Custom bike geometry questions

Discussion in 'Cycling Equipment' started by Michael, Apr 1, 2003.

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  1. Michael

    Michael Guest

    I'm having a custom bike built and want opinions on some of the unusual aspects I'm having done
    (especially as the custom geometry affects bike handling).

    This will be a commuting bike, especially for wet weather and winter. A road bike is very important
    to me, so don't even open a debate on the right kind of bike for commuting.

    Personal requirements for the bike, in order of importance: 1) Road bike with traditional road
    geometry (73/73 angles with short wheelbase
    - not cyclocross, not touring) 2) Wet weather capable (disc brakes, fenders) 3) Versatile (rack
    mounts, triple drivetrain). My biggest concern is bike handling - I love the quick and stable
    handling of my current Cannondale road bike - I basically want that with disc brakes and fenders.

    So... I'm having Litespeed build a custom Tuscany (comes with the same geometry as the Cannondale),
    plus disc brake mounts, rack and fender mounts, non-integrated headset, and 135mm axle spacing (to
    fit disc hubs).

    Here are the open questions I want to resolve:

    1) I could go with the standard Tuscany 57cm frame dimensions (56.5cm top tube length) since it's
    close to my cannondale (58cm road frame with 58cm top tube) and I've ridden a stock one and like
    it. Or I could go to the exact dimensions the fit kit suggests - 55cm frame with 58cm top tube,
    but then there's some risk it'll feel different or handle differently. Opinions?

    2) Litespeed says that to fit the fenders, the chainstays will have to be lengthened about 1 cm.
    Would that affect handling? I don't like Cyclocross geometry because the bikes don't lean
    into high speed turns as well as the road geometry (is that because of the longer wheelbase
    or the slacker steering angle?) I still want this bike to take high speed turns as well as
    the stock Tuscany.

    3) I'll need an aftermarket or custom fork with disc mounts. The ones I've seen for 700c wheels have
    a 45mm or 50mm rake compared to the stock 40mm rake of the Tuscany and my Cannondale. What
    steering/handling impacts would that have?

    If I get a custom fork built with 40mm rake, what would be the best material - ti (probably best
    but most expensive?), steel (cheaper but heavier? though weight isn't really an issue for me),
    carbon (can be done?)?

    Thanks
     
    Tags:


  2. Harris

    Harris Guest

    Michael <[email protected]> wrote:
    > I'm having a custom bike built and want opinions

    > This will be a commuting bike, especially for wet weather and winter.

    > So... I'm having Litespeed build a custom Tuscany (comes with the same geometry as the
    > Cannondale), plus disc brake mounts, rack and fender mounts, non-integrated headset, and 135mm
    > axle spacing (to fit disc hubs).

    This sounds kinda pricey for a wet weather commuter bike.

    > Litespeed says that to fit the fenders, the chainstays will have to be lengthened about 1 cm.
    > Would that affect handling? I don't like Cyclocross geometry because the bikes don't lean into
    > high speed turns as well as the road geometry (is that because of the longer wheelbase or the
    > slacker steering angle?) I still want this bike to take high speed turns as well as the stock
    > Tuscany.

    No problem. Did you ever see the chainstays on Jobst's bike? They must be over 45cm, and he leans
    into turns quite well!

    http://www-math.science.unitn.it/Bike/Countries/Europe/Tour_Reports/Tour_of_the_Alps_Gallery/ti-
    retest.jpg

    Art Harris
     
  3. Michael

    Michael Guest

    > This sounds kinda pricey for a wet weather commuter bike.
    >

    Well, it's an "any-weather" commuting bike. Thus the disc brakes for rain and the road racing
    geometry for going fast in nice weather.
     
  4. Ted Shwartz

    Ted Shwartz Guest

    Michael

    I had similar ideas when I had my bike made up...

    I ended up with wheels with ceramic rims, and ceramic brake pads. My braking is good, dry or
    wet. The design of the bike is much more conventional since I use regular brake (albeit long
    reach brakes, because of fenders). You get to use a conventional fork this way.

    Longer chain stays are good for commuter/touring bikes. Your feet will not hit the panniers.

    Watch out for fender clearances. Have the mfg put in attachment points for the fenders by
    your bottom bracket and under your fork. This way your fenders will not vibrate as much.

    Ted

    "Michael" <[email protected]> wrote in message
    news:[email protected]...
    > I'm having a custom bike built and want opinions on some of the unusual aspects I'm having done
    > (especially as the custom geometry affects bike handling).
    >
    > This will be a commuting bike, especially for wet weather and winter. A road bike is very
    > important to me, so don't even open a debate on the right kind of bike for commuting.
    >
    > Personal requirements for the bike, in order of importance: 1) Road bike with traditional road
    > geometry (73/73 angles with short wheelbase
    > - not cyclocross, not touring) 2) Wet weather capable (disc brakes, fenders) 3) Versatile (rack
    > mounts, triple drivetrain). My biggest concern is bike handling - I love the quick and stable
    > handling of my current Cannondale road bike - I basically want that with disc brakes and
    > fenders.
    >
    > So... I'm having Litespeed build a custom Tuscany (comes with the same geometry as the
    > Cannondale), plus disc brake mounts, rack and fender mounts, non-integrated headset, and 135mm
    > axle spacing (to fit disc hubs).
    >
    > Here are the open questions I want to resolve:
    >
    > 1) I could go with the standard Tuscany 57cm frame dimensions (56.5cm top tube length) since it's
    > close to my cannondale (58cm road frame with 58cm top tube) and I've ridden a stock one and
    > like it. Or I could go to the exact dimensions the fit kit suggests - 55cm frame with 58cm top
    > tube, but then there's some risk it'll feel different or handle differently. Opinions?
    >
    > 2) Litespeed says that to fit the fenders, the chainstays will have to be lengthened about 1 cm.
    > Would that affect handling? I don't like Cyclocross geometry because the bikes don't lean into
    > high speed turns as well as the road geometry (is that because of the longer wheelbase or the
    > slacker steering angle?) I still want this bike to take high speed turns as well as the stock
    > Tuscany.
    >
    > 3) I'll need an aftermarket or custom fork with disc mounts. The ones I've seen for 700c wheels
    > have a 45mm or 50mm rake compared to the stock 40mm rake of the Tuscany and my Cannondale. What
    > steering/handling impacts would that have?
    >
    > If I get a custom fork built with 40mm rake, what would be the best material - ti (probably best
    > but most expensive?), steel (cheaper but heavier? though weight isn't really an issue for me),
    > carbon (can be done?)?
    >
    > Thanks
     
  5. Terry Morse

    Terry Morse Guest

    Ted Shwartz wrote:

    > I ended up with wheels with ceramic rims, and ceramic brake pads. My braking is good, dry or wet.

    How does a ceramic braking surface make for good braking? I know that ceramic have good wear
    resistance, but how could that possibly improve braking over bare aluminum?
    --
    terry morse Palo Alto, CA http://www.terrymorse.com/bike/
     
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