We have a few emails regarding gear hangers breaking/snapping a year, sometimes within weeks of receiving the bike usually after a few months/years of riding. Gear hangers are not a part that is usually covered under warranty and unless this the result of a crash then having them snap on you can generally be avoided. So for those people who are not sure what these are, or those who are buying their first bike and want to avoid the inconvenience of this, and a gear hanger breaking mid ride is pretty inconvenient, here is all the information I have on them and how to preserve their life as long as possible.
How they fit and what they do!
Gear hangers, or replaceable dropouts as they are otherwise known, are designed to be replaceable. They are usually made of alloy and will break under extreme stress in order to save your frame from being damaged. This can be the result of a crash, mis-shift or most usually simply being in the wrong gear when the chain and derailleur are under the most load either when the road goes upwards sharply or setting off from a standing/stationary start.
All the hangers for our bikes are of the cast alloy type and attach to the frame using either one, two or in some cases three countersunk bolts. The mech itself then attaches to the hanger. There are many different types of hangers and you usually find that each model of frame will have a specific one unique to it. This can sometimes change year by year, which doesn’t make things easy when trying to source a replacement.
Why do they break and how to avoid it! (Overshifting)
As previously mentioned hangers are made from a soft metal designed to break under extreme stress, this may sound a bit strange, but the reasons for this are to protect the more expensive parts of the bike firstly the rear derailleur and then frame, they are if you like the ‘weakest link’ on a bike’s drivetrain. A broken rear mech, although dependent on which one, can be relatively expensive and a bit annoying. It is nothing however compared to the cost of replacing the frame.
There are a few reasons why they break aside from crashes, which are usually pretty much unavoidable. The most common on new bikes is usually however down to rider error. Either being in the wrong gear combination for the terrain or when starting off, i.e. the big ring on the chainset paired with the biggest sprocket on the cassette, or trying to change gear when the load on the chain and gears is at its greatest on steep inclines.
Other reasons can be an incorrectly fitted or worn chain, a chain that is too short for the chainset/cassette combination fitted, debris in the chain or derailleur and incorrectly set up gears can also cause undue stress on the hangers.
Dos and Don’ts!
Do keep your chain well maintained. Clean and lube regularly. The same goes for your derailleur, cassette and chainset.
Do check your chain regularly for stiff links or possible bent links.
Do ensure that after fitting any new parts to the bikes drivetrain that you check the gears are correctly set up – reset and adjust if necessary.
And lastly Do make sure that you are in the right gear for starting off and climbing, always start off in the small/inner ring at the front, and ensure you are in a suitable gear combination before the road ramps up on a steep climb.
Hopefully then your hanger will last as long as you have the frame and you won’t have to try and limp home if one does snap on you!