Bent derailleur hanger

[Janzep]

This hanger is bent slightly inward. Is it a result of being bent via wear and tear or could there be a mechanical advantage to aligning the cage that way? On a Canadian Raleigh with Suntour Honor RDR. The hanger is stamped 4532. Should I replace? Bend straight? Or just mount the Suntour.

 

[GTs58]

Those and or the Derailleur gets bent when the bike is laid down hard on that side. I've just bent them back on my Schwinns. Then make sure the cage or jockey wheel cage is not bent.

 

[Andrew Gorman]

Are the same parts going back on the bike? If so, do you know how well it worked before? My first thought would be to straighten it out, just on general principles. And while you have the bike stripped down, take a few minutes to check and adjust the frame alignment-scroll down to the picture with the string:

Bicycle Frame/Hub Spacing

A bicycle frame and fork should match the wheels that are to be used in it. Older bicycles used narrower spacing, but older frames can often be spread out to match more modern wheels.

sheldonbrown.com

It can make a huge difference.

 

[Cranky Chain Cycles]

You need one of these.

https://www.parktool.com/assets/img/product/_productDetail/DAG-2.2_001.jpg

Sent from my iPhone using Tapatalk

 

[bulldog1935]

(probably belongs on the Lightweights page)
The correct part is easy- and cheap-enough to find on ebay, I'd probably replace it.
The RD will probably function with the bent hanger, but you might end up with shorter pulley life and possibly reduced chain clearance.
Oops is the highest probability why it's bent, but trying to increase derailleur travel in one direction for gearing change is a possibility.

The Suntour slant parallelogram derailleur body design patented in 1964 became the norm for everyone after the patent expired - Shimano in 1983, and even Campy bit the bullet and copied Suntour by 1988.

 

[rustjunkie]

this:

FFG-2 Frame and Fork Dropout Alignment Gauge Set

Measure and correct the alignment of frame and fork dropouts.

www.parktool.com

before this:

DAG-2.2 Derailleur Hanger Alignment Gauge

Diagnose and correct a variety of shifting issues by measuring the alignment of the derailleur hanger compared to the rear wheel.

www.parktool.com

 

[bulldog1935]

No offense meant, but bike shops have better tools for this task.
My Moser frame was received with dropout misaligned from shipping and poor packing - also had my International frame spread and properly aligned to 126mm OLD - quick and inexpensive work for bike shops.
I was really impressed with the tool they used to remove the fixed BB cup on my Lenton - and curb service.

 

[bikewhorder]

Maybe I'm a hack mechanic but on an old steel bike like that I just grab the derailleur and bend it back till it looks right. If you want to "Do it right" remove the derailleur and put a big adjustable wrench on the hanger and bend it back. Make sure the rear wheel is on and clamped down tight before trying to bend anything obviously.

 

[AndyA]

I'm in the Hack Mechanic Club with Bikewhorder. So is Al Carell, author of "The Super Handyman's Big Bike Book." Carell says this about adjusting derailleurs: "Turn the pedals and look to be sure the jockey wheel is tracking in the center of the chain. If not, this could be caused by either the mounting bracket or the derailleur cage being bent. Either one can be bent back in place, but be gentle. The best method is to use a pair of pliers and slowly straighten the guilty party. Usually, a slight twist is all you need."

Nothing against more advanced methods and tools, but we Hack Mechanics have a proud history to defend.

 

[Janzep]

Are the same parts going back on the bike? If so, do you know how well it worked before? My first thought would be to straighten it out, just on general principles. And while you have the bike stripped down, take a few minutes to check and adjust the frame alignment-scroll down to the picture with the string:

Bicycle Frame/Hub Spacing

A bicycle frame and fork should match the wheels that are to be used in it. Older bicycles used narrower spacing, but older frames can often be spread out to match more modern wheels.

sheldonbrown.com

It can make a huge difference.

Yes I intend to put the SunTour RD back on. I was able to shift through all cogs before dismantling the bike. That’s why I’m wondering if the hanger was sold in that bent position. Intuitively I feel it should be flat.