CJ wrote:I'm just back from leading a tour where on three other people's bikes (one because it was bent already, two after crashes!) I straightened gear hangers by the simple expedient of poking an allen key into the derailleur's attachment screw socket and pulling on it until everything looked alright. In each cases it only took two or three pulls to get the mech near enough parallel to the wheel that indexing worked in all gears, which is all that matters.
I do have and would much rather use the proper Shimano tool, but it's a bit too big to take on tour! So I thought I'd share the welcome news that when necessary, near enough can actually be good enough!
Hint: orient the allen-key of your multi-tool so it's folding axis is aligned with the direction you need to pull. Depending on the size of the multitool, this can give you a reasonably long lever that will not fold up when you pull on it.
Most bikes with aluminum hangers can be dealt with this way; the hangers are pretty soft. Steel hangers require a bit more effort. Needless to say if one of a party has a nutted wheel, it takes a bit longer but you can do a 'proper fix' using the wheel as a tool. [You can check the alignment using a QR wheel but it mightn't be strong enough where it matters to tweak the hanger]. However the first sort of fix can eventually come back and bite you; some years ago I tweaked a gear hanger on a friend's steel frame so that the RD would work OK (i.e. so the RD looked OK but I didn't really know if the hanger was straight or not) and recently a different RD was fitted. The replacement RD looked miles out, really terrible. I tweaked the hanger so that the replacement RD would work, but not until the RD was 'perfect', little believing that the hanger was bent so far, and reckoning that part of the error would have to be in the replacement RD. When I later checked it with the correct tool, it turned out that the hanger had been that bent and so had the old RD. At least I didn't over straighten the hanger, which could easily have happened if the RD had been bent too.
I am part way through making a better tool for checking/ straightening RDs now; I am not keen on bending another gear hanger away from straight for no good reason....
cheers