Dumb Question: Road bike stems

cookdn
cookdn Posts: 410
edited October 2011 in Road beginners
My post is getting plenty of reads but no answers :-(. The answer to the question might seem obvious but I am a bit ignorant about current bits & bobs on bikes and road bikes in general :? :oops: .

I'm probably going to need to buy a shorter stem for a new Boardman CX. Am I correct that the standard 100mm stem is for oversize handlebars (31.8mm) and a 1 1/8" steerer tube? Also is there any difference between road and MTB stems other than branding etc.

Thanks

Stem1.png
Stem2.png
Boardman CX Team

Comments

  • crankycrank
    crankycrank Posts: 1,830
    The most popular at the moment would be 1 1/8" x 31.8mm stem and it looks like that is what is used for your Boardman but to know for sure check to see if it might be etched on the stem somewhere already. You could also go to the Boardman website for specs or measure yourself. Also note that stems come with different angles measured from 90 degrees perpendicular to the fork tube. common are +6/-6deg (same as an 84/96deg stem) which is what yours appears to be and +8/-8 or 10deg are other popular angles usually used (but not nescessarily) by roadies who want a lower or higher position than the bike or spacers will allow. Generally the difference between road and mtn stems is the mountain versions are a little beefier and heavier but the difference is not much and as long as it fits your bar and fork tube will work perfectly well.
  • cookdn
    cookdn Posts: 410
    Hi crankycrank

    Thanks for the info. I haven't got the bike yet but you have confirmed what I thought. It seems unlikely that the Boardman would be using non-standard stuff, unfortunately the Boardman website is not specific about the stem details.

    As I would be reducing the stem length I doubt the real-world weight difference between road and MTB stems is going to be a factor. I just figured that if MTB stems were ok then it would widen choice/availability. I am going to have a rummage on eBay and see if I can find something suitable around 700mm at 6 degrees so I can experiment with reach/comfort when the bike arrives.

    Best regards
    Boardman CX Team
  • gasman_dave
    gasman_dave Posts: 129
    Just a thought - Why are you wanting to change things before you've even got the bike? Try the bike one size down first.

    I made the mistake of buying my first road bike 4 years ago that was too long and ended up with back problems when riding. I ended up with a 60mm MTB stem which was closer to the right length, but this makes the steering much twitchier.

    Do a DIY bike-fit. Competitivecyclist.com do a free service and give 3 different fits, then look back and see what the Boardman's geometry is.

    I went down the Van Nicholas route. You put your measurements into the site and it recommends the frame and stem in that model. Then I found that frame on Bike Radar and never looked back. The difference in comfort on my Yukon is unbeleivable.
  • cyberknight
    cyberknight Posts: 1,238
    have a lok at the website , each bike has a geometry tab that tells you the exact size of the frame , length of top tube and length of the supplied stem...

    http://www.boardmanbikes.com/cx/index.html
    FCN 3/5/9
  • cookdn
    cookdn Posts: 410
    gasman_dave wrote:
    Just a thought - Why are you wanting to change things before you've even got the bike? Try the bike one size down first.
    I tried the medium frame in the Leicester store and while I could ride it I was at maximum comfortable reach. Unfortunately the small is only available on-line which I have ordered from my non-expert interpretation of the relative geometry.
    gasman_dave wrote:
    I made the mistake of buying my first road bike 4 years ago that was too long and ended up with back problems when riding. I ended up with a 60mm MTB stem which was closer to the right length, but this makes the steering much twitchier.
    Thanks for sharing that, obviously this is something I'll need to consider if I need to shorten the stem.
    gasman_dave wrote:
    Do a DIY bike-fit. Competitivecyclist.com do a free service and give 3 different fits, then look back and see what the Boardman's geometry is.
    Thanks for the pointer to the Fit Calculator (http://www.competitivecyclist.com/za/CCY?PAGE=FIT_CALCULATOR_INTRO). Based on my measurements the geometry of the small Boardman CX is in the correct range for their less aggressive 'Eddy Fit' which best reflects my expected riding style. As you suggest I should stop worrying about the stem length until I get the bike, the Fit Calculator has reassured me that my instinct was probably correct. :)
    Boardman CX Team

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