DIY cargo trailer

Discussion in 'Recumbent bicycles' started by [email protected], Jan 18, 2006.

  1. Tags:


  2. [email protected] wrote:
    > A while ago I built my third trailer, made without welding. And this
    > time I did a full photo documentation as I went along:
    >
    > http://drumbent.com/trailer_big.html
    >
    > Cheers,
    > Mark


    Nice.

    I am contemplating building a single wheel trailer (similar to a BOB)
    for carrying children. I don't like the wide unwieldy feel of a 2-wheel
    trailer with such valuable cargo.

    Anyone have any suggestions or tips?

    Joseph
     
  3. On Wed, 18 Jan 2006 11:24:52 -0800, <[email protected]> wrote:

    >
    > [email protected] wrote:
    >> A while ago I built my third trailer, made without welding. And this
    >> time I did a full photo documentation as I went along:
    >>
    >> http://drumbent.com/trailer_big.html
    >>
    >> Cheers,
    >> Mark

    >
    > Nice.
    >
    > I am contemplating building a single wheel trailer (similar to a BOB)
    > for carrying children. I don't like the wide unwieldy feel of a 2-wheel
    > trailer with such valuable cargo.
    >
    > Anyone have any suggestions or tips?
    >
    > Joseph
    >


    Don't. One wheel trailers are excellent for light cargo but any movement
    in the trailer will be transmitted to the bike. I used to use a BOB Coz
    and now use a BOB Yak and then I take my cat to the vet in a carrier in
    the trailer her movement can be felt significantly. A child doing what a
    child does could knock your bike around to a dangerous extent. Two wheel
    trailers are more unwieldy, but more stable for live cargo.

    Lorenzo L. Love
    http://home.thegrid.net/~lllove

    "Americans are broad-minded people. They'll accept the fact that a person
    can be an alcoholic, a dope fiend, a wife beater, and even a newspaperman,
    but if a man doesn't drive there's something wrong with him."
    Art Buchwald
     
  4. Lorenzo L. Love wrote:
    > On Wed, 18 Jan 2006 11:24:52 -0800, <[email protected]> wrote:
    >
    > >
    > > [email protected] wrote:
    > >> A while ago I built my third trailer, made without welding. And this
    > >> time I did a full photo documentation as I went along:
    > >>
    > >> http://drumbent.com/trailer_big.html
    > >>
    > >> Cheers,
    > >> Mark

    > >
    > > Nice.
    > >
    > > I am contemplating building a single wheel trailer (similar to a BOB)
    > > for carrying children. I don't like the wide unwieldy feel of a 2-wheel
    > > trailer with such valuable cargo.
    > >
    > > Anyone have any suggestions or tips?
    > >
    > > Joseph
    > >

    >
    > Don't. One wheel trailers are excellent for light cargo but any movement
    > in the trailer will be transmitted to the bike. I used to use a BOB Coz
    > and now use a BOB Yak and then I take my cat to the vet in a carrier in
    > the trailer her movement can be felt significantly. A child doing what a
    > child does could knock your bike around to a dangerous extent. Two wheel
    > trailers are more unwieldy, but more stable for live cargo.
    >
    > Lorenzo L. Love
    > http://home.thegrid.net/~lllove
    >
    > "Americans are broad-minded people. They'll accept the fact that a person
    > can be an alcoholic, a dope fiend, a wife beater, and even a newspaperman,
    > but if a man doesn't drive there's something wrong with him."
    > Art Buchwald


    Sometimes I ride with one of my kids in a seat mounted where a rear
    rack would go. I notice when they wiggle around, but I think my 215
    pounds sort of anchors us. Do you think a kid's movment on a BOB type
    trailer would have a more pronounced affect? This is a regular bike, so
    the kid's center of gravity is pretty high in the rear mounted seat, vs
    pretty low siting in a roll-caged BOB.

    What about a narrow 2-wheeled trailer, but long for 2-kid tandem
    seating?

    Joseph
     
  5. Ron Ruff

    Ron Ruff Guest

    [email protected] wrote:
    >
    > What about a narrow 2-wheeled trailer, but long for 2-kid tandem
    > seating?


