To conclude the thread, I purchased a Shimano LX M581 rear derailleur
for the bike. Wow how modern derailleurs have improved. The
spring action is super light, the pulley cage is 2cm. longer than the
vintage Deore was,allowing for a 45t capacity, up from the 38t of the
Deore. Needless to say,
Jim, I checked the RD travel with no chain on, and it hits the 28t cog
despite the B screw all the way in, at the highest tension.
I'm not sure what value the Park Tool idea is though, as on my road
bike, the XT RD will hit the 32t cog with the chain off, but with the
chain on it's not too
I'm going to answer as if Jim might be wrong. That rarely happens,
but just in case. :)
I'm assuming there are zero lateral movement issues for this
derailleur
The thing that makes a rear derailleur run on top of your biggest cogs
is not directly a capacity issue. It's more of a max cog
The RD is nearly new. Wear isn't an issue. Maybe it's just not so
great.
The bike has just been put together, a Bombadil. The SRAM PC-850 chain
is new, 114 links, 57 inches long, plus the power link.
I used Park's formula for chain length
http://www.parktool.com/repair/readhowto.asp?id=26
With
As I said though ,pedaling normal you'd never know the pulleys were so
close, it was only when I was lubing my chain and pedaling backwards
did I notice this.
I suspect there is no harm being done, but I'll likely replace it
anyways when I can get a new one.
This is the first time I've
on 7/28/10 1:18 PM, Garth at garth...@gmail.com wrote:
The RD is nearly new. Wear isn't an issue. Maybe it's just not so
great.
(snipped)
The chain doesn't sag at all in the small/small combo.
Then, I'd add a link pair (mebbe two) and see what happens. It sounds like
it's at the edge of its
This must be if Jim is wrong day
By looking at the picture of the derailleur the upper pivot and upper
jockey pulley are in different places. Look at the picture and
imagine a shorter chain, it would rotate the cage counter-clockwise,
pulling the upper jockey pulley away from the cog.
Angus
On
on 7/28/10 6:09 PM, Angus at angusle...@sbcglobal.net wrote:
This must be if Jim is wrong day
Y'know I'm wrong _every_ day.
In fact, I strive to be wrong every day.
Somedays I do six wrong things before breakfast...
By looking at the picture of the derailleur the upper pivot and upper
