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¿Por Que?
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Discussion Starter · #1 ·
For the math nerds out there. Can anyone tell me the difference in handlebar height between:

a 110mm stem, 8 degrees, with a 40mm stack height, on top of 10 mm of spacers

*and*

a 110mm stem, 10 degrees, with a 35mm stack height, on top of 15mm of spacers

Thanks
 

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¿Por Que?
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Discussion Starter · #3 ·
Cool, thanks for the info. A point of clarification here--I should have been more specific that those are both negative rises. I left that out. So they could also be called 82 degrees and 80 degrees respectively.

So Wim, were you assuming a negative rise or a positive rise based on the numbers. If you were assuming the positive rise, could you tell me the calculations based on a negative rise?

Thanks.
 

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The setup with the minus-10-degree stem will put the bar 1.5 mm lower than the setup with the minus-8-degree stem—for all practical purposes, at the same height.

In case you're interested: the software I normally use to lay out geographic data in designing maps is pretty good at figuring these sort of things if you set the base unit to millimeter instead of kilometer. Keep in mind that the computer snapshots do not show head tube angle. The differences are calculated for the stem centerlines, but since you only needed a delta and not actual handlebar height, this worked fine. Do check after me on the negative rise on the lower drawing—did I understand that term correctly?
 

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bikenerd said:
If they're negative rise, the 8 degree is actually 1mm higher than the 10 degree. Do you agree Wim?
Totally agree, see what I posted same time you posted. The 0.405 mm difference is probably due to my sloppiness when plotting points on the grid, but I love to do things visually. I know, I know, math/trig would have been quicker and dead-on, but how much fun is that? :D
 

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Cyclocross fool
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wim said:
Totally agree, see what I posted same time you posted. The 0.405 mm difference is probably due to my sloppiness when plotting points on the grid, but I love to do things visually. I know, I know, math/trig would have been quicker and dead-on, but how much fun is that? :D
Yeah, I just have a little spreadsheet with the trig formulas, so I can compare different combos of stem length, stem angle, and spacer to see where bar rise and reach wind up. Head angle is figured in too. Back to the question at hand, if I extend to another decimal place, the -8 stem is 1.3mm higher, and .2mm farther away. As far as I'm concerned, that's the same. If you're sensitive enough to feel it - wow.
 

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¿Por Que?
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Discussion Starter · #10 ·
bikenerd said:
Yeah, I just have a little spreadsheet with the trig formulas, so I can compare different combos of stem length, stem angle, and spacer to see where bar rise and reach wind up. Head angle is figured in too. Back to the question at hand, if I extend to another decimal place, the -8 stem is 1.3mm higher, and .2mm farther away. As far as I'm concerned, that's the same. If you're sensitive enough to feel it - wow.
Very similar. That's what I was imagining. Thanks everyone for putting some numbers to it for me.
 
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