Stem Sizing Frustrations
Moderator: robbosmans
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So, why when a stem is marked with 100mm or whatever length it might be, does it actually measure 5mm more? Is this just a little trick of manufacturers/re-sellers intended to mess us cyclists around? Why is there no industry-wide convention on this matter for the benefit of us consumers? Why do consumers seemingly count for naff-all on matters of convention in the cycle industry?
How about a directory folks indicating how stems are measured, eg.
A Felt stem typically measures 5mm more than the stated length.
How about a directory folks indicating how stems are measured, eg.
A Felt stem typically measures 5mm more than the stated length.
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the stated length would be if the stem had no angle to it. When you have a drop or rise, the hypotenuse is longer than the effective length. If you measure the other side of the stem you will probably get 95mm for a claimed 100mm stem. Simple geometry. Same kind of thing with effective vs. actual top tube lengths.
+1 on using the local shop.
+1 on using the local shop.
Agreed.
I understood Syntace makes or used to make some sort of "stem ruler" which allows you to calculate x and y positions
And I thought that different manufacturers measure slightly differently, similar to c-c or o-o for bars.
But bottom line it doesn't matter so much, unless you believe it matters to have your stem to within less than 5mm of its ideal position. IMHO you dial this out with thicker bar tape, minutely shifting your levers, bending elbows 1 degree more etc.
I understood Syntace makes or used to make some sort of "stem ruler" which allows you to calculate x and y positions
And I thought that different manufacturers measure slightly differently, similar to c-c or o-o for bars.
But bottom line it doesn't matter so much, unless you believe it matters to have your stem to within less than 5mm of its ideal position. IMHO you dial this out with thicker bar tape, minutely shifting your levers, bending elbows 1 degree more etc.
Who, in their right mind, would go for a thicker bar tape to compensate for a 5mm taller stem? That's just ludicrous. One of the things I like about cycling is that you can be as OCD as you like about the fit. And when it all matches up just right, it is just freakin' heavenly!
"Changing your bar tape............"
Also, when the fit actually is perfectly dialled, then 5mm is a big deal. Not that you couldn't adapt, but for the OCD of it I feel you shouldn't have to adapt to the bike, the bike adapts to you. This is the beauty of it.
"Changing your bar tape............"
Also, when the fit actually is perfectly dialled, then 5mm is a big deal. Not that you couldn't adapt, but for the OCD of it I feel you shouldn't have to adapt to the bike, the bike adapts to you. This is the beauty of it.
I have never had a problem with stems being anything but what they have claimed.
But I have never had a Felt stem. Maybe it is just that one ?
And I have always just assumed that stem length was "center to center" along a line that intersects the fork tube's longitudinal axis and the bars' axis.
But I have never had a Felt stem. Maybe it is just that one ?
And I have always just assumed that stem length was "center to center" along a line that intersects the fork tube's longitudinal axis and the bars' axis.
I'd say that there are many stems that measure over the top, not along the center (height wise), of the stem, which with an angled stem ofcourse comes out longer than a center measurement. It seems quite common practice. With a -17 degree stem the difference would be huge.
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wpccrunner wrote:the stated length would be if the stem had no angle to it. When you have a drop or rise, the hypotenuse is longer than the effective length. If you measure the other side of the stem you will probably get 95mm for a claimed 100mm stem. Simple geometry. Same kind of thing with effective vs. actual top tube lengths.
How many stems have you come across in that shop of yours, if you indeed run one?
I have in my left hand a 4ZA Cirrus stem. It is marked 100mm/7 degree angle, and it measures 100mm from c-c.
I have in my right hand a Felt Ultralite that is marked exactly the same as the stem in my left hand, ie. 100mm/7 degree angle, but it measures 105mm c-c.
And it's like that with plenty of other companies as well.
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