If I Buy A New Rear Mech Hanger, Does It Need Re alingnment?

[Big John]

If you're lucky enough to have a bike charity near to where you live if they're anything like the one I work for they'll either do it for a small charge OR they'll show you how the tool works and let you have a go yourself. I've done the checks myself often FOC and then only charged if anything needed doing e.g. straightening out, replacing, etc. If you haven't got that facility nearby even a LBS shouldn't charge the earth. To them it's not a time consuming job. However, you may have to wait for them to fit you in.

 

[Gunk]

Bottom line is, I need to invest in an alignment tool. Looking on Amazon, they range from £30 to £90 and they all claim to do the same thing.

Any recommendations?

I've never aligned one, just fit it and see how you get on. Cheaper option then dropping £90!

 

[slowmotion]

No need to buy an alignment tool......

[media]

]View: https://www.youtube.com/watch?v=TnwreRrorIA[/media]

 

[ChrisEyles]

I always use a rear wheel as in the video above to tweak mech hanger alignment.

Quite an easy job, don't be afraid to have a go at it, just be gentle!

 

[raleighnut]

With the cheaper bikes like mine, I can't believe for a second that the Chinese assembly plant would fart about doing an alignment check prior to shipping.

And forgive me if I am wrong, but I can't see the Halfords assembly kid doing it either just before delivery.

After watching a few videos, I fully understand the need for a well aligned rear mech but I'd have thought that a brand new hanger would have sorted that?

I'd think a factory would have a jig that checked all alignments on Steel/Aluminium frames after they'd been welded up, metal tends to distort when it has been heated.

View: https://youtu.be/icWIGDHl6sA

 

[screenman]

I've never aligned one, just fit it and see how you get on. Cheaper option then dropping £90!

Why pick the bigger price, I found one for £25 which will last a lifetime. You may never have checked yours, but I bet they are out of alignment, not that it matters to most people.

 

[Lovacott]

Why pick the bigger price, I found one for £25 which will last a lifetime. You may never have checked yours, but I bet they are out of alignment, not that it matters to most people.

I've seen them online for around £25. Not sure which one to get though?

But I am also thinking that a one metre length of inch by inch angle iron would also do the job.

A hole at one end with a used axle set at 90 degrees to the flange. Screw the other end of the axle into the hanger and then align the angle iron up parallel to the rear wheel. Then bring the angle iron up to vertical.

I've also heard that if you run the rear wheel when off the ground, a badly aligned rear mech hanger will cause a wobble in the freewheel when viewed from behind. No wobble, no problem (apparently?). I'm not sure if that theory also applies to a cassette?

 

[screenman]

I've seen them online for around £25. Not sure which one to get though?

But I am also thinking that a one metre length of inch by inch angle iron would also do the job.

A hole at one end with a used axle set at 90 degrees to the flange. Screw the other end of the axle into the hanger and then align the angle iron up parallel to the rear wheel. Then bring the angle iron up to vertical.

I've also heard that if you run the rear wheel when off the ground, a badly aligned rear mech hanger will cause a wobble in the freewheel when viewed from behind. No wobble, no problem (apparently?). I'm not sure if that theory also applies to a cassette?

I will try your last bit today, all my rear mechs are well aligned and I can see no reason not to have them so, certainly you could make your own, personally I paid £35 for mine years ago which equates to way less than I charge per hour for my labour so consider it money well spent, I have used it a lot of times on mine and my friends bikes as I said before all needed tweaking to get the change better.

 

[raleighnut]

I've seen them online for around £25. Not sure which one to get though?

But I am also thinking that a one metre length of inch by inch angle iron would also do the job.

A hole at one end with a used axle set at 90 degrees to the flange. Screw the other end of the axle into the hanger and then align the angle iron up parallel to the rear wheel. Then bring the angle iron up to vertical.

I've also heard that if you run the rear wheel when off the ground, a badly aligned rear mech hanger will cause a wobble in the freewheel when viewed from behind. No wobble, no problem (apparently?). I'm not sure if that theory also applies to a cassette?

No the axle and the frame are totally seperate systems.

 

[Lovacott]

I will try your last bit today, all my rear mechs are well aligned and I can see no reason not to have them so, certainly you could make your own, personally I paid £35 for mine years ago which equates to way less than I charge per hour for my labour so consider it money well spent, I have used it a lot of times on mine and my friends bikes as I said before all needed tweaking to get the change better.

I can understand the need for it to be 100% aligned because otherwise, the chain links would be eating away at the sides of the sprockets.

The wobble on the freewheel (apparently) indicates that the chain is entering and exiting the freewheel on an plane offset to the plane of the rear wheel. Spinning the rear wheel in a stand will cause the freewheel to appear to wobble as it is being held by the mech at a less than perfect angle. I can see a slight wobble in my freewheel which prompted me to start this thread.

 

[Lovacott]

No the axle and the frame are totally seperate systems.

I was referring to a used axle which is also threaded the same as the mech hanger mounting hole.

 

[screenman]

I can understand the need for it to be 100% aligned because otherwise, the chain links would be eating away at the sides of the sprockets.

The wobble on the freewheel (apparently) indicates that the chain is entering and exiting the freewheel on an plane offset to the plane of the rear wheel. Spinning the rear wheel in a stand will cause the freewheel to appear to wobble as it is being held by the mech at a less than perfect angle. I can see a slight wobble in my freewheel which prompted me to start this thread.

That would of course indicate you had wear in your freewheel.

 

[raleighnut]

I can understand the need for it to be 100% aligned because otherwise, the chain links would be eating away at the sides of the sprockets.

The wobble on the freewheel (apparently) indicates that the chain is entering and exiting the freewheel on an plane offset to the plane of the rear wheel. Spinning the rear wheel in a stand will cause the freewheel to appear to wobble as it is being held by the mech at a less than perfect angle. I can see a slight wobble in my freewheel which prompted me to start this thread.

If you take the chain off and spin the wheel whilst holding the freewheel stationary then it will still oscilate.

 

[Lovacott]

If you take the chain off and spin the wheel whilst holding the freewheel stationary then it will still oscilate.

I'd thought of that and it does oscillate but hardly noticeable compared to when the chain is on.

I'm pretty happy with my drivetrain and indexing but like most people on here, if there is a simple fix I can do to create perfection, I'm all up for it.

 

[Lovacott]

That would of course indicate you had wear in your freewheel.

Brand spanking new last Saturday.