Build a Bike from the Box
You bought a bike over the net and it arrived in a box. Now you need to build it. You can do it.
We describe how we build a new bike in our shop. The job takes an experienced builder on average about 40 uninterrupted minutes, if there are no problems.
For more details and photographs on each topic, click on the links.
Tools needed:
metric hex wrenches, usually 4, 5, and 6 mm
crank bolt wrench
pedal wrench, or 15 mm open wrench
small Phillips head screwdriver
round bastard file
bicycle cable cutter
bicycle work stand
wheel truing stand
bike specific grease
Important point: Don't presume that the manufacturer did everything right. They don't. And bikes are often damaged in shipping. Any part that you do not carefully check might fall off or malfunction. The bike builder is responsible for everything on the bike, including fixing things the manufacturer screwed up.
The procedure to build a boxed bike is:
1. Prepare the bike to start work:
a. Take the bike out of the box.
b. With a round bastard file, file around the top of the inside of the seat tube to remove burrs left when the tube was cut.
c. Coat the inside of the seat tube with a light layer of bicycle specific grease.
d. Insert the seatpost and secure the quick release or binder bolt.
e. Put the bike in the work stand, clamping the seatpost. Don't clamp any of the frame tubes--the clamp could damage the frame. Make the drive side face out, so it is easy to reach.
f. Remove all the packaging.
2. Make sure the crank arm bolts are very tight. Torque down on each crank arm bolt with a proper crank arm wrench. Manufacturers frequently fail to adequately tighten crank arm bolts.
3. Lightly grease the threads of the pedals, and install them with a pedal wrench or 15 mm open ended wrench. The right pedal threads clockwise. The left pedal threads counterclockwise. Install pedals by turning them toward the front of the bike. Tighten snugly, but be careful--you can strip the threads in the crank arms.
4. Install the stem.
Stems for threaded forks (usually on cheaper bikes) usually are not preinstalled on the bike. Lightly grease the chock and insert it in the head tube, and tighten the chock bolt clockwise, usually with a 6 mm hex wrench. Don't tighten it very hard--the final stem setup is one of the last steps.
Stems for threadless forks are usually preinstalled on the bike, but they are often installed upside down (to fit in the box better). Most cyclists prefer the stem angle going up. If the stem is upside down, take it off and flip it over. Threads are right-handed (tightens clockwise). A 5 or 6 mm hex wrench is needed.
Do not over-tighten the bolts. The threads strip easily. Final setup of the stem is one of the last steps.
5. Install the handlebar to the stem.
Usually the brakes, shifters, cable, and grips or bar tape are already installed, and the handlebar is rubber-banded to the frame. Figure out how to mount the bar to the stem so the cable routing is correct. The rear shifter goes on the right. Usually 2 cables go to the left of the stem and 2 to the right, and usually all the cables go under the bar. Cable and housing should never be kinked, and the handlebar must move freely all the way to the left and right.
Threads are right-handed. A 5 or 6 mm wrench is needed.
Be careful not to cross-thread the bolts or tighten them too much. They strip easily. Final handlebar setup is one of the last steps.
6. Inspect and install the front wheel.
First put the front wheel in the truing stand and inspect it. True the wheel if necessary--it often is.
Notice if your front tire is directional--designed to rotate in a particular direction. Most mountain bike front wheels are directional. If the tire is directional, it should have an arrow on the sidewall pointing in the right direction. When you install the wheel, make sure it rotates in the right direction.
Inspect the axle for proper adjustment. Move it with your fingers. It should rotate freely and have no play or slop. Adjust the hub if necessary.
Put a little dab of grease on the threads of the quick release skewer, and install it so that the lever will be on the left side of the bike.
Install the wheel on the bike. Make sure the axle firmly rests against the top of the fork dropouts.
Inspect the front wheel's situation. Did it fit properly between the fork dropouts? If not, the fork may be bent. Does the wheel appear to be centered in the fork? If not, you probably don't have the axles firmly against the fork dropouts, or perhaps the fork is bent, or perhaps the wheel itself is not centered.
7. Inspect the rear wheel.
The rear wheel is usually preinstalled, with the brakes, cassette, derailleur, and cable already attached.
Rotate the wheel while looking at the gap between the brake pads and the rim. If the wheel needs to be trued (which is often the case), true it in a truing stand.
If you took the wheel off to true it, before putting it back on inspect the axle for proper adjustment. Move it with your fingers. It should rotate freely and have no slop or play. Adjust the hub if necessary.
Reinstall the wheel on the bike, making sure the axle firmly rests against the top of the dropouts and that the chain is in the right position.
