Today's Forum Topics
Set as homepage
|
View
New Forum Topics Today's Forum Topics Set as homepage |
 |
|
|||||||
| |
||||
Welcome to CyclingForums.com You are currently viewing our website as a guest which gives you limited access to view most discussions. You will have to register before you can post to this thread. By joining our free online community you will have access to post new topics, communicate privately with other cyclingforums.com members (PM), respond to polls, upload photos and access other special features like product reviews and classifieds. |
|
|
Thread Tools | Search this Thread | Display Modes |
24-06.-2008, 11:43 AM
|
#1 |
|
Guest
Posts: n/a
|
Is it bent?
Looking down at my big chain ring today, I noticed the chain wobbles
maybe 1/8" (as seen against the derailer) over one part of the ring as I pedal. Is this part of the STI design, or is the ring bent and I need to straighten it? Pat Email address works as is. |
|
|
24-06.-2008, 12:06 PM
|
#2 |
|
Guest
Posts: n/a
|
Re: Is it bent?
Patrick Lamb wrote:
> Looking down at my big chain ring today, I noticed the chain wobbles > maybe 1/8" (as seen against the derailer) over one part of the ring as > I pedal. Is this part of the STI design, or is the ring bent and I > need to straighten it? Shift to the other ring. Spin your crank and watch the tooth profile. Is one tooth bent? Now sight along the length of the chain as you backpedal. Do you see a damaged or errant section? That can be dangerous so if the chain itself varies attend to the before riding. -- Andrew Muzi <www.yellowjersey.org/> Open every day since 1 April, 1971 ** Posted from http://www.teranews.com ** |
|
|
|
24-06.-2008, 12:20 PM
|
#3 |
|
Guest
Posts: n/a
|
Re: Is it bent?
"A Muzi" <am@yellowjersey.org> wrote in message
news:2c8b5$4860563a$635@news.teranews.com... > Patrick Lamb wrote: >> Looking down at my big chain ring today, I noticed the chain wobbles >> maybe 1/8" (as seen against the derailer) over one part of the ring as >> I pedal. Is this part of the STI design, or is the ring bent and I >> need to straighten it? > > Shift to the other ring. Spin your crank and watch the tooth profile. Is > one tooth bent? > > Now sight along the length of the chain as you backpedal. Do you see a > damaged or errant section? That can be dangerous so if the chain itself > varies attend to the before riding. And not knowing what age your bicycle is can be a problem as well. Older bicycles with adjustable bottom brackets could get loose enough for the chainrings to wobble and all it required was proper adjustment. |
|
|
|
24-06.-2008, 05:36 PM
|
#4 |
|
Guest
Posts: n/a
|
Re: Is it bent?
On 2008-06-24, Patrick Lamb <pdl678NOSPAM@comcast.net> wrote:
> Looking down at my big chain ring today, I noticed the chain wobbles > maybe 1/8" (as seen against the derailer) over one part of the ring as > I pedal. Is this part of the STI design, or is the ring bent and I > need to straighten it? 1/8" isn't much, but also check for play in the bottom bracket because that can cause the same symptom. Just get off the bike and see if you can wobble the cranks. |
|
|
|
25-06.-2008, 11:59 AM
|
#5 |
|
Guest
Posts: n/a
|
Re: Is it bent?
On Mon, 23 Jun 2008 21:06:34 -0500, A Muzi <am@yellowjersey.org>
wrote: >Patrick Lamb wrote: >> Looking down at my big chain ring today, I noticed the chain wobbles >> maybe 1/8" (as seen against the derailer) over one part of the ring as >> I pedal. Is this part of the STI design, or is the ring bent and I >> need to straighten it? > >Shift to the other ring. Spin your crank and watch the tooth profile. >Is one tooth bent? > >Now sight along the length of the chain as you backpedal. Do you see a >damaged or errant section? That can be dangerous so if the chain itself >varies attend to the before riding. Thanks, I'll have to check it when my garage light comes up tomorrow morning. (I could fix the other one, but that would take riding time!) I didn't think about chain problems -- this one only has 500-1,000 miles on it, IIRC. Pat Email address works as is. |
|
|
|
25-06.-2008, 12:00 PM
|
#6 |
|
Guest
Posts: n/a
|
Re: Is it bent?
On Mon, 23 Jun 2008 19:20:59 -0700, "Tom Kunich" <cyclintom@yahoo.
com> wrote: >"A Muzi" <am@yellowjersey.org> wrote in message >news:2c8b5$4860563a$635@news.teranews.com... >> Patrick Lamb wrote: >>> Looking down at my big chain ring today, I noticed the chain wobbles >>> maybe 1/8" (as seen against the derailer) over one part of the ring as >>> I pedal. Is this part of the STI design, or is the ring bent and I >>> need to straighten it? >> >> Shift to the other ring. Spin your crank and watch the tooth profile. Is >> one tooth bent? >> >> Now sight along the length of the chain as you backpedal. Do you see a >> damaged or errant section? That can be dangerous so if the chain itself >> varies attend to the before riding. > >And not knowing what age your bicycle is can be a problem as well. Older >bicycles with adjustable bottom brackets could get loose enough for the >chainrings to wobble and all it required was proper adjustment. It's only a couple years old, so I doubt that's the problem. I'll check to make sure. Pat Email address works as is. |
|
|
|
25-06.-2008, 12:00 PM
|
#7 |
|
Guest
Posts: n/a
|
Re: Is it bent?
