Author Topic: Derailleur hanger alignment tool  (Read 3079 times)

Derailleur hanger alignment tool
« on: July 07, 2016, 12:18:56 am »
Following an incident on the Wild Atlantic Way audax, my derailleur hanger is somewhat bent ... Steel frame, so roadside attention with a pair of pliers got it straight enough that I had most gears - but it needs fettling. Happily, I'd been meaning to acquire an alignment tool anyway, so this just accelerates the process.

Clearly I'm not about to spend $185 on the work of art from Abbey Bike Tools or £180 on Shimano's offering, but is it worthwhile spending £55 on the Park Tool version rather than Wiggle's Lifeline variant at £25 - or, seeing as that's currently out of stock, £32 on the one Chain Reaction sells? Is there another one I should look at? (The Unior looks solid, but no saving over the Park. Merlin has a Cyclus one for £28.)

Kim

  • Timelord
Re: Derailleur hanger alignment tool
« Reply #1 on: July 07, 2016, 12:25:34 am »
I've got the Cyclus one.  It works, as I expect do all the others.
Careful, Kim. Your sarcasm's showing...

Re: Derailleur hanger alignment tool
« Reply #2 on: July 07, 2016, 06:59:34 am »
you don't need a tool if you have a spare wheel with a 10x1 threaded axle.

Just;

a) fit the usual (non-disc) wheel in the frame the other way round (this makes room for the other 'tool' wheel to be fitted).

b) fit the spare wheel to the right-hand side of the gear hanger by screwing the 10x1 threaded axle through the hanger.

c)  If the bend is bad, fit the track nut on the inside of the hanger.

d) tweak away

What you are aiming for is a hanger with 0 to 1 degree 'toe out' and 0 to 1 degree 'negative camber' (NB the latter is the opposite to what happens when the bike falls over).

You can get close enough by eye (probably more easily than with 'the proper tool' in fact), but if you want to be super accurate, on a 700C wheel 1 degree is a difference of ~11mm between the gap on one side and the gap on the other.

hth

cheers

[edited to change 'toe in' to 'toe out'...d'oh! ]

Torslanda

  • Professional Gobshite
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Re: Derailleur hanger alignment tool
« Reply #3 on: July 07, 2016, 08:03:37 am »
Wot 'e sed...
VELOMANCER

Well that's the more blunt way of putting it but as usual he's dead right.

Re: Derailleur hanger alignment tool
« Reply #4 on: July 07, 2016, 08:11:10 am »
I know about the wheel trick - this is probably at least partly an excuse to buy something New! Shiny! (and a hanger tool is a damn sight cheaper than a lot of other things I could be eyeing up).

Thanks for the guidance on technique and the accuracy needed - I'll try to contain my natural tendency to aim for +/- 1mm difference ...


Re: Derailleur hanger alignment tool
« Reply #5 on: July 07, 2016, 08:46:17 am »
BTW with a steel frame, depending on the dropout design, there is a chance of the dropout bending (where you don't want it to) when the hanger is being tweaked.

To mitigate against this possibility, it is usually a good idea to brace everything by fitting a solid axle hub into the dropouts when you are tweaking the hanger.  Needless to say, the stronger the axle in the bracing hub is, the more good it can do.

cheers

jiberjaber

  • ... Fancy Pants \o/ ...
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Re: Derailleur hanger alignment tool
« Reply #6 on: July 07, 2016, 10:25:24 am »
I have the wiggle tool and it's OK but I find there is a little bit of slop in the fittings, so you need to keep them loaded/ tensioned to ensure a consistent measure. 

I've used it a good few times since I bought it over a year ago now.
Regards,

Joergen

Torslanda

  • Professional Gobshite
  • Just a tart for retro kit . . .
    • John's Bikes
Re: Derailleur hanger alignment tool
« Reply #7 on: July 07, 2016, 11:56:41 am »
Mostly it's bent hangers on Carreras and other 'cheaper' bikes I fix. Usually soft cast alloy rather than CNC machined.

Couldn't see it pointed out above so I'll stress that you mustn't try to straighten a hanger on the bike without the wheel (or a hub) firmly fitted in the rear dropout and if you see any signs of stress or cracking on the hanger then don't mess about, just replace it. When they crack they have done their job...
VELOMANCER

Well that's the more blunt way of putting it but as usual he's dead right.

jiberjaber

  • ... Fancy Pants \o/ ...
  • ACME S&M^2
Re: Derailleur hanger alignment tool
« Reply #8 on: July 07, 2016, 12:04:32 pm »
Mostly it's bent hangers on Carreras and other 'cheaper' bikes I fix. Usually soft cast alloy rather than CNC machined.

Couldn't see it pointed out above so I'll stress that you mustn't try to straighten a hanger on the bike without the wheel (or a hub) firmly fitted in the rear dropout and if you see any signs of stress or cracking on the hanger then don't mess about, just replace it. When they crack they have done their job...

