{"id":50668,"date":"2023-06-06T10:00:00","date_gmt":"2023-06-06T08:00:00","guid":{"rendered":"https:\/\/www.bikeradar.com\/?p=270322"},"modified":"2023-06-06T10:35:44","modified_gmt":"2023-06-06T08:35:44","slug":"how-to-straighten-a-bent-derailleur-hanger","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/cyclingplus\/rss_feed\/how-to-straighten-a-bent-derailleur-hanger\/","title":{"rendered":"How to straighten a bent derailleur hanger"},"content":{"rendered":"

Straighten your derailleur hanger to fix poor shifting <\/p>

By Oscar Huckle\n \t\t<\/p>

Published: Tuesday, 06 June 2023 at 12:00 am<\/p>

\n\n

If your gears aren\u2019t shifting properly and you can\u2019t get them to index, a bent derailleur hanger can often be the culprit.<\/p>\n

The derailleur hanger<\/a> keeps the rear derailleur aligned perfectly with the cassette cogs and is designed to bend or break in the event of an impact. Because the hanger is typically constructed from soft aluminium, it doesn\u2019t take a lot to knock it out of alignment.<\/p>\n

If the hanger isn\u2019t bent too badly, it\u2019s often possible to straighten it, but if it\u2019s too far gone, it\u2019s best to replace the component.<\/p>\n

In this guide, we\u2019ll take you through the step-by-step process of straightening a bent derailleur hanger, as well as replacing a broken one.<\/p>\n

How to straighten a bent derailleur hanger<\/h2>\n
\""Oscar\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
There isn\u2019t a substitute for a derailleur hanger tool.<\/span><\/figcaption> Kaden Gardener \/ Our Media<\/i><\/span><\/div>\n

As well as the correct-sized hex or Torx key to remove and reinstall the rear derailleur, you will need a derailleur hanger alignment tool for the job.<\/p>\n

These can be expensive, but there isn\u2019t a substitute. If you own multiple bikes, it\u2019s worth investing in, or perhaps sharing, a tool among your riding friends.<\/p>\n

Bear in mind you run the risk of the derailleur hanger snapping, because you\u2019ll weaken the material by bending it back.<\/p>\n

Some suggest using the jaws of an adjustable spanner to bend it back in place by eye, but we wouldn\u2019t recommend this \u2013 it\u2019s more likely to break given the increase in force and it won\u2019t provide an accurate gauge of where it is misaligned.<\/p>\n

Step 1<\/h3>\n
\""Oscar\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Remove the rear derailleur.<\/span><\/figcaption> Kaden Gardener \/ Our Media<\/i><\/span><\/div>\n

Make sure the rear wheel is installed correctly into the frame dropouts.<\/p>\n

This is particularly important with quick-release axles. Installing the wheel while the bike stands on the floor is best because gravity helps guide the axle in place so the wheel sits squarely in the dropouts.<\/p>\n

Shift the chain into the smallest cog and remove the rear derailleur. Hold the rear derailleur as you remove it to prevent it from springing back.<\/p>\n

Step 2<\/h3>\n
\""Oscar\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Thread the alignment gauge into the hanger.<\/span><\/figcaption> Kaden Gardener \/ Our Media<\/i><\/span><\/div>\n

Lightly grease the threads of the derailleur hanger alignment tool and install it into the hanger threads. Be careful not to cross-thread it \u2013 the threads will need re-tapping if you do. Most derailleur hangers use an M10 x 1.0 thread.<\/p>\n

Step 3<\/h3>\n
\""Oscar\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Position the gauge of the tool with the valve at the 12 o\u2019clock position.<\/span><\/figcaption> Kaden Gardener \/ Our Media<\/i><\/span><\/div>\n

Position the valve of the rear wheel at 12 o\u2019clock. It\u2019s best to use the valve as your reference point, because this takes wheel trueness out of the equation.<\/p>\n

Move the arm of the alignment tool so the end of it touches the rim. Some tools include O-rings, which act as a visual guide for the hanger\u2019s alignment.<\/p>\n

Next, move the valve to the 6 o\u2019clock position and, without adjusting the arm of the tool, note where it sits.<\/p>\n

\""Oscar\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
This gap is larger than 3mm and requires adjustment.<\/span><\/figcaption> Kaden Gardener \/ Our Media<\/i><\/span><\/div>\n

There will be three possible scenarios:<\/p>\n

  • The end of the arm touches the rim. This means the vertical alignment of the tool is correct and you can move on to the next step<\/li>\n
  • There is a gap between the end of the arm and the rim. If the gap is more than 3mm, you\u2019ll need to perform an adjustment<\/li>\n
  • The end of the arm wants to go further inwards towards the rim. Reset the arm of the tool so it touches the rim and use the 12 o\u2019clock position as your second reference point<\/li>\n<\/ul>
    \""Oscar\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
    This is the end result.<\/span><\/figcaption> Kaden Gardener \/ Our Media<\/i><\/span><\/div>\n

    If the hanger requires an adjustment, gently pull or push the tool in the direction the hanger needs to be bent in. Once adjusted, check the vertical alignment of the hanger again using the previous steps until there is a gap of 3mm or less.<\/p>\n

    Step 4<\/h3>\n
    \""Oscar\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
    You can now move to the 9 o\u2019clock position.<\/span><\/figcaption> Kaden Gardener \/ Our Media<\/i><\/span><\/div>\n

    We\u2019ll now move on to the horizontal alignment.<\/p>\n

    Without adjusting the arm of the hanger, check the hanger is aligned both in the 3 o\u2019clock and 9 o\u2019clock positions. Bend the hanger as above if you need to make an adjustment.<\/p>\n

    Step 5<\/h3>\n
    \""Oscar\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
    Take care if you need to make an adjustment.<\/span><\/figcaption> Kaden Gardener \/ Our Media<\/i><\/span><\/div>\n

    Check the derailleur hanger tool is aligned perfectly at all four points.<\/p>\n

    Step 6<\/h3>\n
    \""Oscar\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
    It\u2019s always wise to put some anti-seize on the rear derailleur\u2019s mounting bolt threads.<\/span><\/figcaption> Kaden Gardener \/ Our Media<\/i><\/span><\/div>\n

    Reinstall the rear derailleur, being careful not to cross-thread, and tighten it to the manufacturer\u2019s recommended torque.<\/p>\n

    Step 7<\/h3>\n
    \""Oscar\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
    You\u2019ll want to check the gear indexing after straightening a bent hanger.<\/span><\/figcaption> Kaden Gardener \/ Our Media<\/i><\/span><\/div>\n

    Check the gears function correctly. You may need to adjust the limit screws and indexing.<\/p>\n

    How to replace a snapped derailleur hanger<\/h2>\n

    If the derailleur hanger is snapped or broken, you\u2019ll need to replace it.<\/p>\n