C
Chalo
Guest
I am trying to buy, build, or adapt a bike trailer for my
electric-assist bike. It will carry 60-80 lbs. of batteries at all
times and hopefully will have room for some groceries. I expect speeds
of 25mph or more, so the trailer's handling qualities at speed are my
greatest concern. I wish to solicit input from those who have used
trailers, in order to help me narrow my choices down to one general
mounting point and pivot location. The trailers I have seen to date
fall into one of three categories:
1) seatpost mount (e.g. CycleTote)
2) left chainstay and/or seatstay mount (e.g. Burley Flatbed)
3) axle mount, rear pivot (e.g. B.O.B. Yak)
Right up front I think it is best to eliminate trailers of the third
category, since the swinging rear-mounted pivot looks like an
invitation to chronic shimmy problems at the speeds I will be
traveling. Furthermore, I'm using a SRAM 7-speed gearhub whose right
axle nut is enclosed by the shifting mechanism and will not be a
feasible location for BOB Nutz or anything like them.
Mounting a trailer of the second type will be complicated: The bike's
stays are elliptical in cross-section and curved along their length,
and thus they present a less-than-ideal place to clamp a hitch mount.
The left side axle stub is short, and it is more or less taken up by a
thick anti-rotation washer. I would have to machine a new part that
functions both as an anti-rotation washer and as a trailer hitch if I
opt to use a trailer that attaches to the rear axle. However, to me it
looks like this mounting location might be the best one insofar as it
may impose the smallest steering forces upon the bicycle.
The least complicated prospective mounting point, mechanically
speaking, is the seatpost. It would be easy for me to make or buy a
satisfactory and secure trailer with a hitch of this type. My concern
with it is that the pivot point will be high on the bike and not
especially close to the bike's yaw axis (which I assume to be a line
passing through the rear contact patch and the rear hub). I'm curious
what effect a seatpost hitch may have on the bike's handling and
stability.
A seatpost hitch would allow the use of a single-wheel trailer, if that
is much preferable to a two-wheeled trailer handling-wise. I had even
considered stripping down a Trail-a-Bike or the like to just the frame
and wheel, and mounting my batteries on the frame. The drawback there
is that I would be left with little or no space for cargo.
I appreciate all relevant input.
Chalo
electric-assist bike. It will carry 60-80 lbs. of batteries at all
times and hopefully will have room for some groceries. I expect speeds
of 25mph or more, so the trailer's handling qualities at speed are my
greatest concern. I wish to solicit input from those who have used
trailers, in order to help me narrow my choices down to one general
mounting point and pivot location. The trailers I have seen to date
fall into one of three categories:
1) seatpost mount (e.g. CycleTote)
2) left chainstay and/or seatstay mount (e.g. Burley Flatbed)
3) axle mount, rear pivot (e.g. B.O.B. Yak)
Right up front I think it is best to eliminate trailers of the third
category, since the swinging rear-mounted pivot looks like an
invitation to chronic shimmy problems at the speeds I will be
traveling. Furthermore, I'm using a SRAM 7-speed gearhub whose right
axle nut is enclosed by the shifting mechanism and will not be a
feasible location for BOB Nutz or anything like them.
Mounting a trailer of the second type will be complicated: The bike's
stays are elliptical in cross-section and curved along their length,
and thus they present a less-than-ideal place to clamp a hitch mount.
The left side axle stub is short, and it is more or less taken up by a
thick anti-rotation washer. I would have to machine a new part that
functions both as an anti-rotation washer and as a trailer hitch if I
opt to use a trailer that attaches to the rear axle. However, to me it
looks like this mounting location might be the best one insofar as it
may impose the smallest steering forces upon the bicycle.
The least complicated prospective mounting point, mechanically
speaking, is the seatpost. It would be easy for me to make or buy a
satisfactory and secure trailer with a hitch of this type. My concern
with it is that the pivot point will be high on the bike and not
especially close to the bike's yaw axis (which I assume to be a line
passing through the rear contact patch and the rear hub). I'm curious
what effect a seatpost hitch may have on the bike's handling and
stability.
A seatpost hitch would allow the use of a single-wheel trailer, if that
is much preferable to a two-wheeled trailer handling-wise. I had even
considered stripping down a Trail-a-Bike or the like to just the frame
and wheel, and mounting my batteries on the frame. The drawback there
is that I would be left with little or no space for cargo.
I appreciate all relevant input.
Chalo