Rear mech alignment tool.

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  • Rear mech alignment tool.
  • bencooper
    Member

    You might find they don’t bend back so happily – often aluminium bends once happily, fractures on the bend back.

    Rohloff?

    t-p 26
    Member

    Derailleur alignnemt tools are for steel frame. Replaceble mech hangers were invented as sacrificial mech hangers attached to aluminium frames, because it doesnt have the “memory” of a steel frame.If the aluminium mech hanger was bent, the frame would be worthless.

    Premier Icon mactheknife
    Subscriber

    My general riding is some rocky stuff up in the Cairngorms. I am pretty clumsy :-), with regularity i find im needing to replace bent mech hangers. I honestly cant justify £20 quid a pop.

    Does anyone use an alignment tool for repairing them? If so do you think they are a good investment.

    Ta

    Premier Icon simonbowns
    Subscriber

    As they’ve said – we’ll straighten a replaceable alu hanger only as an emergency fix and even then with the note that it’ll likely break as we try! Does depend on how out they are – sometimes a minor tweak to a slightly wonky new hanger will work, but a fresh hanger is always best.

    argoose
    Member

    Heat it up, will make it more maliable and less likely to fracture

    Premier Icon mactheknife
    Subscriber

    cheers for the feedback, usually my hangers just take a bit of a knock and as it is usually nothing substantial I was hoping for an easy fix. More hangers will be on order i reckon. 🙁

    A banger hanger helps a bit too and they’re cheap/unobtrusive. It’s a bit of metal with a different skewer nut that mounts over the mech and takes more knocks. It also crisps your shifting up a little as it reduces mech flex.

    £12 at CRC:

    http://www.chainreactioncycles.com/Models.aspx?ModelID=19016&utm_source=Google&utm_medium=Shopping&utm_name=UnitedKingdom&gclid=COiJ_IrtprYCFcbKtAodPVcAvA

    Or ebay for £9.99:

    http://www.ebay.co.uk/itm/4-JERI-Banguard-Hanger-Saver-Alloy-Rear-Mech-Protector-/190752549729#vi-content

    They work, unfortunately they don’t come in Maxle size 🙁

    EDIT: It’s worth ensuring your cable outer is out of the way so it won’t get pinched if/when you crash.

    oldnick
    Member

    Well worth having one in the toolkit.

    Prevention is better than cure so the banger hanger would be a worthwhile addition but for £21+P&P from bikediscount a straightener will pay for itself pretty quickly.

    Obviously a hanger bent to a jaunty angle may well snap, but you can feel if it’s weakening as you bend it.

    mav12
    Member

    i used another wheel screw in to mech hanger and use as a gauge worked for me suppose it depends how bent the hangar is

    I used to use the Park Tool to align hangers when in the bike shop. Park Tools. However at £60 I wouldn’t recommend buying one. You can do exactly the same with a big adjustable spanner. They both rely on aligning by eye. (The slide bar on the Park Tool is of little help)

    Alternatively you can bend many hangers back into shape by squashing it flat in a bench vice. As others have said aluminium ones will likely snap after a couple of bashes. You could try heating it up first?

    I wonder why they don’t make the replaceable hanger out of steel?

    adlyhobart
    Member

    I wonder why they don’t make the replaceable hanger out of steel?

    because they would last too long.

    Premier Icon mrelectric
    Subscriber

    Depends on the hanger material too; the diecast ones from Canyon are quite britlle; CNC from BETD better.

    I could do with some hack tool to check if it is bent while its on the bike. Sometimes the shifting goes awry and you cant see properly if the hanger really is a little twisted or bent.

    argoose
    Member

    Probably not made of steel as it needs to be softer than the frame material, as it’s a sacrificial item.
    £20 as opposed to £xxx for frame.

    I wonder why they don’t make the replaceable hanger out of steel?

    because they would last too long.

    What argoose said, no point making the sacrificial bit stronger than the frame (£100-£3000 if you rip a dropout off and write off the frame?) or the mech gives out first (£30-£150). Best have a soft £25-£20 sacrificial bit between the two!

    I’ve got a straightener, seems to work pretty well. Easier than doing it by eye, and good for checking if it’s only bent a bit and the gears wont index, but it doesn’t look bent. Probably wouldn’t save a really bent one, but paid for itself in tweaking minor bends over the years.

    Premier Icon Northwind
    Subscriber

    Hanger Banger/etc- a way to protect your £10 dropout with your expensive frame.

    Right, how to straighten perfectly without the proper tool. Do you have an old cup-and-cone axle? (you can use the whole wheel but it’s easier with a loose axle). The rear axle (and maybe the front, I don’t know) uses the same thread as mechs do. So, take your axle, with one nut on it, thread it in (sticking out to the outside of the frame) til the nut butts against the hanger.

    Now, you can see how squint it is fairly easily. But to make it easier, get a suitable straight edge and stick it in the dropouts, so it sticks out beside the exle (I use a bit of M10 threaded bar but anything straight will do, it’s just simpler). Now you’ve got 2 parallel lines, and a nice lever to do your bending with. Could not be easier once you’ve got that.

    Don’t do it too often on an alu one- I take the approach that I’ll tweak one if it’s a wee bit off but I won’t do wholesale straightening.

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