    Off hand, I'd say you either need a single wheel or a *wide* double
    wheel. With two wheels the width is what keeps it from tipping over.
     
  6. Ken M

    Ken M Guest

    Ron Ruff wrote:
    > [email protected] wrote:
    >
    >>What about a narrow 2-wheeled trailer, but long for 2-kid tandem
    >>seating?

    >
    >
    > Off hand, I'd say you either need a single wheel or a *wide* double
    > wheel. With two wheels the width is what keeps it from tipping over.
    >

    How about some sort of narrow tandem design with two wheels say maybe 16
    inches apart?

    Ken
    --
    You never have the wind with you - either it is against you or you're
    having a good day. ~Daniel Behrman, The Man Who Loved Bicycles

    Homepage: http://kcm-home.tripod.com/
     
  7. On Wed, 18 Jan 2006 13:54:28 -0800, Ken M <[email protected]> wrote:

    > Ron Ruff wrote:
    >> [email protected] wrote:
    >>
    >>> What about a narrow 2-wheeled trailer, but long for 2-kid tandem
    >>> seating?

    >> Off hand, I'd say you either need a single wheel or a *wide* double
    >> wheel. With two wheels the width is what keeps it from tipping over.
    >>

    > How about some sort of narrow tandem design with two wheels say maybe 16
    > inches apart?
    >
    > Ken



    Which would be stable as long as the kids didn't shift the trailer's
    center of gravity by more then 8 inches. Look at commercially made
    children trailers. They are all relatively wide for a reason. Even back
    when BOB made a kid's trailer it was a two wheeler. But hey, it's your
    kids.

    Lorenzo L. Love
    http://home.thegrid.net/~lllove

    "The danger of the road is not in the distance,
    Ten yards is far enough to break a wheel."
    Meng Chiao, eighth century A.D.
     
  8. In article <[email protected]>,
    "Lorenzo L. Love" <[email protected]> wrote:

    > On Wed, 18 Jan 2006 13:54:28 -0800, Ken M <[email protected]> wrote:
    >
    > > Ron Ruff wrote:
    > >> [email protected] wrote:
    > >>
    > >>> What about a narrow 2-wheeled trailer, but long for 2-kid tandem
    > >>> seating?
    > >> Off hand, I'd say you either need a single wheel or a *wide* double
    > >> wheel. With two wheels the width is what keeps it from tipping over.
    > >>

    > > How about some sort of narrow tandem design with two wheels say maybe 16
    > > inches apart?
    > >
    > > Ken

    >
    >
    > Which would be stable as long as the kids didn't shift the trailer's
    > center of gravity by more then 8 inches. Look at commercially made
    > children trailers. They are all relatively wide for a reason. Even back
    > when BOB made a kid's trailer it was a two wheeler. But hey, it's your
    > kids.


    Time to bring back swaddling.

    --
    Michael Press
     
  9. Yup. Until you've ridden with a trailer you have no idea how it will
    can behave, both laden and unladen, in an emergency or through driver
    error. The narrow ones will tip over quite easily unless a) they are
    as low as possible, and b) you turn corners quite slowly. For kids you
    definitely want as wide a track as you can get away with.

    My friend Mike built a trailer, and decided to attach it to the bike
    from the rear ala the BOB. Though as you'll read at the bottom of his
    page he was able to inadvertently make it do a complete 360 roll! See:

    http://mbowler.drunkcity.com/cycling/trailler.html

    Mark
     
  10. Yup. Until you've ridden with a trailer you have no idea how it will
    can behave, both laden and unladen, in an emergency or through driver
    error. The narrow ones will tip over quite easily unless a) they are
    as low as possible, and b) you turn corners quite slowly. For kids you
    definitely want as wide a track as you can get away with.

