Twitchy steering fix?

Discussion in 'Cycling Equipment' started by al sharff, Jun 26, 2008.

  1. al sharff

    al sharff Guest

    --
    I bought an Independent Fabrication steel Crown Jewel used - it's a
    stock frame (non custom) with an IF steel fork - straight blades.

    It has very "twitchy" steering when I'm in a descending tight corner.
    I tend to oversteer in those situations. The bike feels like it pulls
    into the turn to a point where I'm about to loose control.

    To compare I have a Trek 5200 (new in 2000, 60cm frame) that I use the
    same wheels on and has almost the same fit. The only major difference
    I can find with my tape measure is the IF has 42cm handlebars while the
    Trek has 44cm. I never notice my cornering problem when I'm on the
    Trek.

    Anyone have opinions on how I can "smooth out" (or slow down, or make
    it less responsive) the high speed cornering on the IF bike? Will
    different forks make a difference - any advise on what to go to? Any
    other changes that make make a difference in handling?

    Thanks,

    Al Sharff
     
    Tags:


  2. Tom Kunich

    Tom Kunich Guest

    "al sharff" <[email protected]> wrote in message
    news:[email protected]
    >
    > I bought an Independent Fabrication steel Crown Jewel used - it's a
    > stock frame (non custom) with an IF steel fork - straight blades.
    >
    > It has very "twitchy" steering when I'm in a descending tight corner.
    > I tend to oversteer in those situations. The bike feels like it pulls
    > into the turn to a point where I'm about to loose control.


    This is probably caused by too much "trail" in the steering. This is easy to
    fix by replacing the fork. The trouble is finding which fork has the correct
    trail for your frame. This requires pretty much a good frame designer to
    know.
     
  3. landotter

    landotter Guest

    On Jun 26, 4:25 pm, "al sharff" <[email protected]> wrote:
    > --
    > I bought an Independent Fabrication steel Crown Jewel used - it's a
    > stock frame (non custom) with an IF steel fork - straight blades.
    >
    > It has very "twitchy" steering when I'm in a descending tight corner.
    > I tend to oversteer in those situations.  The bike feels like it pulls
    > into the turn to a point where I'm about to loose control.
    >
    > To compare I have a Trek 5200 (new in 2000, 60cm frame) that I use the
    > same wheels on and has almost the same fit.  The only major difference
    > I can find with my tape measure is the IF has 42cm handlebars while the
    > Trek has 44cm.  I never notice my cornering problem when I'm on the
    > Trek.
    >
    > Anyone have opinions on how I can "smooth out" (or slow down, or make
    > it less responsive) the high speed cornering on the IF bike?  Will
    > different forks make a difference - any advise on what to go to?  Any
    > other changes that make make a difference in handling?


    Track bikes have less trail usually and are inherently less stable
    because they're meant to be ridden differently than road bikes. Not a
    whole lot you can do other than swap out for wider handlebars so that
    more input means less response. There might be a way to fit a fork in
    there to give you some more trail, but that's bigger bux, and the
    clearances are already tight.


    If you're really uncomfortable with the handling of a track bike on
    the road--sell it and buy a single speed bike with road geometry like
    a Salsa Casserole, Redline 925, Kona Paddy Wagon, etc, instead of
    making bunging up this bike. I've ridden a bike with a fork I hated
    for a couple years--a crazy short trail old Tange crit fork, and the
    twitchy handling can drive one nuts. Better to offload it to someone
    that enjoys it.
     
  4. On Jun 26, 4:25 pm, "al sharff" <[email protected]> wrote:
    > --
    > I bought an Independent Fabrication steel Crown Jewel used - it's a
    > stock frame (non custom) with an IF steel fork - straight blades.
    >
    > It has very "twitchy" steering when I'm in a descending tight corner.
    > I tend to oversteer in those situations.  The bike feels like it pulls
    > into the turn to a point where I'm about to loose control.
    >
    > To compare I have a Trek 5200 (new in 2000, 60cm frame) that I use the
    > same wheels on and has almost the same fit.  The only major difference
    > I can find with my tape measure is the IF has 42cm handlebars while the
    > Trek has 44cm.  I never notice my cornering problem when I'm on the
    > Trek.
    >
    > Anyone have opinions on how I can "smooth out" (or slow down, or make
    > it less responsive) the high speed cornering on the IF bike?  Will
    > different forks make a difference - any advise on what to go to?  Any
    > other changes that make make a difference in handling?


