Technical Tuesday: Straightening Your Derailleur Hanger
Your bike can shift poorly for a lot of reasons, one of them being a bent derailleur hanger. Today's Tech Tuesday shows you how to fix this common problem and get your ride's shifting back up to par. Inside you can watch a great video guiding you through the process from start to finish.
Read on...There are plenty of reasons why your rear shifting may have gone haywire, but one of the more common ones is that your bike is suffering from a bent derailleur hanger. I wouldn't think of this as it being "broken" per say, as the job of a replaceable derailleur hanger is to absorb abuse (bend or even snap if need be) so that your derailleur or frame are spared. The hangers are made to be weaker than the actual derailleur that attaches to them for this very reason. A bent hanger can happen quite easily, although a simple way to limit the chances of having to do this repair is to simply avoid laying your bike down or against anything on its driveside. I can't count how many times I've seen bikes bouncing up and down on their driveside as the shuttle truck makes its way up a rough road.
Before starting this repair it is important to note the differences in derailleur hanger types. The most common design is the simple bolt on hanger that is held in place by one or two bolts. If they do snap they are usually the most inexpensive type to replace. Some full suspension bikes (and a few hardtails) use a larger unit that encompasses both the dropout and derailleur hanger and bolts to the rear stays. This can make for a stiffer interface as the hanger is built into the dropout and may result in better shifting for that reason, especially when using the latest 10 speed gearing. The downside is that this piece is likely to be far more expensive than the simpler common bolt on hanger. The last type is the much less common non-replaceable hanger. While it can make for precise shifting, the consequences are high if you manage to severely damage it. This type is far less common and I'd recommend taking it to a professional shop to have it straightened if you manage to bend yours. Regardless of the type of hanger that your bike has, they all use the same technique to straighten and I can't stress enough that you need to be gentle and take your time throughout the repair. Spending an extra ten minutes doing this job may end up saving you money and downtime. Like a lot of repairs, this one requires special tools and if you don't have them, or don't feel comfortable doing the work, take the bike to your local shop to have them do the work.
Tools needed: Hanger Alignment Gauge, 5 mm allen key
Watch the video to learn how to straighten your derailleur hanger
Past Tech Tuesdays:
Technical Tuesday #1 - How to change a tube.
Technical Tuesday #2 - How to set up your SRAM rear derailleur
Technical Tuesday #3 - How to remove and install pedals
Technical Tuesday #4 - How To Bleed Your Avid Elixir Brakes
Technical Tuesday #5 - How To Check And Adjust Your Headset
Technical Tuesday #6 - How To Fix A Broken Chain
Technical Tuesday #7 - Tubeless Conversion
Technical Tuesday #8 - Chain Wear
Technical Tuesday #9 - SRAM Shift Cable Replacement
Technical Tuesday #10 - Removing And Installing a Headset
Technical Tuesday #11 - Chain Lube Explained
Technical Tuesday #12 - RockShox Totem and Lyric Mission Control Damper Mod
Technical Tuesday #13 - Shimano XT Crank and Bottom Bracket Installation
Have you found this tutorial helpful? Share any of your hints or tips below!
Visit Parktool.com to see their entire lineup of tools and lubes.
Read on...There are plenty of reasons why your rear shifting may have gone haywire, but one of the more common ones is that your bike is suffering from a bent derailleur hanger. I wouldn't think of this as it being "broken" per say, as the job of a replaceable derailleur hanger is to absorb abuse (bend or even snap if need be) so that your derailleur or frame are spared. The hangers are made to be weaker than the actual derailleur that attaches to them for this very reason. A bent hanger can happen quite easily, although a simple way to limit the chances of having to do this repair is to simply avoid laying your bike down or against anything on its driveside. I can't count how many times I've seen bikes bouncing up and down on their driveside as the shuttle truck makes its way up a rough road.
Before starting this repair it is important to note the differences in derailleur hanger types. The most common design is the simple bolt on hanger that is held in place by one or two bolts. If they do snap they are usually the most inexpensive type to replace. Some full suspension bikes (and a few hardtails) use a larger unit that encompasses both the dropout and derailleur hanger and bolts to the rear stays. This can make for a stiffer interface as the hanger is built into the dropout and may result in better shifting for that reason, especially when using the latest 10 speed gearing. The downside is that this piece is likely to be far more expensive than the simpler common bolt on hanger. The last type is the much less common non-replaceable hanger. While it can make for precise shifting, the consequences are high if you manage to severely damage it. This type is far less common and I'd recommend taking it to a professional shop to have it straightened if you manage to bend yours. Regardless of the type of hanger that your bike has, they all use the same technique to straighten and I can't stress enough that you need to be gentle and take your time throughout the repair. Spending an extra ten minutes doing this job may end up saving you money and downtime. Like a lot of repairs, this one requires special tools and if you don't have them, or don't feel comfortable doing the work, take the bike to your local shop to have them do the work.
Tools needed: Hanger Alignment Gauge, 5 mm allen key
Past Tech Tuesdays:
Technical Tuesday #1 - How to change a tube.
