C y c l i s t R e c u m b e n t The RANS Fusion - Steve Briggs

Short Cranks: Slicker, Quicker & EasierRecumbents vary greatly in length,steering, and riding position, andas RCNʼS Bob Bryant likes to say,different bikes and their components donʼt fit“every body” the same way. However, theremay be exceptions, and my recent experiencesuggests that most recumbent riders wouldbenefit from shorter cranks. By that I meancranks of 140-155mm, rather than the standard170-180mm. Short cranks simply workbetter on recumbents, so much so that it nowseems remarkable to me that most of us stillmake do with our long, road-bike-adaptedcranks.I became interested in short cranks afterreading Bobʼs comments about them in hisarticle on “Recumbent Bicycle Components”in RCN 086 (sold out issue). I had neverthought much about crank-arm lengths. Iassumed that manufacturers knew what theywere doing, crank performance-wise, andmy Ryan Vanguard, Barcroft Virginia, VisionSaber, and 1998 and 2001 RANS V-Rexesall arrived with 175mm Shimano 105 cranks.Only my present Rotator LWB was a bit different;it had 170mmʼs.Thatʼs why Bobʼs article got my attention.It so happened that I liked pedaling the Rotatorsomewhat better than pedaling my V-Rexor Saber. It just somehow felt better and moreefficient. Could the slightly shorter cranks bethe reason?Although nervous about this irreversiblemodification (shortening the cranks), I nonethelessdecided to mail the 175mm Shimano105ʼs from the V-Rex to Mark Stonich ofBikesmith Design for shortening to 153mm.This seemed to me at least worth a try. I hadcranks on my mind and the Shimanos wereFOR SHORT CRANKS• Smaller pedal circle• Promotes spinning• More aerobic• Better climbing• Lower gears• Shortens chain• Lightens chain, crank and bike• Custom chainring combinationAGAINST SHORT CRANKS• Hard to find• Only a few models can be shortened• This is a foreign language to builders, anditʼs difficult to find information if youʼrenot "in the know."• Adds x-seam to your seat or boom adjustment— allow for an extra inch (With a44.5” x-seam, this bumps me out of the fitrange of several recumbents)• Still a bit experimentalBy Thad Sitton, sitton_1@grandecom.netalready off the V-Rex. I had just tried andfailed to find any significant performanceadvantage from a set of Rotor Cranks of conventionallength (returned for a full refund).After hazarding $750 for the Rotors, $45 forcrank shortening (plus mailing, etc.) didnʼtseem like much.The 153mm Shimanos soon arrived fromMark, complete with a handsome, new,slightly downsized FSA 24/39/48 chainringset — and I gave them a try. (An unnecessarydownsizing, I now believe) I shouldremind you again of Bobʼs comment that“every body” is not the same, but Iʼm ofaverage height and weight, 5ʼ 9” and 165,and I loved these short cranks from the firsttime around the block. What were they like,you ask? Basically, they just felt much easierto use. Riding the bike was suddenly morefun. The effect was dramatic, as if somebodyhad stopped beating me with a stick! The153mmʼs were slicker, quicker, and easierthan the long cranks, which I had availablefor ready comparison on two other familiarrecumbents.While on the V-Rex my feet now whizzedaround a reduced pedaling circle at a fastercadence, and my knees now passed throughapproximate right angles at maximum flexinstead of going an awkward distance beyondthat. Riding seemed easier and more efficientright from the start.I almost couldnʼt believe it, and for twomonths I went back and forth between the153mmʼs and the 175mmʼs, though the V-Rexwith the 153mmʼs became my main ride. ButI found nothing to change my initial impressions.The bike with the short cranks just feltbetter and seemed to work better — as I said,Author Thad Sittonquicker, slicker, easier. The bikes with longcranks, each of which I had ridden severalthousand miles, now felt awkward. Ridingthem, my knees seemed to thrash aroundfuriously with inadequate payoff in vehicularmotion and a lot more muscle and joint wearand-tear.They felt like “Yuck!”So, at least for me, the “feel” differencebetween the cranks was very great, but whatabout performance? That also improved, Iconcluded. In fact, if the $750 Rotor Crankshad worked as well as this $45 crank shortening,I would have kept them! I went faster ondowngrades, spinning faster and up-shiftingsooner. The bike also accelerated better withthe short cranks, rapidly jumping speed tomake a green light, attacking a roller hill, orescaping a pursuing roadie.Hill climbing performance was more difficultto figure out, and that is a critical factorfor any recumbent. The quickened accelerationhelped with the run-up to roller hills,spinning seemed easier, and steep, grind-uphills seemed at least no worse. The shortercrank arms decreased my leverage on thepedals, but I now used a stronger leg thrustderived from a shortened power stroke. Asany weight lifter knows, you can use moreweight in a partial squat than in a full squat.Leg power peaks in the last one-third of legextension, and I now climbed hills using thatend-of-leg thrust advantage.After a month, I put the matter to the acidtest in a favorite, very hilly, 26-mile ride inthe famous Lost Pines of Central Texas, acourse that I rode on a V-Rex in its longcrankconfiguration at least fifty times. ThisCCC-built (Civilian Conservation Corps)road between state parks is a veritable rollerSeptember/October 2005 27