
Jim’s Tech Talk
By Jim Langley
Thank you for the thoughtful comments and questions about last week’s product review on Wolf Tooth’s revolutionary derailleur hanger alignment tool. In case you’ve been out riding and missed it, here’s a link to catch up: https://www.roadbikerider.com/wolf-tooth-pack-hanger-tool-review/.
In my eagerness to get the word out that a better tool is finally available for aligning derailleur hangers on frames, I may not have explained clearly enough why Wolf Tooth’s new tool is better. Because, you asked for more details. So, this week, I’ll try to explain more clearly and fully. Please see my old-tool/new-tool use diagram, too.
Your Comments
Did you do a shootout of the new and old tools?
Don Macrae asked,
“This tool looks smart, and I’m sure it produces a result with less fiddling about. I have a Park Tool aligner, and it always takes several iterations before I’m happy. But.. I am wondering upon what basis you say it produces ‘more accurate’ alignment? Have you conducted a shoot out?”

My reply
Thanks, Don. Yes, I compared the results of using standard tools and using Wolf Tooth’s new hanger alignment tool and the Wolf’s was both easier to use and more accurate. This is apparent as soon as you use the new tool. I tried to show this in my video:
But to explain, with the “old” tools, you are trying to take a measurement with a moving pointer/indicator. Yes, you can set the indicator at each point where you take the measurement at the rim. However, because the hanger hole where the tool is attached is not at the same height as the axle, you have to keep moving the indicator’s holder up and down so that the indicator is at the same height as the rim.
You also have to move the indicator so it doesn’t hit the seatstays or chainstays. These adjustments to the indicator make it difficult to get truly accurate measurements. Shimano made an alignment tool that had a ruler as the indicator but even with that tool, it was difficult to get accurate measurements.
When you use Wolf Tooth’s tool it’s a no-brainer comparison of 2 parallel lines formed by the 2 rods extending from the hanger and axle. You don’t have to move tools, worry about whether the rim is straight or not (or if the wheel is centered in the frame), or measure anything.
And, you are looking at indicators that are right next to each other, they might even be touching with a badly bent hanger. This is very different from the old tool where your point of reference is far away from the hanger and on a line 90 degrees to the hanger not in line with it the way Wolf Tooth’s is.
You will see straight away with Wolf Tooth’s tool if the hanger needs aligning or not. And then to align the hanger you will love how accurately you can fine tune the hanger’s position with the straight rod attached to it, versus the old tool’s long arm attached to the side of the hanger. That long arm often results in over bending and having to try again, too.
But new bikes have replaceable and protected hangers…
“Kenneth” wrote,
“I thought most, if not all frames today come with a replaceable derailleur hanger? I know all my frames have them. I do know that it is risky bending a replaceable hanger and most manufactures of said hangers strongly recommend not re-aligning them. I just carry a spare hanger in my rattle bag and it’s a quick easy fix on the road or trail. Been doing this for years and it is really needed mostly on long all day MTB rides as rocks and roots seem to just jump out and grab that derailleur.
And with the newer derailleurs that sit under the chainstay and help protect it from damage I think carrying an alignment tool on every ride is kind of overdoing it a bit. In my 30+ years I’ve not seen too many riders break or bend a rear hanger, and if you hit hard enough the hanger is meant to break instead of damaging the derailleur so you’ll need a replacement hanger anyway.”
My reply,
Yes, most modern bikes have replaceable derailleur hangers, Kenneth, yet when a hanger gets bent you never know if the replacement hanger is aligned perfectly or not because whatever bent the old hanger could have damaged more than the hanger. So, it’s always smart to check the alignment even with replacement hangers once they are in place on the frame.
Hangers are the Achilles heel of the bicycle. It’s great that companies are trying to save the hanger with improved derailleurs. But there are millions of bicycles out there in use and not all new bikes with replaceable hangers or the latest derailleur designs. So, I’m sure Wolf Tooth’s new packable tool will be popular with many riders who like to be equipped to help friends on rides with whatever goes wrong with their bikes. But, it’s definitely a good idea to carry a replacement hanger for your bike if it takes one – good point.
On-the-road tips and tricks for dealing with bent derailleur hangers
Chuck Procner said,
“This sounds like a terrific tool to have, particularly on the road with you. One thought though, carry a spare hanger with you, either in your bag or taped under your saddle. It seems like it might be easy to go “GODZILLA” with this tool and break an already weakened hanger particularly while stressed on the trail.”
