Introduction
Have you ever been pedaling along on your bicycle when you suddenly feel the pedal slip out from under you. If your pedals/cranks suddenly lose resistance, the chain frequently slips off the gears, or your bike shifts into lower gears unexpectedly without input from the shifters, you've come to the right place. Read on to get the common causes and solutions to chain slippage and get back to riding!
Causes
Over time, a bike chain may become loose due to wear on the chain itself or on the cassette cogs. This looseness can lead to the chain skipping when pedaling with force or slipping off entirely.
To adjust the chain:
Check Chain Tension
Ideally, you should be able to move the chain up and down by about half an inch. Too much slack or tension can cause issues.
Position the Bike
Ensure the bike is stable and positioned so you can easily access the rear axle. Using a bike stand or flipping the bike upside down can help.
Loosen Rear Axle
Use the appropriate tools (usually a wrench) to carefully loosen the nuts on the rear axle. Do not remove them completely.
Adjust Chain Tension
Gently pull the rear wheel back until the chain feels sufficiently tight. Ensure the wheel remains aligned with the frame to avoid misalignment.
Check Wheel Alignment
Before tightening the axle nuts, make sure the wheel is properly aligned in the frame. This is crucial for safety and efficient riding.
Tighten Rear Axle
Securely tighten the axle nuts while maintaining the wheel's position. Check the tension again to ensure it's still correct.
Test Ride
Once everything is tightened and aligned, take a short test ride to ensure the chain operates smoothly without slipping or skipping.
You refer to this guide for more details.
- 5 minutesEasy
If the bike cables are too loose it can cause noise, trouble switching between gears, and even skipping gears. To ensure that your cables perform properly you'll want to do a careful inspection of all the surrounding areas that house the cables and make sure they are both clean and undamaged.
Use the barrel adjusters on the shifters or derailleurs to fine-tune cable tension. Turn the barrel adjuster counterclockwise to increase tension and clockwise to decrease tension.
You'll also want to make sure the front and rear derailleurs are properly adjusted and your wheels are aligned. Derailleurs are only on multi-speed bikes
Lastly you'll want to inspect your shifters themselves damages or frayed cables.
If your chain is worn out you'll probably want to replace it. Here's the process you'll want to follow to properly install a new one.
Determine Chain Length:
Lay the new chain next to the old chain and align them to determine the correct length. Ensure that the new chain matches the old chain in terms of links.
Shift to Smallest Chainring and Smallest Cog:
Shift your bike to the smallest chainring (front) and smallest cog (rear). This helps in removing and installing the chain more easily.
Break the Old Chain:
Use a chain tool to break the old chain. Position the tool's pin over one of the chain rivets, then turn the handle of the chain tool to push the pin out. This will break the chain.
Remove the Old Chain:
Once the chain is broken, remove it from the bike. You may need to thread it through the rear derailleur and around the front chainrings.
Clean the Drivetrain:
Use a rag to clean the chainrings, cassette, and jockey wheels of the derailleur. This helps ensure a smooth and clean surface for the new chain.
Thread the New Chain:
Thread the new chain through the rear derailleur and around the cassette. Ensure that the chain is correctly threaded through the jockey wheels.
Connect the New Chain:
Use the chain tool to connect the ends of the new chain. Align the chain ends and push the pin through the outer plates. Turn the handle of the chain tool to push the pin in until it's flush with the outer plate. If you're using a quick link, follow the manufacturer's instructions for installation.
Check Chain Tension:
Lift the rear wheel off the ground and spin the pedals. Check the chain tension. There should be a slight amount of play in the chain, but it should not be too loose. If necessary, adjust the rear wheel position to achieve the correct tension.
Shift Through Gears:
Shift through all gears to ensure that the chain engages smoothly with the cassette and chainrings.
Trim Excess Links (if needed):
If the new chain is longer than necessary, you may need to use the chain tool to remove excess links. Be sure to follow the manufacturer's recommendations for chain length.
Lubricate the Chain:
Apply chain lubricant to the new chain. Run the chain through the gears to ensure that the lubricant is evenly distributed.
Check Chain Wear (Optional):
If you have a chain checker tool, use it to check the wear on the old chain. If the old chain was significantly worn, it's a good idea to keep track of the wear on the new chain for future maintenance.
Dispose of the Old Chain:
Properly dispose of the old chain and enjoy!
Appendix
Single sprocket bike
Identify what is causing the problem
If the chain is to loose it will skip when you are pedaling under a load or when you are going over bumps. If the chain is worn out (which does happen after about 1000 miles depending on how well chain has been maintained) it can also cause slipping and may wear out drive train components. If your chain is too long see the Chain Link Removal Guide to remove a chain and the Chain Reassembly Guide for reconnecting your chain.
Adjust slop
Loosen the two axle nuts or quick-release lever and slide the wheel towards the rear of the bike to take up the slack in the chain. Be careful to not over tighten the chain as it will put unnecessary pressure on the chain and bearings causing more friction on the drive system. Multiple adjustments may be necessary to achieve the perfect tension.
Alignment
Check to make sure the rear wheel is centered in the rear. Use the seat tube (the part of the bike that your seat post is inserted into) as a guide to center tire. Looking down the length of the chain, it should not have to bend side to side when it goes around either sprocket.
Multi-speed bike
Identify what is causing the problem
The chain can be either slipping while staying on the same gear or the chain can be randomly jumping from one gear to the next. It can be difficult to distinguish between the two. Multi-speed bikes have derailleurs which keep the chain in tension on all gears so chain tension should not cause the chain to slip although you can adjust the chain tension with the derailleur. Check the Rear Derailleur Adjustment Guide for help adjusting your derailleur.
If your chain is slipping
The chain could have a stiff link. A stiff link can be caused by rust or a bent link. You can try to putting some oil on the chain and cycle the chain a bit to get rid of rust, but don't expect this to eliminate the problem. It is hard to straighten bent links so it is better to just remove them with a chain cutter tool or replace the chain altogether. (See the Chain Removal Guide. While putting the chain back together make sure you use a new chain pin since they require a press fitting and reusing the old one could cause chain to break apart under load.
If your chain is shifting at random
This may be a problem with the derailleur adjustment, with cable corrosion, or you may have a bent derailleur hanger. See the Derailleur Adjustment Guide
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