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That plastic cog thingy....

Old 10-13-05, 07:14 PM
  #1  
gapowermike
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That plastic cog thingy....

Just upgraded my wheelset to Bontrager Race Lites and used my old cassette. Do I need to put that plastic shield back on? Seems to be a dirt, dust, stick cover but I don't know. I left it off because it didn't go on very easily. I haven't ridden it yet but plan to in the morning.

Bike is a Trek 1000 with the stock SRAM cassette.
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Old 10-13-05, 07:36 PM
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That is a spoke protector, or as some of us call them "dork discs".

For a mountain bike, unless you are very confident of your skills as a bike mechanic, and are thus sure that your chain isn't going to go over the largest cog and into your spokes, then I would leave it on.

However, since this is a roadie, might as well leave it off. Just be sure that your upper limit stop is correctly set. I lost a hub on my mountain bike when this happened.
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Old 10-14-05, 01:56 AM
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Dork disc, I like that. They do save a lot of trouble for MTB, but on the road, forget about it.
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Old 10-14-05, 06:32 AM
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If your low-limit setting is adjusted correctly on your rear derailleur, you don't need it at all.
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Old 10-14-05, 06:48 AM
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Excellent, thanks for the help. I'm upgrading the RD & cassette to ultegra sometime in the next two weeks and I'll be sure that the stop is set correctly. I knew I could count on you guys.

I just got back from a 17 mile ride with it off so I'm glad it's o.k. On a side note, I'm in south Georgia and we don't have a hill large enough to use the big cog on anyway.
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Old 10-14-05, 11:38 PM
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Originally Posted by duckliondog
Dork disc, I like that. They do save a lot of trouble for MTB, but on the road, forget about it.
The plastic ones cause more trouble than they prevent. They have a nasty habit of shattering and dropping pieces on the trail.
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Old 10-15-05, 02:17 PM
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"The plastic ones cause more trouble than they prevent. They have a nasty habit of shattering and dropping pieces on the trail."

..or coming loose and rubbing/sticking against the freewheel/cassette, like mine once did and for the rest of the ride I had a fixed wheel
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Old 10-15-05, 06:20 PM
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Originally Posted by shane45
If your low-limit setting is adjusted correctly on your rear derailleur, you don't need it at all.
But if it's not and the chain drops between the large cog and the spokes, you may be respoking your rear wheel and buying a new derailleur.
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Old 10-15-05, 06:47 PM
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"The plastic ones cause more trouble than they prevent. They have a nasty habit of shattering and dropping pieces on the trail."

Raiyn, what do you suggest then? I dont care what people think, I just want to prevent my wheel from shredding if I loose my chain. I have an XT/rhynolite 36h and the LBS's don't seem to understand why I want one or have one that fits the XT hub.
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Old 10-15-05, 07:22 PM
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Originally Posted by supcom
But if it's not and the chain drops between the large cog and the spokes, you may be respoking your rear wheel and buying a new derailleur.
That's why people should learn how to check and adjust their own derailleurs. Nothing screams "I don't know anything about bikes except how to ride them" louder than cassette spoke guards (and possibly reflectors).
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Old 10-16-05, 10:40 PM
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Nooooooooo Juuusssttt Tttaaakkkeee Iiittttt Oooooofffff!!!!!!!!!!
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Old 10-16-05, 11:13 PM
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Leave it on so it can get all dirty and yellow.



