Literally every time I have a back wheel out in the garage, I check the hanger. THough not with one of those- with an old cup-n-cone axle and a straight edge, because it makes me feel 3.8% more like fred dibnah.

Lol, yeah,I wish I did have the patience to have made one.

In truth I didn't think the hanger would be out as it looked fine to the eye.... Just goes to show you can't trust your vision with things like this.

How much was it? I.e is it just easier to buy a new bike?

Depends on your bike. 😉

£39.99.... Which is a lot of money for what it is.

Cheapest I found (other than making one) is from that German site, different make but worked out sub £30 posted I think.

Got a lifeline one from wiggle last year when they were half price... not used it yet! Would probably be a good idea to get into the habit though, I’ll have to remember where I put it!!

I got one a while ago after buying a second hand frame and thinking the hanger looked a bit out. It was so the tool saved a bit of heartache/head scratching.

My newest toy is a torque wrench 🙂 wanted one for ages so thought I'd treat myself.

aha ok. OP can I borrow yours?

How much was it? I.e is it just easier to buy a new bike?

I’ve seen the guys at my LBS use one on a new bike. Just because it’s new doesn’t  mean everything is square. Not a cheap bike either.

Yep great tool, i had indexing issues last year with a brand new xt mech on my cx bike, checked it and the hanger was bent. Straightened it out and voila, gears work perfectly.

This, and a headset press, and a torque wrench.

More important than any tool though, is knowing how to use it properly.

OP, I think the "wheel wobble" would have to be pretty bad to make a massive difference over that ratio. Worth being aware of, yeah, but not a massive concern.

I can't work out how that tool fits - anyone enlighten me?

It address into the mech hanger mate.

It just checks the mech hanger is parallel to the wheel at it's fundamental simplest. Some vids on YouTube no doubt.

Ta - just wondering if I can 3D print something that would do the same job. I reckon I could with an M10x1mm pitch bolt (not cheap to be honest).

I can’t work out how that tool fits – anyone enlighten me

You remove the rear mech and screw it in its place. (that's the bit at the RHS of the photo) You then slide the bit on the left to align with the rim, the little rod at right angles is then adjusted to just touch the rim. You then swing the whole assembly to several positions, the little rod should stay the same distance from the rim at all points. Because the mount point isn't central to the wheel you have to slide the rod in and out along the main shaft.

If the  hanger isn't straight you use the main bar as a lever to ease it back. A bit primitive but it works.

I've been eyeing these up and you've just encouraged me to buy it! My trusty Prince Albert has taken a few too many hits to the mech hanger, this might just save the frame.

I’ve seen the guys at my LBS use one on a new bike. Just because it’s new doesn’t  mean everything is square. Not a cheap bike either.

As a wild guess, id say that it's probably 50/50 as to whether a new bike has a misaligned hanger or not.

Number of people i've seen complaining that their gear issue isn't fixed "even though they bought a new hanger".

Yeah, the mounting face isn't perpendicular to the wheel axis either.........

I paid about 8-10 quid for mine ~20 years ago. Still use it regularly.

Ta – just wondering if I can 3D print something that would do the same job. I reckon I could with an M10x1mm pitch bolt (not cheap to be honest).

You'll need something stronger than plastic. You could 3D print the gauge part but the bar and attachment to the hanger need to be metal.

You’ll need something stronger than plastic. You could 3D print the gauge part but the bar and attachment to the hanger need to be metal.

Yep, I didn't realise until after I posted that the tool is also used to straighten the mech hanger.

AlexSimon
Ta – just wondering if I can 3D print something that would do the same job. I reckon I could with an M10x1mm pitch bolt (not cheap to be honest).

The point of the tool is that it is robust enough to bend a hanger straight into alignment.

Very simple but useful tool and soon pays for itself in saved hangers

One thing I've wondered with these - I'm assuming they rely on the wheel rim (that's being used) also being true? Or if it's not (true), do you just use another section of the rim?

One thing I’ve wondered with these – I’m assuming they rely on the wheel rim (that’s being used) also being true? Or if it’s not (true), do you just use another section of the rim?

