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Kreitler rollers and flywheel factor(4 posts)

Kreitler rollers and flywheel factorfujipro
Jan 12, 2003 12:38 PM
Our group was riding on the rollers yesterday and we decided to do a few 2 mile TT in preparation for roller races. Most of us have the Killer fan, but not the 15 lb flywheel. I was wondering if anybody knows or can guess the factor that the flywheel will increase our times? Any thoughts would be greatly appreciated!
Thoughts onlyKerry
Jan 12, 2003 5:17 PM
It will depend on the friction of the flywheel and the connecting machinery. Once the flywheel is spun up, there is no extra energy required beyond overcoming system friction. Based on the general quality of Kreitler stuff, it seems likely that friction would be low. The flywheel is there to give a more realistic feel to things, not to increase the work load.
more thoughtsmicha
Jan 12, 2003 6:13 PM
Agree with Kerry that the Kreitler flywheel is there to bring the feel of roller riding a bit closer to real road riding. The kinetic energy of a 170-pound rider/bike combo moving at speed over the road is not there on rollers. The flywheel aims to replace some of that lost energy with 15 pounds of rotating mass.

In theory, the flywheel could make you a bit "faster." Once spun up, most of the energy stored in the flywheel will be released back into the bike wheel the instant you ease up on the pedals. The result should be a slower rate of wheel deceleration for a brief moment, allowing the rider to very briefly scale back power every so often. If nothing else, the psychological advantage of having your bike "keep on rolling" even during a momentary lapse in concentration should give the flywheel rider some advantage.
real world experiencerolleur
Jan 12, 2003 8:51 PM
If Al was still around I am sure he could give you a better answer - but hopefully this will help.
We have done 2 mile races with the fan fully open both with and without the flywheel and the w/flywheel times are significantly slower (about 20-30sec). Even though there is very little friction - the initial acceleration takes a lot of extra effort (we are starting from a stopped position - haven't tried a flying start). I think this extra effort may be a debt that you don't recover from during the race. We even tried a race with 2 flywheels once - ouch...it was like pulling a trailer to get going.
Hope that helped.
If you are bored check out this old photo - I sure wish there hadn't been a flywheel during this race.
http://gallery.consumerreview.com/roadbike/gallery/files/P1200024.asp