Jeff Willis wrote:

(snip)
but the better instructors lead people by perceived extertion.
"50%", "75%", and "100%" effort levels are different for each person,
and thus any preset tension level is meaningless.

Not preset, but "dial-able", unlike the twist knob that adjusts the
felt pads on the Tomahawk bikes I've used or seen in a couple of
different places. This arrangement makes it difficult to go to a level
of resistance consistently, especially when changing back and forth
between "climbs" and "sprints". Useful would be something like having
one-tooth cog jumps but even smaller. Then the rider picks the "gear"
that takes them to some imaginary percentage of effort. Um,
"repeatability". And quicker than fishing with a dial. The felt-pad
bikes are also inconsistent from machine to machine, which partly
reflects a lot of use. Remember, I'm recommending to the OP. I just
ride what they have and make it work at Spin sessions. "Could be
better".

Thanks for the Lemond link. Curious to see how they did "infinite adj."
securely.

I prefer to hear the instructor, though- coordinated exercise is one
of
the attractions of Spin classes. It bugs the heck out of me when I
*can't* hear the instructor.

Hey, cute girls are another attraction. Let's tell the truth, the ratio
is generally up compared to the usual road ride.

Some instructors have no idea what their audience is hearing. Your ears
are especially delicate during exercise as has been noted here and
elsewhere. Earplugs are probably declasse but nice bright orange ones
would send a message. "Spin mix console" as another option? At the YMCA
where I go, they started using radio. Cool, you don't use the
earphones, you can hear the instructor but *not* the music. Brilliant
f'n solution, concentration on mechanics and effort is made much
easier. --TP