20 years ago I've bought a second hand bike with XT components: ST-M739, FC-M739, FD-M739, RD-M739. I have no idea what chain and cassette was installed on the bike at that time. Since then I was facing shifting problems on rear derailleur. The chain was randomly dropped from 5th to 6th cog when putting more force on pedals. The bike has been tuned in several specialized shops without success. The bike made less than 5k km.
After 10 years of resting I've revived the bike by myself.
I've bought a new 8s cassette CS-HG51 and have also tried with some similar ones. If the rear derailleur was aligned on 8th cog then the chain was rubbing in 2nd and 3rd cog and randomly dropped from 1st to 2nd cog. So I've aligned the rear derailleur to 4th cog but the chain was still rubbing on 1st and 8th cog. I've also replaced a current RD with Alivio 8s RD but no improvements. H & T limit screws were set properly. I've also replaced an old chain with a regular 8s chain (HG-71) but that chain was too wide for RD's cage so the chain was rubbing on the cage.
Now I have installed 9s HG53 chain which seems to be OK with that RD's cage. At this point I became suspicious about shifter. So I've replaced 8s cassette with an old 9s Shimano cassette and it woks well so far with 8s shifter, but without using 1st cog.
I have wondering if Shimano ST-M739 shifter have a different pull cable ratio than other Shimano 8s series and which 8s cassette would be compatible with that shifter?
Would RD-M739 derailleur be able to pull a chain to a cog with more than 32 teeth? (Nowadays I can get a cassette with 36T or 42T on 1st cog so why not
)
Thanks in advance, M.
After 10 years of resting I've revived the bike by myself.
I've bought a new 8s cassette CS-HG51 and have also tried with some similar ones. If the rear derailleur was aligned on 8th cog then the chain was rubbing in 2nd and 3rd cog and randomly dropped from 1st to 2nd cog. So I've aligned the rear derailleur to 4th cog but the chain was still rubbing on 1st and 8th cog. I've also replaced a current RD with Alivio 8s RD but no improvements. H & T limit screws were set properly. I've also replaced an old chain with a regular 8s chain (HG-71) but that chain was too wide for RD's cage so the chain was rubbing on the cage.
Now I have installed 9s HG53 chain which seems to be OK with that RD's cage. At this point I became suspicious about shifter. So I've replaced 8s cassette with an old 9s Shimano cassette and it woks well so far with 8s shifter, but without using 1st cog.
I have wondering if Shimano ST-M739 shifter have a different pull cable ratio than other Shimano 8s series and which 8s cassette would be compatible with that shifter?
Would RD-M739 derailleur be able to pull a chain to a cog with more than 32 teeth? (Nowadays I can get a cassette with 36T or 42T on 1st cog so why not

Thanks in advance, M.