Stephen Turk shared,
“The rear derailleur mounts to the hanger with a 10x1mm bolt, which is the same thread as a typical threaded rear axle (e.g., Shimano). So an old method, in the absence of a fancy alignment gauge, was to screw a spare axle into the hanger and eyeball it for alignment. Seems like Wolf Tooth has taken an old concept and done a very nice job of making a new, improved version.”
My reply,
For doing as Chuck says – and always carrying a replacement hanger on rides, you will need to get the correct hanger for your frame. An online resource is Wheels Manufacturing’s Quick Fit Finder here: https://wheelsmfg.com/derailleur-hanger-tech-help. You can also purchase the hanger from them.
Stephen’s tip is great. I have heard of riders taking a wheel off their buddy’s bike and using its axle to thread in to the bent hanger. That way, in theory (I haven’t tried this), you’d have a second wheel aside your rear wheel and you’d use it to carefully straighten the hanger.
Carrying a spare axle is easier but you wouldn’t have a reference point except to use an imaginary line through the rear derailleur. However, Stephen could be right that it’s the idea that sparked Wolf Tooth’s tool.
What we used to do to align hangers that wasn’t very accurate, but would get you home, is to carry the right size allen wrench to fit into the rear derailleur’s pivot bolt. The allen would give you a lever and a gauge of sorts to straighten the hanger best you could. The advantage of that approach is that you don’t have to remove the rear derailleur.
Thanks for the feedback everyone.
Head Badges Follow-up

A few issues back, I wrote about my bicycle head badge collection and shared some photos of a few of my favorites, including the lovely badge that Ibis Cycles features on their bikes.. That story is here: A Classic Finishing Touch.
Afterward, I heard from an old friend and fellow badge addict, Jeff Conner, who sent this photo of another beautiful Ibis badge (Jeff believes it’s French). From the badge’s shape and design, I’d say it’s from the 1890’s. Interestingly, for a badge of this vintage, it’s made of aluminum. Most badges at that time were brass.

Hearing from Jeff reminded me that he wrote one of the only books about head badges I’ve seen, A Cycling Lexicon, Bicycle headbadges from a bygone era. It’s a small format book of some 400 pages with 380 photographs – most showing a single badge in wonderful detail. It’s a miniature coffee-table book ($19.95) sure to wow your bike loving friends.
You can get it here: http://gingkopress.com/shop/cycling-lexicon/.
Ride total: 9,317
Jim, Reading through the comments and from personal experience, RD hangers bend which causes misalignment. A couple of questions for you and the readers
1) How do you as a rider, know when the hanger is bent enough to warrant taking to a shop?
2) Is it true that you look for mis-shifing in the middle cassette gears while highs and lows work fine?
3) Once hanger is straightened, why does it go out of alignment again (even if the rider never touches the RD, nor has the bike been laid down on its drive-side)?
4) ROAD BIKE POLL Q1: How many of you have ever had a hanger go out of alignment?
5) ROAD BIKE POLL Q2: In response to statement “I always carry a spare hanger”, How many of you have ever had a hanger break while out on a ride?
Thanks
Thanks, Rick! Here are my answers:
1) If I start having hesitation or new noises from the rear derailleur, I will stop and look from the rear to see if it looks bent. If not, I’ll try cable tension settings or Di2 adjustments to fine tune the derailleur. If it looks bent, I’ll use the hanger alignment tool to check/see.
2) Actually, both high and low and middle hesitation.
3) Hangers are weak – it doesn’t take much to knock them out. But, I believe they do get knocked out – it doesn’t happen on its own. Bikes get knocked over at events and then picked up by someone and you don’t even know it happened. Or someone trying to help loads your bike in a car or rear rack and puts another bike right on top bending the hanger. Stuff like this causes lots of bent hangers – and there are lots of other examples, I’m sure you can think of 😉
4) POLL Q1 I have
5) POLL Q2 I haven’t broken a hanger but I have had a friend break on on a ride
Thanks for the questions, Coach!
