Originally Posted by
verktyg
@
plonz It would help to know the make and model of the cranks in question plus the BB shell width. Some pictures would be even better.
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6. The small chainring should clear the chain stay by at 5mm, If it doesn't or if it sticks out too far, you have to use a different spindle or BB.
Q-Factor like chain line is another throw back affectation... Q-Factor is a one size fits all fit fascist fantasy...
Chainline was a Brit obsession when they used SS and internal hub gears with stiff 1/8" chains. In mid 70's 3/32" bushingless chains became the standard. They have a lot of lateral flexibility so chainline is much less of a concern.
Wow that is some great information. I especially like your comments on
#6 . If I read this correct, as long as the chainring clears the stay by 5mm and doesn't extend past the derailleur movement, there is a bit of wiggle room in chainring and Q-factor allowances.
My current conundrum is with a late(er) model SR Suntour Superbe crankset that I picked up from forum member @
guygadois. He pointed me in the direction of a Shimano UN55 but does not know the spindle length. I have also emailed SR Suntour and will try calling them as well. In the meantime I was asking to see if there was a way for me to just figure this out on my own. I do have a couple of spare BBs so I can assemble one and start measuring from there.
Here is the sellers pic of the item. They look a lot like vintage Superbe cranks but I'm not assuming same dimensions. Frame shell width is 68mm. Thanks for the help!
