noglider 

Even more useful than a dork disc is a derailleur guard. (We need a pejorative term for this, too. Any suggestions?) This thing really is useful, but we won't use them because they come on BSOs.

3alarmer 

...how do you attach the helment to the rear cluster to prevent the chain from dropping in against the spokes ?

3alarmer 

...I have a couple of those Duopars in the box with the dork discs.

3alarmer 

...bike dropper's doohickey.

3alarmer 

...there's your answer. Live someplace flat.

cudak888 

Applies just the same to new derailers too, if we are lump everything into one basket. Some of the low-end modern crap will loosen up quickly without any help, while other "old derailers" will hold their position for 30 years.

*cough* Suntour *cough*

There are so many good C&V derailers (to bad) in regular circulation that I tend to suspect the mechanic in these situations, if their first inclination is to blame the part on a blind assessment of age.

-Kurt

mech986 

Put one on the other side and you can call them Nerf Bars for performing Pitt maneuvers on other bikes.

As far as damaged spokes, I had a similar issue with my Campagnolo NR with Rally cage apparently causing damage to 4 drive side spikes before Eroica 2019. Luckily was caught when I brought the wheel into my LBS for bearing service and a freewheel swap - besides the damaged spokes, I had at least 6 other spokes loose. Thankfully they were replaced, retightened, and trued. I rechecked and adjusted the limit screws prior to the ride.

Shutter to think what might have happened on the Santa Rita or Cypress climb at maximal effort.

Lascauxcaveman 

I've never thought of it that way, but you're right.

I don't have dork disks on all my bikes, but I also don't take them off the ones that came with them. I rarely ride without a helmet, though, because my dorky head has hit the ground several times with significant force.

Aubergine 

Kurt, I blame the mechanic (me) too. I adjusted the derailleur when I put it on the bike, so I take responsibility. I just hoped to save other C&V spokes from the
same fate.

Aubergine 

cudak888 

You came out of it OK, that's all that matters!

In your defense, the Duopar can be quite the handful to install. Lots of bits moving about, occasionally a retaining nut on the back depending on the model, and it's easy to get distracted from the limit screws just by trying to get the thing on.

-Kurt

unterhausen

I had a wheel that had lasted over 30 years finally break a spoke because the derailleur hit the spokes. I am pretty sure in that case it was the hangar bending, that happens sometimes. I'm trying to remember what happened to the other wheel that died fairly soon after that, the hub failed on that one. There were some derailleur-related shenanigans, but I don't remember exactly what they were.

qcpmsame 

Can't believe no link to the burnt-off, plastic dork disk thread in Road Cycling, has been posted yet. Not going to take the time to search for it, but that one takes the cake for strange wrenching behavior.

Bill

ApolloSoyuz1975

Apropos of nothing: I really wish that steel/alu pie plates were still used instead of cheap plastic discs. Can we start a letter/e-mail campaign to the CPSC?

Kent T

Suntour VGT, the reliability king of Disraeli Gears. Reliable as ever was made.

unterhausen

Old plastic disks are worthless, that's true. It's pretty common for them to shatter when used, if the bike rack at work is any indication. But metal disks were always the mark of a cheap bike.

noglider 

It's common for the hanger to bend inwards, and there are often no symptoms initially. Your derailleur appears to work normally, but you have to shift farther than before. But you don't notice that. You don't remember the bike being banged in a self-closing door or laying the bike on its drive side or something else bumping against it. And it might get banged and bent several times before the derailleur goes into the spokes. You might even readjust the limit screws so it works properly, not noticing the bend in the hanger. I've worked as a shop mechanic, and I've seen this many times. Often the bike owner will swear with 100% certainty that the hanger or derailleur was never bent, but I've seen it enough to know what's really going on. This is why a derailleur guard is even usefuller than a dork disk, because it prevents the bending, and the bending is why the dork disk is necessary.