Technical Tuesday #2 - How to set up your SRAM rear derailleur
Technical Tuesday #3 - How to remove and install pedals
Technical Tuesday #4 - How To Bleed Your Avid Elixir Brakes
Technical Tuesday #5 - How To Check And Adjust Your Headset
Technical Tuesday #6 - How To Fix A Broken Chain
Technical Tuesday #7 - Tubeless Conversion
Technical Tuesday #8 - Chain Wear
Technical Tuesday #9 - SRAM Shift Cable Replacement
Technical Tuesday #10 - Removing And Installing a Headset
Technical Tuesday #11 - Chain Lube Explained
Technical Tuesday #12 - RockShox Totem and Lyric Mission Control Damper Mod
Technical Tuesday #13 - Shimano XT Crank and Bottom Bracket Installation
Have you found this tutorial helpful? Share any of your hints or tips below!
Visit Parktool.com to see their entire lineup of tools and lubes.
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Even the video admits you can use the derailleur cage to check the alignment, therefore there is no point in having that unpractical tool to check alignment using your rim as reference.
I'm surprised he didn't mention to make sure the rim is straight, you must also buy a parktools truing stand and spoke wrench prior to using this tool
The reason hangers bend is to prevent the bending of your derailleur, which unless you're still running alivio is by far more costly than replacing you hanger.
Having straightened hundreds of hangers over the years I know that simply sighting from behind doesn't cut it 90% of the time when trying to get everything aligned correctly. My reference to looking from behind is only to see if things are out of whack, but I can't count how many times that a hanger was only out a touch, not enough to straighten with just your eyes, but enough to hinder shifting. A hanger alignment tool is the right tool for the job, no matter if its a Park model or from another less expensive brand. This is especially true now that more and more bikes are shipping with 10 speed and tolerances need to be even tighter.
Regarding mentioning if your rim is straight... If you use the same spot on the rim, I used the valve stem for reference, it does not matter if your wheel is true or in dish. Just I say in the video, rotate the rim with the tool.
1. Get an expensive tool to fix the hanger
2. Take it to the shop
You never mentioned how cheap it would be to get a new hanger (which you install yourself easily) vs. buying the tool or paying someone to use the tool to fix it. I can tell you most people are not going to buy that tool, which only leaves #2. So then where's the real useable advice?
If this video was directed at mechanics, I can see the importance of the tool, but again they will already know this. If it was directed at road or XC racers demanding the best out of their 10/11 spd drive trains, I can also see the importance of the tool, but again, they will already know to take it to the shop.
Which leaves the average young male on pinkbike beating around on their mtb for fun with a dirty cassette, probably a chain that's too long, and mashing gears - all the while still enjoying their bike and have it work well enough to have fun! They won't find this advice helpful at all.. they will continue to use sticks or hammers to fix their hangers.
Maybe if you renamed the title to "how a shop mechanic straightens out your derailleur hanger" it would be more suitable for the majority of us.
agreed on everything else though
Hard Way: Adjustable wrench
It's a pretty easy method to figure out.
@seraph: pretty easy just for some of us.
for the price of the tool how many hanger could just go out and buy??
Not a bad investment at this price, cost just 2.5 hangers.
I've worked at DH shop for years and have used the alignment tool maybe two or three times, and only for frames that have a built in hangar. The fastest and easiest way to tell if a hangar is bent is to remove it from the bike and lay it on a flat surface. The drive side of most all hangars is designed to be a completely flat surface, so you will know it's bent right away if its not sitting flat. Now all you have to do is bang it flat with a hammer, or stick it in a vise and squeeze it flat. Literally takes five minutes and doesn't cost you the price of an unnecessary tool.
Since you are of the wise old age of 17, I imagine that you must have started working in a shop when around the ages of 2 or 3 to be filled with such an incredible amount of knowledge. Since you've "...worked at DH shop for years and have used the alignment tool maybe two or three times" I'm betting that they don't let you get past using the broom too often?
In well over a decade of working as a mechanic I can say without exaggerating that I've used a hanger alignment tool hundreds and hundreds of times. It is the correct tool for the job, whether you use this Park version or a less expensive model. When you, or a customer, wants their bike to shift perfectly (especially if they are paying for it to be done), hammering it flat is not the right way to do it when the tolerances are so small. I'd love to see the look on your paying customers face as he watches you smash his expensive bike's hanger "flat" with a hammer.
There is also no need to remove it to lay it on a flat surface just to see if it is straight. If a hanger is bent, the amount that it is out is usually made clear by the length of the derailleur cage magnifying the hangers mis-aligment. If you can't spot it, but still suspect that its bent, a hanger alignment tool will tell you - for the same reason that a derailleur cage can. I can understand the average rider not having one of these expensive tools, but for a guy working as a mechanic to not use them, especially when they are at his disposal, makes me wonder.
Also, we're all patiently waiting for your Tech Tuesday video.
right after that i'll clean up my bench, because i will be fired....
I'll tell you what, bestow upon me the legendary "plus" status and I'll throw together a tech tutorial on re-shimming any shock of your choosing. Probably whatever shock you're currently riding, Brule, as yes--you've obviously eaten more than your fair share of rice.
What do you say? You get some more midrange and I get to be the first "plus" member who's not also on the payroll--sounds fair to me.