Yep, mines on a steel frame, but I honestly couldn't see doing a straightening without the wheel being in place as you use that (rim) as the point of reference  ???
Regards,

Joergen

caerau

  • SR x 3 - PBP fail but 1090 km - hey - not too bad
Re: Derailleur hanger alignment tool
« Reply #9 on: July 07, 2016, 12:06:10 pm »
The cyclus one has always worked well for me - got it from Rosebikes


You need to have the wheel in to use these things so isn't the above a bit of a moot point? [edit - i.e. what Torslanda said)
It's a reverse Elvis thing.

Torslanda

  • Professional Gobshite
  • Just a tart for retro kit . . .
    • John's Bikes
Re: Derailleur hanger alignment tool
« Reply #10 on: July 07, 2016, 12:15:26 pm »

Yep, mines on a steel frame, but I honestly couldn't see doing a straightening without the wheel being in place as you use that (rim) as the point of reference  ???


Ah, to explain. I use the same method as outlined so eloquently by Brucey upthread. Using the hub as the datum, a Shimano axle screwed into the hanger and a handlebar over the axle for leverage. A long lever allows quite precise adjustment in small increments.

I also keep a small number of new hangers - the most common - for those that have been BTF.
VELOMANCER

Well that's the more blunt way of putting it but as usual he's dead right.

LEE

  • "Shut Up Jens" - Legs.
Re: Derailleur hanger alignment tool
« Reply #11 on: March 24, 2017, 04:17:53 pm »
Today I bought the Park Tools DAG 2.2 (2.2 fits more frame types).

It's a tool that will last a lifetime and has already got one derailleur changing more slickly.

If you're going to go to the trouble of adjusting gears on your's, and family members', bikes then this gets you off to a perfect start.
Some people say I'm self-obsessed but that's enough about them.

Rhys W

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Re: Derailleur hanger alignment tool
« Reply #12 on: March 24, 2017, 11:38:01 pm »
I have a long-standing policy that whenever I need a tool, I buy the Park one. It's cheaper in the long run.

I've never felt the need to buy a hanger alignment tool though - I think I've had two bent hangers in the last 25 years, and I've just taken it to a shop. Although if you follow Doctor D on facebook, you'll see that most frames would benefit from a tweak, even new ones straight from the factory.

Re: Derailleur hanger alignment tool
« Reply #13 on: March 25, 2017, 12:29:56 am »
While I'm largely a believer in the notion that there's nothing so expensive as cheap tools, I do quite like to know what the extra money is paying for. Given that most alignment tools seem to be a bit of box section, a pointer, and an M10 screw, with any minor slop easy enough to compensate for during occasional home use, I hadn't really managed to convince myself that the Park was worth going for above some of the cheaper options.

That makes it even more of a mystery how I seem to have ended up with the Campag alignment tool. It's actually almost elegant.

SoreTween

  • Most of me survived the Pennine Bridleway.
Re: Derailleur hanger alignment tool
« Reply #14 on: July 12, 2020, 02:13:38 pm »
Thread necromancy.

I've just bought a cyclus alignment tool to sort out our TSO, it has a bash guard fitted in a stable door manner1. If I'm understanding Brucey's directions above I want on a 26" wheel:
Zero gap behind the pointer at the top of the wheel and 10mm between pointer & rim at the bottom.
Zero gap behind the pointer at the front of the rim and 10mm between pointer & rim at the rear.

Is that correct?

1Carefully protecting alignment gaps of about 40mm in the vertical plane & 17mm horizontal, both the wrong way.
2020 targets: None
There is only one infinite resource in this universe; human stupidity.

Re: Derailleur hanger alignment tool
« Reply #15 on: July 12, 2020, 05:08:10 pm »
I just realised I said 'toe in' when I meant to say 'toe out' (I've edited my original post accordingly).  In any event the dimensions quoted are the maximum allowable rather than a target.

There is a better description here (SI instructions for RD-7400)

https://si.shimano.com/pdfs/si/SI-N-81A-000-00-ENG_GER_FRA_DUT_ITA_JPN.pdf

which appear to permit ~0.5 degree 'toe in' to ~1 degree 'toe out', and recommends a small amount of 'toe out'. Interestingly it doesn't mention camber angle of the hanger, but other SI techdocs do, IIRC.

cheers

LittleWheelsandBig

  • Whimsy Rider
Re: Derailleur hanger alignment tool
« Reply #16 on: July 12, 2020, 05:19:13 pm »
Just go for the hanger bolt parallel with hub axle in both directions. Easy to understand and achieve.
Wheel meet again, don't know where, don't know when...

Re: Derailleur hanger alignment tool
« Reply #17 on: July 12, 2020, 05:33:23 pm »
further to the above this is the park tool diagram (with which I do not entirely agree)



to meet the shimano specs I suggest that you set the pointer at C then check at A. The clearance at A should be ~5mm greater than at C.

Similarly set the pointer at D then check at B. The clearance at B should be ~5mm greater than at D.

