How to do it reliably without resorting to £55 of Park tool alignment guage. Especially on my kids' bike which they always seem to be knocking out of line. I have put kickstands on their bikes now which has helped a bit as they don't just pile them up, but I always seem to be adjusting one of them. Does anyone else make a cheaper tool, or know of a bodge using threaded bar, a tape measure and angle iron?

Adjustable spanner and align by eye.

This tool is just £20
(I own one but have not had a chance to use it yet)

Cyclus Gear Hanger Alignment Tool

Why not single-speed their bikes? That'll teach 'em!

You have to Anneal http://en.wikipedia.org/wiki/Annealing_%28metallurgy%29 the alloy before and after bending back. It might look straight after you've 'thugged' it back, but it aint gonna be strong. Easy to do with the correct blow torch (very fine, not that expensive from most DIY stores)….you'll loose paint though.

I did this on a Scott road frame that didn't have drop outs.

I have one of the Cyclus tools and can vouch for its functionality.

I suggest you fit steel derailleur protectors on the axle-end so they take the brunt of a fall.
Hellfrauds and low-end LBSs sell them, approx £5.
They work with QR or axle bolts.
I have these on some of my MTB and road bikes as spills happen without warning.
They have always saved the mech and hanger, but add 100-200grams to the bike.

Leave the mech on. Park triple allen key in the bolt and heave.

I suggest the application of a big hammer.

Also, you'll need to find something to straighten the mech after you've taught the kids to take better care of their bikes.

Actually I'd second BW, but expect that mos stwers will need the "correct tool".

Take the hanger off and use a vice. Seems to put less strain on the hanger. Most kids bikes have steel hangers so they bend back without really losing much strength.

using a hammer on kids is probably cruel, but would teach them a lesson.
adjustable as suggested.
then take off the gears and put a tensioner in there. kids don't need gears ( or at least, they'll manage ).

Another + for the Cyclus tool – excellent bit of kit, use mine lots (mind you quite alot on other peoples bikes who don't have one!)

Somebody once showed me a trick using a wheel (think it has to be one with cone/bearing arrangement – take out the skewer and the axle screws into the mech hanger, and you can use the wheel to lever it back into position – trailside trick that one!

Love Tubs – Member

You have to Anneal http://en.wikipedia.org/wiki/Annealing_%28metallurgy%29 the alloy before and after bending back. It might look straight after you've 'thugged' it back, but it aint gonna be strong. Easy to do with the correct blow torch (very fine, not that expensive from most DIY stores)….you'll loose paint though.

I did this on a Scott road frame that didn't have drop outs.

Slight misunderstanding of cold work and annealing there, I would say do not go any where near it with a blow torch. Just bend it back gently.

I'v tried doing it by eye and it never works – the shifting is always out so I just buy a new hanger 🙂

Nope Toys, your talking to an Engineering Physicist and you do have to use heat to prevent fatique related cracking … especially with alloy! I may have used a pants link via WPed to put my point across.

Granted, you get away with small 'fettles' but anything gross and you'll be compromising the integrity. You have to clean the paint off, heat the alloy until it goes just off colour sort of darkish…then allow it to cool on it's own. Reshape/bend then repeat the process.

It's actually very very easy with isolated sections of alloy such as drop outs.

🙂

Forgive me all, I'm totally fudged (re-writting an essay), my last reply was poor.

Essentially, you'll get away with very small cold adjustments (couple of mm). However, and depending on the 'speed/rate' of the original bend, the alloy grain field's integrity ( 'like' tectonic plates of the earth)will affected.
Thus, if you cold bend it back without heat treating the grain fields (think of this as healing a cut on your hand, for example)then more damage occurs (granted, this might only be initially small). This is where the risk sets in, if you DO NOT have dropouts that can be unbolted and replaced, once the area is weakened then it takes less force to bend it again and thus the cycle repeats until failure.

My Scott road bike had dropouts welded to the frame, I bent the rear mech hanger and could not risk weakening it as the frame would have been useless…or would have to have been sent out for a repair…prob costing more that it's worth.

I hope this helps to explain things a little better, please forgive my initial 'brash' response guys/gals 🙂 I'm so mentally scrambled 🙂

LT

get two old axles. one goes in the dropouts (where the axle always goes, but no wheel) Other axle screws in the hanger. You can see if they're parallel and adjust carefully as required.

(yes yes annealing yadda yadda. I may not have a degree, but I am a trained blacksmith, give me a hammer…)

Nope.. We'll remember this forever!

You can always tell one that's beyond straightening as the surface on the bent bit takes on a rippled pattern.

LT are you a student of "Engineering Physics" then?

Step 1) buy tool for £20
Step 2) use the correct too for the job
Step 3) bask in the glory of a straight mech hanger

The tools are so cheep its not worth the effort of hammering/molgripping/monkeywreching them back into shape. I usualy do mine every time the gears need setting up jsut in case its drifted away from being straight.

I have had one of these for a few years now and it works a treat. It has easily paid for itself many times over.

http://www.wiggle.co.uk/p/cycle/7/Cyclus_Gear_Hanger_Alignment_Tool/5300003490/

I have found that with regular checking the jockey wheels tend to last a bit longer as well as a bent hanger seems to shred jockey wheels IME.

yep…

http://www.wiggle.co.uk/p/cycle/7/Cyclus_Gear_Hanger_Alignment_Tool/5300003490/

works great

and actually in stock!