How To? Crank Without Crank Arm

[Tony]

Hi Gang,

I'm building up an Econbent frameset. The Econbent plans call for making an intermediate drive from
a freewheel, mounting the drive to a bottom bracket shell which is already in place on the frame.

However, I thought using a second bottom bracket (similar to the BikeE RX or Cannondale intermediate
drives) would provide a neater chainline, easier shifting, and smoother operation.

How do I mount chainrings on the second bottom bracket without a crankarm?

You can tell I'm a mechanical tyro, right?

Thanks,

Tony

 

[Tony]

Hi Gang,

I'm building up an Econbent frameset. The Econbent plans call for making an intermediate drive from
a freewheel, mounting the drive to a bottom bracket shell which is already in place on the frame.

However, I thought using a second bottom bracket (similar to the BikeE RX or Cannondale intermediate
drives) would provide a neater chainline, easier shifting, and smoother operation.

How do I mount chainrings on the second bottom bracket without a crankarm?

You can tell I'm a mechanical tyro, right?

Thanks,

Tony

 

[Dave Larrington]

Tony asked:

> How do I mount chainrings on the second bottom bracket without a crankarm?

Chainset, hacksaw, elbow grease?

Dave Larrington - http://legslarry.crosswinds.net/
===========================================================
Editor - British Human Power Club Newsletter
http://www.bhpc.org.uk/
===========================================================

 

[Tom Sherman]

Tony wrote:
>
> Hi Gang,
>
> I'm building up an Econbent frameset. The Econbent plans call for making an intermediate drive
> from a freewheel, mounting the drive to a bottom bracket shell which is already in place on
> the frame.
>
> However, I thought using a second bottom bracket (similar to the BikeE RX or Cannondale
> intermediate drives) would provide a neater chainline, easier shifting, and smoother operation.
>
> How do I mount chainrings on the second bottom bracket without a crankarm?
>
> You can tell I'm a mechanical tyro, right?

Hi Tony,

Another option would be to use a simple idler and an internally geared rear hub such as the SRAM
Dual Drive 3x8 or 3x9. These are fairly expensive at ~$170 (used Sachs/SRAM 3x7 hubs should be well
under $100), but you should be able to afford it unless you have already spent all my money.

Tom Sherman - Quad Cities USA (Illinois side) RANS "Wavewind" and Rocket, Earth Cycles Sunset and
Dragonflyer

 

[Dave Larrington]

Tony asked:

> How do I mount chainrings on the second bottom bracket without a crankarm?

Chainset, hacksaw, elbow grease?

Dave Larrington - http://legslarry.crosswinds.net/
===========================================================
Editor - British Human Power Club Newsletter
http://www.bhpc.org.uk/
===========================================================

 

[Tom Sherman]

Tony wrote:
>
> Hi Gang,
>
> I'm building up an Econbent frameset. The Econbent plans call for making an intermediate drive
> from a freewheel, mounting the drive to a bottom bracket shell which is already in place on
> the frame.
>
> However, I thought using a second bottom bracket (similar to the BikeE RX or Cannondale
> intermediate drives) would provide a neater chainline, easier shifting, and smoother operation.
>
> How do I mount chainrings on the second bottom bracket without a crankarm?
>
> You can tell I'm a mechanical tyro, right?

Hi Tony,

Another option would be to use a simple idler and an internally geared rear hub such as the SRAM
Dual Drive 3x8 or 3x9. These are fairly expensive at ~$170 (used Sachs/SRAM 3x7 hubs should be well
under $100), but you should be able to afford it unless you have already spent all my money.

Tom Sherman - Quad Cities USA (Illinois side) RANS "Wavewind" and Rocket, Earth Cycles Sunset and
Dragonflyer

 

[Mikael Seierup]

"Dave Larrington" skrev... *snip*

A man with a black Elan tailbox on his Baron.

Managed to catch your webpage at a time where it wasn't down. Do you have the carbon version and if
so ... is it painted/gelcoated black or can you see the carbon? (hard to tell from the pics)

Mikael

 

[Mikael Seierup]

"Dave Larrington" skrev... *snip*

A man with a black Elan tailbox on his Baron.

