From fit to frame - reach, grip location and stem sizing

Education
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Hi all,

Hoping to pick some brains on the more experienced builders here on how to got from fitting number to frame design.
I’m currently planning to build a new hardtail frame for my wife, for which she did a bikefit first where we got out an ideal saddle height, saddle setback and BB to Bar X/Y measurement. The rear triangle can be locked down quite easily between ride characteristics, tire size and clearance and saddle position. However, the front and especially the reach or front center seems a lot more tricky. The mock fit-up was done with a dummy stem with a completely flat bar, which doesn’t really map all that well to the real world where backsweep and upsweep numbers give little to no indication on where your hands will land.

How do you typically adjust or design for these kind of scenarios? I was pretty much bang on with my first draft (stack of 620, reach of 440, for a BB to Bar X/Y of 670/465) for BB to Bar (clamp), if I went for a 50mm stem and a completely dead straight handlebar. However, with a slightly swept back handlebar, you easily lose 3-4 cm from the looks of it. Compensating in stem length doesn’t seem like the right move, but moving the frame out another 3cm creates a very long reach for what I expected for her size (1m65) and maybe more importantly, a very long wheelbase? Split the difference somewhere in the middle?

Do you typically measure a bar beforehand, or keep a log of bars you have used/owned and their measurements somehow? In the end the grip location is the defining factor in your fit from what I understand, but it also feels like the trickiest to design for due to missing dimensions.

Would love to hear some input that is slightly more attainable for the beginner builder than PvD’s blog :slight_smile:

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I would just buy the bar and measure it if I had such a precise fit from a professional bikefitter.

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I have never done a fit but why didn’t the fitter run through bars as part of the fit? Seems like a glaring oversight. I am pretty sure the local shop to me that does MTB and road fits will swap out a number of different bars in order find the one that completes the whole fit.

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It doesn’t have everything, but maybe this will be helpful: MTB Handlebar Dimensions. My opinion is that you should try to nail down which bar you will be using while still in the design phase, then break out your measuring tools and make anatomy-driven design decisions.

PVD’s blog does contain some useful information, but the explanations often complicate relatively straightforward ideas, so I’ve found that the accompanying photos tend to be more informative than the text itself. Take a look at the photos about 1/3 of the way down here to see an approachable and systematic way to measure bars you have on hand.

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As others have said, buying and measuring the bar you want to use is the best way to go. Then please contribute your measurements to the MTB Handlebar Dimensions thread as a reference.

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Maybe the bar you’re interested in is on this site?

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