    Talk to IF. I didn't see a geometry table for the CJ. Steep head
    angles (common in track bikes) need less fork rake (offset) to have
    the same trail as a (commonly, usually, often, etc.) slacker-angled
    road frame.

    (Is it plugged in dept): Is the headset on the IF in good shape and
    adjusted correctly?

    Grabbed a table:

    http://www.bianchiusa.com/07_pista_concept.html#

    28mm rake on 74-75deg head tube angle. Hmmm... 1.1", about what the
    builder of my track bike said he built for that bike, with
    "about" (or, "at least") 75deg head tube angle.

    If you find a real (oval blades, straight brake bolt hole <g>) road
    fork with 28mm rake, let me know, would you?

    Although I haven't had any problems with the old "Cinelli" (and maybe
    it is a Cinelli) road fork that's in the bike for FG road use, which
    is probably a 43-45mm offset, I'd like to have something closer or the
    same as the original fork, as that bike handled great on the track and
    was not "twitchy", nor did it tighten line in corners unless I wanted
    it to.

    Please. "Responsive". Typical of the track bikes I've ridden (not
    many, true enough, but I went through the rental fleet at Alkek),
    rides straight just fine, turns quickly when asked. Not "twitchy".
    Doesn't tighten line unless you want. Steep head tube angle, short
    rake. --D-y
     
  5. landotter wrote:

    >> It has very "twitchy" steering when I'm in a descending tight corner.
    >> I tend to oversteer in those situations.


    Well, don't do that...

    > The bike feels like it pulls
    >> into the turn to a point where I'm about to loose control.
    >>
    >> To compare I have a Trek 5200 (new in 2000, 60cm frame) that I use the
    >> same wheels on and has almost the same fit. The only major difference
    >> I can find with my tape measure is the IF has 42cm handlebars while the
    >> Trek has 44cm. I never notice my cornering problem when I'm on the
    >> Trek.
    >>
    >> Anyone have opinions on how I can "smooth out" (or slow down, or make
    >> it less responsive) the high speed cornering on the IF bike?


    I think that you will become accustomed to the way the IF bike handles.
    Think about what you are asking. Why would you want a bike which is
    _less_ responsive? Ride it for a while, and see if you become more
    comfortable with it.

    > Track bikes have less trail usually and are inherently less stable
    > because they're meant to be ridden differently than road bikes.


    BS. Track bikes have shorter fork rake, thus more trail, than road
    bikes. But they also do not handle badly just because they are track
    bikes. My track bike has always been the best-handling bike I ever
    owned. I can ride it for long periods no hands, and it is as responsive
    as any bike can be.

    But this nonsense of track bikes being ridden "differently" than road
    bikes. How different? Why would you want poorer handling with a track
    bike? You wouldn't.

    Not a
    > whole lot you can do other than swap out for wider handlebars so that
    > more input means less response.


    Let's see. The difference between 42cm bars and 44cm bars is less than
    5%. Not very impressive. Get the bars that fit your body.

    --

    David L. Johnson

    Anyone who is capable of getting themselves made President should on
    no account be allowed to do the job.
    -- Douglas Adams
     
  6. landotter

    landotter Guest

    On Jun 26, 9:11 pm, "David L. Johnson" <[email protected]>
    wrote:
    > landotter wrote:
    > >> It has very "twitchy" steering when I'm in a descending tight corner.
    > >> I tend to oversteer in those situations.  

    >
    > Well, don't do that...
    >
    > > The bike feels like it pulls
    > >> into the turn to a point where I'm about to loose control.

    >
    > >> To compare I have a Trek 5200 (new in 2000, 60cm frame) that I use the
    > >> same wheels on and has almost the same fit.  The only major difference
    > >> I can find with my tape measure is the IF has 42cm handlebars while the
    > >> Trek has 44cm.  I never notice my cornering problem when I'm on the
    > >> Trek.

