Twelfth Bike

or Ride What You Will

650b Conversion!

Posted by Susan on June 1, 2011

Liz loved her Casati, but felt limited by the high pressure skinny tires. This light and fast Italian racing bike made a good candidate for a 650b conversion.

Liz with her Casati

Liz loves her Casati

The 650b Conversion allows her to ride with a larger tire, which means she can now ride our favorite dirt paths.

650b allows for more tire clearance on the casati

32c Gran Bois 'Cypress' tires fit the frame, with room for fenders, if desired

Before the conversion Liz’s saddle was too low to permit clearance for a Carradice Saddle bag. But now, there’s plenty of room!

Carradice bag on the casati

Now the Carradice won't drag against the tire.

Also, there is no more toe overlap!

No toe overlap

No more toe overlap!

Liz enjoys riding this bike more than ever. With the fatter tires, it is more comfortable over Boston’s rough roads and able to conquer many a dirt path. She can’t wait to ride it at D2R2!

liz riding with lucy

Lucy likes 650b!

Some notes about the Casati set up

It sports a compact double crankset. Again, I converted a triple to a double using a chainguard for the outer ring. Due to oversized oval tubing (Columbus Oversized EL tubing ) The Casati cannot take a clamp-on derailleur.  This presents a problem, as the derailleur braze on is located too high for use with a compact crankset. The problem is solved using a triple derailleur with a chainguard. Right now, gearing is 44, 32.

Another triple converted to a double.

Another triple converted to a double.


6 Responses to “650b Conversion!”

  1. RJD said


    What a delightful surprise to find your blog! Thanks to Lovely Bicycle for that. I like your posts very much. You’ve already shared lot of pertinent experience and advice here. Please keep it up.

    Where did you find that chain guard? I’ve been thinking about moving the outer chainring on my trucker to the middle, but could not find an aesthetically pleasing chainguard? If it’s not custom, Harris should carry it. I think there is a demand.

    And your trip from PA to DC. I’ve been talking that up with my wife and son for a while now. Can’t believe you have already posted a great travel log about it.

    See you soon at the shop,

    • Susan said

      Thanks Richard! I’m trying to keep it updated and make improvements. As for that chainguard, it is a Salsa “Crossing Guard” 44T, available through the Harris special order catalog. I do not believe that an outer ring will work in the middle position because it would have to be installed “backwards” (because of the way the bolts install – I could show you what I mean, but I’m not sure of the correct terminology to explain it here.) On the Casati, I have installed a 44t middle ring.

      The trip from PA to DC was really delightful, and the C & O was our favorite part. We’re hoping to do it again this year, only we’re thinking of starting in Cumberland.

      • RJD said

        Right. The recessed or countersunk part of the holes need to be on the other side. Thanks.

        When/if we do the trip my family will only want to do a segment. Will ask for some recommendations once we decide to do it.

  2. Just saw this bike today and it looks great; wonderful job with the conversion. Also good to know that the Grand Bois (Cypress?) tires are fast and comfortable.

    • Susan said

      Thanks! Yes, these tires are really nice, very light and supple, and Liz noticed the difference in ride quality immediately. They are the same quality as the Gran Bois Hetres, only these are 32c instead of 42c.

  3. […] Liz has been with Harris Cyclery for over 2 years now. She is an all-around mechanic. Tune ups, wheel truing, repairs – she does it all. Fascinating facts: Liz grew up in Italy and was a graduate student in literature in her past life. Current ride of choice: a Casati 650B conversion. […]

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