What caused this crash (front wheel turned too far)?

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  • What caused this crash (front wheel turned too far)?
  • crikey
    Member

    I’ll have to say it before anyone else does; user error.

    It’s not the tyres, or the bike, or the angles, or the stem, or the saddle-bars drop.

    It’s you… 😉

    Premier Icon Normal Man
    Subscriber

    Excess hip fat! 😉

    Sorry that was just too tempting.

    Hope you heal up ok mate 🙂

    Premier Icon Drac
    Subscriber

    How would the wheel turn too far if you had a hold of the bars?

    Sounds like it washed out as you were going too fast, easy done.

    Premier Icon roverpig
    Subscriber

    Thanks folks. Actually, probably not enough hip fat, I could have used a bit more padding, but apparently we all have a bit of subcutaneous fat.

    Of course it’s me. The bike didn’t crash itself 🙂 But this is the second crash like this I’ve had on the FF29 (the other one didn’t hurt though). It could just be coincidence, but I wonder whether it is more susceptible to this particular type of crash and whether I should change anything. More weight over the bars in turns maybe.

    Ironically I’d decided to take it easy at the start of the descent. Forget times and just enjoy the beautiful day. Ain’t that always the way. I may well just have relaxed and carried more speed into that turn than I could handle I guess.

    banks
    Member

    29er’s fault. Sell it whilst you can

    Premier Icon roverpig
    Subscriber

    Surely it’s worthless now that the one true wheel size is among us. So, I might as well keep it 🙂

    maxtorque
    Member

    Get some cornering tuition. If only we had some sort of MTB Jedi who could teach us that kind of thing…………….. 😉

    (seriously, there’s a huge variation in the amount of grip to be gained, and lost, through ‘good cornering’, from bike setup, to body positioning, and sometime, just being shown it by another better rider is enough)

    Premier Icon rickon
    Subscriber

    Probably:

    1. Not enough weight over the front wheel, as you were a little scared so hanging off the back of the bike. Which lightens the front wheel and is easy for it to wash out and then the bars would turn.

    2. Not enough weight on the outside pedal, reducing grip and pushing your centre of gravity off, so instead of grip on the edges of the outside of your tyre, you effectively pushed your bike from under you.

    3. Front wheel braking while in a section/turn. Thisll reduce grip and wash the front end out. Brake unto the turn, not in it.

    4. Not looking where you want to go, but looking where you are. This causes you to micro adjust your position and wheel, so you try to force the bike around a turn by steering with the wheel. When you should be steering the bike with you body. Head up, look where your exit is, outside foot down, pump, and let your body tell your bike where to go.

    Spend some time practicing cornering, you can get by 90% of the time with poor technique, but if you want to push your limits you need to understand how to dynamically shift your weight with the bike. After seeing Jedi a lot of things clicked and I spent the last 12 months practicing skill in Scotland. No real long rides, just lots of riding and lots of sessioning. Its hugely worth doing.

    Rubbish tyres won’t help. Steep head angle will make you feel safer with less weight over the front end. But ultimately…. Youre weight was wrong. 🙂

    This is all coming from a man sat with a wrist support and a smashed face.

    Premier Icon mattjg
    Subscriber

    What caused this crash (front wheel turned too far)?

    the answer’s in the question

    Premier Icon Cheezpleez
    Subscriber

    Weight over the front. Lean the bike, not you. Weight outside foot and inside bar. Look round the corner and into the distance.

    fizzicist
    Member

    Ralphs are shit on the front…I’ve had that same accident. Swap it for a Nobby Nic or Rocket Ron.

    Or Fat Albert if you actually want grip….

    Premier Icon mattjg
    Subscriber

    or are you really asking “what is the cause of the cause of the cause of this crash?”.

    that’ll keep you quiet for a while

    Premier Icon mattjg
    Subscriber

    it has a 75mm stem with 700mm bar

    too long too narrow go wide young man!

