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.
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?”
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…
“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.”
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.”
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 Langley is RBR’s Technical Editor. He has been a pro mechanic and cycling writer for more than 40 years. He’s the author of Your Home Bicycle Workshop in the RBR eBookstore. Check out his “cycling aficionado” website at http://www.jimlangley.net, his Q&A blog and updates at Twitter. Jim’s streak of consecutive cycling days has reached more than 8,000. Click to read Jim’s full bio.