clubman 

This is an update from a previous thread in my quest to build bikes I can ride with my limited knee rotation, (post replacement). Someone suggested some TA specific Phil crank shorteners for a tandem so I found a pair and built up a mid-eighties Norco with parts bin kit. As installed, they reduce the cranks to 138 mm.


Turns out it was too good to be true as the Phil bodies required a long spindle to clear the chainstays but they also interfere with a derailleur, at least on a TA with it's low Q factor. So I used a TA triple with a 48 mid/32 small and limited the front gear range to stay away from the outside ring and interference with the shorteners.



Too bad the (rear) NOS LX shifters I bought years ago are stripped right of of the box. Note to self, don't buy things you don't immediately need. Nor does the MT60 Deore front gear like the TA crank. Need to try a 9 speed chain methinks, the current one is too short anyway. I'll swap out the broken rapidfires for some Suntour thumbies. I've got some ESGE mudguards, should be a good ride once I sort it. How about that 1" Girvin Flexstem! Perfect bike for it.

The good news is I can move through the rotation without any stress or rocking of my body. Still have to build the 145 mm Cobb crankset on my Lemond. Other Norco pics here.

MnHPVA Guy

Check out Short Bicycle Cranks from Bikesmith Design.
and
Range of Motion Limitations & Crank Length

juvela

T.A.'s Trois Attachees model was offered in a 150mm length. Item nr. 1693.

Typically, the "small wheeled junior road bikes" were fitted with cranks of 150mm or 152mm length.

There is detailed discussion of them in this lively forum thread:

https://www.bikeforums.net/classic-vi...roadbikes.html

One inexpensive trial you could perform would be to fit a cottered steel 150-152 length set from a jr. road machine to the bike to see how the length works for your needs.

wesmamyke

What kind of LX shifter? Those 7/8 speed era parts are notorious for failing because the old grease turned into glue while sitting. Sometimes they just need a very thorough flushing with solvent and re-lube.

The bike looks like it had the dual thumb trigger shifters, was it a replacement for that? Those are the worst offenders when it comes to gummed up shifters, they have this very weak spring behind one of the pawls and it sticks if you even look at it funny.

gaucho777 

Glad you found a solution. How bad is the contact with the FD? I wonder if you went with a different chainring combination, if that would help. For instance, move the 48t ring from the middle position to the outside, and then find a new middle somewhere between than and the 32 small?

Also, if those were mine, I might consider some sort of plug or cap for the normal pedal threads so they don't get gunked up or damaged in some way.

noglider 

I like where you're going with this.