Stance width on my MTB is 178mm. The GRX cranks I'm looking at are 151mm. That's a massive difference. I appreciate that I may it may not notice, but pedal manufacturers offer pedals with 5mm longer axles, bike fitters use 2mm washers, cleats can slide about 3mm sideways. These adjustments seem insignificant compared to the range of cranks.
Surely if I can buy cranks with a 30mm variance (without even thinking about fatbikes) why are the tweaks to correct for it, so small?
13ish mm a side isn't a lot. I regularly go from clipped in on my grav bike to a fat bike with no issues
Check out SQ Labs, I believe they do reasonably priced SPD clones with extra long axles that can accommodate those sorts of differences.
That being said I tried exactly what you're suggesting but of course it just seemed to muck up other aspects of fit, suddenly my saddle felt more uncomfortable etc. etc. I just went back to living with the differences.
It's a curious one, because there are lots of articles out there that say that Q factor matters, but very few that give guidance on how to determine what it should be. AFAIK there is a variation in how sensitive people are to changes in Q factor. Most of my MTBs have been around 170mm (167mm current for Hope Evo on my hardtail; 170mm for Middleburn RS7 on my previous hardtail) and that's been fine for me, but then again I use flats, so 2mm (or even 5mm) is neither here nor there in terms of a difference. Maybe Q factor/stance width is signficant if you run cleats, but I don't think it's something most people worry about unless it affects them.
I regularly go from clipped in on my grav bike to a fat bike with no issues
This. Other than a higher risk of pedal strike, I couldn't tell you what the Q factor difference is.Â
At one point i had a fat bike, pinion gearbox bike, road & gravel bikes plus regular MTBs.
Never noticed a difference in how far apart my feet were
Anecdotally, I think wider stances typically aren't an issue but going too narrow seems to be when people notice. I think most people have a fairly wide band of accomodation. However, once you step outside that personal band, it doesn't take much for things to start going wrongÂ