Low End Bicycle Shifting Question
#1
Senior Member
Thread Starter
Join Date: Jan 2011
Location: Pinehurst, NC, US
Posts: 1,716
Bikes: 2020 Trek Emonda SL6, 90's Vintage EL-OS Steel Bianchi with 2014 Campy Chorus Upgrade
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 452 Post(s)
Liked 162 Times
in
110 Posts
Low End Bicycle Shifting Question
I have a inexpensive (Trek 700) bike that I ride around town on occasion for errands, it is my rain bike, etc. It has a single chainring and 7sp cassette where the big cassette is this huge 34t thing. And 'behind that' (between the biggest cassette and the spokes) is this plastic thing that looks like a small plate.
This 'plastic plate' has come loose and bangs around (looks like it was held by plastic tabs which broke, I think). What is the purpose of this? Is it strictly to keep the chain from 'overshifting' into the spokes? Can I just take this thing off?
Thanks.
dave
This 'plastic plate' has come loose and bangs around (looks like it was held by plastic tabs which broke, I think). What is the purpose of this? Is it strictly to keep the chain from 'overshifting' into the spokes? Can I just take this thing off?
Thanks.
dave
#2
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,714
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 140 Post(s)
Tagged: 1 Thread(s)
Quoted: 5784 Post(s)
Liked 2,578 Times
in
1,429 Posts
The plastic pie plate is "spoke protector" aka dork disk, which just goes to show what many more experienced riders think of it. It's purpose is to protect the spokes if the chain is overshifted beyond the largest sprocket, and on many bikes, is also to keep the RD cage from snagging in the spokes. Putting the RD into the spokes is an expensive proposition, so this added measure of protection is worth the added weight or name calling.
Better bikes usually lack spoke protectors because their owners can be relied on to keep their bikes properly adjusted, and to an extent, better derailleurs hold adjustment better.
Keep in mind, that it's not only a matter of the derailleur adjustments. If the bike falls on it's right side, the hanger on which the RD can get bent inward, throwing all adjustments off in that direction, and causing an overshift next time you shift to low.
So that's why it's there, and it's your call whether you want one or not -- I'm 100% neutral, and don't use one, and don't advise against them either.
Since it's broken there are two ways to remove it. If the metal part where the plastic was affixed isn't also bent and causing problems, you can simply cut the plastic and discard it. Or you can remove it properly by removing the cassette and slipping the entire disc off, then remounting the cassette. In some cases you may need a spacer to replace the thickness of the disc, but not always.
Better bikes usually lack spoke protectors because their owners can be relied on to keep their bikes properly adjusted, and to an extent, better derailleurs hold adjustment better.
Keep in mind, that it's not only a matter of the derailleur adjustments. If the bike falls on it's right side, the hanger on which the RD can get bent inward, throwing all adjustments off in that direction, and causing an overshift next time you shift to low.
So that's why it's there, and it's your call whether you want one or not -- I'm 100% neutral, and don't use one, and don't advise against them either.
Since it's broken there are two ways to remove it. If the metal part where the plastic was affixed isn't also bent and causing problems, you can simply cut the plastic and discard it. Or you can remove it properly by removing the cassette and slipping the entire disc off, then remounting the cassette. In some cases you may need a spacer to replace the thickness of the disc, but not always.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
Last edited by FBinNY; 05-28-15 at 04:17 PM.
#3
Senior Member
Yes, you can remove it. It is a spoke protector, often derisively referred to here as a dork disk or, in the old days, pie plate.
Just make sure your derailleur's limit screw is set to prevent the derailleur cage from overshooting the large inboard cog and you're good to go. If the bike ever falls on the derailleur side or the derailleur or its hanger suffers some other trauma, be sure to check that you still cannot shift it into the spokes before you resume riding it.
Just make sure your derailleur's limit screw is set to prevent the derailleur cage from overshooting the large inboard cog and you're good to go. If the bike ever falls on the derailleur side or the derailleur or its hanger suffers some other trauma, be sure to check that you still cannot shift it into the spokes before you resume riding it.
#4
Senior Member
Thread Starter
Join Date: Jan 2011
Location: Pinehurst, NC, US
Posts: 1,716
Bikes: 2020 Trek Emonda SL6, 90's Vintage EL-OS Steel Bianchi with 2014 Campy Chorus Upgrade
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 452 Post(s)
Liked 162 Times
in
110 Posts
FB/Jim, thanks for the responses. But you do realize that I had to wait 8 MINUTES for two high quality answers. Hopefully folks will do better next time
dave
dave
#5
Senior Member
#7
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,714
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 140 Post(s)
Tagged: 1 Thread(s)
Quoted: 5784 Post(s)
Liked 2,578 Times
in
1,429 Posts
You're very lucky. Just as often you'll get two fast, quality answers that are in 100% disagreement in every detail.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
#8
Senior Member
Join Date: Feb 2014
Location: Cabot, Arkansas
Posts: 1,538
Bikes: Lynskey Twisted Helix Di2 Ti, 1987 Orbea steel single speed/fixie, Orbea Avant M30, Trek Fuel EX9.8 29, Trek Madone 5 series, Specialized Epic Carbon Comp 29er, Trek 7.1F
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
#9
Senior Member
Join Date: Sep 2010
Location: Roswell, GA
Posts: 8,319
Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta
Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 1438 Post(s)
Liked 1,092 Times
in
723 Posts
I use spoke protectors. I always keep my bikes well adjusted but they can save a lot of grief when some knucklehead knocks into your derailleur (like in a bike rack) and bends it inwards without you knowing it or you pick up a stick on the trail.
I use chain catchers in front, too. Digging a greasy chain out of the works can spoil a pleasant ride.
I use chain catchers in front, too. Digging a greasy chain out of the works can spoil a pleasant ride.
#10
Senior Member
Thread Starter
Join Date: Jan 2011
Location: Pinehurst, NC, US
Posts: 1,716
Bikes: 2020 Trek Emonda SL6, 90's Vintage EL-OS Steel Bianchi with 2014 Campy Chorus Upgrade
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 452 Post(s)
Liked 162 Times
in
110 Posts
dave
#11
Senior Member
Join Date: Mar 2015
Location: Ohio
Posts: 1,040
Bikes: S-Works Tarmac, Nashbar CX, Trek 2200 trainer bike, Salsa Casseroll commuter, old school FS MTB
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 31 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
The rule Ive heard is you can take it off if you can remove it without having to break it. Basically this gets down to being able to remove a cassette, which requires two tools used only for removing and installing cassettes. The assumption is, if you own those tools you're probably trustworthy with setting your own limit screws as well.
As usual, FBinNY hit it on the head though.
As usual, FBinNY hit it on the head though.
#12
Super Moderator
Join Date: Jul 2004
Location: Ffld Cnty Connecticut
Posts: 21,843
Bikes: Old Steelies I made, Old Cannondales
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 1173 Post(s)
Liked 927 Times
in
612 Posts
If you're willing to wait 16 minutes, I can give you an answer that's half as good.
__________________
Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike.
FYI: https://www.bikeforums.net/forum-sugg...ad-please.html
Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike.
FYI: https://www.bikeforums.net/forum-sugg...ad-please.html
#13
Senior Member
Join Date: Apr 2010
Location: Forked River, NJ
Posts: 694
Bikes: 1973 Peugeot UE-8, 1985 Schwinn Voyageur, 2010 Trek 1.2, 2012 Bianchi Siempre
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Thread
Thread Starter
Forum
Replies
Last Post
BradMitch
Bicycle Mechanics
10
06-06-14 05:31 PM