This is a follow-up to my recent post about Sugino cranks and the major failure with the Superieur crank.
With this Superieur crank,
the horizontal distance between the left and right cranks to the pedal mounting surface (which I'll call Q-factor from now on)
became 136.5mm, but the chainline moved too far inward,
making the front inner × rear low two sprockets practically unusable—
so I gave up on it the other day.
The Q-factor is around 148mm on Shimano's FC-7900,
and around 145mm on Sugino's OX801D,
but to use inner × low on this Superieur, desk calculations showed
it would be around 142mm, so I'd abandoned the idea.
However, I managed to make the inner × low combination usable
while getting the Q-factor to 138mm, so I went with the Superieur after all.
An even bigger advantage is that the BB rotation is extremely smooth.
Even with a sealed bearing type (Hollowtech II type) with ceramic bearings
tuned to spin crisp on the outside of the frame,
it doesn't come close to this smoothness.
The downside is that the recipe for achieving this Q-factor is limited to
almost exclusively the Suntour Superieur or Sugino Super Mighty (the reason is a secret).
The reason I have so many old Sugino cranks lying around is because of this.
With a 144mm PCD 5-arm design, the smallest cog is 42T.
It's not suited for climbing.
I use the Superieur instead of the Mighty because I think this one looks cooler—
it mimics the design of Campagnolo's Super Record.
This morning during early practice, a former Suntour employee even told me it was beautiful.
For the front derailleur, I'm using a modified Record cage from a 10-speed model with the fins filed down.
There's a caution point about this.
If the width of the inner link visible between the outer links of the chain
(dimension A in the diagram above)
is greater than
the vertical width of the filed-down cage fins (dimension B in the diagram above),
around inner × top,
the chain can lift up like this.
If you're filing down a front derailleur, please be careful.
(I won't accept any comments like "as if anyone would do that")
With the FC-7800, the chain did lift up, but with this crank
the inner chainring is positioned too far inward, so this doesn't happen.
Besides, I only ever put it in inner × top when I'm adjusting the derailleur anyway, so there's no problem.
With this Superieur crank,
the horizontal distance between the left and right cranks to the pedal mounting surface (which I'll call Q-factor from now on)
became 136.5mm, but the chainline moved too far inward,
making the front inner × rear low two sprockets practically unusable—
so I gave up on it the other day.
The Q-factor is around 148mm on Shimano's FC-7900,
and around 145mm on Sugino's OX801D,
but to use inner × low on this Superieur, desk calculations showed
it would be around 142mm, so I'd abandoned the idea.
However, I managed to make the inner × low combination usable
while getting the Q-factor to 138mm, so I went with the Superieur after all.
An even bigger advantage is that the BB rotation is extremely smooth.
Even with a sealed bearing type (Hollowtech II type) with ceramic bearings
tuned to spin crisp on the outside of the frame,
it doesn't come close to this smoothness.
The downside is that the recipe for achieving this Q-factor is limited to
almost exclusively the Suntour Superieur or Sugino Super Mighty (the reason is a secret).
The reason I have so many old Sugino cranks lying around is because of this.
With a 144mm PCD 5-arm design, the smallest cog is 42T.
It's not suited for climbing.
I use the Superieur instead of the Mighty because I think this one looks cooler—
it mimics the design of Campagnolo's Super Record.
This morning during early practice, a former Suntour employee even told me it was beautiful.
For the front derailleur, I'm using a modified Record cage from a 10-speed model with the fins filed down.
There's a caution point about this.
If the width of the inner link visible between the outer links of the chain
(dimension A in the diagram above)
is greater than
the vertical width of the filed-down cage fins (dimension B in the diagram above),
around inner × top,
the chain can lift up like this.
If you're filing down a front derailleur, please be careful.
(I won't accept any comments like "as if anyone would do that")
With the FC-7800, the chain did lift up, but with this crank
the inner chainring is positioned too far inward, so this doesn't happen.
Besides, I only ever put it in inner × top when I'm adjusting the derailleur anyway, so there's no problem.