Roll Your Own Tandem Child Stoker Kit?
Steve Freides
I have a few reasons for wanting to "roll my own" here, the main reason
being that most of the options I've seen have the chain ring permanently
affixed to the spindle. I would like the flexibility to choose the
crank length and ring size as I see fit.
To elaborate a bit, my oldest now rides 150mm cranks on his single bike,
but our child stoker kit has 125mm cranks that appear to be Sugino
arms. I would like, on the kit I'm going to build for my youngest, to
be able to give him 125mm cranks now and 150's later. This stoker kit
is going on the middle seat of our triplet so we will not have the
problem with hitting the front derailleur that we would have on the
tandem.
I'm also searching for a good source for 125mm and 150mm cranks.
Because of the multiple uses they may have, I need to get left cranks
with a spider and right cranks with and without a spider.
The BB shell seems like an easy-to-get item and will give me the
flexibility to choose my own BB and, therefore, the best spindle length.
If anyone has any used equipment I could use here, please let me know.
Thanks in advance for comments and suggestions.
-S-
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I ride:
1999 Bilenky (2x9 Ergo)
1981 TI-Raleigh Team (2x6 Super Record)
Unknown Bianchi Special (fixed)
1970's Araya (fixed)
1994 Bilenky Tandem (3x9 Ergo)
1994 Trek 750 Hybrid (3x7 RapidFire)
Sheldon Brown
>
> [also posted on the tandem mailing list]
>
> I have a few reasons for wanting to "roll my own" here, the main reason
> being that most of the options I've seen have the chain ring permanently
> affixed to the spindle. I would like the flexibility to choose the
> crank length and ring size as I see fit.
>
> To elaborate a bit, my oldest now rides 150mm cranks on his single bike,
> but our child stoker kit has 125mm cranks that appear to be Sugino
> arms. I would like, on the kit I'm going to build for my youngest, to
> be able to give him 125mm cranks now and 150's later. This stoker kit
> is going on the middle seat of our triplet so we will not have the
> problem with hitting the front derailleur that we would have on the
> tandem.
>
> I'm also searching for a good source for 125mm and 150mm cranks.
> Because of the multiple uses they may have, I need to get left cranks
> with a spider and right cranks with and without a spider.
Not pretty enought to put on a Bilenky, probably, but...
When my kids were little, I made my own stokid adaptors from parts
salvaged from low-end bike frames. I cut the bottom brackets out of a
couple of Huffys, leaving a few inches of seat tube and down tube attached.
From my homebuilt tandem construction, I also had left over a couple of
half head tubes (the front half.) I mitered the tube stubs on the Huffy
bottom brackets and brazed them to the half-cylindrical head tube parts.
The half-head tubes were a good fit against the seat tube, and I secured
them in place with 3 worm-drive hose clamps.
This rig uses "Ashtabula" type one-piece cranks, which have a number of
advantages in this application:
匹ranks are readily available in a wide variety of lengths for about
$15 each.
謬he crank can be replaced independantly of the chainring.
漂ou can reverse left/right pretty easily, as long as you tignten
everything down securely (stokid stresses are much lower than adult stresses.)
標hen the kids were quite small, I was able to install Shimano "Front
Freewheel" mechanisms, so the stokid could coast while the parent
continued to pedal.
We got a lot of use out of these, including multi-day tours.
For more about this, see:
http://www.sheldonbrown.com/tandem_build.html
and
http://www.sheldonbrown.com/chartres.html
Sheldon "On My Way To Take My First Stokid Off To Cornell University" Brown
Newtonville, Massachusetts
+-----------------------------------------+
| A ship in the harbor is safe, but |
| that is not what ships are built for. |
| --John A. Shedd |
+-----------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772, 617-244-1040 FAX 617-244-1041
http://www.sheldonbrown.com/harris
Hard-to-find parts shipped Worldwide
John Thompson
>[also posted on the tandem mailing list]
>
>I have a few reasons for wanting to "roll my own" here, the main reason
>being that most of the options I've seen have the chain ring permanently
>affixed to the spindle. I would like the flexibility to choose the
>crank length and ring size as I see fit.
>
>To elaborate a bit, my oldest now rides 150mm cranks on his single bike,
>but our child stoker kit has 125mm cranks that appear to be Sugino
>arms. I would like, on the kit I'm going to build for my youngest, to
>be able to give him 125mm cranks now and 150's later. This stoker kit
>is going on the middle seat of our triplet so we will not have the
>problem with hitting the front derailleur that we would have on the
>tandem.
>
>I'm also searching for a good source for 125mm and 150mm cranks.
>Because of the multiple uses they may have, I need to get left cranks
>with a spider and right cranks with and without a spider.
>
>The BB shell seems like an easy-to-get item and will give me the
>flexibility to choose my own BB and, therefore, the best spindle length.
>
>If anyone has any used equipment I could use here, please let me know.
>
>Thanks in advance for comments and suggestions.
I built my own kidback stoker setup a few years ago. I just
brazed a piece of angle iron to a lugless BB shell (bought from
Cyclopedia for about US$5 IIRC) and attached it to the frame
using hose clamps. You can dip the angle iron in tool-grip
plastic to help it hold in place better and protect the frame a
little. Pop a standard BB set into the shell and attach a set of
cranks. Cyclopedia also had (has?) short-arm cranks; 120mm and
150mm arms IIRC. I got a set of clamp-on crank-shorteners
instead and just put them on an old crankset I had lying around.
Total cost for the project was about US$40 and it's been working
for at least 5 years now.
-John (John.T...@ibm.net)
JGREBED
is Da Vinci's homepage and they are selling a kit with 125 and 145 crank arms
for $85 with an clamp on bottom bracket. It seems like a good deal to me.
Steve Freides
kiddie cranks for $85 but the complete child stoker kit is $200. The
kit also comes only sized for a 1-1/4" seat tube and must be shimmed to
use on smaller (not a problem as I understand it but yet one more
complication).
-S-
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