Thursday, December 3, 2015

Another stab at an inexpensive super compact crank.



Sugino Messenger Racing Triple, re-purposed into a wide ranging double!

Some time last year, I had replaced the nice Velo Orange compact crank I had on my Mercian tourer with an older Shimano RSX triple crank, which I had converted to a wide ranging double by using the small, (74mm BCD) inner chainring and the middle 110mm BCD chainwheel for my big ring. See this blog entry: An economical super compact road crank.

The RSX triple converted to a wide range double.
While I was satisfied with the performance of this rig, it gave me all the right gearing and performed well with the rest of my drivetrain, it did lack a little in the looks department, plus flipping a big ramped and pinned ring over, (in order to recess the bolt holes), wasn't exactly elegant. I started scouting around for a decent looking replacement. I still wanted at least a 74mm BCD for the inner ring, but I realized that the 110mm BCD was not really needed for the outer ring, as long as I could find a 46 tooth ring for it.

I found the Sugino Messenger, a 130mm/74mm BCD triple at Universal Cycles that was cold forged and looked pretty nice. Also, it used a square taper bottom bracket which is the most useful for me. Unfortunately, by the time I got around to buy it, Universal had run out. I eventually found one on E-bay st a "Buy it now or best offer" and made an offer, $75 shipped, that was accepted. So I actually got a little better of a deal than if I had purchased it from Universal.

The Spirit of Japan! When I saw the box, I hoped the spider's arms were curved as shown. Alas, they were not.
Anyway, the crank arrived and it was pretty good looking. It came with all the bolts you needed to mount the double rings and the granny gear, which is neatly mounted directly to the machined back side of the crank. I had to order some track(single ring) chainwheel bolts and a 46 tooth outer ring. Fortunately, Sugino makes plain, unramped rings for this bolt circle size. I had a spare 26 tooth 74mm ring already on hand.

46/26 gear combination. The blue tape over the Sugino name was protection during shipping.
Installation went forward uneventfully. I used the same bottom bracket, a 120mm UN-54 I believe. Again, I reversed the large ring so that the inboard side of the bolts would be recessed. I used a slightly smaller granny, a 26 instead of a 28, so I figured I'd have to reduce chain length a tad so I removed one link. This worked well and I found that I could use up to 5 of my eight sprocket combos with the granny gear! The old unit only let me get away with three before I started rubbing against the outer ring! Now I have an even wider range of gears, with a sub-27 inch gear, (a 26/28 combo) for heavy climbing.

I'm very happy with how this turned out. for a cost of around $115, I was able to set this up. If you had to buy another chainring, the cost is still under $150. Still a pretty inexpensive crankset.


 With this new crankset my gear combination is now 46/26 in front and 11-28 in back. I find this gearing is just about perfect for my riding. I live in the Sierra foothills so I often have lots of climbing. This past Fall I did some loaded touring on this bike and found that even with the 46/28 combo of the older unit, I had a sufficiently low gear.

Full shot of the Mercian with the new crank installed.

3 comments:

  1. Hello. I intend to do the same. Is your larger chainring (46t) not indexed? don't have the pins (index)? will it work well? Grateful. Greetings from Brazil.

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  2. Replies
    1. Hi! The ring I used was not pinned (or indexed) at all, but it has worked well with a standard front derailleur, (I believe it was an older Shimano RSX double front derailleur).

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