|Pulley cage rubbibg against spokes||superdog|
Mar 1, 2003 1:33 PM
|Just got my new wheels from Colorado Cyclist. They are Mavic Open Pro rims/Dura-ace hubs. I had my LBS install my 11-21 cassette. When I put the wheel on my bike and shift into the lowest gear, the pulley cage hits the spokes. My old wheels are Rolf Vector Pros and the spokes have a little more clearance.
I don't think the rear derailleur is out of adjustment because it still shifts flawlessly. Any idea how I can solve this problem?
|re: Pulley cage rubbibg against spokes||Rusty Coggs|
Mar 1, 2003 1:43 PM
|Being as I have no problem with OP/ultegras in any application,I would suspect the deralier or hanger.Orhave the wheel dish checked.|
|re: Pulley cage rubbibg against spokes||ibhim|
Mar 1, 2003 2:15 PM
|CAUTION: Ten years ago, I destroyed a rear derailleur when caught in spokes and had to have a new dropout installed to frame as it broke where the derailleur attaches.
I now run Chorus/OP no problem. First thing I would do is check the buildout as the center of the axcel is nearer the drive side spokes. Place on trueing stand and make sure rim is centered laterally and not skewed to right nearer the cassette. Could probably tell on bike by looking at brake to rim center, but trueing stand more accurate.
If above OK, rear derailleur may need fine adjustment. Was this the the same cassette/derailleur combo prior to new wheels?
|Three possibilities (not the wheel)||Kerry|
Mar 1, 2003 4:01 PM
|There is virtually no reason for this to be a wheel problem. Most likely it can be solved by just a tweak of the upper limit screw - it will still shift fine but it will no longer ding the spokes. Second in line would be a bent derailleur hanger or a bent derailleur. You can see these problems by viewing the bike from the rear - the plane of the deraileur pulley cage must be perfectly perpendicular to the axis of the hub axle. Depending on frame material and the degree of bend, it is pretty easy to fix a derailleur hanger with a large adujustable wrench. Bent derailleurs can often be straightened bare handed, though serious misalignment is a bad sign. I bet you can just "turn the screw" and be OK.|
|it could be the wheel...||satanas|
Mar 1, 2003 6:26 PM
|...I've had this problem (slight contact under load in bottom gear) quite a bit with Dura-Ace 8 speed hubs and Open 4CDs (Open Pro predecessor) on two different bikes. I'm still using Dura-Ace 8 speed, and the rear mech could be a contributing factor. For the record the frames, derailleur hangers and derailleurs are all straight, as are the wheels.
Unfortunately, what tends to happen is that all the spokes don't lie in the same plane; for some ungodly reason, some of the them bend out towards the derailleur at the outer crossing. This isn't really amenable to being "flattened", at least without massively excessive force. Even 1mm seems to cause problems. I've had this happen with 14g plain gauge and butted spokes, as well as bladed spokes...
My experience is noise can still occur when the limit screw is wound in as far as possible. Grinding the (slightly protruding) upper pulley retaining bolt may help -- be careful!
|it could be the wheel...||12x23|
Mar 1, 2003 7:16 PM
|I had this with a pr of 8-sp D/A and Mavic Reflex clinchers a few yrs ago. The der cage would just "ping" the spokes under heavy load (like on a really steep, stand and grind, short kinda hill). It was limited to one bike, a Litespeed Classic, and the r.der. was properly adjusted and der hanger was ok .. proof being I rode those wheels until the rims developed cracks around several eyelets.
I always thought it happened on the Classic because it flexed a bit on hills, and maybe a few component and wheel build tolerances "came together."
|I checked the cage||superdog|
Mar 1, 2003 9:47 PM
|When I mount the bike in a trainer and view from behind, the pulley cage appears to be vertical. The 11-21 cassette is new. My other wheels have a 12-25.
This is unrelated but I also noticed the 3X spoke lacing. At the point where two spokes cross, they touch each other and are slightly bent. I've never noticed the bend in the spokes before.
I guess I'll end up taking it in to the shop. Better peel off the Colorade Cyclist stickers first.
|Derailuer ping on spokes...||MrDan|
Mar 2, 2003 6:44 PM
|Does this only happen while climbing ... I'll bet you
only hear it when climbing, and your right pedal is on the down stroke... frame is twistin' with the effort.
One other thing ... the 21 cog is smaller diameter than the 25, and hence now the upper portion of the cage will be closer to the vertical center of the wheel. This, combined with the angle of the spokes probably is causing the difference. Try putting the 12-25 back on, it will probably disappear. Sometimes they dont lace the rear wheels quite right with respect to over/under lacing of
the spokes... Doing it right ensures that the spokes which run from the outside edge of the hub flange are pulled as far as possible toward the center of the wheel/hub thereby giving more clearance for the derailleur cage.
I believe I read about this on sheldon browns website. He's quite the character, and knows his ~hit!
|sounds like a bent deraileur hanger to me (nm)||laffeaux|
Mar 3, 2003 4:47 PM