    Premier Icon roverpig
    Subscriber

    Hi All,

    I’m looking for some tips on what caused today’s crash. I was coming off one of the hairpins on the Pitfichie descent. This is a pretty sharp (bermed) left turn, which then drops fairly sharply and tunrs a bit further left at the bottom. I lost it on that second turn-in at the bottom and went down pretty hard on my left hip. Ended up with a nice deep gash (must have landed on a sharp rock), plus the usual trail rash etc. After a bit of debate at A&E they eventually decided to push the bit of fat that was hanging out back in and see if a few strips and a gel dressing would hold it together. So, no big deal really, but I’m still confused about what caused the crash.

    The trails are very dry and the bit where I crashed is loose rock and sand. So, originally, I just assumed that the front wheel had washed out and was ready to just blame the dusty trails and lightweight Racing Ralph tyres. However, when I picked the bike up I noticed that rather than just laying on its side on the edge of the trail the bars had turned right round, as if the wheel had turned too far, which would fit with me being thrown forwards rather than just landing beside it.

    So, what would cause the front wheel to turn too far on a dusty corner and is there anything I should do (either bike setup or technique) to try and avoid this? The bike is a Kinesis FF29; a 29er hardtail with a fairly steep head angle (70-71 degrees) and it has a 75mm stem with 700mm bars set about level with the saddle.

    Premier Icon scaredypants
    Subscriber

    If you fell that hard, I don’t see why your bike shouldn’t have “done stuff” after you left it rather than lying still on the trail exactly as it first went down.

    My guess, if your bike really was left in a state caused by the initial “fault”: You kept your weight back and turned the bars rather than leaning enough (mostly ‘cos it’s what I’d do if I was half expecting a crash, even though I know it’s wrong)

    Premier Icon jameso
    Subscriber

    Impossible to be sure but sounds like a normal tuck-under where the front folds under and rolls away from you, away from the cornering direction or corner apex – too much weight on the front, too long a stem, too steep HA, etc. Those things combined with soft ground is tuck-under cornering waiting to happen.

    alpin
    Member

    crikey – Member

    I’ll have to say it before anyone else does; user error.

    It’s not the tyres, or the bike, or the angles, or the stem, or the saddle-bars drop.

    It’s you…

    +1

    and hairpins in my experience don’t have berms in them. my i dea of a hairpin is this:

    [/url] DSCN2529 by sod_the_taxman, on Flickr[/img]

    Premier Icon rickon
    Subscriber

    You mean not enough weight on the front, the more weight you have the more grip you have. As long as its in the right place.

    Premier Icon jameso
    Subscriber

    You mean not enough weight on the front, the more weight you have the more grip you have. As long as its in the right place.

    my post? I meant too much, combined with a front end that is more likely to tuck, ie a trail distance shorter than the contact patch length where the tyre almost jack-knifes or twists and overtakes the steering axis under sharp cornering (hard to describe but it’s basically what happens in a tuck-under, slow-speed steep corners are a prime spot for it, also fast, leant-over corners on soft ground with steeper front end bikes). Crikey’s basically right, technique can account for it but there’s also a reason CX bikes don’t descend steep hairpins well or DH bikes have long trail and front ends and grips way behind the front axle.
    May have been something totally different tho so who knows.

    Premier Icon roverpig
    Subscriber

    Thanks Folks,

    Some useful ideas to try once the hip gets better. The front wheel folding under is certainly what it felt like (both times), but I’ll still start with user error as that’s usually what it is 🙂

    Premier Icon scaredypants
    Subscriber

    and hairpins in my experience don’t have berms in them. my i dea of a hairpin is this:

    What do you call the slightly raised & cambered bits at the outside of those curves then ?

    What do you call the slightly raised & cambered bits at the outside of those curves then ?

    +1 🙂
    To the OP, was it one of the ones quite early on? I’m guessing it’s the one about 1:54 in this:
    http://www.youtube.com/watch?v=VoGGBCe1IPk
    In which case, on the current dry loose conditions at Pitfichie, I’d say combination off rubbish front tyre and simply leaning on the front too hard for the conditions. That corner is pretty tight for carrying much speed and I’d agree with those that are saying you simply washed it out and it tucked under on you.