Jim
Hello Jim,
When using the tool on QR bikes, do you trust the outer face of the frame to be consistent enough to give accurate results? I purchased the tool and it gave terrible results on QR bikes when compared to previously available options. When using on Thru axle bikes it did a better job. Only issue was that i felt the need to get a caliper out to measure the distance between the two rods as my eyes were not good enough to tell small differences. I ended up running my finger along it and trying to look at it from all angles. I wish it had more lines lasered into the long rod for at least something to line up with at odd angles. I guess I still prefer the old options as it gives you a hard reading about how far out you are at a given length instead of a subtle difference in angle. Setup initially took longer as well. Will that change as a person gets used to the tool? i dont think so, theres more steps involved in the process. Thanks for the review and in depth look at this tool!
Richard.
Thanks for the feedback, Richard. It sounds like you might have some chipped paint or ? on your right dropout interfering with the fit of the tool.. You could ensure the surface on the dropout is even to get accurate readings, by sanding the chipped paint flat, for example. But, it’s a good point that if a dropout isn’t flat or it’s damaged somehow, you will need to make it flat.
You said the old tools “gives you a hard reading,” which I disagree with. You have to take 4 readings and none are “hard” because the tool, the tool pointer and the rim can and do move – so the readings at best are approximate. Wolf Tooth’s tools stay exactly where you put them and you only need to compare the two rods by sight or with a caliper if you prefer. So, you can actually get “hard readings” because measurements can be taken from fixed not moving/changing points.
Thanks for sharing your experience with the Wolf Tooth aligner,
Jim
Anodized hanger on a carbon bike. Not gonna sand it to try to make this tool work…. Should not need to.
When I say hard readings, I mean to say that If you take the 4 readings (You really only need 3) at 4 different spots in space at the same spot on the wheel it should be accurate. You can then measure the distance between the rim and the pointer at all of those positions to tell you how bent the hanger is at that amplification level. Where on the WT you can measure 1 direction at reduced amplification.
Do you think the Wolftooth tool amplifies the reading as much as a traditional tool? It seems to me it gives half the amount of amplification of the reading, So you need to have twice the eye accuracy on a tool that is giving a reading that could be interpreted differently from person to person. Example: I straightened a hanger with WT’s tool. Had a friend come to see what he thought. He ended up thinking it needed more tweaking, when i thought it was dead on. Then I checked his adjustment with one of the other tools and the hanger was off slightly. The wolftooth tool IMO is subjectivly “accurate”. Good on Wolftooth for innovation and pushing to try new things. The parts of the tool that are really neat to me are the fine ACME thread, the quick nut, and having the ability to try to straighten a hanger without a wheel in the bike.
Thanks for sharing and testing the tool!
Richard
I agree that it would be nice to have some kind of way to measure the exact distance between the tool and the guide at the various angles. But your comment about your friend thinking it wasn’t dead on and verifying the measurement with the other tools, assumes the other tools are superior. What matters is how the bike shifts when you’re done! I haven’t yet tried this tool, but like the idea that it removes a lot of potential pitfalls of the old tools, like using the wheel for a reference point – wheels go out of true, and you reduce the margin of error if you use the same reference point on the rim for each position check, but, provided your frame (dropouts) is not bent, your axle is a much more reliable reference point.
I have frequently encountered issues with bent derailleur hangers, especially on mountain and cx bikes. I carry an extra hanger when I go on a road trip with my bike, but don’t carry it on every ride. I’ve only broken one once, after a stick took out the derailleur, which in turn took out some spokes. I ended up walking out of the woods that day (luckily not a long way). I have definitely had to resort to manually bending the hanger, using a combination of a multitool and/or the derailleur itself, in order to finish my ride after a crash. I would not plan to carry this tool unless I’m on a long ride such that I’d be using a camelback with ample storage.
The Wolf tool appears to be a great tool.
However, I have never personally had a hanger bend so much that I could not ride home…nor have I had that happen to any fellow rider.
And, I use a home made hanger tool…very similar to the standard straightening tool. It is simply a long, square tube handle on a bolt which screws into the DR hole. I then spin the wheel to the stem at the four positions (12, 3, 6 and 9 oclock) and use an accurate small steel ruler to measure the distance from the handle to the rim. I have straightened some severely bent hangers and have never had an issue getting the hanger true and shifting back to normal. I have even taken the straightened hangers to a few bike shops to have them check and they could not improve the alignment over what this home made tool did.
Yes, an elegant solution to what may not be a problem…but, then I am old school,-)
Congratulations on making your own hanger alignment tool, Walt – and thanks for explaining how you did it so that others can copy your idea. Hmm… with your skills you could probably make your own version of the Wolf Tooth tool and make your own comparison.
Thanks a lot for sharing your tips!
Jim