Thank you for the link. http://mgagnon.net/velo/pedalier4.en.shtml
It provides some usfull information. I made the following observatios:
A standard front derailleur with 22t range can accommodate a 30T to 32T range. But Im willing to try and do surgery on a derailleur to make the cage longer.
The smallest chain-ring at 30t would only be useful on the lowest speeds (larges cogs) because the rear derailleur wouldn’t be able to take up the extra chain slack.
I will need a friction shifter, but a twist shifter might work. So I will try it.
To answer MR U’s questions, Remember that a recumbent racing bike has a different riding profile then something like a Trek Madone diamond frame bike. Were the recumbent rider is not able to stand on the pedals and push hard for extra uphill power. But at speeds over 15mph there is a significant aerodynamic advantage that compensates for this climbing loss. The course I will be pedaling is the Texas Time Trials see http://www.tt24tt.com
. It has some rolling hills that I need to compensate for. I did a practice run of 3 laps (60 miles) and I can get up all of the hills in the middle chain-ring, but I need to spin more to pace myself, and I fear that latter laps will require me to drop down into the granny gear because of fatigue. To take advantage of the aerodynamic feature of the recumbent, I want to push the down hills speeds a as higher then I can get with a 54T ring. Yes its insane, like being on a broken roller-coaster. But the high speeds help eat-up the accents.
FYI I have an Optima Baron with triple QRings 30-40-54 (Aero ring) mounted on a custom 200mm (not a misprint) Velokraft.com carbon cranks. This drive-train powers a 650C tire with a Michilan Pro2 23mm tire. I currently have a custom 9speed 11-28 cassette with cogs of 11-12-13-14-15-17-19-24-30. The extra long 200mm crank makes it difficult for me to spin a higher 120rpm Lance Armstrong cadence so Im planning on a 100rpm. According to my calculations, In the 54/11 gears a cadence of 100rpm will yield over 35.7 miles per hour. If I run a 65t chain-ring with the 11t cog at a 100rpm cadence then I will be rolling at 43mph. This parameters will change as my skills and power output increases. I attached a few eye-candy photos. My low racer is the one with the dual 650C wheels. the other photos are the 200mm Cranks with Q-rings and a gold KMC X9SL hollow pin chain.
For your viewing enjoyment here is a video of us riding around White Rock Lake in Dallas http://video.google.com/videoplay?do...140&pr=goog-sl
It was shot with a helment cam, I had to mute my speakers due to Gregs poor choice in background music.
Last edited by terranimo; 05-29-07 at 05:27 PM.