    Premier Icon Northwind
    Subscriber

    You can’t discern anything from how the bike ends up, there’s a lot of energy knocking about in a bike crash, they end up in unexpected places. So since that seems to be all you’re basing the theory on, I’d just say you’re starting from nothing and going nowhere.

    Premier Icon roverpig
    Subscriber

    robinlaidlaw: To the OP, was it one of the ones quite early on? I’m guessing it’s the one about 1:54 in this:
    http://www.youtube.com/watch?v=VoGGBCe1IPk

    Yes, that’s the one. I crashed just where you can hear his brakes squealing, although I don’t remember being on the brakes. Maybe that was my problem. To be honest I’ve never felt comfortable on that particular bend and as you say, the trails are as dry and dusty as I’ve ever seen them.

    Northwind: I’d just say you’re starting from nothing and going nowhere.

    That sounds par for the course :-), although it’s not just how the bike ended up. It’s also how it felt and the fact that I got thrown forwards rather than coming down beside the bike that makes me think the front wheel slipped and turned in too far rather than washing out. But our memories of accidents are notoriously unreliable, so I may just have to chalk this up to experience. Maybe I did go down beside it, but just slid further down the trail, being heavier. I’ve got a few ideas for adjustments to make to setup and technique though, so it’s been a useful discussion.

    Thanks All.

    Premier Icon twonks
    Subscriber

    Sometimes we just crash 😆

    I did exactly that two weeks ago today and don’t remember how I did it or what happened 30 minutes after, and I have a big (ish) bill to repair the damage that I am not sure how happened.

    20 years ago I suggested to a friend that mountain biking needed a crash every now and again to pull back egos and brush up on skills – not sure I entirely agree with that now it hurts a lot more in my 40’s lol.

    Premier Icon jameso
    Subscriber


    Tuck-under .. how a short-trail bike or soft ground increases the risk by reducing the distance between steering axis and contact patch towards the risky overlap area.
    (excuse the scrawl, still got 2 fingers and a thumb with little feeling after too many miles recently)

    Premier Icon rickon
    Subscriber

    Cheers for the diagram James, I like pictures 🙂

    You’d get the same affect from slamming the front brake on to, as that’d cause the front to stutter, lose grip, and tuck.

    That video gives a perfect example of how not to corner, the rider goes in fast, pedaling, and then slams on the brakes during corner. Go in slow, and come out fast – the corner should mean you pick up speed, not lose it.

    Plus he need to clean those brakes 😯

    If it helps about 2 years ago now I had real issues of tucking my wheel in super dry, and then wet conditions. Tyre baldness didn’t help, but ultimately it was not weighting the bike properly.

    Premier Icon gofasterstripes
    Subscriber

    Wut?

    Unless I haven’t reached full caffeination yet and mis-read this: Either the stem bolts are too loose and the stem has rotated around the steerer, or it has not.

    Assuming you haven’t changed them yet, wedge the wheel between your thighs [ooooh, matron] and twist the bars. If you can force the stem to rotate around the steerer without breaking/bending your front wheel then your pinch bolts were/are too loose.

    If it has not then you either pushed your Center of Mass over the effective* edge of the bike’s points of contact with the ground and washed out [perhaps twisting the bars/wheel interface in a bodyslam with the pointy groundy bits] or your breaking and turning did something similar with the rake angle of the forks and their flexation, forcing the bike to pivot over the front [tuck under] and throw you off.

    *I say effective as cornering will force you down against the ground which makes it too complicated for me to try and put into word on a slightly hung-over saturday AM – uhhhhh :zombie mode:

    Premier Icon bruneep
    Subscriber

    Just jump the berms next time.

    Was this on the lower section?

Viewing 29 posts - 1 through 29 (of 29 total)

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