If you did not remove the wheel to true it, readjust the quick release. Manufacturers often over-tighten them--so much that you can't move the lever with your bare hand. It's better to fix this while in your shop than deal with it when you have your first flat tire.
Inspect the rear wheel's situation. Test the hub axle adjustment. Did the wheel fit properly in the dropouts? If not, the frame may be misaligned. Does the wheel appear to be centered between the stays? If not, the axles may not be firmly against the top of the dropouts, or perhaps the frame is misaligned, or perhaps the wheel is not dished.
8. Inflate the tubes to the recommended psi, which is often printed on the tire sidewall.
9. Adjust the rear brake. Even though the rear brake is usually preinstalled, it probably needs adjustment.
Make sure the pads hit the rim squarely--do not hang over the rim edge, do not touch the tire, are parallel to the rim.
Move the barrel adjuster on the rear brake lever all the way in. Inspect the cable and housing. If necessary tighten the cable tension: loosen the cable anchor bolt on the brake arm, pull the cable tight so the pads are against the rim, let about 2 mm of cable slip back through the bolt, and retighten the bolt.
Center the pads so they are both the same distance from the rim, by manipulating the brake spring tension screw.
Inspect and test the brake.
10. Install and adjust the front brake.
Road bikes. Road bike front brakes are often not preinstalled. To install the brake, insert the anchor bolt in the hole on the fork crown. The nut and spacers go in the back of the fork and tightens clockwise. Squeeze the pads against the rim with your left fingers, and tighten the brake into the fork with your right hand (usually with a 5 mm hex wrench). This usually results in the brake being close enough to center, but you may need to repeat the process later to improve the centering.
Mountain and hybrid bikes. Bikes with V brakes usually have the front brake arms installed, but the cable is not connected to the brake arm. Find the brake noodle and little rubber dust cover in the parts box. Slide the noodle over the cable and onto the housing first, and then the dust cover. Insert the noodle in the slot on the right brake arm. Insert the cable under the cable anchor bolt on the left brake arm. Push the brake pads loosely against the rim, and loosely tighten the anchor bolt.
Make sure the pads hit the rim squarely--do not hang over the rim edge, do not touch the tire, are parallel to the rim.
Move the barrel adjuster on the front brake lever all the way in. Inspect the cable and housing. If necessary tighten the cable tension: loosen the cable anchor bolt on the brake arm, pull the cable tight so the pads are against the rim, let about 2 mm of cable slip back through the bolt, and retighten the bolt.
Center the pads so they are both the same distance from the rim, by manipulating the brake spring tension screw.
If you have disc brakes, read the disc brake section.
Inspect and test the brake.
11. Adjust the brake cable tension for feel at the levers. Some like a tight feel, some like it loose. Most like both levers to feel the same. Small adjustments can be made with the barrel adjusters at the levers, larger adjustments are made at the cable anchor bolt on the brake arm.
12. Adjust the rear derailleur, which is usually preinstalled. For this step, you should first read the section on rear derailleurs and study the photographs.
a. Adjust the high cable stop.
The stops are designed to prevent the derailleur from shifting too far to the left or right--insuring that the chain stays on the cassette.
Pedaling with one hand, shift the front derailleur into the middle ring.
Shift the rear derailleur into the smallest cog. While lightly manipulating the high cable stop limit screw (usually the screw on top), closely watch the derailleur jockey wheels. If the jockey wheels move immediately (just a tiny bit) the high stop is probably adjusted correctly, and you can go to the next step.
If the high stop is not adjusted correctly, fix it. Loosen the cable at the derailleur cable attachment bolt. The derailleur spring will pull the derailleur as far to the outside as the stop allows. Manipulate the cable stop limit screw until the jockey wheels are immediately below the small cog. Shift into the highest gear (letting out all the cable). Inspect the cable and housing. Pull the cable through the attachment bolt (finger tight is enough) and tighten it. Make sure you pulled the cable though the right side of the attachment bolt. There's a little groove on the derailleur or the washer that indicates the right side.
b. Set the low cable stop.
Shift the front derailleur into the small ring.
Shift the rear derailleur into the second largest cog. Pedal with one hand and with the other hand, pull the rear derailleur cable anywhere it is exposed on the frame. You want the chain to easily go onto the largest cog but not to fall off the cog to the inside. Manipulate the low cable stop screw (usually the bottom screw) until you set the stop just right.
c. Adjust cable tension.
While pedaling with your hand:
Shift the front derailleur into the middle ring.
Shift the rear derailleur into the smallest cog.
