Jim’s Tech Talk
By Jim Langley
Price: $116.95
Source: https://www.parktool.com/product/derailleur-hanger-alignment-gauge-dag-3
Availability: This is brand new – Park says it will be in stock soon
How acquired: Sample from the company
Is their less expensive DAG-2.2 still available? Yes. It sells for $79.95
I couldn’t have been more surprised when I opened the box Park’s new derailleur hanger alignment tool arrived in. They had told me a new version of their DAG (Derailleur Hanger Alignment Gauge) was on its way for me to take a look. I assumed it would be a new take on their sturdy, reliable welded-steel chrome plated hanger measurer and fixer. The DAG has been a staple in shops and with home mechanics for decades.
Brilliant Redesign
I was flat wrong. Inside the package was a completely new design. Even at first glance it was obvious that Park pulled out all the stops to reinvent the derailleur hanger tool. They ditched the welded steel and went with a one-piece forged aluminum construction. I asked them about this and learned that it’s made like a seatpost because they’re incredibly straight, strong and light.
The forged aluminum comprises the body of the tool, which is also the handle/lever used to wrestle bent hangers back straight. It’s also what all the tool’s other parts attach to. Here, Park did their homework and nailed it again.
Fits More Bikes
The shaft with threads that you screw into the hanger is the smallest diameter (16mm) of any they’ve made on previous DAGs. This allows it to fit into hangers even if they’re tucked under frame pivots and hard to access. Also, the threaded end that’s screwed into the hanger is replaceable should you eventually wear the threads. Just unscrew it with a 5mm hex key and screw in a new one. (The DAG 2.2’s is also replaceable.)
No Play in Any of the Parts
When you screw the tool into a hanger you feel the impressive tolerances of the DAG-3’s movable pieces. There’s absolutely no slop between the shaft and the body of the tool. Should any develop over the years, there’s an adjustment screw to easily remove it.
Play/slop is what makes hanger alignment tools hard to use. It makes it difficult to impossible to get accurate readings. And if you’re not sure your readings are correct, it’s a guessing game trying to straighten hangers. The worst thing you can do, too, is bend the hanger repeatedly trying to fix it.
Looking at another important working part of an alignment tool, the gauge, it too is masterfully designed and executed. It’s made of an injected molded composite. The natural friction reducing nature of the material lets the gauge slide up and down the tool smoothly and again, there’s zero play between parts. The gauge is kept oriented exactly 90 degrees to the wheel because it’s keyed to a groove in the DAG’s aluminum body.
Precision Measurements with Ease
One of the nicest features of the tool is that the pointer of the gauge swings in and out from the tool. This lets you set your measurement at the rim and then swing the pointer out of the way without changing the measurement or risking bumping the pointer and changing it.
Also, being able to swing the pointer out of the way lets you pivot the DAG-3 from 3 to 9 o’clock or 9 to 3 – without hitting the frame stays. The pointer is nicely marked to see exactly how bent or perfectly aligned your hanger is. And the fact that the pointer folds in next to the body of the tool protects it from damage when the tool’s packed in a toolbox.
Conclusion
Overall, I think Park has set the bar higher for derailleur hanger alignment tools with this impressive new model. It’s lighter, easier to use, more accurate, fits more bikes, and has replaceable parts for a long, long hanger-fixing life. Plus, it’s only $37 more than their DAG-2.2.
Also, I appreciate how this tool feels in use. It’s a subtle thing but the aluminum body and composite parts and the tool’s overall lightness seems to me nicer to wield than the all-steel hanger aligners I’ve used for so long.
Here’s my video about the tool so you can see it in use. I talk a bit about how derailleur hangers get bent and quickly demonstrate using the tool. Note that I do not go into great or full detail on fixing hangers.
For full instructions on using Park’s DAG-3, you can read them without even owning the tool here: https://www.parktool.com/assets/doc/product/DAG-3_instructions_2021-03-08-155711.pdf.
