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8 sp DA cranks with 9 sp components?(6 posts)

8 sp DA cranks with 9 sp components?southbayca
Nov 28, 2001 1:50 PM
Can I use older 8sp DA cranks with an upgrade to 9sp? or do I need to change the rings?

lc
re: 8 sp DA cranks with 9 sp components?scoob
Nov 28, 2001 3:18 PM
It didn't work for me, but I've heard others say they've had good results. You can't put 9 sp rings on an 8 sp crankarm because of the ring thickness difference - they mount ok but will be spaced improperly. If you look at a spider arm you can see that they're machined for a specific ring thickness.
re: 8 sp DA cranks with 9 sp components?Eric
Nov 29, 2001 8:46 AM
You can put 9spd rings on the 8spd D/A 7410 cranks. I've done it. There is NO difference in thickness with the spider. The difference is in the little ring, which is moved over towards the big ring by a millimeter or so compared to an 8spd little ring. This is done in the machining of the ring.

Shimano recommends replacing the 8spd inner ring with a 9spd ring for using 8spd cranks with 9spd drivetrain. There is a possibility of the chain getting wedged between the rings on a downshift. But only the inner rings needs to be replaced.
Yes, No (nm)KStone
Nov 28, 2001 3:24 PM
Yupgrzy
Nov 28, 2001 3:37 PM
The advice is usually that you replace the inner CR with an 9 speed version. This keeps the chain from sitting in between the CR's and sliding. it will work if you don't do anything, but just not very well.
re: 8 sp DA cranks with 9 sp components?Maxx
Nov 28, 2001 7:44 PM
2 years ago I purchased the parts to upgrade to 9 spd DA which included the STI levers, front and rear derailleur, cassette,inner chain ring, and chain. I already had 8 spd DA wheels, cranks, BB, headset, brakes and seatpost.
I am using a DA 7410 8 spd crank with a newer 39 inner chain ring and it runs as smooth as my 7700 9 spd cranks.