This is the snapped derailleur gear hanger tutorial to complement our growing list of emergency roadside repair solutions. If you snap your gear hanger, the mechanism that changes the gears will dangle off the back of the bike. The chain will no longer track the rear sprockets and will continually derail if you try to pedal. If this happens far from home you will be facing a long walk or even worse if the bike doesn’t roll.
More often than not, this is a problem with no immediate remedy. The best you can hope for is to be able to walk the climbs and roll down the hills! For this reason it is always advisable to have a spare hanger in your tool pouch. There are literally hundreds of versions of hangers for all the different frames and brands out there. Because of this huge variety, many bike shops only stock the most common types. If you do have a hanger issue you may find the correct part will need to be ordered from central distributors.
If you have a snapped derailleur gear hanger, the remedy is dependant apon the tools and parts you have available. In an ideal world you will have allen keys to remove and install new parts; a new hanger to replace the old and a ‘hanger alignment gauge’ to insure the new one is parallel to the rear wheel and sprockets. If you have these things, great! Go and find a full guide on how to do this job properly!
If you have a chain tool and allen key that’s also great! This is going to be cheaper and easier for you! If you have nothing it’s gonna cost you the price of a new chain and maybe a gear cable. The idea of this fix is to get you rolling again so don’t expect miracles!
With a chain tool you should brake the chain and decouple it from the rear gear mechanism. Reinstall the chain on the ring at the front and a sprocket on the rear wheel that most closely align and that eliminates chain slack and puts as much tension on the chain without making it ‘tight’. Using the chain tool again rejoin the chain to create a single speed. With the transmission resolved, use the allen keys to remove the gear cable from the gear mechanism. Put the gear mech in your bag and tidy the gear cable out of the way. It is a good idea to decouple it from the cable bosses all the way back to the bars where you can wrap it out of the way until you get home.
This quick fix can cause problems you should be aware of before you try it yourself. The Chain is much more likely to derail without the mech there to guide and tension it properly. If the chain derails it can move to a larger sprocket which will stress it catastrophically, causing it to snap. If the chain snaps you might loose your balance which may cause an injury or damage. The gear cable could snag as it is not in its’ frame bosses under tension. If the cable snags it could cause you to loose balance which may cause damage or an injury. It is advisable to change the chain after this treatment.
It is impossible to ride and difficult to even push your bike if you have snapped your derailleur gear hanger. With no tools the options are very limited. The main issue is that the mech is no longer keeping the chain under tension. They are now able to tangle and jam in other components. The mech is no longer attached to the frame and can swing into the rear wheel. This can potentially damage spokes, the mech itself and possibly the frame. If you’re without tools the only solution is to snap the chain. Once it’s free, wrap the mech and gear cable round the bars or top tube and roll or walk back to civilisation.
If you need to snap the chain, you will find it is very simple. Repeatedly bend it 90 degrees opposite to the way it wants to bend. Once the chain is off you should select the smallest sprocket with the lever. Manually push the gear mechanism towards the wheel into the largest sprocket. This will remove tension from the gear cable. You can now pop the outer cables from the frames’ bosses. With the cable free you can wrap it and the mech out of harms way.
If you have no tools and have internally routed cables you will need a different approach. Disassociate the cable from the mech by bending the cable repeatedly at one point. Do this near the mechs’ barrel adjuster the cable will hopefully eventually snap. Removing the cable, chain and derailleur mechanism will enable the bike to roll again at least!