    >
    > >> Anyone have opinions on how I can "smooth out" (or slow down, or make
    > >> it less responsive) the high speed cornering on the IF bike?  

    >
    > I think that you will become accustomed to the way the IF bike handles.
    >   Think about what you are asking.  Why would you want a bike which is
    > _less_ responsive?  Ride it for a while, and see if you become more
    > comfortable with it.
    >
    > > Track bikes have less trail usually and are inherently less stable
    > > because they're meant to be ridden differently than road bikes.

    >
    > BS.  Track bikes have shorter fork rake, thus more trail, than road
    > bikes.  But they also do not handle badly just because they are track
    > bikes.  My track bike has always been the best-handling bike I ever
    > owned.  I can ride it for long periods no hands, and it is as responsive
    > as any bike can be.
    >
    > But this nonsense of track bikes being ridden "differently" than road
    > bikes.  How different?  Why would you want poorer handling with a track
    > bike?  You wouldn't.
    >


    Track bikes have less trail because of the steeper head angle, thus
    needing less rake or offset to dial in the trail.I've had a bike with
    very quick handling from a really curvy fork with tons of rake--which
    isn't poor handling--but it can feel "nervous" to someone that's not
    used to it. It's supposedly good for when you're doing a lot of
    standing and muscling around and want very little caster effect, and
    just want point and squirt. My setup was said to be more "crit" from a
    guy that was more expert than I am--but still in the same idea of
    close quarters riding of laps on a circuit, but with a bike that has
    gears and brakes.

    At any rate, my current fixed gear is set up as classic as a road bike
    can get with 72.5 angles, etc--and it's a different creature
    altogether. It feels slower, but a lot more secure due to the longer
    trail. On long sweeps you can really just pick a line instead of
    feeling like you're being sucked down like with a shorter trail bike
    that demands to be steered.
     
  7. jim beam

    jim beam Guest

    al sharff wrote:
    >
    > I bought an Independent Fabrication steel Crown Jewel used - it's a
    > stock frame (non custom) with an IF steel fork - straight blades.
    >
    > It has very "twitchy" steering when I'm in a descending tight corner.
    > I tend to oversteer in those situations. The bike feels like it pulls
    > into the turn to a point where I'm about to loose control.
    >
    > To compare I have a Trek 5200 (new in 2000, 60cm frame) that I use the
    > same wheels on and has almost the same fit. The only major difference
    > I can find with my tape measure is the IF has 42cm handlebars while the
    > Trek has 44cm. I never notice my cornering problem when I'm on the
    > Trek.
    >
    > Anyone have opinions on how I can "smooth out" (or slow down, or make
    > it less responsive) the high speed cornering on the IF bike? Will
    > different forks make a difference - any advise on what to go to? Any
    > other changes that make make a difference in handling?


    you can try monkeying about with different forks, but given that the
    frame appears to be standard diameter steel tube, i wouldn't hold out
    much hope. i'd stick the trek personally. or get a big tube aluminum
    frame. big diameter tubes are very torsionally stiff and pretty much
    eliminate this kind of problem. modern thin wall steel tube, especially
    in standard diameters, is not very stiff.
     
  8. On Jun 26, 9:11 pm, "David L. Johnson" <[email protected]>
    wrote:
    (Someone opined):
    > > Track bikes have less trail usually and are inherently less stable
    > > because they're meant to be ridden differently than road bikes.


    (DLJ replied):
    > BS.


    Well said! Continuing:

    > Track bikes have shorter fork rake, thus more trail, than road
    > bikes.  But they also do not handle badly just because they are track
    > bikes.  My track bike has always been the best-handling bike I ever
    > owned.  I can ride it for long periods no hands, and it is as responsive
    > as any bike can be.


    Same here. Track bike, one road bike, a Roberts Crit/TT bike, IMS
    74deg head tube, 1" of rake. Maybe 1.25, I believe it was 1" though.

    Maybe A. Muzi will remember those as I think he was USA importer?

    My favorite road bike, ever. Rode straight straight straight, turned
    "now".

    > But this nonsense of track bikes being ridden "differently" than road
    > bikes.  How different?  Why would you want poorer handling with a track
    > bike?  You wouldn't.