Ok... take it off.
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Old 10-17-05, 06:07 PM
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Originally Posted by gapowermike
Just upgraded my wheelset to Bontrager Race Lites and used my old cassette. Do I need to put that plastic shield back on? Seems to be a dirt, dust, stick cover but I don't know. I left it off because it didn't go on very easily. I haven't ridden it yet but plan to in the morning.
Bike is a Trek 1000 with the stock SRAM cassette.
Actually since you're asking a question about the 'plastic thingy', I'd say leave it on. The folks who are embarassed by it, know exactly what it does and how to make up for it's absence by playing with the limit screws. On the other hand not knowing your rear derailleur as well, mtb or road bike you may as well leave it on and enjoy the ride...
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Old 10-17-05, 06:26 PM
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Originally Posted by rufvelo
Actually since you're asking a question about the 'plastic thingy', I'd say leave it on. The folks who are embarassed by it, know exactly what it does and how to make up for it's absence by playing with the limit screws. On the other hand not knowing your rear derailleur as well, mtb or road bike you may as well leave it on and enjoy the ride...
This advice to leave the dork disc on is BAD. It is more than an issue of fashion. I have had no less that TWO of these stupid "guards" break on two different bikes in les than 2 years. Each time it happened far from home and made for a LONG ride. It causes the freewheel to no longer work and so every time you stop pedaling the chain wants to gather up and fall off.

TElling people to leave them of mountain bikes is horrible advice. Both instances were on mountain bikes for me and I don't even ride hard. I don't trail ride, do jumps or any of that stuff. I just go out on the country roads and ride, and the spoke protectors simply broke unexpecedly.
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Old 10-18-05, 09:44 AM
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I don't think there is a good right answer on this one. I think that the people who have had them break, especially more than once, have been very unlucky, and their experience, while real and painful, may not be representative of what you can expect. It's kind of a matter of statistics. What's more likely to fail, a person, or the equipment? Anyone who argues that a person fails less often than equipment is a fool, a liar, or naive (or all three). Human failure is sometimes as simple as distraction. The best in every field fail at something from time to time, almost always more often than their equipment fails. Remember NASA's martian lander that crashed instead of landing? Someone forgot to convert feet to kilometers. Planes crash and people die all the time due to human error, probably orders of magnitude more often than due to equipment failure. I too felt that this silly little disk looked foolish, and that my skills and attention to detail were "reliable." Well, I have some pretty bad looking spokes to prove me wrong. "Somehow" my chain overshot the top cog and stuck between it and the spokes - ouch! Lukily, no spokes were sheared in the episode.

I'd say that over time, just about everyone's chances of screwing up a derailleur adjustment, or any other circumstance that will cause a repeat of my (or a similar) experience far exceeds the chance of one of these items breaking. Also keep in mind that attention to vanity will always increase your chance of screwing up (just one guy's opinion).
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Old 10-18-05, 10:00 AM
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Originally Posted by ridesoldtrek
I don't think there is a good right answer on this one.
I think there is.

Learn to adjust your derailleur, and get rid of the disc. UV rays WILL deteriorate the thin plastic disc, and they become prone to warpage and very brittle over a surprisingly short period of time.
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Old 10-18-05, 10:15 AM
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Originally Posted by Ranger
...TElling people to leave them of mountain bikes is horrible advice. Both instances were on mountain bikes for me and I don't even ride hard. I don't trail ride, do jumps or any of that stuff. ..
I disagree. He's obviously not as sophisticted as you are and the plastic disc is there for just such a person. You may have had a bad experience, but for the overall majority of new bike owners, the disc does the job, hence placed there by the manufacturer.

I don't use/like the disc, but I can't assume that everyone can adjust their gears and build a wheel from scratch either.
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Old 10-18-05, 12:22 PM
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Originally Posted by rufvelo
I disagree. He's obviously not as sophisticted as you are and the plastic disc is there for just such a person. You may have had a bad experience, but for the overall majority of new bike owners, the disc does the job, hence placed there by the manufacturer.

I don't use/like the disc, but I can't assume that everyone can adjust their gears and build a wheel from scratch either.
Exactly. I don't use one either, but I ride with a guy that really needs one. He took it off because he thought it looked dumb. A week later we were riding together. I looked down at his wheel and saw that he had three broken spokes. On closer inspection, several more were getting ready to go, having been sawn partway through by his frequently thrown chain.
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Old 10-18-05, 12:40 PM
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Some people really need these things because they don't pay attention to anything. It's not always being stupid - some people are just not very mechanically competent. I've been riding derailleur bicycles for almost 35 years, and have had one of these protector things for maybe the first of those 35. I only remember one incident (on one of my bikes) of having the chain go over the top (not to say there isn't another one lurking in the mists of time). I'm not a professional bike mechanic, but I do (and design) all sorts of sophisticated mechanical stuff, and pay alot of attention to fine details. The spokes I messed up are on a set of wheels I built.

