Rich Pinder wrote:
> I picked up a Stronglight crank a while ago after someone mused about
> the possibilities of converting it into a triple.
> It has a 'protective' ring that sits in front of the large ring. So
> there are positions that three rings could mount.
> The name on the back of the crank is 'Modelo Depose' - and I see
> reference on the net to this name being also in the '93' family. BCD is
> 71.7.
>
> Sheldon's page mentions that Stronglight rings in this size go down to
> 38 teeth (yes ?) - my current rings are 52/45.
>
> If anyone has a used (or new) STRONGLIGHT ring, I'd appreciate it.
>
> Here's a picture to compare with: *http://tinyurl.com/b5jjk*
>
> Has anyone ever tried to convert such a crank over to a triple?? Would
> there be a BB / Axle that would compensate for the spacing changes ?
> Appreciate any thoughts you could give.
Yes, you should be able to convert it to a triple. Stronglight made a wide range of axles:
http://www.os2.dhs.org/
You'll also want the longer chainring bolts and spacers to attach the inner ring.
The model 93 is a lovely crank, but as you note it only accommodates rings down to 38T. If you want a real stump-puller gear, look for a model 99, which goes down to 28T.
Be aware that the dustcap threading is *NOT* standard 22mm, but 23.15mm; you will need the official Stronglight crank extractor tool to remove the arms. Don't try a TA -- they seem to fit (23mm) but often will strip the threads on the crank when you muscle down on the tool.
--
John (john@os2.dhs.org)
Appleton WI USA