I am just getting into my 36 year old bike after running for the last 25 years (last 4 years idle on herbs, vitamins, and prayers). The web really helped me jump into biking with Sheldon, this site, bike photo sites, and many, many great bikers/vendors that are willing to share useful information.
Good thing I live in flat landscape, but still my sweet gears are 53-17t with 27x1.25" Kevlar tires. I can go constant with that, and I don't stress my knees or bottom bracket out neither. Don't have my pacer pc, but think it may be a waste of time at this point: never had one running. I am working on ratchet shifters/cables and rear derailleur/freewheel needs work and eventually, I am working towards more capability. But when I shift to smaller teeth gears, I just switch right back to keep my constant rpm's up.
Nothing magical or hard rules, but its just my initial level of conditioning. Everyone is different and hopefully everyone knows their limits. When you are over 230 lbs, you learn quick and plan carefully or you hurt yourself and quit riding while your body repairs. I already know stretching, correct motion form, and water-food intake cycles, so 175mm Dura Ace crank on bikes is really a breeze to catch on fast; and its hard to think of anything more efficient in excercise than a road bike. Already I can see like heel-toe in running, constant spinning and changing handlebar postions constantly and seating slightly (to handlebar postions) is how I can be spin constant with no after effects and a good clean ride. Everyone's different though.
This market is headed towards a 20 speed cassette from 11 to 32 teeth, with variations based on which ONE of 20 gears you want to switch at 2 teeth per single shift. There will be an automatic shifter as well. Then it will be constantly shifting so you can never pedal forcefully, much less stand up since you will always be shifting gears. It will be one of those CVT's that shuts off at red lights, lol. It will weigh 40 lbs and cost $7,000 for CVT alone which needs to be computer adjusted once a month and rebuilt every year at half the purchase price. Except for the rare racers, the bike market has really gone wild with $500 plastic carbon parts that will splinter if you weigh over 150 lbs with any orthogonal (muti dimensional right angle) forces.
As an engineer, its a blast though if you like planning and designing. Bio mechanical forces are that important though. I'm just glad there are lots of kind bikers that help others out frequently :-)
Phil Bailey,
Sarasota, FL