I just bought a set of new, wider handlebars for my old (2002) Stumpjumper hard tail. My old set-up were 580mm bars (ugh, righ?) with a 90mm stem.
With the new bars I have to buy a new stem, because my old stem doesn’t fit the 31mm-diameter handlebars. Would you recommend I go with another 90mm stem with the wider bars, or drop it down to 70mm? I see the new Stumpys all have 100mm stems, but they’re also 29ers. I’m just not sure about this bike as it has pretty aggressive geometry. I don’t want to make the bike too twitchy.
I like your thinking. Here is my thinking:
As bars get wider, the trapezoid formed by your bars, arms and shoulders gets wider and shorter. Everything else being equal, this supports the notion that shorter stems go with wider bars. If you go from old school narrow to new school wide (say 580 to 800 mm), the trapezoid gets 10-20 mm shorter.
Grossly simplified quickie infographic:
If you like the way your bike handles, but you want a wider bar, switching from a 90 mm stem to a 70 mm stem makes sense.
But wait, there’s more!
For most people on most bikes, shorter stems enhance handling. You get more range of motion and cleaner lines of force. I have a fit system that I use with my skills clients.
If you want that bike to shred, try a 60 or 50 mm stem. Don’t worry, that won’t make your bike twitchy.
My new Stumpy hardtail has a 50 mm stem and 800 mm bars, and it’s awesome!
Know more. Have more fun!
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