Push the rear shifter one click. You want the chain to move precisely one gear. If the chain did not move to another gear, the cable is too loose. Tighten it the cable at the attachment bolt and start over.
Once one shifter click moves the derailleur one gear, make fine adjustments. Move the derailleur barrel adjuster counterclockwise (this tightens the cable) until the chain starts to rub the next (3rd) gear, and then move it the opposite direction until it does not rub. This should result in perfect shifting. Shift through all the rear gears while in the middle ring. Is each shift neat and crisp? If not, recheck the cable tension adjustment. If tension adjustment seems ok, perhaps you have a bent derailleur dropout, which you will need to replace.
d. Consider the B spring. The B spring adjustment screw controls the distance between the top jockey wheel and the cogs. If the top jockey wheel rubs against the cogs in any gear, move the jockey wheel away by turning the B spring adjustment screw clockwise. This adjustment is rarely needed.
13. Adjust the front derailleur. This is the hardest procedure to get right. Manufacturers seldom completely, correctly install the front derailleur. First read the section on front derailleurs and study the photographs.
a. Inspect the derailleur position. The bottom of the outside plate of the derailleur should be 1-2 mm above the big chainring. The outside plane of the outside plate of the derailleur should be parallel with the big chainring. If the position needs to be adjusted, loosen the cable anchor bolt and the derailleur attachment bolt (5 mm wrench turned counterclockwise to loosen), and juggle the derailleur around until it is right. If this seems hard, you're not crazy. It's hard to get right. Reattach the derailleur attachment bolt and the cable and inspect the position again. You may have to repeat this step.
b. Set the low cable stop.
Shift the rear derailleur to the biggest cog. Shift the the front derailleur to the small chainring. The inside plane of the inside plate of the derailleur should be about a millimeter from the chain. Manipulate the low stop screw until the inside plate is very near the chain, but the gears will easily shift from the middle ring to the small ring. The goal is to easily shift from the middle to the small ring, without the chain falling off to the inside.
c. Set the high cable stop.
Manufacturers almost never set the high stop correctly.
Shift the rear derailleur to the smallest cog. Shift the front derailleur to the middle chainring. While pedaling with your hand, pull on the exposed cable with the other hand, and observe what happens. You want the chain to move easily to the big ring but not to come off on the outside. Manipulate the high stop screw until the inside plane of the outside derailleur plate is about a millimeter from the chain when it is in the big ring and you are pulling on the cable with your hand.
d. Adjust the cable tension. The easiest adjustment is at the barrel adjuster. Mountain and hybrid bikes usually have a barrel adjuster at the shifter. Road bikes usually have a barrel adjuster on the frame along the cable route. You may need to loosen the cable anchor bolt on the derailleur and pull the cable tighter. Note that the cable must be on the right side of the cable anchor bolt, or the adjustment will be off. Look for a little groove on the derailleur or a washer indicating the correct side.
With the chain in the middle chainring, shift the rear derailleur through all the gears. The chain should not rub the front derailleur cage in any gear.
When in the big chainring, start on the small cog and shift the rear derailleur through the first half of the gears. The chain should not rub the front derailleur cage. It is ok if the chain rubs as you approach the bigger cogs--you should not ride with a crossed chain in any event.
When in the small chainring, start on the big cog and shift the rear derailleur through the first half of the gears. The chain should not rub the front derailleur cage. It is ok if the chain rubs as you approach the smaller cogs--you should not ride with a crossed chain in any event.
If you can't cure inappropriate front derailleur rub with chain tension, revisit the derailleur's position--it is probably wrong.
Congratulations. When you can set up a front derailleur, you are a bike mechanic.
14. Make sure the miscellaneous nuts and bolts are tight. Test the bolts for:
derailleur hanger
front derailleur
rear derailleur
chainrings, both sides of the crankset
15. Test to make sure the bottom bracket rotates freely and has no slop or play.
16. Test the headset to make sure it rotates freely and has no slop.
17. Take the bike off the work stand to make final adjustments to the front end.
Align the stem with the plane of the bike, and tighten it. Stem bolts need to be snug enough so the stem won't move. Be careful, though, because threadless stem bolts strip easily.
Align the handlebar the way you like it, and tighten the bolts that hold the bar to the stem. These bolts strip easily, so be careful, but get it snug enough.
Test the headset again--it's easier to test the headset with the front wheel on the ground.
18. Adjust the seat so it is level with the ground.
19. Install the reflectors.
20. Cut off any excess cable. A bicycle-specific cable cutter is best. Normal wire cutters will crush bicycle cable. Attach cable tips to the end of each cable.
21. Go for a test ride, but be careful.