Shimano tolerances

Nick Ingamells said:

Does anyone have any insights into Shimano tolerances? I've just built up a MB with Alivo rear mech, Deore front, 8spd and FCMC20 front chainset. All bolted together fine, chainline correct etc. BUT getting the position of the front mech correct to allow quiet running throughout all gears has been a nightmare. Yes, I did use the stick-on guide before adding the (IG) chain but have had to resort to a noisy bottom gear to enable a quiet top! Have I missed something or are the required tolerances so tight that I'm unlikely to get it spot on! Any thoughts people? - Nick

you wont get all gears to work without noise, you shouldnt need to or want to, if you could if its 8 or 9 speed using the small c/ring and small cog at the back will cause the chain to rub on the 2nd c/ring, it doesnt work eitehr way, its not supposed to, also if you could you would be promoting wear by uusing that sortof gear combination or the reverse combination firstly because the chain is coming off the rings at an angle and chains arent really meant to be bent sideways under load. also if your using small/small combination theres less surface area and will rpobly slip in the abck if you put alot of load on nomatter how good condition the drivetrain is and also since theres less surface area its not going to be spreadin the wear.
and why since you con replicate the same ratio or close enough to it by using a different chainring and cog at the back.

Try a FD Co50 or co51. The co51 is longer and works better with larger chainrings 28/38/48. Deore is 9 speed HG.