Cannondale Trail SL Strength?

FBM.BMX
FBM.BMX Posts: 148
edited January 2011 in MTB general
Hey everyone,

I have a cannondale trail sl 2011 frame, i'm trying to decide whether the frame has some good strength to it or not.

It has a 1.5" headtube with the down tube formed into quite large box section, where it meets the head tube, teamed with very slick welds, the head tube won't be going anywhere, will it?

The seat stays and chain stays are also flattened in spots relative to the ground, to give the aluminuim a small amount of steel like bump compliance. I'm thinking this should give the rear triangle an area to disperse some impact energy, saving the weak points at the welds.

This is the bike, http://www.bikeradar.com/forums/viewtop ... t=12751467, it weighs about 29lbs, but none of the parts are particularly light, suggesting the frame is on the light side of things.

Peoples experiences with the typical mid level, complete aluminuim hardtail frames would be gratefully received.

The bike is used for everything, used pretty aggressively too. been doing a bit of downhill involving 4ish ft drops, im concerned about my front end coming away upon landing, should i be worrying?

Cheers.

Comments

  • .blitz
    .blitz Posts: 6,197
    IIRC one of the latest CEN tests is that a MTB frame has to withstand a flat landing of 9g. Your legs will break before the frame does.
  • FBM.BMX
    FBM.BMX Posts: 148
    .blitz wrote:
    IIRC one of the latest CEN tests is that a MTB frame has to withstand a flat landing of 9g. Your legs will break before the frame does.

    I've always known of this standard, but never had a proper read. Just pulled up the standard, did some calcs.

    The first test i looked at was a weight dropped vertically, with the bike vertical, with the weight striking the bottom of the fork leg.

    In the test scenerio, the impact energy is 40Joules, for myself riding along at 10mph, hitting a brick wall, all 79kg of myself (should of really included the weight of the bike), that is 789J of energy. That's a big difference. Even if i hit a brick wall at 5mph, that's 200J the bike has to deal with.

    I'm just gonna do some more calc.

    Cheers, i should have paid more attention to it.

    There are 4 frame tests-

    .Weight (22.5kg) dropped vertically on front end from 360mm
    .Weights on rider contact points (90kg), lifted pivoted about rear axle, then dropped from 300mm
    .Pedal Fatigue
    .Front end loading fatigue

    Where is there 9g of force occuring?
  • Zziplex
    Zziplex Posts: 190
    Just ride the basta*d FFS. :wink:
    Guinness for strength
  • .blitz
    .blitz Posts: 6,197
    FBM.BMX wrote:
    Where is there 9g of force occuring?
    If you're looking at EN 14766 I guess it's test 4.8.6.

    All laboratory stuff of course but I think modern frames are a lot stronger than people think. Product liability and all that.
  • W00DENT0P
    W00DENT0P Posts: 211
    Zziplex wrote:
    Just ride the basta*d FFS. :wink:

    Exactly !!
    Just the ride the thing, folk worry about things way to much on here.
  • Dave_P1
    Dave_P1 Posts: 565
    You're be surprised what a decent XC frame can do.
    It's not always down to the size of drops / jumps but whether your a smooth rider or not.
    Product & Race Reviews Here
    Various vids including many Trail Centres
  • supersonic
    supersonic Posts: 82,708
    Do cannondale even have to reach CEN standards?
    GT ZASKAR CARBON TEAM

    VOODOO CANZO

    Come and see me at https://www.facebook.com/biketyke/
  • FBM.BMX
    FBM.BMX Posts: 148
    ^My frames got the EN14766 sticker on it.
  • Uncle Peter
    Uncle Peter Posts: 324
    FBM.BMX wrote:
    .blitz wrote:
    IIRC one of the latest CEN tests is that a MTB frame has to withstand a flat landing of 9g. Your legs will break before the frame does.

    I've always known of this standard, but never had a proper read. Just pulled up the standard, did some calcs.

    The first test i looked at was a weight dropped vertically, with the bike vertical, with the weight striking the bottom of the fork leg.

    In the test scenerio, the impact energy is 40Joules, for myself riding along at 10mph, hitting a brick wall, all 79kg of myself (should have really included the weight of the bike), that is 789J of energy. That's a big difference. Even if i hit a brick wall at 5mph, that's 200J the bike has to deal with.
    I'm just gonna do some more calc.

    Cheers, i should have paid more attention to it.

    There are 4 frame tests-

    .Weight (22.5kg) dropped vertically on front end from 360mm
    .Weights on rider contact points (90kg), lifted pivoted about rear axle, then dropped from 300mm
    .Pedal Fatigue
    .Front end loading fatigue

    Where is there 9g of force occuring?

    Warning!!

    DO NOT RIDE YOUR BIKE

    BASED ON YOUR CALCULATIONS, IF YOU RIDE YOUR BIKE YOU WILL DIE!

    Although if you do ride it, I'm sure you'll enjoy yourself.

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