I have used the park tool and the pointer is annoying because it gets in the way if you have a tyre on the rim. Another annoyance is that the tool is usually a slack fit on the post so can flap about. You need to allow for any backlash when using the tool.

NB the wheel in the bike needs to be true else this alignment procedure won't work. Similarly if you are using a spare wheel as a tool (in the hanger) to check/set the hanger alignment, it too needs to be true.  You can overcome either or both issues by turning the wheel(s) so that you are always measuring at the same point on the rim.

BTW I think it is worth the effort  to set a little 'toe out' as recommended; shifting is often noticeably improved vs a perfectly 'square on' hanger.

cheers

Re: Derailleur hanger alignment tool
« Reply #18 on: July 12, 2020, 08:38:01 pm »
Loving life with a beautiful Bianchi.

Tim Hall

  • I want to eat the fleeting shade of your lashes
Re: Derailleur hanger alignment tool
« Reply #19 on: July 12, 2020, 09:04:49 pm »
Regarding using an untrue wheel in ther bike inconjunction with a Park , or similar approved, tool, is a valid work around to rotate the wheel to positions A, B, C and D with the pointer of the tool? I did this the other day, using the valve as a handy marker.

Assuming the untrueness of the wheel is a wobble in the rim and not a more serious failing, I can't see why this won't work.

There are two ways you can get exercise out of a bicycle: you can
"overhaul" it, or you can ride it.  (Jerome K Jerome)

Re: Derailleur hanger alignment tool
« Reply #20 on: July 12, 2020, 09:32:24 pm »
Regarding using an untrue wheel in ther bike inconjunction with a Park , or similar approved, tool, is a valid work around to rotate the wheel to positions A, B, C and D with the pointer of the tool? I did this the other day, using the valve as a handy marker.

Assuming the untrueness of the wheel is a wobble in the rim and not a more serious failing, I can't see why this won't work.

yes, hence

…….  You can overcome either or both issues by turning the wheel(s) so that you are always measuring at the same point on the rim.

cheers

Tim Hall

  • I want to eat the fleeting shade of your lashes
Re: Derailleur hanger alignment tool
« Reply #21 on: July 12, 2020, 09:36:49 pm »
Regarding using an untrue wheel in ther bike inconjunction with a Park , or similar approved, tool, is a valid work around to rotate the wheel to positions A, B, C and D with the pointer of the tool? I did this the other day, using the valve as a handy marker.

Assuming the untrueness of the wheel is a wobble in the rim and not a more serious failing, I can't see why this won't work.

yes, hence

…….  You can overcome either or both issues by turning the wheel(s) so that you are always measuring at the same point on the rim.

cheers
Ah. Memo to self: Read the whole thing first. Idiot (me).
There are two ways you can get exercise out of a bicycle: you can
"overhaul" it, or you can ride it.  (Jerome K Jerome)

Re: Derailleur hanger alignment tool
« Reply #22 on: July 12, 2020, 10:31:34 pm »
I’ve got one of the cheap ones and it works. I’d rather not have to use it often mind. I sorted the hanger on the big yellow truck a few weeks ago, only after buying a couple of spares (it’s alloy) from China. The bike has been blown over and I was quite surprised the SLX mech and road link seems to survive bu the hanger not.

LittleWheelsandBig

  • Whimsy Rider
Re: Derailleur hanger alignment tool
« Reply #23 on: July 12, 2020, 10:40:32 pm »
That is the intent. The replaceable hanger is the weak link that saves everything else from damage.

Shimano’s misaligned tolerances regarding hanger alignment for recent mechs are a bit of a shit solution. Campag engineered its triple mechs to hang skew-wiff from a correctly aligned hanger for better chain management.
Wheel meet again, don't know where, don't know when...

Re: Derailleur hanger alignment tool
« Reply #24 on: July 12, 2020, 11:21:51 pm »
….Shimano’s misaligned tolerances regarding hanger alignment for recent mechs are a bit of a shit solution....

only since 1984...?

FWIW several manufacturers (esp SRAM) use imperfect parallelograms such that the toe angle of the mech varies through the stroke, apparently to better match the chain entry angle at the bottom of the mech.   To me this seems a little in conflict with the observation that the tolerances  specified by shimano appear to be set so that positive camber and 'toe-in' are avoided. Certainly if these become excessive indexed gear systems can work a lot less well, and with a perfectly square-on hanger you are still 'in tolerance' but by the time you strap a mech on these errors are just a bit more likely to happen.

BTW I modified my Park Tool hanger aligner so that I could adjust the slack out it; no more annoying wobbling about. I also made it so that the part that screws in the hanger is

a) able to be 'bolted through' (i.e. the hanger is clamped from both sides securely instead of relying on the screw threads) and
b) can more easily be replaced should the need arise.

I normally use it with a set of Vernier calipers to measure the setting. If I ever reinstate the original pointer, I shall modify it so that it is on a hinge, so that it can be moved out the way (without losing the setting) when the tool is being swung between positions.

cheers