    My friend Mike built a trailer, and decided to attach it to the bike
    from the rear ala the BOB. Though as you'll read at the bottom of his
    page he was able to inadvertently make it do a complete 360 roll! See:

    http://mbowler.drunkcity.com/cycling/trailler.html

    Mark
     
  11. Peter Cole

    Peter Cole Guest

    Lorenzo L. Love wrote:
    > On Wed, 18 Jan 2006 11:24:52 -0800, <[email protected]> wrote:
    >
    >>
    >> [email protected] wrote:
    >>
    >>> A while ago I built my third trailer, made without welding. And this
    >>> time I did a full photo documentation as I went along:
    >>>
    >>> http://drumbent.com/trailer_big.html
    >>>
    >>> Cheers,
    >>> Mark

    >>
    >>
    >> Nice.
    >>
    >> I am contemplating building a single wheel trailer (similar to a BOB)
    >> for carrying children. I don't like the wide unwieldy feel of a 2-wheel
    >> trailer with such valuable cargo.
    >>
    >> Anyone have any suggestions or tips?
    >>
    >> Joseph
    >>

    >
    > Don't. One wheel trailers are excellent for light cargo but any
    > movement in the trailer will be transmitted to the bike. I used to use
    > a BOB Coz and now use a BOB Yak and then I take my cat to the vet in a
    > carrier in the trailer her movement can be felt significantly. A child
    > doing what a child does could knock your bike around to a dangerous
    > extent. Two wheel trailers are more unwieldy, but more stable for live
    > cargo.
    >


    I don't know about that. I pulled a child for 5 years with a
    trailer-bike, and have used a BOB Coz for several years also. Most of my
    riding with them was/is on single-track off-road. 2-wheel trailers want
    to tip, 1-wheelers don't, since they lean in the turns. The downside is
    you'll feel the cargo shift since the trailer is free to flop, but I
    never found it dangerous from a control POV.
     
  12. Peter Cole wrote:
    > Lorenzo L. Love wrote:
    > > On Wed, 18 Jan 2006 11:24:52 -0800, <[email protected]> wrote:
    > >
    > >>
    > >> [email protected] wrote:
    > >>
    > >>> A while ago I built my third trailer, made without welding. And this
    > >>> time I did a full photo documentation as I went along:
    > >>>
    > >>> http://drumbent.com/trailer_big.html
    > >>>
    > >>> Cheers,
    > >>> Mark
    > >>
    > >>
    > >> Nice.
    > >>
    > >> I am contemplating building a single wheel trailer (similar to a BOB)
    > >> for carrying children. I don't like the wide unwieldy feel of a 2-wheel
    > >> trailer with such valuable cargo.
    > >>
    > >> Anyone have any suggestions or tips?
    > >>
    > >> Joseph
    > >>

    > >
    > > Don't. One wheel trailers are excellent for light cargo but any
    > > movement in the trailer will be transmitted to the bike. I used to use
    > > a BOB Coz and now use a BOB Yak and then I take my cat to the vet in a
    > > carrier in the trailer her movement can be felt significantly. A child
    > > doing what a child does could knock your bike around to a dangerous
    > > extent. Two wheel trailers are more unwieldy, but more stable for live
    > > cargo.
    > >

    >
    > I don't know about that. I pulled a child for 5 years with a
    > trailer-bike, and have used a BOB Coz for several years also. Most of my
    > riding with them was/is on single-track off-road. 2-wheel trailers want
    > to tip, 1-wheelers don't, since they lean in the turns. The downside is
    > you'll feel the cargo shift since the trailer is free to flop, but I
    > never found it dangerous from a control POV.


    Most of my riding with the kids will also be on single-track. I was
    figuring on a secure 5-point belt and NASCAR-type webbing to keep the
    arms inside. The seating would be low with the kid's rump about 10" off
    the ground. Given that the kid will be only able to move the head and
    arms and within the width constraints of the narrow cage, and being so
    low, I don't see how they could affect the balance that much.

    Crashing would be a bad thing, but with a single wheel trailer we can
    ride where our only hazards are trees, vs being stuck on roads (lightly
    travelled dirts ones) with a wide trailer where we risk getting mowed
    down.