My point is that people make mistakes. The most arrogant folks out there actually make as many or more than the rest of us, they just would never admit it. You can tell just by listening to them.

If you want to avoid the breakage factor, get a steel one and cut it down to size. How's that for crummy (not the word I wanted to use) looking?
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Old 10-18-05, 01:41 PM
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Like this one...

http://www.bikepartsusa.com/product_...tml?p=01-94646
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Old 10-18-05, 02:07 PM
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That's actually one of the nicer specimens I have seen. Don't know if it would really do the job cut down.
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Old 10-18-05, 03:35 PM
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Originally Posted by rufvelo
I disagree. He's obviously not as sophisticted as you are and the plastic disc is there for just such a person. You may have had a bad experience, but for the overall majority of new bike owners, the disc does the job, hence placed there by the manufacturer.

I don't use/like the disc, but I can't assume that everyone can adjust their gears and build a wheel from scratch either.
I'm far from sophisticated. Just reporting that i ONLY have TWO mounatain bikes. And each bike had a dork disk break on me and ruin to different rides. In fact out of the 12,000 plus miles i have logged on my mountain bikes in the last 25 months, the dork disk is really the only mechanical trouble i have had short of one crash with a bent derailleur hanger and several flats.

YMMV, but the spoke protector is a very weak link on a bicycle. Ride long enough, and you'll find out why. I agree that a complete moron probably needs one to keep from throwing his chain into the spokes. With that said, a complete moron like that probably shouldn't even be on the bike to start with.
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Old 10-18-05, 08:44 PM
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Ranger, I sure wouldn't argue with your experience. Whether it is common or you were just very unlucky, well, I can't say. Just goes to show you, there's always something new to learn.

Hey, here's an idea: make one of these "dork disks" to look like titanium, stamp "Campagnolo" and a facsimile of their logo on it, and you'll have people fighting for the chance to bid one up over $100 on ebay!
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Old 10-18-05, 08:54 PM
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I bought a new bike this summer and it has the spoke protector still on it. I am a good bike mechanic and I could remove it now if I felt the need to do so. If someone thinks I'm a dork because of the disc, it does not bother me. I'll keep it there until I have to work on the hub or replace the cassette, no big deal.
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Old 10-18-05, 11:30 PM
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Originally Posted by PoorBehavior
Raiyn, what do you suggest then? I dont care what people think, I just want to prevent my wheel from shredding if I loose my chain. I have an XT/rhynolite 36h and the LBS's don't seem to understand why I want one or have one that fits the XT hub.
Learn to properly adjust your derailieur for a start. You won't lose a chain "up and over" if things are set properly Offroad there's more things that can happen to bust a spoke or a derailieur such as foriegn objects or a crash. Neither of which will be prevented by a spoke guard. However if you MUST get a dork disc get one of these and please keep it from rusting.
Originally Posted by ridesoldtrek
I'd say that over time, just about everyone's chances of screwing up a derailleur adjustment, or any other circumstance that will cause a repeat of my (or a similar) experience far exceeds the chance of one of these items breaking. Also keep in mind that attention to vanity will always increase your chance of screwing up (just one guy's opinion).
An old yellow spoke protector will protect two things Jack and **** and needless to say Jack doesn't care. Your limit screws are STILL your best friends
Originally Posted by shane45
I think there is.

Learn to adjust your derailleur, and get rid of the disc. UV rays WILL deteriorate the thin plastic disc, and they become prone to warpage and very brittle over a surprisingly short period of time.
Preach on Brother Shane
Originally Posted by urban_assault
I bought a new bike this summer and it has the spoke protector still on it. I am a good bike mechanic and I could remove it now if I felt the need to do so. If someone thinks I'm a dork because of the disc, it does not bother me. I'll keep it there until I have to work on the hub or replace the cassette, no big deal.
I'm good with that. I left mine on about that long
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