How many times to s...
 

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[Closed] How many times to straighten an alloy mech hanger before you replace?

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Straightened the hanger on my jeffsy about 4 times now.

Not to too worried about it actually snapping with the repeated bending. More thinking about it being easier to bend out on the trails then when new??

Thoughts?


 
Posted : 18/09/2018 4:24 pm
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Buy a new one, they're about 20 quid.


 
Posted : 18/09/2018 4:28 pm
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After a significant straightening, I'd buy a new one and keep this in my pack until the original broke. You may as well keep bending this one back into shape until it snaps, impossible to say how many times that might be.


 
Posted : 18/09/2018 4:32 pm
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Wot he said - if it ain’t broke don’t fix it - but do have a spare to hand...


 
Posted : 18/09/2018 4:50 pm
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Id be surprised that an aluminium hanger has survived multiple sraightenings. If nothing else, get yourself a spare for when the inevitable happens.


 
Posted : 18/09/2018 5:04 pm
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Honestly, I probably wouldn't ride one I'd straightened any significant amount, unless I really had to.  I just couldn't trust it not to be weaker and the step between broken mech-hanger and shredded rear spokes is a short one.


 
Posted : 18/09/2018 5:05 pm
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Depends what you mean by straightening. Do you mean you've ****ted it and had to pull it back 45° or do you mean it wasn't shifting well on a wide range cassette? Does it need checking after dropping/crashing the bike, or does it go out of check just from regular use?


 
Posted : 18/09/2018 5:09 pm
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More thinking about it being easier to bend out on the trails then when new??

From what I remember the opposite happens.  It will strain harden making it less likely to bend where it was straightened and more brittle.

How much will doubtless differ a lot according to the actual alloy. A mild steel one would probably straighten lots:D


 
Posted : 18/09/2018 5:11 pm
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Once - and then it's usually relegated to the spare.


 
Posted : 18/09/2018 6:14 pm
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Zero. Get a new um and keep it for an emergency.

APF


 
Posted : 18/09/2018 6:44 pm
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It'll be work hardened so won't bend so easily if anything. At least until it has cracked most of the way through.

Just carry a spare.


 
Posted : 18/09/2018 9:30 pm
 Leku
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Jeffsy ones do seem to be made of cheese. It's the 9 euro postage that pisses me off.

Shame no one else makes one to fit.


 
Posted : 18/09/2018 10:22 pm
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^^Yes mate, does seem a bit soft to be honest.

In answer to how much I've had to straighten it. Not massive amounts,at a guess around 10 degrees or so. Not huge amounts luckily!


 
Posted : 18/09/2018 11:57 pm
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for me until it breaks then replace.  Never had one break tho so never had to replace one.  I do have a spare for the tandem tho


 
Posted : 19/09/2018 12:07 am
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I've never tried to straighten an alloy hanger. The ones I've damaged have just snapped (3 in 30yrs). What are you doing to repeatedly bend one ??


 
Posted : 19/09/2018 12:18 am
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taxi25

....What are you doing to repeatedly bend one ??

It's not hard to do if you take your bike through 3" wide deer tracks in heather. About 2 or 3 minutes will do it. 🙂

It amazes me that the mtb derailleur has persisted in a design that's perfectly good for road, but leaves it dangling and exposed to all the trail hazards on an mtb.

It's surely not beyond the wit of man to redesign it with the tensioning done tucked up behind the BB like some of the early designs did.

There should be no need to carry spare parts for your transmission.


 
Posted : 19/09/2018 8:03 am
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0. Since 10-speed cassettes I've not managed to straighten one sufficiently to have it work even enough to act as a backpack spare. If it's bent it's spent.


 
Posted : 19/09/2018 8:32 am
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I wouldn't say 10 degrees is an insignificant amount to be bending an alloy hanger, warpcow is bang on, when you send a mech into your spokes, you'll have wished you'd paid that 9 quid.


 
Posted : 19/09/2018 8:37 am
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It's aluminium so the material will have the same modulus as any other frames hanger. It must be something to do with the design or manufacturing that is causing a problem.

You could anneal it before and after straightening.


 
Posted : 19/09/2018 8:37 am
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If it's a case of re-aligning in the workshop, then I'd probably do it a few times without worrying. If it's properly bent on the trail, then I'd replace without question. A broken mech hanger can ruin a day for everyone.


 
Posted : 19/09/2018 10:12 am
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I'd get a spare but keep straightening it until it's clearly weaker.

Do peope ever used damaged stuff they "keep for spares"?


 
Posted : 19/09/2018 10:45 am
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As above. YMMV.  Once you’ve straightened an alloy hanger it is weaker and much closer to snapping.  In my experience, hangers that have been bashed back into shape are rarely properly true anyway so may be allowing riding but probably are causing shift problems at one end or the other.

Plan for failure and have a spare to hand but if you can live with the repaired hanger for now then by all means wait for it to fail.


 
Posted : 19/09/2018 12:26 pm

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