Serious Question about Chain Stay Damage
05-29-14, 04:52 AM
#1
Senior Member
Thread Starter
Join Date: Mar 2013
Location: Southern Ontario, Canada
Posts: 873
Bikes: Too, too many....
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 125 Post(s)
Likes: 0
Liked 130 Times
in
57 Posts
Serious Question about Chain Stay Damage
Maybe I'm missing something obvious....
I have seen a lot of older and newer 10-speed road bikes that have various amounts of cosmetic damage to the paint on the top of the right chain stay from where the chain has impacted the stay.
I'm not talking about singular impacts but evidence that the chain has hit the stay frequently enough to blast the paint off.
How does this happen ??
If the chain is pulled tight across the top part of the loop while the rider is peddling, and held tight by the derailleur spring tension while coasting... when does the chain become slack enough to impact the stay ??
Binky
I have seen a lot of older and newer 10-speed road bikes that have various amounts of cosmetic damage to the paint on the top of the right chain stay from where the chain has impacted the stay.
I'm not talking about singular impacts but evidence that the chain has hit the stay frequently enough to blast the paint off.
How does this happen ??
If the chain is pulled tight across the top part of the loop while the rider is peddling, and held tight by the derailleur spring tension while coasting... when does the chain become slack enough to impact the stay ??
Binky
05-29-14, 05:09 AM
#2
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
Chain bouncing forces > spring tension when coasting. Especially on bumpy roads.
__________________
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
Last edited by Homebrew01; 05-29-14 at 06:52 AM.
05-29-14, 06:34 AM
#3
Randomhead
Join Date: Aug 2008
Location: Happy Valley, Pennsylvania
Posts: 24,392
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked 3,693 Times
in
2,515 Posts
the problem is sticky freewheels, the chain is sitting on the chainstay when the rider stops coasting and starts pedaling
05-29-14, 08:38 AM
#4
Old fart
Join Date: Nov 2004
Location: Appleton WI
Posts: 24,782
Bikes: Several, mostly not name brands.
Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 3587 Post(s)
Liked 3,398 Times
in
1,932 Posts
Or chain drop that occurs when the front derailleur isn't properly adjusted.
05-29-14, 09:01 AM
#5
Senior Member
Join Date: Dec 2009
Location: Houston, TX
Posts: 28,682
Bikes: 1990 Romic Reynolds 531 custom build, Merlin Works CR Ti custom build, super light Workswell 066 custom build
Mentioned: 109 Post(s)
Tagged: 1 Thread(s)
Quoted: 6556 Post(s)
Likes: 0
Liked 58 Times
in
36 Posts
05-29-14, 09:21 AM
#6
Senior Member
Binky, There doesn't need to be a problem on a bike for this to happen. In my experience it happens when coasting or braking and occurs most frequently on my mountain bike.
Brad
Brad
05-29-14, 09:40 AM
#7
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,689
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: 5772 Post(s)
Liked 2,566 Times
in
1,421 Posts
Chain slap is a common "problem", especially on mountain bikes. When on smaller sprockets the chain passes above the chain stay with limited clearance. Chains a re relatively heavy and have high inertia, so when the bike hits a bump the chainstay rises and slaps the chain.
About the only way to prevent chain slap is to keep pedaling so as to keep the upper loop under high tension. However most people coast over bumps so chain slap happens.
About the only way to prevent chain slap is to keep pedaling so as to keep the upper loop under high tension. However most people coast over bumps so chain slap happens.
__________________
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.
05-29-14, 12:44 PM
#8
Senior Member
Join Date: Aug 2006
Location: Portland OR
Posts: 7,639
Bikes: 61 Bianchi Specialissima 71 Peugeot G50 7? P'geot PX10 74 Raleigh GranSport 75 P'geot UO8 78? Raleigh Team Pro 82 P'geot PSV 86 P'geot PX 91 Bridgestone MB0 92 B'stone XO1 97 Rans VRex 92 Cannondale R1000 94 B'stone MB5 97 Vitus 997
Mentioned: 146 Post(s)
Tagged: 0 Thread(s)
Quoted: 392 Post(s)
Likes: 0
Liked 49 Times
in
31 Posts
Common and unattractive, but immaterial and easy enough to cover up with a chainstay protector decal.
05-29-14, 09:12 PM
#9
Senior Member
Thread Starter
Join Date: Mar 2013
Location: Southern Ontario, Canada
Posts: 873
Bikes: Too, too many....
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 125 Post(s)
Likes: 0
Liked 130 Times
in
57 Posts
What put me in mind of it was a perusal of a Aquila Strada Max from the early 1990s that my wife dragged home from a garage sale last weekend: It was filthy and had been hanging like Nosferatu for over a decade and the chain stay under the chain was perfect. Not even a flea bite.
Bink
05-30-14, 04:34 AM
#10
Senior Member
Bink, Going by brake track wear, that's a low mileage Aquila. Nice find by your wife!
I've on occasion found evidence of chain slap (lube on the chain stay protector) during a post ride check and can't remember any significant bumps. This may even happen when the bike is strapped onto the car rack?
Brad
PS The wide 3M vinyl electrical tape makes for a decent chain stay protector.
I've on occasion found evidence of chain slap (lube on the chain stay protector) during a post ride check and can't remember any significant bumps. This may even happen when the bike is strapped onto the car rack?
Brad
PS The wide 3M vinyl electrical tape makes for a decent chain stay protector.
05-30-14, 07:08 AM
#11
30 YR Wrench
Join Date: Aug 2005
Location: Oxford, OH
Posts: 2,006
Bikes: Waterford R-33, Madone 6.5, Trek 520
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 3 Times
in
2 Posts
Think about it: one good hard bump while coasting and you can wind up with a dozen or so marks in the chainstay paint from the bottoms of the links. Hardly a derailleur bike of any kind comes in without these marks. No big deal. There are myriad devices sold to prevent the damage.
05-30-14, 08:12 AM
#12
Senior Member
Join Date: Aug 2005
Location: Pittsburgh, PA
Posts: 33,656
Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!
Mentioned: 39 Post(s)
Tagged: 0 Thread(s)
Quoted: 2026 Post(s)
Likes: 0
Liked 1,096 Times
in
742 Posts
The problem is common enough that many bikes come with a clear plastic cover on the drive side chainstay to protect the paint and there are aftermarket protectors also available. As noted, well ridden bikes, even road bikes, with no signs of chainstay scratches are rare.
05-30-14, 11:01 AM
#13
Banned
That black sticker piece on top of the chainstay is there to Do that, To be more chip resistant than the Paint.
maybe the size of it is Not big enough for your desires , if so you can go find a bigger one ..
maybe the size of it is Not big enough for your desires , if so you can go find a bigger one ..
Thread
Thread Starter
Forum
Replies
Last Post
tahoeeddie
Road Cycling
24
05-08-13 04:00 PM
frantik
Bicycle Mechanics
33
10-12-11 10:33 PM
