After a final check over, the mechanic test-rides the bike, running through all the gears, testing the brakes, etc. Then he or she makes appropriate adjustments. The assembled bike is then passed to a senior mechanic for a final check.

Complete bike assembly comprises a long –and perhaps somewhat boring– list of steps (we actually sneak in a few more, less important ones), but you should care about this for the following reason: after all, a bicycle is not just a random collection of parts. It is a vehicle, whose performance depends on a series of complex systems working together in harmony.

And your safety depends on that.

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