Originally Posted by
Duragrouch
Yes, spindle designed for 68 or 70mm, used on 68, should give you at least 2mm to play with.
For my 2X conversion (from 1X), I'm a retrogrouch in wanting a 5 arm spider, symmetrical, not proprietary BCD. I found a generic hollow spindle road crank, 5x110mm BCD in 50/34, so could easily go larger on the big ring, 5x110mm BCD was a common touring bike crank, often with a 5x74mm BCD inner pattern for the low ring on a triple. Mine looks like this:
Was dirt cheap, $60 for crank with rings and external BB bearings, 3 years ago on amazon. I've been tickled with it. Also available with aluminum rings only a few bucks more; Mine was advertised as aluminum, came with steel rings, I told seller as much, they mailed me aluminum rings, just took a month from China.
Thanks a lot for the tip, I see that Prowheel has a lot of road cranksets with a Q factor greater than 150 (I found 158, 162, etc.). They even indicate the I-factor, which is the internal distance between the crank arms, which is absolutely crucial information for my purposes.