On Tue, 24 Jun 2008 02:36:08 -0500, Ben C <spamspam@spam.eggs> wrote:
>On 2008-06-24, Patrick Lamb <pdl678NOSPAM@comcast.net> wrote: >> Looking down at my big chain ring today, I noticed the chain wobbles >> maybe 1/8" (as seen against the derailer) over one part of the ring as >> I pedal. Is this part of the STI design, or is the ring bent and I >> need to straighten it? > >1/8" isn't much, but also check for play in the bottom bracket because >that can cause the same symptom. Just get off the bike and see if you can >wobble the cranks. I'll double check, but since it's quite localized, I doubt if it's the bottom bracket. Pat Email address works as is. |
|
|
|
25-06.-2008, 12:55 PM
|
#8 |
|
Guest
Posts: n/a
|
Re: Is it bent?
"Patrick Lamb" <pdl678NOSPAM@comcast.net> wrote in message
news:bk9364pc594juq8nqm9t61afn5mlqaqsef@4ax.com... > On Mon, 23 Jun 2008 19:20:59 -0700, "Tom Kunich" <cyclintom@yahoo. > com> wrote: >> >>And not knowing what age your bicycle is can be a problem as well. Older >>bicycles with adjustable bottom brackets could get loose enough for the >>chainrings to wobble and all it required was proper adjustment. > > It's only a couple years old, so I doubt that's the problem. I'll > check to make sure. Well, sealed bottom brackets could have a bad bearing in them as well. So the idea is to see if the movement follows the cranks arms because of a loose bearing, because the crank or rings are loose or because of a bent chainring. |
|
|
|
26-06.-2008, 11:49 AM
|
#9 |
|
Guest
Posts: n/a
|
Re: Is it bent?
On Tue, 24 Jun 2008 20:59:28 -0500, Patrick Lamb
<pdl678NOSPAM@comcast.net> wrote: >On Mon, 23 Jun 2008 21:06:34 -0500, A Muzi <am@yellowjersey.org> >wrote: >>Patrick Lamb wrote: >>> Looking down at my big chain ring today, I noticed the chain wobbles >>> maybe 1/8" (as seen against the derailer) over one part of the ring as >>> I pedal. Is this part of the STI design, or is the ring bent and I >>> need to straighten it? >> >>Shift to the other ring. Spin your crank and watch the tooth profile. >>Is one tooth bent? >> >>Now sight along the length of the chain as you backpedal. Do you see a >>damaged or errant section? That can be dangerous so if the chain itself >>varies attend to the before riding. > >Thanks, I'll have to check it when my garage light comes up tomorrow >morning. (I could fix the other one, but that would take riding >time!) I didn't think about chain problems -- this one only has >500-1,000 miles on it, IIRC. Responding to myself, bad form, I know. However... The chain looked pretty straight as I sighted up it. As I suspected, there's about 3" of ring that's displaced inward, by just about the width of the chainring. I'm guessing it got bent leaning up against a pole or tree at some point, or maybe the bike fell over and hit the ring on a curb. Is it worth trying to fix it? I'm sort of leaning toward leaving it as is, to make sure I don't make things worse by trying to bend it back. It's a Shimano Deore crank, and I don't know if the big ring is steel or some flavor of aluminum. Pat Email address works as is. |
|
|
|
26-06.-2008, 12:57 PM
|
#10 |
|
Guest
Posts: n/a
|
Re: Is it bent?
"Patrick Lamb" <pdl678NOSPAM@comcast.net> wrote in message
news:53t564ltd98u6f3modh0k379s0uuhian3p@4ax.com... > > Is it worth trying to fix it? You can bend it back and in some cases it's almost perfect. |
|
|
|
26-06.-2008, 03:08 PM
|
#11 |
|
Guest
Posts: n/a
|
Re: Is it bent?
On Wed, 25 Jun 2008 20:49:56 -0500, Patrick Lamb
<pdl678NOSPAM@comcast.net> wrote: >Is it worth trying to fix it? I'm sort of leaning toward leaving it >as is, to make sure I don't make things worse by trying to bend it >back. It's a Shimano Deore crank, and I don't know if the big ring is >steel or some flavor of aluminum. Try to determine if the ring is bent or the arm of the spider at that location is bent. If both chainwheels move in as you spin the cranks, it's the spider arm - if one moves in, it's the chainwheel. A good way to straighten the arms is to use an adjustable wrench, 8" - 10", on the spider arm itself and gently bend the spider back into shape. Spin frequently to check as you go and get a feel for it. For the chainwheels, you may need two adjustable wrenches, one on either side of the bend to lever it back out to where it belongs. If the bend is tricky, you might have to get more creative with placement and levers. They do bend easily, so work slowly. |
|
|
Linear Mode