If the wheel isn't true, just turn the wheel so that you are always measuring against the same spot on the rim (i.e. the valve stem).

^^

What joe says, I use the valve as the reference for obvious reasons. 😏

Mech hangers are fine pitch metric, but you can get bolts in that thread online.  Then just bolt a length of steel angle or similar to the hanger with a wheel in (for straightness reference) and eyeball it.  But both the newer frames I have have rock solid mech hanger arrangements which I doubt are bendable.

^thst iswhat I have done mm. Bolt + washers + angle iorn and use a rule to measure.

Be gentle if you feel the need to realign. That tool can tear a mech hanger when you apply the pressure. Not all hangers are made of cheese, but the one on my Boardman frame was! Replaced with something much more robust.

I find shifting woes are more commonly due to cable friction, usually in the last loop, and the rear mech can tolerate a reasonable amount of wonkiness, certainly more than can be detected by eye. One up and two down or vice versa is always cables. Often at the cable ferules, which develop tiny kinks.

And I bought mine at Wiggle last year when half price too. It's a nice tool, but I've not used it many times.

I am with TiRed here, I am perhaps even more skeptical than him. This feels like a tool to solve a problem that does not exist. I have bent a few hangers, all bent back by eye and pliers, and never had shifting problems that were not solved by adjustment and well maintained cables. I am convinced that no two hangers are at the same angle on any bike, due to manufacturing tolerances etc. This is whey the derailleur is such a great piece of kit. If you don't believe me, just wiggle any mech from side to side and you will find more movement than any undetectable by eye misalignment anyway.
A buddy uses one of these, but every time he has "fixed" a problem hanger, he has also renewed cables. I know what I think the fix is.

The instructions that come with the tool mention that once within a few mm variation around the rim you are within tolerance. It's much more about getting things within the right ball park before you start messing with cables, outers, etc.

In my case the hanger was out in two dimensions and the tool definitely helped in finding the fore-aft twist.

Getting it right in the vertical plane is the more important.  My original Scandal worked fine with 9 speed but when I went 10 speed i couldn't get the shifting to work across the range, if it worked in big gears it was off in samll ones and vice versa.  If that is the prob it is likely to be hanger-related.  In my case it was not the hanger's fault, the frame was made that way (obvious when you looked at it).  I amagine 11 and 12 speed are even more sensitiver.  Which may be why modern frames have beefier hanger arrangements.

I agree some alu separate hangers are made of cheese and you have to be careful.

I bought the Lifeline one from WIggle a few years ago (£25 at the time). Reading the reviews, a few people mentioned undoing the grub screw, removing the central bolt that screws into the hanger and wrapping it twice with PTFE tape before reassembling. I followed these instructions when mine arrived and it cured the slight wobbble/play that was present. Getting the hanger 'hanging' correctly makes indexing the gears so much easier. If you know it's straight you can discount it from the equation. I've only used it three or four times but it's saved me hours of grief. I was trying to index a new derailleur for hours before buying one and couldn't get it to work, I eventually discovered that the hanger was about 5mm out. Straightened the hanger, gears indexed in about 5 minutes.

Vital tool for any mountain biker.

BTW if you still have indexing problems after straightening a hanger, new cables etc and you have ruled out compatibility issues, It's most likely a bent mech cage or mech linkage! Sometimes you can bend them back, but it's surprisingly difficult by eye and a bit hit and miss. I've even hammered both plates flat on a bench and it's still not quite right until I put a new mech on!

Adjustable spanner does it for me

I did mine today using the attach a second wheel to the mech hanger method, it was way out, simple to fix and made a huge difference, cost nowt too.

Use one on every service bike & every new bike. Part of the PDi checklist.only  1in 100 come in perfectly aligned, most need a tweek

I used to bolt a bit of flat stock to the hanger and use a pair of stilsons to tweak it.

But I had a odd bit of box left over and decided to make a hanger tool.

I also made a chain whip, mainly as the scrap of metal seemed to look like one.

I didn't really have any problem indexing with moderately bent hangers, but I hated looking down and seeing a cage pointing all over the place.

Got one after struggling with my road bike gears.  The mech hangers seem to bend in a strong breeze or hard stare.