31.8 vs 31.7mm bars/stems

DiscoBoy
DiscoBoy Posts: 905
edited April 2014 in Workshop
I currently have a 31.8mm bar and stem.

If I were to buy a 31.7mm set of bars (Deda Presa carbon) would I also need to buy a new stem?
Red bikes are the fastest.

Comments

  • ugo.santalucia
    ugo.santalucia Posts: 28,235
    Have you ever seen 1/10 of a millimeter? :roll:

    My guess is NO
    left the forum March 2023
  • DiscoBoy
    DiscoBoy Posts: 905
    ugo.santalucia wrote:
    Have you ever seen 1/10 of a millimeter? :roll:

    My guess is NO

    That's my guess too, but I'd like more than a guess when it comes to my shiny new parts :)
    Red bikes are the fastest.
  • drlodge
    drlodge Posts: 4,826
    If its a standard clamping arrangement (front plate with 4 screws sandwiching the bars), it'll be fine.
    WyndyMilla Massive Attack | Rourke 953 | Condor Italia 531 Pro | Boardman CX Pro | DT Swiss RR440 Tubeless Wheels
    Find me on Strava
  • brearley
    brearley Posts: 165
    I use 31.7 bars with 31.8 although having read up online deda's 31.7 is 31.75 rounded down whereas most 31.8 bars are 31.75 rounded up. Maybe that's what they do with their product weights and tolerances too ;)
  • drlodge
    drlodge Posts: 4,826
    Probably 0.05mm is within manufacturing tolerances...I had a new 31.8 seat post measured the i/d of the seat tube...31.6mm Damn I thought, I got the wrong one. But it fits just fine, probably just some dust making the measurement inaccurate.
    WyndyMilla Massive Attack | Rourke 953 | Condor Italia 531 Pro | Boardman CX Pro | DT Swiss RR440 Tubeless Wheels
    Find me on Strava
  • DiscoBoy
    DiscoBoy Posts: 905
    Okay thank you all :)
    Red bikes are the fastest.
  • drlodge
    drlodge Posts: 4,826
    Well the seat post fitted just fine after I used a crow bar to widen the seat post :shock: :roll: :lol:
    WyndyMilla Massive Attack | Rourke 953 | Condor Italia 531 Pro | Boardman CX Pro | DT Swiss RR440 Tubeless Wheels
    Find me on Strava
  • cq20
    cq20 Posts: 207
    They are the same. Like many things in cycling e.g. chain links, the actual size is in Imperial units and in this case it is 1.25 inches. This converts to 1.25 x 25.4 = 31.75mm, which some manufacturers call 31.7mm and others call 31.8mm

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