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Old 10-03-21, 04:18 PM
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Bikes: Surly Disk Trucker, 2014 w/Brooks Flyer Special saddle, Tubus racks - Duo front/Logo Evo rear, 2019 Dahon Mariner D8, Both bikes share Ortlieb Packer Plus series panniers, Garmin Edge 1000

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Bikes for shorter people - ideas?

I am researching bike geometry here. My girlfriend is pretty short (5'2", 26-1/4" inseam). I'd like to come up with some better bike options for her.

She has an old bike now that we've made work. It has 26" wheels. I am not sure what the rest of the dimensions are, but it is an old Murray step-thru with drop bars and, I believe, 10spd trans.

The challenge with it is she rides it with the seat bottomed out and she isn't getting proper leg extension. This is leading to hurt knees on rides over about 15 miles. We did a day ride last Fall ('20) that was around 30 miles, with mostly descending terrain, and she had to walk the last mile or so.

What I am trying to weed through is this:
- She wants to have the comfort and stability of being able to plant her feet on the ground while sitting on the saddle
- She needs to get her leg extension out more

The above are direct opposites of each other. If one were to attempt to set "normal" (upright triangular frame) bike geometry up to do this the pedals would be on the ground.

I thought about a custom frame that would allow for a low bottom bracket, but the problem is immediately pedal strike and there is no way to get a crank low enough that would allow the proper leg extension.

In another thread recently the Giant Revive crank-forward design came up. That is closer to a recumbent than a conventional bike. The benefit, in any case, in the fitment challenge here is that leg extension is achieved by increasing the distance of the saddle, horizontally (mostly), to the crank. This is as opposed to vertically in the case of a conventional bike design.

Are there any other design methods that we can look at for ideas?

I recall seeing bikes made for much smaller people in years past that were conventional bike geometry - upright bikes - only the seat tube, crank, and headset were lower. I don't recall the wheel sizes, I'd think maybe 20-24". They couldn't be very big - the headset height would be the limiting factor as you can only set the angle back so far. However, I can't imagine the physics of how the two issues mentioned above would be any different - same issues, different scale.
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