Hanger/derailleur

[livpoksoc]

Not so long ago I posted that my chain went through my spokes & my lbs did a less than satisfactory repair as they didn't replace any mech parts, except the broken spokes. When I took it out the next day, the gears weren't chsnging smoothly & when I went back to the lbs, they said that something was bent, but not enough in their eyes to warrant a replacement.

Anyway, i bought another bike in my haste to get back on the road and avoid a continuous back and forth with the lbs. Now I want to repair the rest of the bike myself, being something 'bent', I assume it's hanger or derailleur or cables or a combination.

How do I know which new parts to buy?

The bike in question is a spesh secteur elite, can't recall what year but I bought it in 2010/11. Pretty sure the groupset is 105.

 

[screenman]

Invest in a rear mech alignment tool, even fitting new parts may not work without checking alignment.

In fact after using the tool you may find no parts are needed.

 

[RebornBumbler]

Take the derailleur hanger off and take a look at it - it should be obvious whether it's significantly bent.

Bear in mind that a new hanger or rear derailleur is likely to be cheaper than the tool and it's unlikely to get much use.
If it were me, I'd ask another LBS to check the alignment and then replace whatever needs replacing.

 

[screenman]

The tool does not only check the hanger, but also what the hanger mounts too. I have checked dozens of bikes since I got the tool, not one of those has not needed tweaking.

My training bike needs adjusting slightly about every 1500 miles to keep it bang on. This even though it is not dropped or even lent on.

 

[Deleted member 23692]

Agree with @screenman. An alignment tool is well worth the outlay

http://www.wiggle.co.uk/lifeline-derailleur-hanger-alignment-tool/

 

[ayceejay]

I recently asked a similar question and ended up buying both a new hanger and the tool. I realized that the hanger is like a fuse in that it is designed to be weaker than the frame or the derailleur as a protection device. Interestingly when I went to remove the old hanger I discovered that the screws attaching it to the frame were loose so I removed them put a drop of thread locker on and replaced them and this solved my problem. I was so delighted with this result I haven't used the tool yet

 

[S.Giles]

I recently needed to re-align the derailleur hanger on my bike, following an (ahem) spontaneous unplanned dismount and didn't have any specialised tools to hand. I'd read somewhere that the rear wheel itself could be used as an alignment tool by removing it from the bike and screwing the axle thread onto the hanger where the derailleur is normally attached (the derailleur having been removed from it first of course - the thread is the same on both). The actual wheel can then be used as a lever to bend the hanger straight, the alignment being judged by the 'straightness' of the wheel in comparison to the rest of the bike.

It wasn't as perfect as having the alignment tool, but worked well enough to get the derailleur straight, and the gears changing properly again. This may be worth a try if you don't want to spend £30 on the proper tool, or you happen to be in the middle-of-nowhere sometime needing to do a quick repair.

IMO, even a new hanger may need to be subtly bent into alignment, on some frames at least (my old Carrera, for instance).

Steve

 

[screenman]

You should use it, just a tad out makes a difference. It is after all part of a proper bike service.

So far I have found the only people who knock them have never used one.

 

[RebornBumbler]

I can't imagine why anyone would criticise their use - If your hanger alignment needs checking or adjusting they are the right tool for the job.
I wouldn't personally consider purchasing one, given the limited use it would likely get (though if I fall off a few more times I might reconsider)

 

[S.Giles]

I can't imagine why anyone would criticise their use

...or those beloved plastic spoke-protector disks, wheel reflectors, rear-view mirrors, crash-helmets, etc, etc.

But they do.

 

[livpoksoc]

...or those beloved plastic spoke-protector disks, wheel reflectors, rear-view mirrors, crash-helmets, etc, etc.

But they do.

The spoke protector on my spesh snapped off snd the chain went through it.

As for another lbs, this one horse town only has Basing Cycles to my knowledge & I've not been overly impressed.

 

[Tim Hall]

I recently needed to re-align the derailleur hanger on my bike, following an (ahem) spontaneous unplanned dismount and didn't have any specialised tools to hand. I'd read somewhere that the rear wheel itself could be used as an alignment tool by removing it from the bike and screwing the axle thread onto the hanger where the derailleur is normally attached (the derailleur having been removed from it first of course - the thread is the same on both). The actual wheel can then be used as a lever to bend the hanger straight, the alignment being judged by the 'straightness' of the wheel in comparison to the rest of the bike.

It wasn't as perfect as having the alignment tool, but worked well enough to get the derailleur straight, and the gears changing properly again. This may be worth a try if you don't want to spend £30 on the proper tool, or you happen to be in the middle-of-nowhere sometime needing to do a quick repair.

IMO, even a new hanger may need to be subtly bent into alignment, on some frames at least (my old Carrera, for instance).

Steve

Even better is to use a second back wheel, keeping the original one on the bike. Measure the gap between the two rims to get an indication of straightness.

 

[S.Giles]

Even better is to use a second back wheel, keeping the original one on the bike. Measure the gap between the two rims to get an indication of straightness.

I suppose that if the hanger is really bent, it would not be possible to attach the second wheel without removing the first one. Your suggestion would still be a big help with the fine-tuning process, though. When I was doing my hanger-straightening, I didn't have a second back wheel, so that option wasn't available to me. Does the front wheel have the same axle thread size? (I should know!)

Another thing that occurs to me is this. It's fine getting the hanger absolutely straight, but that's no good if the derailleur is less than perfect. Could the hanger possibly need to be adjusted so that it cancels-out any mis-alignment of the derailleur? If so, a fancy measuring tool wouldn't help. I suppose this is more of a concern for cheapskates (like me!) who don't always use premium-quality parts or maybe someone restoring an old bicycle with damaged parts.

Steve

 

[livpoksoc]

Ok so given the lbs has said sommething is bent, would it be better to replace them? Or should I get the straightening tool?

 

[slowmotion]

I have exactly the same bike. Evans Cycles have the replacement hanger for about £10. Take off the old one and go to the shop with it just to check that the replacement is the right one. I made the decision not to buy the alignment tool. There's probably a DIY solution on YouTube somewhere.