Managed to catch your webpage at a time where it wasn't down. Do you have the carbon version and if
so ... is it painted/gelcoated black or can you see the carbon? (hard to tell from the pics)

Mikael

 

[John Foltz]

Tony wrote:

>> BTW how did they suggest you mate the freewheel to the bb shell?
>
> If I understand correctly, the freewheel is modified by removing the pawls (just like rorschandt
> mentioned earlier in the thread) and cross threading the BB shell.
>
Nothing needs to be cross-threaded. You use the right hand cup from an old-style bottom bracket.
Screw it into the freewheel, then screw the other end into the bb shell on the bike. This setup
might look better, but the chainring idea will probably work better.
--

John Foltz --- O _ Baron --- _O _ V-Rex 24/63 --- _\\/\-%)
_________(_)`=()___________________(_)= (_)_____

 

[Jeff Wills]

[email protected] (Tony) wrote in message news:<[email protected]>...
> On Fri, 10 Jan 2003 17:17:47 -0000, "Dave Larrington" <[email protected]> wrote:

> >Chainset, hacksaw, elbow grease?
>
> Why didn't I think of that?
>
> Actually, I was hoping to find a manufactured, armless crank spider. Does such a beast exist?
>

Bikee and Cannondale have both used this animal ("armless spider", indeed!). There's a picture at
http://www.cannondale.com/bikes/02/cusa/model-2BM.html

However, I would be willing to bet that getting one from Cannondale or from whoever has the cache of
Bikee spares would be as difficult as making your own from a bunged-up right side crank from a shop.
Heck, I've got one sitting in my "spares" bin right now- but it might go onto a project tomorrow, so
you can't have it. So there. ;-)

Jeff

 

[John Foltz]

Tony wrote:

>> BTW how did they suggest you mate the freewheel to the bb shell?
>
> If I understand correctly, the freewheel is modified by removing the pawls (just like rorschandt
> mentioned earlier in the thread) and cross threading the BB shell.
>
Nothing needs to be cross-threaded. You use the right hand cup from an old-style bottom bracket.
Screw it into the freewheel, then screw the other end into the bb shell on the bike. This setup
might look better, but the chainring idea will probably work better.
--

John Foltz --- O _ Baron --- _O _ V-Rex 24/63 --- _\\/\-%)
_________(_)`=()___________________(_)= (_)_____

 

[Jeff Wills]

[email protected] (Tony) wrote in message news:<[email protected]>...
> On Fri, 10 Jan 2003 17:17:47 -0000, "Dave Larrington" <[email protected]> wrote:

> >Chainset, hacksaw, elbow grease?
>
> Why didn't I think of that?
>
> Actually, I was hoping to find a manufactured, armless crank spider. Does such a beast exist?
>

Bikee and Cannondale have both used this animal ("armless spider", indeed!). There's a picture at
http://www.cannondale.com/bikes/02/cusa/model-2BM.html

However, I would be willing to bet that getting one from Cannondale or from whoever has the cache of
Bikee spares would be as difficult as making your own from a bunged-up right side crank from a shop.
Heck, I've got one sitting in my "spares" bin right now- but it might go onto a project tomorrow, so
you can't have it. So there. ;-)

Jeff

 

[Tony]

On Fri, 10 Jan 2003 17:48:17 -0500, John Foltz <[email protected]> wrote:

> >
>Nothing needs to be cross-threaded. You use the right hand cup from an old-style bottom bracket.
>Screw it into the freewheel, then screw the other end into the bb shell on the bike. This setup
>might look better, but the chainring idea will probably work better.

Thanks for clearing that up for me, John. Now I see how both methods would work, and I'm still
leaning to using a chainset.

Regards,

Tony

 

[Tony]

On Fri, 10 Jan 2003 17:48:17 -0500, John Foltz <[email protected]> wrote:

> >
>Nothing needs to be cross-threaded. You use the right hand cup from an old-style bottom bracket.
>Screw it into the freewheel, then screw the other end into the bb shell on the bike. This setup
>might look better, but the chainring idea will probably work better.

