Another chain drop thread?

mbruno

Well-Known Member
Team MTBNJ Halter's
I'm running a Sram Red Etap 11s drivetrain on my VD Hellafaster. 52-36 rings and 11x28 cassette. When in the big ring, and say... 22, 25, 28t cog, the drivetrain is very noisy. I know, I know, this is cross chaining, a nearly mortal sin. Sometimes, the chain will drop off the inside of the 52 ring when I'm in the 52-28. The FD isn't contacting the chain in this configuration, so it seems like a chainline issue. Interestingly, I upgraded from Force 11s mech drivetrain and really didn't have the same issue. Thoughts?
 

Patrick

Overthinking the draft from the basement already
Staff member
Just my $.02 -

try to stay in the middle of the cassette.

(ok, here it comes, Pat is going to do math again.)

There is a loss of power when cross chaining because of the chain angle.
Not only from the mechanic friction, but the power is transferred at the cosine of the angle.
i'm thinking big-big is about 15 degrees, so 3.5% loss. might be on both sides,
so 7%.
(i'm guessing here too - but i think it makes sense.;))

DI2 can be tuned to each cog? tune it up to make less noise?
 

mbruno

Well-Known Member
Team MTBNJ Halter's
Just my $.02 -

try to stay in the middle of the cassette.

(ok, here it comes, Pat is going to do math again.)

There is a loss of power when cross chaining because of the chain angle.
Not only from the mechanic friction, but the power is transferred at the cosine of the angle.
i'm thinking big-big is about 15 degrees, so 3.5% loss. might be on both sides,
so 7%.
(i'm guessing here too - but i think it makes sense.;))

DI2 can be tuned to each cog? tune it up to make less noise?
cosine of the angle? I'm getting 10th grade flashbacks.
 

Pearl

THIS CHANGES EVERYTHING
i can trade u my 10 speed rival setup that doesn't do this, i'd even cover the shipping
 
Top Bottom