mmcc73

If you look at the photo below, you may not be surprised to learn that the derailleur cage rubs against the spokes when it is on the largest cog.

From what I've read, it sounds like the way to fix this situation, in general, is to bend the hanger. Is that the right approach here? It is a Suntour GT in case that matters at all.

davester

Usually it is the hanger that is bent, not the derailleur, so yes, removing the derailleur and bending the hanger is generally the correct remedy. Park even makes a special $80 alignment tool that threads into the hanger and helps you get the hanger perfectly aligned. Every bike shop worth its salt will have that tool. Either pay the mechanic to straighten it for you (should be a minimum charge) or go it alone with a big crescent wrench and eyeball it. For 5-speed friction shifting like you have it doesn't have to be perfect.

T-Mar

In this case, the the mounting claw is not parallel to the cogs. It's hard to tell if the bend is completely in the claw but it appears to be the major contributor. The claw can be removed from the derailleur to be straightened. Once re-assembled, that will tell you if there is additional bend to look for elsewhere A lot of cyclists would just grab the derailleur and bend it back into position, which may fix the issue but still cause problems if installed on another bicycle, as you're not necessarily addressing the root cause.

ridelikeaturtle

If you don't want to fix it "properly" with an alignment tool directly on the rear derailleur mount, you could bodge it by using the correct sized allen key in the rear derailleur mounting bolt and *carefully* torque it (bend it) so it effectively straightens the rear derailleur hanger and the whole assembly lines up more correctly. There's probably a YouTube video...

mmcc73

By the claw, do you mean the bit that is clamped between the quick release skewer nut and the dropout?

I think I will give straightening it a go myself. It actually runs pretty well now (except in the largest cog of course) - it can only get better

noobinsf 

Yes, that's the hanger claw. But recall Astronaut Chris Hadfield -- "There is no problem so bad you can't make it worse."

ryansu

Or you can buy a whole new vintage looking RD from Amazon for about $10 or get one from a bike co-op

dweenk

Just remove the wheel and chain, and then fix the claw or buy a new one. What @T-Mar said about everything else. A dropout with no integrated hanger is not too hard to align - if it needs aligning at all. I may have a Suntour hanger in my stash if you need one.

gugie 

A tip I picked up from @Andy_K:

Most rear QR hubs are M10 x 1mm pitch.
Most derailleur hangers are the same thread.

Remove QR, thread in your wheel, carefully bend. It's easy to see if the rear wheel on your bike is parallel with the "tool" wheel.

davester

Those Sunraces are much crappier derailleurs than the one he's got. Also, why buy a derailleur when it's just the hanger that's bent?

mmcc73

As someone who appreciates a good bodge, I gave this a go. it actually worked... it takes a large enough allen key (6mm I think), and the allen fits tightly enough that I was able to get it straightened out adequately without having to remove anything.

3speedslow

It’s the American way!

cudak888 

If you're not confident bending the hanger back, just replace the existing one: https://www.ebay.com/itm/Sunrace-Der...wAAOSw8Dxc3sNB

-Kurt

Aubergine 

I am a fan of using a Crescent wrench to straighten hangers. I have been pretty successful with indexed derailleur hangers as well, although the Park tool is definitely a better choice for that.

Prowler 

Keep in mind that the hanger or claw needs to be parallel to the wheel, all the way around. Best to start with a nicely true wheel. Otherwise always check at the valve stem. Check it both top to bottom and back to front. You can check more spots but diminishing returns. I find that getting it to within 1/8"at the rim, back to front and top to bottom is sufficient. Yes, less fussy with friction shifting but is very nice when friction shifting is so smooth and predictable.

I find that around half of the bikes that come into the shop have bent hangers, even right out of the box. Some top to bottom, some back to front, some both. All my own bikes get checked and adjusted.

ridelikeaturtle

I agree on the frequency of bent hangers, it made me go buy the proper Park alignment tool. Expensive, but I've gotten great mileage out of it. If you have multiple bikes and/or like to tune & build up your own, it's very useful to have on hand.

davester

Just be aware that replacing the hanger may not fix the problem because sometimes its the dropout that's bent.

The Golden Boy 

I resemble that remark.

cudak888 

Very true. This often shows up combined with a sticking or loose rear wheel if it's been bent long enough - the dropout tends to bend the axle along with it.

OP's pic most definitely shows a bent hanger though. I'm giving the dropout the benefit of the doubt. The stamped Raleigh dropouts tend to get chewed down by the axle cone nuts - if the dropout is bent. I don't see that here.

-Kurt