    Joseph
     
  13. Jon Meinecke

    Jon Meinecke Guest

    <[email protected]> wrote
    >
    > Peter Cole wrote:
    > > Lorenzo L. Love wrote:
    > > >> I am contemplating building a single wheel trailer (similar to a BOB)
    > > >> for carrying children. I don't like the wide unwieldy feel of a

    2-wheel
    > > >> trailer with such valuable cargo.
    > > >>
    > > >> [...]
    > > >
    > > > Don't. One wheel trailers are excellent for light cargo but any
    > > > movement in the trailer will be transmitted to the bike.
    > > > [...] A child
    > > > doing what a child does could knock your bike around to a dangerous
    > > > extent. Two wheel trailers are more unwieldy, but more stable for

    live
    > > > cargo.


    My experience with single-wheeled trailers matches Lorenzo's. In
    my opinion. it's also not just CYA tort-avoidance (though that may
    be a large part) that causes BOB trailers to carry a warning that
    they should not be used to carry kids. There are real design and
    usability issues.

    > > I don't know about that. I pulled a child for 5 years with a
    > > trailer-bike, and have used a BOB Coz for several years also.


    There's significant difference between a child on trail-a-bike and
    a child in a single-wheeled trailer,-- both in the likely age and (self)
    control of the kid, and in the effect of control on the (adult) bike.
    I don't know of any trail-a-bike systems that connect to the
    rear fork as do the BOB trailers.

    > Most of my riding with the kids will also be on single-track
    > [...] Given that the kid will be only able to move the head and
    > arms and within the width constraints of the narrow cage, and being so
    > low, I don't see how they could affect the balance that much.


    I know from experience that as little as 45 "static" lbs in a BOB
    trailer can make handling difficult on *some* bikes on *some*
    surfaces at even only moderate speeds. Google for "BOB trailer
    wobble" in newsgroups to see a number discussions over the
    past years.

    Perhaps it is possible to design a single-wheeled bike trailer and
    bike attachment system that would work well for a purpose-built
    child carrier intended for single-track use. Borrowing a BOB trailer
    and trying some experiments with shifting contents that simulate
    "live" loads would seem like a good starting point.

    Jon Meinecke
     
  14. Bob

    Bob Guest

    [email protected] wrote:

    > Most of my riding with the kids will also be on single-track. I was
    > figuring on a secure 5-point belt and NASCAR-type webbing to keep the
    > arms inside. The seating would be low with the kid's rump about 10" off
    > the ground. Given that the kid will be only able to move the head and
    > arms and within the width constraints of the narrow cage, and being so
    > low, I don't see how they could affect the balance that much.
    >
    > Crashing would be a bad thing, but with a single wheel trailer we can
    > ride where our only hazards are trees, vs being stuck on roads (lightly
    > travelled dirts ones) with a wide trailer where we risk getting mowed
    > down.
    >
    > Joseph


    Helmet, roll cage, secure 5-point belt, and NASCAR-type webbing all
    sounds safe enough (and I'm sure the kids will really enjoy the ride)
    but why stop there? Simply weld a 55 gallon barrel to a BOB Yak
    trailer, insert kid(s), and fill with polystyrene packing peanuts.

    Regards,
    Bob Hunt
     
  15. Peter Cole

    Peter Cole Guest

    [email protected] wrote:
    > Peter Cole wrote:
    >
    >>Lorenzo L. Love wrote:
    >>
    >>>On Wed, 18 Jan 2006 11:24:52 -0800, <[email protected]> wrote:
    >>>
    >>>
    >>>>[email protected] wrote:
    >>>>
    >>>>
    >>>>>A while ago I built my third trailer, made without welding. And this
    >>>>>time I did a full photo documentation as I went along:
    >>>>>
    >>>>>http://drumbent.com/trailer_big.html
    >>>>>
    >>>>>Cheers,
    >>>>>Mark
    >>>>
    >>>>
    >>>>Nice.
    >>>>
    >>>>I am contemplating building a single wheel trailer (similar to a BOB)
    >>>>for carrying children. I don't like the wide unwieldy feel of a 2-wheel
    >>>>trailer with such valuable cargo.
    >>>>
    >>>>Anyone have any suggestions or tips?
    >>>>
    >>>>Joseph
    >>>>
    >>>
    >>>Don't. One wheel trailers are excellent for light cargo but any
    >>>movement in the trailer will be transmitted to the bike. I used to use
    >>>a BOB Coz and now use a BOB Yak and then I take my cat to the vet in a
    >>>carrier in the trailer her movement can be felt significantly. A child
    >>>doing what a child does could knock your bike around to a dangerous
    >>>extent. Two wheel trailers are more unwieldy, but more stable for live
    >>>cargo.
    >>>

