Sloping top tubes

supertwisted
supertwisted Posts: 565
edited October 2008 in MTB beginners
Due to having a dwarf like inside leg of only 27", I've found that bikes with a more sloped top tube fit me better. They allow (more) adequate clearance while still allowing me a reach which isn't too cramped.

What is the affect of this on the bikes handling though? I'm guessing (and this is purely based on feel) that a more horizontal top tube results in a racier, less chuckable bike, whereas the sloped tube gives the bike a more laid back but moveble character?

Or am I way off the mark?
Less internal organs, same supertwisted great taste.

Comments

  • nicklouse
    nicklouse Posts: 50,675
    edited October 2008
    has no effect.

    Most bikes has sloping top tubes now.

    the length to the top tube is more important.

    Too long and too stretched. the shape of the top tube does not matter.

    but then the bikes designed usage come into it as well.

    I dirt jumper will be a pain to XC on.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
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  • Cheers nick, pretty much clears that up. :D
    Less internal organs, same supertwisted great taste.
  • dave_hill
    dave_hill Posts: 3,877
    The angles of the head and the seat tube of the frame are also important.

    "Slack" geometry such as that found on a downhill bike will make the bike very stable at high speed but increases the wheelbase. This can make climbing a chore because the front end will tend to "flop" from side to side when pointed up hill and moving slowly.

    On the other hand, if you go very steep, the steering will be twitchy and nervous when pointing downhill, but the bike will climb like a scalded cat.
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  • LordBanks
    LordBanks Posts: 358
    Sloping toptubes also save yer clacka-bags.
  • nicklouse
    nicklouse Posts: 50,675
    dave_hill
    nice description but it has nothing to do with a sloping top tube.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • dave_hill wrote:
    The angles of the head and the seat tube of the frame are also important.

    "Slack" geometry such as that found on a downhill bike will make the bike very stable at high speed but increases the wheelbase. This can make climbing a chore because the front end will tend to "flop" from side to side when pointed up hill and moving slowly.

    On the other hand, if you go very steep, the steering will be twitchy and nervous when pointing downhill, but the bike will climb like a scalded cat.

    Cheers dave, that's helped me understand things a little better.
    So to compare, using rubbish diagrams:
    \----\ slack geometry, better downhill.
    |----| upright, better climber.
    Any other differences between these? I hear a lot of reviews refering to a bike being more chuckable or racier than another. I'll assume slack geometry = chuckable, upright = racy?

    As for top tube slope, apart from the safety of my clacka-bags (cheers LordBanks :lol: ) there's not much in it.
    Less internal organs, same supertwisted great taste.
  • nicklouse
    nicklouse Posts: 50,675

    As for top tube slope, apart from the safety of my clacka-bags (cheers LordBanks :lol: ) there's not much in it.
    correct. It is the rest of the angles lengths that effect hoe the bike rides and feels.
    as does the wheel base, chainstay length etc etc...

    But nothing beats bums on saddles.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown