andrewchng

Hi, I'm riding a 9speeed diamondback. I've put some upgrades to it and I've found that my chain jumps quite abit when in certain gear configurations.
Here's my gears:

FrontD - DeoreLX M580
RearD - DeoreLX M580 GS
Cassette - 11-32t 9spd
Crankset - DeoreLX HollowTech M572 44t/32t/22t
Chain - SRAM PC-49

I've heard that maybe my chain is too long, but I've also heard that it maybe too short for some other mechanics. Tuning it don't seem to help.
So which is it?
Or this isn't the problem at all.
Please help...

Raiyn

What combinations is it jumping in? If it's the big chainring / big rear cog or the small/ small combos that's called "crosschaining" and should be avoided
Crosschaining places undo stress on both chain and cogs as they are simply not designed to cope with force being applied at an angle as severe as big/big or small/small
As for the sizing issue see this: https://www.parktool.com/repair/readhowto.asp?id=26

andrewchng

Ok.. I've noted down some of the problems.
I've labelled the gears to their numbers. The higher the number, the bigger the gear used.
The combinations that gave me problems are:

1) Front (3), Rear (8, 9) -- jumps
2) Front (2), Rear (1) -- chain burshed against front D
3) Front (2), Rear (2) -- slow in changing to (2), (2)
4) Front (1), Rear (8) -- chain burshed against front D
5) Front (1), Rear (3) -- chain burshed against front D

any solutions?

Curtis_Elwood

There was this great article I read last week about the proper shift pattern. I wish I could find it. Here's the gist. There is overlap between rear cog/middle ring ratios. You shouldn't be shifting the RD up through all 9 gears before moving into the middle ring. You should only go up to 3-4 in the rear before moving into the middle ring. Once you've gotten up to about 7 in the rear, then you can move into the big ring up front. With this technique, you may have to do a double shift; shifting down in the rear while moving up in the front. A rough rule of thumb that I use is that 3 gears on the rear is equal to 1 in the front. This technique keeps you from experiencing the condition that Raiyn described above. This should remedy conditions 1-4. Not sure about number 5. May be a FD adjustment? I can't get my visual aide to format correctly, but here's a pattern. I hope this helps.

Front Rear
small 1,2,3,4
middle 3,4,5,6,7
large 6,7,8,9