    >>
    >>I don't know about that. I pulled a child for 5 years with a
    >>trailer-bike, and have used a BOB Coz for several years also. Most of my
    >>riding with them was/is on single-track off-road. 2-wheel trailers want
    >>to tip, 1-wheelers don't, since they lean in the turns. The downside is
    >>you'll feel the cargo shift since the trailer is free to flop, but I
    >>never found it dangerous from a control POV.

    >
    >
    > Most of my riding with the kids will also be on single-track. I was
    > figuring on a secure 5-point belt and NASCAR-type webbing to keep the
    > arms inside. The seating would be low with the kid's rump about 10" off
    > the ground. Given that the kid will be only able to move the head and
    > arms and within the width constraints of the narrow cage, and being so
    > low, I don't see how they could affect the balance that much.
    >
    > Crashing would be a bad thing, but with a single wheel trailer we can
    > ride where our only hazards are trees, vs being stuck on roads (lightly
    > travelled dirts ones) with a wide trailer where we risk getting mowed
    > down.
    >
    > Joseph
    >


    Practically speaking, if you're going on single-track, one-wheeled
    trailers are the only way to go. That said, given the bumpy ride, the
    "window" for a trailer might only be between ages 2-4 (earliest for
    off-road trailer to earliest for trailer-bike), so I don't know whether
    it's worth the effort.

    I pulled my daughter from age 4 - 9, a weight change from perhaps 40-90
    lb (reaching the limit of the trailer-bike spec.). The trailer-bike had
    a u-joint seatpost mount as opposed to the BOB's rear axle attachment.
    The t-b (Adams) always had a significant amount of play in the joint,
    allowing it to "flop". As my daughter got older and heavier, the flop
    had more effect on balance, but she got much better at balancing
    herself, so flops became rare. Part of the equation is the ratio of
    parent to child weight, I'm sure. I'm a big person (6'10", 235), I'm
    sure a smaller person would have more difficulty with control.

    The low CG of the BOB is nice, but I have caught it on rocks/logs a
    couple of times, once tossing myself over the bars when I came to an
    abrupt stop. The structural members of my BOB are significantly bent
    from frequent collisions. Likewise, the trailer-bike's pedals and
    chainrings got smashed a few times.

    I never crashed with my daughter (100's of rides). You have to be
    careful not to weave too close to trees and the combination rig has a
    tendency to jackknife, especially on soft surfaces with too much front
    brake. On the plus side, the tongue weight completely prevents endos on
    the steepest trail descents. I've never had wobble with either trailer,
    at any speed.

    I would think of a DIY as being a sketchy proposition though,
    particularly with hitch design/fabrication. Some of my friends expressed
    concern over the kind of riding I did with my child, and I admit to the
    occasional second thoughts. I had a few data points such as the Adams
    design being used on tandem trailer-bikes with heavier loads. Even being
    an engineer, I'm not sure I'd have the confidence in my own design/build
    skills to trust my kid's safety to them (or I'd so over-engineer it'd be
    a pig).

    I could see buying a BOB and using it as a platform to mount a child
    seat. It probably wouldn't be any less safe than a lot of the
    contraptions people carry children with, but on singletrack, with such a
    small rear wheel, the ride would would be dangerously harsh for a
    toddler. I'd just wait for trailer-bike age. Although I did less of it
    than the woods, we took the trailer bike on city streets many times,
    even negotiating busy downtown (Boston) loops. The agility of the
    trailer-bike works very well in those conditions.
     
  16. >From what I've read, the seatpost is not the best place for attaching a
    trailer (though it is easier to concoct for the homebuilder).

    What happens upon sudden braking is that the unbraked trailer keeps
    pushing ahead into the bike. If it's mounted to the seatpost it can
    tend to push the bike either up, which is not good if it actually
    causes the rear wheel to lift, or push sideways, which is not good if
    you're trying to maintain control.

