Are there any advantages of S shaped down tubes over the traditional ones on MTB?

For example: what do you think of this design?

Jamis Exile Comp 2013

Jamis Exile Comp


1 Answer 1


The S shape allows for:

  • stronger head tube and bottom bracket welds without the need for gussetting. You'll find this on more trail focused bikes (such as AM, FR and DH).

  • wheel clearance for long travel forks

  • wheel clearance for the front wheel (ie. 29er's)

  • Still allows for room for a water bottle within the front triangle

  • 4
    Why does the down tube come out of the bottom bracket horizontally for 250mm? Surely that reduces wheel clearance, defeating wheel clearance advantage
    – mattnz
    Sep 12, 2013 at 21:20
  • 1
    I'd say there's a certain element of aesthetics that creeps into the design here as well. But you're spot on with the points listed above. +1
    – Saxman
    Sep 13, 2013 at 14:32
  • 2
    mattnz, I guess it's to allow room to get a bottle in as jm2 is suggesting. If the down tube was slacker there'd be marginally more room clearance but not really enough room to negotiate a bottle in and out easily.
    – DWGKNZ
    Sep 13, 2013 at 19:30
  • 1
    Vladimir - these are just things I've picked up over time reading about different types of mtb bikes, not one place I could suggest you look other than google.
    – DWGKNZ
    Sep 13, 2013 at 19:32
  • 1
    +1 for the answer. Given the lack of definitive resources I can find, and the current design trends in everything are more towards organic, curvy, soft looks, one has to wonder if the main reason is style, the rest just marketing twist......
    – mattnz
    Sep 13, 2013 at 21:32

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