A low "Q" triple!
My knees really like small Q-factors. (Chronromalacia patellae for the past 45 years. Keeping those knees happy is a matter of them or replacements.) My bikes over the years are all become either fix gears where low Q-factor is easy to do or triples. But the Q-factor on my geared bikes keeps getting worse, or at least did until I started going out of my way to reduce it. This seems to be a trend promoted by Shimano. Their influence is such that everybody else falls in line.
I set the TiCycles frame I had made 11 years ago with a Shimano Hollowtech 105 splined triple crankset. Sweet! Light, stiff. Made to go forever. And the biggest Q-factor my knees have ever seen. I started noticing my knees tended to be happier on my fix gears!
Two years ago I set my Mooney up fix gear using an old Sugino crankset as a triple using 1/8" chainrings, chain and cogs. Used an old Sugino crankset Now the inside boltholes for the 74 BCD chainring were useless as I was never going to see 1/8" rings to fit them, so I mounted the inner chainring on the normal inner double spot, the middle on the normal outer double spot and the third chaining cantilevered out close to the crank arm. (No front derailleur so all it had to do was miss the chain.) I set this up on a Shimano BB, measured accurately how far in I could move both cranks before hitting the chainstays and ordered a Phil Wood BB from the factory. (Turned out a stock symmetrical 105mm would do just fine.) Inside chainring is VERY close to the chainstay and the left crank misses by an amount I haven't seen since I raced decades ago. (My knees love it!)
This spring I re-did the Mooney as a gravel bike; back to a triple but now a 50-38-24, lowest I've ever used. Fun! Specialized old-school straight cranks (probably made by SR; similar to Sugino but the little details re different). But I went back to the fix gear after having it clearly shown to me that my gravel days are past; not something someone with what I call "loose brain syndrome" should be doing. (I made that term up but any NFL guard would know exactly what I am talking about.) So I had this sweet crankset lying around.
Well ... that sweet ti bike was falling out of favor. My knees. Also I'm aging. 53-42-28 isn't working so well, especially with the 12-23 9-speed cassette I love so much. But ... that unused triple. Put it on using a 118.5 square taper Shimano BB I had. Nice, but the cranks sat way out on both sides. A full cog too far outboard and missed the left chainstay by roughly a library book. So I measured the misses. Ordered another Phil Wood BB, 105 mm 2mm offset. It is so close it took me a bunch of tries to dial it in. I've done real damage to paint, heard the click of the left crank hitting but I finally got it. All clear. No room to spare on either side. Middle ring sits just inside the middle cog. And the Q-factor ... 139mm! So last night I measured up my 4 assembled bikes for Q-factor
TiCycles 139
Mooney as triple fix gear 135
Trek (winter/rain/city fix gear) 137
Raleigh Competition (Sugino triple with Shimano BB) 164
Custom fix gear (currently not assembled but runs a Sugino 75 crankset on a Miche track BB. Probably less than 140)
Obviously that Competition is the next project.
And a comment/question re current "standards" - why are Q-factors so high? I know it makes design brain-dead easy. But for a lot of us, our knees are not meant to be bowed out. Why do cranks miss the chain by more than 3 mm? That 's plenty. Why are BBs for large offset cranksets symmetrical? My knees don't care that my feet are a cm to the right. They do care about every cm they get forced beyond where my feet would land without a bike forcing them apart. And ... increasing Q-factor is easy. Wider BB. Symmetrical BB. Pedal extenders. But reducing BB is a real challenge. Cost me a BB close to $200 and finding a crankset made 25? years ago. (Perspective - those BBs cost ~ one PT visit. For the deductible on knee replacements I can go Phil on all my bike the rest of my life.)
Ben (celebrating the little "q")