    As Peter has stated, his size and weight would probably resist most
    efforts the trailer and cargo might make to influence the bike with
    this design. But for anyone smaller / less weighty the seatpost hitch
    seems to be a risky idea. That's why you no longer see them on
    commercially-built trailers. it's much better to keep the attachment
    point down low, but more difficult to make a good hitch design for that
    by yourself.

    Mark
     
  17. Bob wrote:
    > [email protected] wrote:
    >
    > > Most of my riding with the kids will also be on single-track. I was
    > > figuring on a secure 5-point belt and NASCAR-type webbing to keep the
    > > arms inside. The seating would be low with the kid's rump about 10" off
    > > the ground. Given that the kid will be only able to move the head and
    > > arms and within the width constraints of the narrow cage, and being so
    > > low, I don't see how they could affect the balance that much.
    > >
    > > Crashing would be a bad thing, but with a single wheel trailer we can
    > > ride where our only hazards are trees, vs being stuck on roads (lightly
    > > travelled dirts ones) with a wide trailer where we risk getting mowed
    > > down.
    > >
    > > Joseph

    >
    > Helmet, roll cage, secure 5-point belt, and NASCAR-type webbing all
    > sounds safe enough (and I'm sure the kids will really enjoy the ride)
    > but why stop there? Simply weld a 55 gallon barrel to a BOB Yak
    > trailer, insert kid(s), and fill with polystyrene packing peanuts.
    >
    > Regards,
    > Bob Hunt


    The view would be lousy!

    The idea is to make it safe enough to be able to go fast enough for it
    to be fun, in an amusement park sort of way.

    Joseph
     
  18. Peter Cole wrote:
    > [email protected] wrote:
    > > Peter Cole wrote:
    > >
    > >>Lorenzo L. Love wrote:
    > >>
    > >>>On Wed, 18 Jan 2006 11:24:52 -0800, <[email protected]> wrote:
    > >>>
    > >>>
    > >>>>[email protected] wrote:
    > >>>>
    > >>>>
    > >>>>>A while ago I built my third trailer, made without welding. And this
    > >>>>>time I did a full photo documentation as I went along:
    > >>>>>
    > >>>>>http://drumbent.com/trailer_big.html
    > >>>>>
    > >>>>>Cheers,
    > >>>>>Mark
    > >>>>
    > >>>>
    > >>>>Nice.
    > >>>>
    > >>>>I am contemplating building a single wheel trailer (similar to a BOB)
    > >>>>for carrying children. I don't like the wide unwieldy feel of a 2-wheel
    > >>>>trailer with such valuable cargo.
    > >>>>
    > >>>>Anyone have any suggestions or tips?
    > >>>>
    > >>>>Joseph
    > >>>>
    > >>>
    > >>>Don't. One wheel trailers are excellent for light cargo but any
    > >>>movement in the trailer will be transmitted to the bike. I used to use
    > >>>a BOB Coz and now use a BOB Yak and then I take my cat to the vet in a
    > >>>carrier in the trailer her movement can be felt significantly. A child
    > >>>doing what a child does could knock your bike around to a dangerous
    > >>>extent. Two wheel trailers are more unwieldy, but more stable for live
    > >>>cargo.
    > >>>
    > >>
    > >>I don't know about that. I pulled a child for 5 years with a
    > >>trailer-bike, and have used a BOB Coz for several years also. Most of my
    > >>riding with them was/is on single-track off-road. 2-wheel trailers want
    > >>to tip, 1-wheelers don't, since they lean in the turns. The downside is
    > >>you'll feel the cargo shift since the trailer is free to flop, but I
    > >>never found it dangerous from a control POV.