    250m, or shorter track (constant cornering), steep banking (over 40deg
    for some tracks), people turning uptrack and down, no brakes. And
    having to stay within fairly narrow lanes, etc. etc. Tight packs, no
    freewheeling "saves", the pedals go around when the rear wheel does.

    No, not the place for a "twitchy" bike.

    Can we please put that one in the grave where it belongs?

    I think it's pretty funny that if "everyone" could ride that Roberts,
    IMHO road steering geometry fashion would change overnight.

    > Let's see.  The difference between 42cm bars and 44cm bars is less than
    > 5%.  Not very impressive.  Get the bars that fit your body.


    I have a twitchy road bike (steep head angle, too much rake); putting
    44's (c-c) made it even more wobbly. I'd say by at least 5% <g> and
    wouldn't that be 10% if you count both sides (wobble implying left and
    right)? --D-y
     
  9. landotter

    landotter Guest

    On Jun 27, 9:57 am, "[email protected]" <[email protected]> wrote:
    > On Jun 26, 9:11 pm, "David L. Johnson" <[email protected]>
    > wrote:
    > (Someone opined):
    >
    > > > Track bikes have less trail usually and are inherently less stable
    > > > because they're meant to be ridden differently than road bikes.

    >
    > (DLJ replied):
    >
    > > BS.

    >
    > Well said! Continuing:
    >
    > > Track bikes have shorter fork rake, thus more trail, than road
    > > bikes.  But they also do not handle badly just because they are track
    > > bikes.  My track bike has always been the best-handling bike I ever
    > > owned.  I can ride it for long periods no hands, and it is as responsive
    > > as any bike can be.

    >
    > Same here. Track bike, one road bike, a Roberts Crit/TT bike, IMS
    > 74deg head tube, 1" of rake. Maybe 1.25, I believe it was 1" though.
    >
    > Maybe A. Muzi will remember those as I think he was USA importer?
    >
    > My favorite road bike, ever. Rode straight straight straight, turned
    > "now".
    >
    > > But this nonsense of track bikes being ridden "differently" than road
    > > bikes.  How different?  Why would you want poorer handling with a track
    > > bike?  You wouldn't.

    >
    > 250m, or shorter track (constant cornering), steep banking (over 40deg
    > for some tracks), people turning uptrack and down, no brakes. And
    > having to stay within fairly narrow lanes, etc. etc. Tight packs, no
    > freewheeling "saves", the pedals go around when the rear wheel does.
    >
    > No, not the place for a "twitchy" bike.
    >
    > Can we please put that one in the grave where it belongs?


    Shorter trail, less caster. It's basic bike frame design. Perhaps you
    can't feel the effects and dismiss it--don't get a big head about it.
     
  10. On Jun 27, 11:20 am, landotter <[email protected]> wrote:

    > Shorter trail, less caster. It's basic bike frame design. Perhaps you
    > can't feel the effects and dismiss it--don't get a big head about it.


    Where does "shorter trail" come from?

    If you look in here (scroll down to charts):

    <http://www.johnforester.com/Articles/BicycleEng/Kvale%20Geometry.pdf>

    you'll see a "track geometry" such as 75deg, 30mm rake, having the
    same or more trail as a "road" geometry of 73-73.5deg, 40-45mm rake
    (the lower range available in road forks, "average" head angle for
    road frames).

    Wondering at your rhetoric dept:

    Caster?

    "Princess and the Pea", reversed?

    "Big head"?

    My Goodness! Sounds like someone is losing an argument here. Tsk tsk!
    --D-y
     
  11. 531Aussie

    531Aussie Well-Known Member

    Joined:
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    This is no guarantee, but maybe try a stiff, broad-bladed carbon fork, preferably with an alu steerer.

    I had an a 1988 531c Raleigh, which always got the wobbles when I rode no hands over about 40km, but it was significantly stablised when I put on a new 1" Roselli fork on it. I now have the Roselli fork on my steel Cervelo Superprodigy, because it rides better than the 1" Columbus Muscle which came with the frame

    The ITM Visia forks are also very stiff
     
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