Derailleur alignment tool recommendations?

[londonbikerider]

Good point, but one needs to take into accounts the type of hanger is dealing with: some are machined and some are stamped, the latter can be incredibly soft (ask me ho do I know), while the former can wreck the frame when this has very small means of holding the hanger (ask a friend of mine how does he know!).

I think the best solution is to get a strong frame in the first place, isn't it?

[Brucey]

further to that, if in doubt, it is always best to fit a solid axle to a (standard QR type) type frameset before doing things with the hanger.

cheers

[Samuel D]

I don't like the faffing around with the tru-axles, extensions, and all that. Seems overkill unless your goal is compatibility with all types of frames.

I haven’t paid attention to through-axles since I don’t have a frame that needs them. Through-axles add fuss to a lot of things we take for granted with quick-release skewers. My comments are about the cheaper quick-release skewer version of the tool.

With the Wolftooth tool, it requires to aim the two bars, which may not always be easy.

But that’s the interesting thing about this tool. Aligning two bars can be done quickly and intuitively with remarkable precision by adjusting your sight-line until the two edges are almost on top of each other, revealing minuscule differences.

Consider aligning a sheet of A4 paper with the edge of a desk. That can be done with great precision by pushing it close to the edge. Accuracy to a tiny fraction of a degree is possible like this, far beyond what is realistically needed for a derailleur hanger.

This tool eliminates a load of moving parts and their expense and slop compared to the Park Tool design. It’s cheaper and smaller. It’s easier to use, requiring negligible mechanical skill. You might be surprised how hard the Park Tool design is to use for some people. I’ve seen them struggle with the minimal coordination and spatial awareness it demands. Just screwing it into the hanger without loading the fractionally engaged thread with a great cantilevered load requires care. In practice, I think most people will do better with this Wolf Tooth tool.

[fastpedaller]

it is also not clear to me that the QR skewer is tight (as tight as normal) when the wolf tooth tool is in use. In many bikes the dropout flexes slightly as the QR is tightened, enough to destroy the accuracy of the hanger alignment if it is not done whilst the QR is properly tight.

cheers

With the Wolf tool there is also a question (IMHO) concerning the degree of accuracy compared to other tools (or indeed the use of a wheel) - the shorter tube looks to be only about 160mm, and thus the accuracy is halved compared to the other tools which take measurements from the wheel rim in the bike.
I've looked again at my planned simple tool, and the only drawback I can see is being able to get the 'gauging' part of the tool correctly at right angles to the axle of the hub without the facility of a surface table or similar.
This is what I have in mind:- A piece of rectangular bar stock welded onto an old fixed sprocket which is then screwed onto a spare track hub - This gives a good rotating part with no play, and the hub can be screwed into the hanger. The bar stock can be used as-is providing it is perpendicular to the hub axle, but I cannot guarantee this easily. I envisage a plate welded on near the end which can be trimmed to give a perpendicular gauging edge so that measurement with a Vernier can be taken. If (before I weld a plate on) I attach the tool and find that measurements show no misalignment on my frames, that may be good enough?

tool.png (1.7 KiB) Viewed 597 times

[fastpedaller]

Here's the measurement tool I welded up yesterday (Brucey and other good welders, please ignore my poor welding it's usually better).
Anyway, as you can see it's a bit of bar on an old Villiers fixed sprocket, screwed onto a track hub. I had to use an axle spacer or the axle would have clashed with the cassette as I didn't want to cut the axle.
In the horizontal plan the measurement from bar to rear of wheel rim was only microns different to that at the front of the wheel. measuring from bar to top of wheel and comparing it to the measurement at bottom of wheel gave a 3mm difference. As this is only 1% I'm not concerned - there's probably more play in the derailleur than that. Secondly, when I released the rear wheel QR and centred the wheel between the seatstays there was no difference between the measurements. It may be paint, a burr on the dropout, or a small misalignment on the dropout height, but when weight is put on the saddle and the wheel takes up its 'natural' position it isn't quite vertical. An interesting exercise, and one which (to me anyway) gives a satisfactory check that my frame derailleur hanger is err..... satisfactory!

