2020-12-14

Fat bike fitting: fixing a wide stance

Alternate post title... Fat Bike, I just can’t quit you!

Alternate alternate post title: I think I fixed my knee discomfort caused by the wide Q-factor of the fatbike!

A couple weeks ago I posted about using the Poseidon X as a trail bike. An update: After a week or two of riding the trails we had several days of rain and hoo-boy does it get tricky on wet, muddy trails. Still, it’s doable and I did it for a couple days. But muddy trails in the cold of winter freeze, re-thaw, freeze and overall don’t tend to dry out. So, while I don’t mind the challenge, the prospect of riding consistently wet, muddy trails for weeks at a time, likely doing damage to the trail that I would have to fix, led me back to the fat bike.

To reiterate, I love the fat bike. It’s a blast to ride and the only reason I was avoiding it was knee discomfort due to the wider stance. So, I made a few more seat adjustments and, I think crucially, decided to try riding with my feet positioned all the way up against the crank. I think the general norm is that you place your foot squarely on the pedal. It occurred to me that if I pulled my feet up closer to, and in contact with the crank arm, I’d be that much closer to the more comfortable riding position I needed for my knees. The Poseidon X has my foot at about 3 1/8” (80mm) away from the seat tube. By comparison, the inside of the pedal on the fat bike is 4” (102mm) away from the seat tube. Putting my feet up against the crank arm has my foot at about 3 1/2” (89mm) away from the seat tube. It’s only a half inch difference but this adjustment seems to have done the trick! That’s the funny thing about bike fitting. Often times it’s just an adjustment of a half inch or an inch, be it seat height, stem length or angle, etc that can make a big difference. This is especially true if you’re doing longer hours on the bike. 30 minutes here and there likely won’t matter much. But 2 to 3 to 4 hours a day, several days a week, well, that’s makes a difference.

It may also be possible to find some different cranks with less of an outward bend and I may look into cranks that are closer to the frame. For now this adjustment to my foot-on-pedal position seems to have done the trick. It’s been about 10 days of riding and the issue has not returned. So happy to be back on this bike!

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