I don't use a derailleur guard or a dork disk, for purely aesthetic, vain reasons. If I ever take a long tour, I would seriously consider both or at least the derailleur guard.

I've been lucky. I have had bent derailleurs that I didn't know about, and as I was shifting it into the spokes, I felt it quickly enough and shifted back out before any damage happened. That's a combination of luck and good sensitivity to what my bike is doing.

John E

The only time I worried about shifting into the spokes was with a normal-low Cyclo bandspring rear derailleur, but that was on a bike with a hybrid transmission (wide-range Sturmey Archer 3-speed IGH with 4-speed cog block) that had no provision for a spoke protector. (On those, if your shift lever comes loose or your cable snaps, the derailleur cage heads right for the spokes.) On my few bikes that have come with spoke protectors, standard procedure is to remove the spoke protector and replace the 5-speed freewheel with a 6-speed (ultra, if necessary), or a 6-speed with a 7-speed. I do shift into the largest cog only at low speeds and only directly from the second-largest cog, so I have never had a low gear overshift issue or dropped a chain into the spokes.

Weresquatch

I bought an '70s Bianchi for my wife that was full ARx....I remember getting it all ready to upgrade it and well....never did. They were very, very reliable. My wife rode that heck out of that bike and I never had to replace a thing other than cables, tires, and tubes. It wasn't high-zoot but it worked well and was reasonably "light".

Weresquatch

Unlike old metal dork discs, these are just plain old aesthetically ugly. I won't do it to my bikes. I love them all too much to harness them with a "clutz clanger".

Kent T

That is what I refer to as a potential Widow Maker. Glad you got it sorted before Eroica. Pitt maneuver comment also quite the delight in wit.

The Golden Boy 

Duopars are awful, unreliable, fragile, quirky, require the unobtanium tabbed washer, display a stunning probability of catastrophic failures, require an unobtanium propriety upper pulley, can’t safely roll backwards, have 2 parallelograms- either one, the other or BOTH can go out of alignment because of the cheap manufacturing, even the titanium looks cheap. And Suntour self destructed trying to chase the Duopar- despite that ANY **** ty cheap, low end Suntour derailleur being better than the Duopar.

“Oh the Duopar will take a 38T cog.” Really. When have you ever used a 38T cog? When have you even WANTED to use a 38T on an old bike? A Suntour XC will do a 38T cog- with none of the potential drama. I’ve personally used Shimano M735 and MT-60 and Suntour XC Pro and XC Comp on 34T cogs. All those were world class units- SIGNIFICANTLY less expensive, significantly more durable, index compatible- and they didn’t look like a cheap stamped derailleur. Plus, even a cheap ATB derailleur would work as well. I’d like to test out a V-GT Luxe and see if that’ll do a 38.

I get that it was a miracle of modern innovation, I get that it was an obscenely expensive component that only the fancy people knew about, and I get that there are serious cyclists that have put more miles on one Duopar than I’ve ever even ridden- period...

There’s just no reason to taunt fate with all the potential catastrophic failures that the Duopar presents.

And the the same thing goes for the clowns who search out and install 1st generation Mountech rear derailleurs.

3alarmer 

...don't hold back. You're among friends here, let it all out.

noglider 

Yes, they're immensely ugly. I've never used one, because (1) they're immensely ugly, (2) my bike has no provisioning bolt holes for them, and (3) I associate them with BSOs. But look what we're doing. We are balancing aesthetics against practicality. If we were sensible, we would use them. And if everyone used them, we would not consider them ugly, especially if they had been on bikes ever since derailleurs came out.

And thanks for the pejorative term. That's a good one.

bikemig 

I rode across the country on my 1983 Trek 720 and a duopar derailleur. It handled all the shifts really well. It does need to be eased into the shift a little more than is the case with the other derailleurs I've used. It could well be somewhat more prone to being mangled. That said it was a good derailleur that can handle a lot of chain. I'd take a suntour over a duopar but it's not quite as bad as all that.