Ride total: 9,934
Jim Langley is RBR’s Technical Editor. A pro mechanic & cycling writer for more than 40 years, he’s the author of Your Home Bicycle Workshop in the RBR eBookstore. Tune in to Jim’s popular YouTube channel for wheel building & bike repair how-to’s. Jim’s also known for his cycling streak that ended in February 2022 with a total of 10,269 consecutive daily rides (28 years, 1 month and 11 days of never missing a ride). Click to read Jim’s full bio.
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I should show you my DAG 2.3 (modified by me), works great!
We really need the ability to show photos here in this comments section, Rick 😉 I’d like to see it.
The Park DAG-3 tool vs Wolf Tooth Pack Hanger Alignment tool also reviewed by Jim: which to buy?
Thanks for asking, David. I’ve been giving this a lot of thought and I’m ready to give the nod to Park’s new tool. The reason is that it addresses all the issues / weaknesses of “old style tools,” that I mentioned in my look at the Wolf Tooth hanger alignment tool.
This new DAG-3 has no play anywhere and the measurement is accurate and easy to take and you won’t “lose” and have to reset the tool as you move it from point to point. Play in the tools and fussy measurements are the bane of hanger aligners because they make it difficult to impossible to align hangers. You can always improve them but you can’t be sure just how straight they really are.
Now that Park eliminated those issues, it’s a game-changer and because of that I give the DAG-3 the highest marks.
Hope this helps and thanks again,
Jim
Maybe it makes no difference, but when measuring should one rotate the wheel as well so one is always measuring at the same point on the rim (to eliminate one variable)?
Yes, Walt, you definitely want to rotate the wheel with the tool. A good way to do it is to measure the rim at the valve and move the wheel so the valve is always at the pointer. That’s one thing that got left out of my video but it’s shown in Park’s instructions and is the best way to do the job. If you don’t, you could have a warped wheel that would skew your readings. Thanks for the great question!
Jim
I would really like to know which tool Jim prefers now. His review of the hanger tool from Wolfstooth made it seem that all previous tools from Campy or Park were now obsolete. This new version from Park is not much different from the last version.
Hi Karl and thanks for the great question,
Actually, this new version from Park is very different from the last version in about every way possible. Please read my reply to David Kamp above who asked which tool I now rate highest to see my answer and my explanation.
Thanks!
Jim
They should discontinue the old tool and this new tool should take it’s place and the price should be the same as the old tool. Money grab
Your comment is completely illogical.
It would be like saying an improved redesign of a car should sell for exactly the same price as an older inferior model car or else it’s a money grab. If you remodel, improve and update your home would you sell it for the same price as before the remodel? If you tried to sell it for more than the premodel price could a prospective buyer claim you are making a money grab by doing that? 😆😆😆
Actually yes. Unless they add more features, the price should not change. The update is fixing shortcomings it should have never had in the first place. In my home if I fix a broken faucet, that does not mean the house is now worth more. It means it is not worth less as what I did was fix something that detracts from the value.
If the new tool costs 1.5x the original to manufacture, in order to make it better you figure they should still sell for the same price? Nonsense!
Nice write up Jim! This new Park tool looks so much better than the old one.
I do have the old Park hanger tool, but my favourite of the ones I have used is the Abbey Tools HAG,
https://www.abbeybiketools.com/products/hag
This tool is like a piece of jewelry!
Cheers
I don’t have the HAG but I do have a few other Abbey Bike Tools and they’re all super nice so I’m not surprised you like your HAG, Bryan. I do think if you try Park’s new tool you’ll be impressed even compared to the HAG.
Thanks!
Jim
HI Jim, always look forward to your articles in RBR. I have the wolf pack tool and really like its simplicity as to not having to be concerned about wheel truing and it seems to do the job. For the average Joe simple is usually best. Riding 9000 Di2, turning 80 in Feb, about 7500 miles in this year, riding faster than I ever have(a lot of our group have turned to ebikes and I can keep up/pass em except on climbs). Installed Absolut black 46/30 chainrings, cs-hg800 11/34 cassette. think after almost 40 years of cycling I’ve finally dialed in my spin and nutrition. john jauss