Bicycle TutorBicycle Tutor

Show off your bike!

Related video tutorials:
Dura Ace CN-7801 stretch
Just installed new Dura Ace chain and noticed when cutting to length
it is just as stretched as old chain. Opened other 2nd box of chain and
found same thing.
Have used this chain for years and it always came tight and waxed,
now Dura Ace CN-7801 is loose and oily.
Checked with 2 chain gauges and found same thing, 75% stretch.
Does anyone have any word from Shimano on this?
Is this part of the switch to CN-7900?

10 speed chains have more side to side play than older chains might have. I think that is what you are seeing. "Stretch" usually refers to the length of the chain getting slightly longer. You can measure this by putting a ruler up against the chain. It should be exactly 12" between pins. If it is over 12 1/8", you need a new chain. I'm not sure what you mean when you say "75% stretch".
Side to side play on a worn chain will get looser, but that, in and of itself, is not an indication that the chain needs to be replaced.
I don't know that any chains came waxed, but they may have used a thicker grease in the past.

Actually the Dura Ace chains came with a wax up to about 8 months ago.
And yes I know what stretch is, the simplest way to check it is with a good
gauge and most of them are calibrated in percent of wear. 100% would be
the time to replace.
The looseness of these new CN 7801's is either a manufacturing error or
for some reason intentional by Shimano. I believe it is an error at the factory.
I'm checking with a Shimano rep to find out more.

I didn't know Dura Ace came waxed. Neat. Sounds like you know what you're talking about. I haven't heard of many manufacturing errors by Shimano, but they should know the answer. Update us...


Possibly Related Threads...
Thread Author Replies Views Last Post
  New Crank Arms for Dura Ace Compact double? troutcreek 4 6,444 06-27-2013, 04:43 AM
Last Post: troutcreek
  New Dura Ace chain broken j beede 11 20,070 03-23-2011, 03:00 PM
Last Post: dave_sd
  Measuring Chain stretch drtolson 1 5,813 09-14-2009, 09:05 PM
Last Post: DaveM
  Dura Ace RD7900 with 11-28T (7900) THITA 1 6,346 06-28-2009, 06:52 PM
Last Post: cyclerUK
  Dura Ace 12-27 on MTB wheels velogirl 1 5,831 04-08-2009, 12:34 AM
Last Post: DaveM

Forum Jump:

ISSN 1918-3445 © Copyright 2007-2010 Bicycle Tutor / Privacy Policy / Created by Alex Ramon