Thanks for clearing that up for me, John. Now I see how both methods would work, and I'm still
leaning to using a chainset.

Regards,

Tony

 

[Rorschandt]

[email protected] (Jeff Wills) wrote in news:[email protected]:

> [email protected] (Tony) wrote in message news:<[email protected]>...
>> On Fri, 10 Jan 2003 17:17:47 -0000, "Dave Larrington" <[email protected]> wrote:
>
>> >Chainset, hacksaw, elbow grease?
>>
>> Why didn't I think of that?
>>
>> Actually, I was hoping to find a manufactured, armless crank spider. Does such a beast exist?
>>
>
> Bikee and Cannondale have both used this animal ("armless spider", indeed!). There's a picture at
> http://www.cannondale.com/bikes/02/cusa/model-2BM.html
>
> However, I would be willing to bet that getting one from Cannondale or from whoever has the cache
> of Bikee spares would be as difficult as making your own from a bunged-up right side crank from a
> shop. Heck, I've got one sitting in my "spares" bin right now- but it might go onto a project
> tomorrow, so you can't have it. So there. ;-)
>
> Jeff
>

There's a good idea. Ask around at the LBS for a crank that has the pedal hole stripped out. 'twould
be a shame to saw up a good crank. easier than my current mid-drive solution, which involved brazing
a spider onto the back of a cassette body, and machining some aluminum stuff for bearings, and ...
rorschandt

 

[Rorschandt]

[email protected] (Jeff Wills) wrote in news:[email protected]:

> [email protected] (Tony) wrote in message news:<[email protected]>...
>> On Fri, 10 Jan 2003 17:17:47 -0000, "Dave Larrington" <[email protected]> wrote:
>
>> >Chainset, hacksaw, elbow grease?
>>
>> Why didn't I think of that?
>>
>> Actually, I was hoping to find a manufactured, armless crank spider. Does such a beast exist?
>>
>
> Bikee and Cannondale have both used this animal ("armless spider", indeed!). There's a picture at
> http://www.cannondale.com/bikes/02/cusa/model-2BM.html
>
> However, I would be willing to bet that getting one from Cannondale or from whoever has the cache
> of Bikee spares would be as difficult as making your own from a bunged-up right side crank from a
> shop. Heck, I've got one sitting in my "spares" bin right now- but it might go onto a project
> tomorrow, so you can't have it. So there. ;-)
>
> Jeff
>

There's a good idea. Ask around at the LBS for a crank that has the pedal hole stripped out. 'twould
be a shame to saw up a good crank. easier than my current mid-drive solution, which involved brazing
a spider onto the back of a cassette body, and machining some aluminum stuff for bearings, and ...
rorschandt

 

[Dave Larrington]

Mikael asked:

> Do you have the carbon version and if so ... is it painted/gelcoated black or can you see the
> carbon? (hard to tell from the pics)

It *is* the carbon version, and it's unpainted, so you *can* see the carbon weave if you
look closely.

Dave Larrington - http://legslarry.crosswinds.net/
===========================================================
Editor - British Human Power Club Newsletter
http://www.bhpc.org.uk/
===========================================================

 

[Dave Larrington]

Mikael asked:

> Do you have the carbon version and if so ... is it painted/gelcoated black or can you see the
> carbon? (hard to tell from the pics)

It *is* the carbon version, and it's unpainted, so you *can* see the carbon weave if you
look closely.

Dave Larrington - http://legslarry.crosswinds.net/
===========================================================
Editor - British Human Power Club Newsletter
http://www.bhpc.org.uk/
===========================================================

 

[Mikael Seierup]

"Dave Larrington" skrev...
> It *is* the carbon version, and it's unpainted, so you *can* see the carbon weave if you look
> closely.

Thank ye. I ascribe to the "If you got it ... flaunt it"-school of thought.

Mikael

 

[Mikael Seierup]

"Dave Larrington" skrev...
> It *is* the carbon version, and it's unpainted, so you *can* see the carbon weave if you look
> closely.

Thank ye. I ascribe to the "If you got it ... flaunt it"-school of thought.

Mikael