[Brucey]

3mm difference top to bottom is only ~0.3 degrees camber angle. The usual recommendation is that you are allowed 0 to 0.5 degrees negative camber (bottom of RD is further out than the top) and 0 to 0.5 degrees 'toe out' (i.e. the RD can be 'aimed' slightly to the right of the bike, looking forwards). So your camber might be 'perfect' or the other thing depending on which way it is angled.

BTW if the axle in the wheel is slightly bent then any such measurements will be different if the wheel goes back in a different alignment.

BTW do you have one of these?



Is it quite well....?

cheers

[fastpedaller]

BTW do you have one of these?



Is it quite well....?

cheers

Can you explain, as that's totally lost on me

[fastpedaller]

3mm difference top to bottom is only ~0.3 degrees camber angle. The usual recommendation is that you are allowed 0 to 0.5 degrees negative camber (bottom of RD is further out than the top) and 0 to 0.5 degrees 'toe out' (i.e. the RD can be 'aimed' slightly to the right of the bike, looking forwards). So your camber might be 'perfect' or the other thing depending on which way it is angled.

BTW if the axle in the wheel is slightly bent then any such measurements will be different if the wheel goes back in a different alignment.

IMHO although it would be great to have everything in perfect alignment (of course 'perfect' doesn't exist - there's always some tolerance). As regards the derailleur hanger, its relationship to the wheel (or more accurately the cassette) is what matters for a good gearchange. We don't want wheels misaligned in frames though! I'll check why the wheel isn't sitting at vertical as desired at some time. BTW the measurement from tool to rim at top was less than at bottom, indicating the bottom of derailleur out a little so within tolerance?

[fastpedaller]

BTW do you have one of these?



Is it quite well....?

cheers

Can you explain, as that's totally lost on me

Ah..... Is it Owl Pellet welding

[Brucey]

Ah..... Is it Owl Pellet welding

sorry about that, pretty lame joke really. BTW your hanger appears to be smack bang in the middle of tolerance.

cheers

[fastpedaller]

Ah..... Is it Owl Pellet welding

sorry about that, pretty lame joke really. BTW your hanger appears to be smack bang in the middle of tolerance.

cheers

That's a Spa Tourer given top marks then! At some time I'll see why the wheel isn't sitting vertical 'naturally', but it's too cold at the moment.

[Northern_Monkey]

The Shimano 105 10-speed has started to be too fussy on my Cross Check even with new cables and a few goes at adjusting the cable tension, limits and b-adjustment.

Most places seem to be out of stock for non-super expensive alignment tools, bad timing as Park have now released an alloy DAG-3 as a replacement to the cheaper steel older model but it’s ~£130 and not in stock.

Worth a punt on a Chinese eBay Park DAG-2.2 copy or using Bicycle Hero (ships Taiwan/US), open to other suggestions? Haven’t got a decent local bike shop anymore and the less local good ones in London are super busy.

https://www.bicyclehero.com/gb/parktool ... gauge.html

https://ebay.us/Dyb20b

[Steve O'C]

If you have a spare rear wheel you can try this technique

https://www.youtube.com/watch?v=TnwreRrorIA

Might it just be that the rear mech bushings are worn?

Steve

[Jdsk]

""Derailleur Hanger alignment tool ?
[topics merged by moderator]

... includes Brucey's advice.

Jonathan

[Northern_Monkey]

Thanks for the replies, will take a look at the thread. Doesn’t surprise me that Brucey had quite a detailed opinion on it and made his own improved version!

Do have another bike, but the rear axle isn’t fully threaded on the end so might not engage properly.

I have popped a XT 9-speed long cage mech without a lot of use and it is still doing the same thing so bushing should be OK.