    > >
    > >
    > > Most of my riding with the kids will also be on single-track. I was
    > > figuring on a secure 5-point belt and NASCAR-type webbing to keep the
    > > arms inside. The seating would be low with the kid's rump about 10" off
    > > the ground. Given that the kid will be only able to move the head and
    > > arms and within the width constraints of the narrow cage, and being so
    > > low, I don't see how they could affect the balance that much.
    > >
    > > Crashing would be a bad thing, but with a single wheel trailer we can
    > > ride where our only hazards are trees, vs being stuck on roads (lightly
    > > travelled dirts ones) with a wide trailer where we risk getting mowed
    > > down.
    > >
    > > Joseph
    > >

    >
    > Practically speaking, if you're going on single-track, one-wheeled
    > trailers are the only way to go. That said, given the bumpy ride, the
    > "window" for a trailer might only be between ages 2-4 (earliest for
    > off-road trailer to earliest for trailer-bike), so I don't know whether
    > it's worth the effort.
    >
    > I pulled my daughter from age 4 - 9, a weight change from perhaps 40-90
    > lb (reaching the limit of the trailer-bike spec.). The trailer-bike had
    > a u-joint seatpost mount as opposed to the BOB's rear axle attachment.
    > The t-b (Adams) always had a significant amount of play in the joint,
    > allowing it to "flop". As my daughter got older and heavier, the flop
    > had more effect on balance, but she got much better at balancing
    > herself, so flops became rare. Part of the equation is the ratio of
    > parent to child weight, I'm sure. I'm a big person (6'10", 235), I'm
    > sure a smaller person would have more difficulty with control.
    >
    > The low CG of the BOB is nice, but I have caught it on rocks/logs a
    > couple of times, once tossing myself over the bars when I came to an
    > abrupt stop. The structural members of my BOB are significantly bent
    > from frequent collisions. Likewise, the trailer-bike's pedals and
    > chainrings got smashed a few times.
    >
    > I never crashed with my daughter (100's of rides). You have to be
    > careful not to weave too close to trees and the combination rig has a
    > tendency to jackknife, especially on soft surfaces with too much front
    > brake. On the plus side, the tongue weight completely prevents endos on
    > the steepest trail descents. I've never had wobble with either trailer,
    > at any speed.
    >
    > I would think of a DIY as being a sketchy proposition though,
    > particularly with hitch design/fabrication. Some of my friends expressed
    > concern over the kind of riding I did with my child, and I admit to the
    > occasional second thoughts. I had a few data points such as the Adams
    > design being used on tandem trailer-bikes with heavier loads. Even being
    > an engineer, I'm not sure I'd have the confidence in my own design/build
    > skills to trust my kid's safety to them (or I'd so over-engineer it'd be
    > a pig).
    >
    > I could see buying a BOB and using it as a platform to mount a child
    > seat. It probably wouldn't be any less safe than a lot of the
    > contraptions people carry children with, but on singletrack, with such a
    > small rear wheel, the ride would would be dangerously harsh for a
    > toddler. I'd just wait for trailer-bike age. Although I did less of it
    > than the woods, we took the trailer bike on city streets many times,
    > even negotiating busy downtown (Boston) loops. The agility of the
    > trailer-bike works very well in those conditions.


    The whole point is to open up new possibilities for rides with the
    kids, who are of varying ages and cycling abilities. A trailer that was
    "cool" and was enough fun that other kids would even want to try is the
    idea. My kids like action and speed, so I want to give it to them for
    as long as I can, til the day comes when I can't keep up with them
    anymore.

    The main issues I have thought about so far are stability, and
    survivability. A crash isn't that big a deal if everyone is well
    protected, and there is no danger of being run over by a car. I was
    figuring on some sort of dual ball-joint type of flex coupling, mounted
    on some sort of bracket to the back skewer, or clamped to the stays.
    The idea is to have some adjustability to be able to tune the
    stability, and ball joints so as not to have any slop/flop. I built a
    few race car suspensions a million years ago, and no one got killed, so
    I'm not too worried about building a robust trailer. A strong
    bash-gaurd/skid plate was also something I planned on so as not to have
    the whole contraption get caught on a root or something. I was also
    thinking about using a suspended 24" wheel.

    Joseph
     
  19. ellis

    ellis Guest

  20. My friend is not using the trailer at the moment, since she has not yet
    become a winter cyclist (making it handy for me to borrow back until I
    build my own). But once she starts using it in the Spring we plan to
    get photos of her towing her dog in it.

    Mark
     
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