Originally Posted by
Ron Damon
That's right. That chart shows that the Shimano SLX RD-M7000-GS RD is rated to 46T max cog while the Shimano Deore RD-M6000-GS is rated to 42T max cog, just I said earlier.
I don't know why you are still talking about SGS RD. They are longer than GS RD, too long on 20" wheels. You trying to fit a square onto a circle, fixing the facts to fit your own narrative. GS and SGS are physically and functionally different. You are beyond help.
I think there's a misunderstanding here.
The measurement I'm using is the center of the pulleys, not the pivots or tangents.
The reason why the M7000 GS and M5120 SGS say 46T max cog is because that's based on the chain wrap of a 1x. On a 2x the max cog rated is 42T, with a 10T difference in the chainrings.
The wrap only goes around slightly less than half the chainring, so the 10T jump is rounded to a reduced wrap of around 4T.
So 46 is reduced by 4 to 42 max cog.
The M6000-GS is rated at 42T for 2x and also 10T front difference. The specs don't say the 1x rating, but you found that it also works with 46T on your 1x setup.
The M4120-SGS has the same rated capacities M6000-GS on the specs.
The images of the M4120-SGS and M5120-SGS on the product site are almost identical, only with a few cosmetic changes, other than the RD Plus clutch that's not on the 4120. They both state 42T max cog for 2x. One says 46T for 1x. The other doesn't specify but it should be the same.
