Hanger Catching Spokes

[Blue Hills]

Guess I must be one of the few who doesn’t remove the “dork” disc just in case.

Was about to start a thread on such a thing. Think I will.

Here

https://www.cyclechat.net/threads/spoke-protectors.242694/

On with this thread.

 

[DCBassman]

Has this recently, was bent mech hanger. Mo clue how it happened. Replaced hanger, all well.

 

[Ajax Bay]

[QUOTE 5449420, member: 9609"]if you and sheldon brown are correct why are so many wheels built the other way ?[/QUOTE]
@Yellow Saddle - care to have a go at answering that?
I have checked half a dozen of my 21st century wheels and they are all laced the 'wrong' way. But the 3 1970s wheels are all laced trailing spoke from the inside of the flange, crossing 'outside' the leading spoke at the derailleur cage point of impact radius.
Pasting Sheldon's take on the issue (scroll 4/5ths of the way down the linked article):
"Which Side of the Flange?
"Derailer rear wheels should be laced with the trailing spokes running up along the inside of the flange. There are three reasons for this:

1. The spokes are bent around each other at the outermost crossing. Under drive torque, especially in low gear, the trailing spokes straighten out and the leading spokes bend even more. If the wheel is laced with the trailing spokes on the outside of the flange, the crossing gets pulled outward toward the derailer cage, and in some cases will actually hit against the derailer under load.
2. If the chain should overshoot the inner sprocket due to the derailer being mis-adjusted or bent, it is likely to get more seriously jammed between the spokes and the freewheel if the spokes slant so as to wedge the chain inward under load.*
3. If the chain should overshoot the inner sprocket, it may damage and weaken the spokes it rubs against. Since the trailing spokes are more highly stressed than the leading spokes, it is better to protect them from this type of damage by keeping them inboard.

"It really doesn't matter which way you go on the left side, but if you have all the trailing spokes face inward it makes lacing the wheel a bit easier.

"Note: This is not an important issue! There is a sizable minority of good wheelbuilders who prefer to go the other way around, and good wheels can be built either way."

 

[fossyant]

The mech is toast. Get another.

 

[Yellow Saddle]

@Yellow Saddle - care to have a go at answering that?
I have checked half a dozen of my 21st century wheels and they are all laced the 'wrong' way. But the 3 1970s wheels are all laced trailing spoke from the inside of the flange, crossing 'outside' the leading spoke at the derailleur cage point of impact radius.
Pasting Sheldon's take on the issue (scroll 4/5ths of the way down the linked article):
"Which Side of the Flange?
"Derailer rear wheels should be laced with the trailing spokes running up along the inside of the flange. There are three reasons for this:

1. The spokes are bent around each other at the outermost crossing. Under drive torque, especially in low gear, the trailing spokes straighten out and the leading spokes bend even more. If the wheel is laced with the trailing spokes on the outside of the flange, the crossing gets pulled outward toward the derailer cage, and in some cases will actually hit against the derailer under load.
2. If the chain should overshoot the inner sprocket due to the derailer being mis-adjusted or bent, it is likely to get more seriously jammed between the spokes and the freewheel if the spokes slant so as to wedge the chain inward under load.*
3. If the chain should overshoot the inner sprocket, it may damage and weaken the spokes it rubs against. Since the trailing spokes are more highly stressed than the leading spokes, it is better to protect them from this type of damage by keeping them inboard.

"It really doesn't matter which way you go on the left side, but if you have all the trailing spokes face inward it makes lacing the wheel a bit easier.

"Note: This is not an important issue! There is a sizable minority of good wheelbuilders who prefer to go the other way around, and good wheels can be built either way."

@Yellow Saddle - care to have a go at answering that?

I can only guess. 1) Ignorance. 2) Don't care less 3) Low necessity.

I agree with the reasons listed in your quote but I disagree with the statement that it is not important.

The fact that RDs don't often collide with spokes doesn't mean it doesn't happen. And when it does happen, the search for the source of the problem becomes a big issue. You can imagine how a mechanic (unawares of the effect) will scratch his head when the customer reports the pinging and the evidence for touching is all there in the scuffing on the RD cage, but in the stand he just cannot replicate the problem.

It is good practice, especially since it doesn't take much to do it right.

I don't know what era that text you quote was written, but in the late 1990s and early 2000s, the touching was a problem on Campagnolo 9-speed setups, especially if the wheel had fewer than 32 spokes. Campagnolo RDs are angled differently from Shimano ones and, the clearance between flange and cassette is smaller.

If I'm building a wheel, I have no idea how that wheel will be used, by whom and how sloppy his/her RD will become in time. Even though the OPs RD is now sloppy, it would not have touched if the wheel was laced differently.

Lastly, it is critical to get the lacing right on disc brake front wheels. On the left hand side the wheelbuilder has to take special care to lace it so that the spokes trailing during braking move inwards, not outwards. On some calipers the clearance is very, very small and a spoke touching the caliper is a messy scenario. Shimano includes special instructions to indicate this lacing method, with all its front disc hubs. Srangely Shimano doesn't state why, but then, no manufacturer ever gives a reason behind the Don'ts on the instructions.

BTW, I don't agree with Sheldon on some of the statements in that quotation. He states that trailing spokes are more stressed than leading spokes, which is nonsense. In a spoke's elastic range, it doesn't matter if the tension increases or decreases cyclically. The effect is the same.

Lacing wheels incorrectly isn't the end of the world. But, doing it right is the right thing to do.

 

[DCBassman]

Really, the spoke issue is not relevant either way unless it is known whether or not everything's hanging right. If it is, go spokes.
Or, as seems likely in this case, a u/s rear mech.

 

[Ajax Bay]

in this case, a u/s rear mech.

Looks like it, but don't decry peripheral 'chat' - often more interesting than the thread subject. Are all your 3 crossed rear wheels laced the same way?

 

[Yellow Saddle]

Thank you.

 

[Yellow Saddle]

[QUOTE 5453111, member: 9609"]would this fit - it is a 7 speed 32t
[/QUOTE]

Yes.

 

[DCBassman]

Wasn't decrying it at all, it's all good stuff!
Just saying that this needs checking first, as the most likely cause of the problem. All OK? Then move on...